Science.gov

Sample records for quanta

  1. Quanta and entropy generation

    NASA Astrophysics Data System (ADS)

    Lucia, Umberto

    2015-02-01

    Is there a link between the macroscopic description of the irreversibility and microscopic behaviour of the systems? Transfer of the exergy, i.e., consumption of free energy will keep the system away from a stable equilibrium. So entropy generation results from the redistribution of energy, momentum, mass and charge. Moreover, irreversible consumption of free energy was underlined to create time's arrow. This concept represents the essence of the thermodynamic approach to irreversibility. The analysis developed in this paper points out that the principle of maximum of entropy generation and the least action can be recognized as the only single law. Quanta are exchanged between a system and its surroundings. Each quantum carries energy. The natural behaviour of the open systems is ascribed to the decrease of free energy in the least time, which can be related to the extremum entropy generation theorem. Irreversibility is the result of the interaction between systems and their environment with the consequence time symmetry breaking. The fundamental result of this paper is to introduce a link between the global analysis of irreversibility and Noether's results.

  2. EDITORIAL: Quanta and leaps

    NASA Astrophysics Data System (ADS)

    Dobson, Ken

    2000-11-01

    On Sunday 7 October 1900 Herr Doktor Heinrich Rubens and his wife dropped in on the Planck's Berlin household for tea and some (inevitable) shop-talk. Rubens and his colleague Ferdinand Kurlbaum had been working on an experimental project dear to Max Planck's heart: the variation of intensity with frequency of the radiation from hot objects. They had developed state-of-the-art techniques for taking measurements in the infrared, and Rubens outlined their latest results, due to be presented to the Prussian Academy on 25 October. Between teatime and suppertime Planck had deduced the final version of the radiation law. He was able to work so quickly because he had been working on the problem of reconciling the obviously incomplete Rayleigh law - and various other versions - for many years. The new data confirmed his fairly ad hoc reconciliation of electromagnetic theory and statistical thermodynamics and he sent the outline of his new relationship to Rubens by postcard the same evening. Almost as quick as an e-mail. This itself was a highly important step forward in physics - but what was really outstanding and original was yet to follow, after `a few weeks of the most strenuous work of my life', said the 42 year-old Planck. He realized the significance of his work: `Today I have made a discovery as important as that of Newton,' he confided to his son. This was his based on his determination to find a physical meaning for what had started off as `fictional' mathematical aids to help him derive his formula. The logic compelled him, somewhat reluctantly it appears, to accept that the vibrating objects in a hot body responsible for the oscillating electromagnetic waves they emitted could change in energy only by small discrete amounts: energy packets (quanta) of a size linked to frequency by the relationship E = hf. Not many people took a lot of notice of all this. One did - the obscure Albert Einstein who generalized it in his annus mirabilis 1905 to show that the

  3. Quanta of Geometry: Noncommutative Aspects

    NASA Astrophysics Data System (ADS)

    Chamseddine, Ali H.; Connes, Alain; Mukhanov, Viatcheslav

    2015-03-01

    In the construction of spectral manifolds in noncommutative geometry, a higher degree Heisenberg commutation relation involving the Dirac operator and the Feynman slash of real scalar fields naturally appears and implies, by equality with the index formula, the quantization of the volume. We first show that this condition implies that the manifold decomposes into disconnected spheres, which will represent quanta of geometry. We then refine the condition by involving the real structure and two types of geometric quanta, and show that connected spin manifolds with large quantized volume are then obtained as solutions. The two algebras M2(H ) and M4(C ) are obtained, which are the exact constituents of the standard model. Using the two maps from M4 to S4 the four-manifold is built out of a very large number of the two kinds of spheres of Planckian volume. We give several physical applications of this scheme such as quantization of the cosmological constant, mimetic dark matter, and area quantization of black holes.

  4. Quanta of geometry: noncommutative aspects.

    PubMed

    Chamseddine, Ali H; Connes, Alain; Mukhanov, Viatcheslav

    2015-03-01

    In the construction of spectral manifolds in noncommutative geometry, a higher degree Heisenberg commutation relation involving the Dirac operator and the Feynman slash of real scalar fields naturally appears and implies, by equality with the index formula, the quantization of the volume. We first show that this condition implies that the manifold decomposes into disconnected spheres, which will represent quanta of geometry. We then refine the condition by involving the real structure and two types of geometric quanta, and show that connected spin manifolds with large quantized volume are then obtained as solutions. The two algebras M_{2}(H) and M_{4}(C) are obtained, which are the exact constituents of the standard model. Using the two maps from M_{4} to S^{4} the four-manifold is built out of a very large number of the two kinds of spheres of Planckian volume. We give several physical applications of this scheme such as quantization of the cosmological constant, mimetic dark matter, and area quantization of black holes. PMID:25793795

  5. High energy particles and quanta in astrophysics

    NASA Technical Reports Server (NTRS)

    Mcdonald, F. B. (Editor); Fichtel, C. E.

    1974-01-01

    The various subdisciplines of high-energy astrophysics are surveyed in a series of articles which attempt to give an overall view of the subject as a whole by emphasizing the basic physics common to all fields in which high-energy particles and quanta play a role. Successive chapters cover cosmic ray experimental observations, the abundances of nuclei in the cosmic radiation, cosmic electrons, solar modulation, solar particles (observation, relationship to the sun acceleration, interplanetary medium), radio astronomy, galactic X-ray sources, the cosmic X-ray background, and gamma ray astronomy. Individual items are announced in this issue.

  6. Quanta image sensor: concepts and progress

    NASA Astrophysics Data System (ADS)

    Fossum, Eric R.; Ma, Jiaju; Masoodian, Saleh

    2016-05-01

    The QIS was conceived when contemplating shrinking pixel sizes and storage capacities, and the steady increase in digital processing power. In the single-bit QIS, the output of each field is a binary bit plane, where each bit represents the presence or absence of at least one photoelectron in a photodetector. A series of bit planes is generated through high-speed readout, and a kernel or "cubicle" of bits (x,y,t) is used to create a single output image pixel. The size of the cubicle can be adjusted post-acquisition to optimize image quality. The specialized sub-diffraction-limit photodetectors in the QIS are referred to as "jots" and a QIS may have a gigajot or more, read out at 1000 fps, for a data rate exceeding 1Tb/s. Basically, we are trying to count photons as they arrive at the sensor. This paper reviews the Quanta Image Sensor (QIS) concept and its imaging characteristics. Recent progress towards realizing the QIS for commercial and scientific purposes is discussed. The QIS represents a possible major paradigm shift in image capture.

  7. Local quanta, unitary inequivalence, and vacuum entanglement

    SciTech Connect

    Vázquez, Matías R. Rey, Marco del Westman, Hans León, Juan

    2014-12-15

    In this work we develop a formalism for describing localised quanta for a real-valued Klein–Gordon field in a one-dimensional box [0,R]. We quantise the field using non-stationary local modes which, at some arbitrarily chosen initial time, are completely localised within the left or the right side of the box. In this concrete set-up we directly face the problems inherent to a notion of local field excitations, usually thought of as elementary particles. Specifically, by computing the Bogoliubov coefficients relating local and standard (global) quantisations, we show that the local quantisation yields a Fock representation of the Canonical Commutation Relations (CCR) which is unitarily inequivalent to the standard one. In spite of this, we find that the local creators and annihilators remain well defined in the global Fock space F{sup G}, and so do the local number operators associated to the left and right partitions of the box. We end up with a useful mathematical toolbox to analyse and characterise local features of quantum states in F{sup G}. Specifically, an analysis of the global vacuum state |0{sub G}〉∈F{sup G} in terms of local number operators shows, as expected, the existence of entanglement between the left and right regions of the box. The local vacuum |0{sub L}〉∈F{sup L}, on the contrary, has a very different character. It is neither cyclic (with respect to any local algebra of operators) nor separating and displays no entanglement between left and right partitions. Further analysis shows that the global vacuum also exhibits a distribution of local excitations reminiscent, in some respects, of a thermal bath. We discuss how the mathematical tools developed herein may open new ways for the analysis of fundamental problems in local quantum field theory.

  8. Quanta: the Originality of Einstein's Approach to Relativity?

    NASA Astrophysics Data System (ADS)

    Bracco, Christian

    2015-01-01

    We suggest that not only quanta may have played a role in Einstein's ideas on relativity, but that they themselves may be related to the dynamical and relativistic behaviour of the electromagnetic field exhibited in a Poincaré's 1900 paper, in particular to the identical transformation law of energy and frequency for bounded plane waves.

  9. Particles, particle labels, and quanta: The toll of unacknowledged metaphysics

    SciTech Connect

    Redhead, M. ); Teller, P. )

    1991-01-01

    The practice of describing multiparticle quantum systems in terms of labeled particles indicates that the authors think of quantum entities as individuatable. The labels, together with particle indistinguishability, create the need for symmetrization or antisymmetrization (or, in principle, higher-order symmetries), which in turn results in surplus formal structure' in the formalism, formal structure which corresponds to nothing in the real world. The authors argue that these facts show quanta to be unindividuatable entities, things in principle incapable of supporting labels, and so things which support no factual difference if two of them are thought of as being switched. When thinking of the metaphysics of quanta, one should eschew the misleading labels of the tensor product Hilbert space formalism and prefer the ontologically more faithful description of the Fock space formalism. This conception eliminates puzzles about the quantum statistics of bosons.

  10. Quantum Random Number Generation Using a Quanta Image Sensor.

    PubMed

    Amri, Emna; Felk, Yacine; Stucki, Damien; Ma, Jiaju; Fossum, Eric R

    2016-01-01

    A new quantum random number generation method is proposed. The method is based on the randomness of the photon emission process and the single photon counting capability of the Quanta Image Sensor (QIS). It has the potential to generate high-quality random numbers with remarkable data output rate. In this paper, the principle of photon statistics and theory of entropy are discussed. Sample data were collected with QIS jot device, and its randomness quality was analyzed. The randomness assessment method and results are discussed. PMID:27367698

  11. Quantum Random Number Generation Using a Quanta Image Sensor

    PubMed Central

    Amri, Emna; Felk, Yacine; Stucki, Damien; Ma, Jiaju; Fossum, Eric R.

    2016-01-01

    A new quantum random number generation method is proposed. The method is based on the randomness of the photon emission process and the single photon counting capability of the Quanta Image Sensor (QIS). It has the potential to generate high-quality random numbers with remarkable data output rate. In this paper, the principle of photon statistics and theory of entropy are discussed. Sample data were collected with QIS jot device, and its randomness quality was analyzed. The randomness assessment method and results are discussed. PMID:27367698

  12. Magnetic and Electric Flux Quanta: the Pion Mass

    SciTech Connect

    P Cameron

    2011-12-31

    The angular momentum of the magnetic flux quantum is balanced by that of the associated supercurrent, such that in condensed matter the resultant angular momentum is zero. The notion of a flux quantum in free space is not so simple, needing both magnetic and electric flux quanta to propagate the stable dynamic structure of the photon. Considering these flux quanta at the scale where quantum field theory becomes essential, at the scale defined by the reduced Compton wavelength of the electron, exposes variants of a paradox that apparently has not been addressed in the literature. Leaving the paradox unresolved in this note, reasonable electromagnetic rationales are presented that permit to calculate the masses of the electron, muon, pion, and nucleon with remarkable accuracy. The calculated mass of the electron is correct at the nine significant digit limit of experimental accuracy, the muon at a part in one thousand, the pion at two parts in ten thousand, and the nucleon at seven parts in one hundred thousand. The accuracy of the pion and nucleon mass calculations reinforces the unconventional common notion that the strong force is electromagnetic in origin.

  13. Outstanding Antibiofilm Features of Quanta-CuO Film on Glass Surface.

    PubMed

    Tripathy, Nirmalya; Ahmad, Rafiq; Bang, Seung Hyuck; Khang, Gilson; Min, Jiho; Hahn, Yoon-Bong

    2016-06-22

    Intelligently designed surface nanoarchitecture provides defined control over the behavior of cells and biomolecules at the solid-liquid interface. In this study, CuO quantum dots (quanta-CuO; ∼3-5 nm) were synthesized by a simple, low-temperature solution process and further formulated as paint to construct quanta-CuO thin film on glass. Surface morphological characterizations of the as-coated glass surface reveal a uniform film thickness (∼120 ± 10 nm) with homogeneous distribution of quanta-CuO. The antibiofilm assay showed a very high contact bacteria-killing capacity of as-coated quanta-CuO glass surfaces toward Staphylococcus aureus and Escherichia coli. This efficient antibacterial/antibiofilm activity was ascribed to the intracellular reactive oxygen species (ROS) generated by the quanta-CuO attached to the bacterial cells, which leads to an oxidative assault and finally results in bacterial cell death. Although there is a significant debate regarding the CuO nanostructure's antibacterial mode of action, we propose both contact killing and/or copper ion release killing mechanisms for the antibiofilm activity of quanta-CuO paint. Moreover, synergism of quanta-CuO with conventional antibiotics was also found to further enhance the antibacterial efficacy of commonly used antibiotics. Collectively, this state-of-the-art design of quanta-CuO coated glass can be envisioned as promising candidates for various biomedical and environmental device coatings. PMID:27248981

  14. Phenomenological characteristic of the electron component in gamma-quanta initiated showers

    NASA Technical Reports Server (NTRS)

    Nikolsky, S. I.; Stamenov, J. N.; Ushev, S. Z.

    1985-01-01

    The phenomenological characteristics of the electron component in showers initiated by primary gamma-quanta were analyzed on the basis of the Tien Shan experimental data. It is shown that the lateral distribution of the electrons ion gamma-quanta initiated showers can be described with NKG - function with age parameters bar S equals 0, 76 plus or minus 0, 02, different from the same parameter for normal showers with the same size bar S equals 0, 85 plus or minus 0, 01. The lateral distribution of the correspondent electron energy flux in gamma-quanta initiated showers is steeper as in normal cosmic ray showers.

  15. How likely are constituent quanta to initiate inflation?

    NASA Astrophysics Data System (ADS)

    Berezhiani, Lasha; Trodden, Mark

    2015-10-01

    We propose an intuitive framework for studying the problem of initial conditions in slow-roll inflation. In particular, we consider a universe at high, but sub-Planckian energy density and analyze the circumstances under which it is plausible for it to become dominated by inflated patches at late times, without appealing to the idea of self-reproduction. Our approach is based on defining a prior probability distribution for the constituent quanta of the pre-inflationary universe. To test the idea that inflation can begin under very generic circumstances, we make specific - yet quite general and well grounded - assumptions on the prior distribution. As a result, we are led to the conclusion that the probability for a given region to ignite inflation at sub-Planckian densities is extremely small. Furthermore, if one chooses to use the enormous volume factor that inflation yields as an appropriate measure, we find that the regions of the universe which started inflating at densities below the self-reproductive threshold nevertheless occupy a negligible physical volume in the present universe as compared to those domains that have never inflated.

  16. Properties of skyrmions and multi-quanta vortices in chiral p-wave superconductors

    PubMed Central

    Garaud, Julien; Babaev, Egor

    2015-01-01

    Chiral p-wave superconducting state supports a rich spectrum of topological excitations different from those in conventional superconducting states. Besides domain walls separating different chiral states, chiral p-wave state supports both singular and coreless vortices also interpreted as skyrmions. Here, we present a numerical study of the energetic properties of isolated singular and coreless vortex states as functions of anisotropy and magnetic field penetration length. In a given chiral state, single quantum vortices with opposite winding have different energies and thus only one kind is energetically favoured. We find that with the appropriate sign of the phase winding, two-quanta (coreless) vortices are always energetically preferred over two isolated single quanta (singular) vortices. We also report solutions carrying more flux quanta. However those are typically more energetically expensive/metastable as compared to those carrying two flux quanta. PMID:26631985

  17. Parametric X-ray radiation as a conversion of virtual to real quanta

    NASA Astrophysics Data System (ADS)

    Shchagin, A. V.; Takabayashi, Y.

    2013-08-01

    The emission of parametric X-ray radiation (PXR) by a relativistic charged particle moving in a crystal rectilinearly is considered in terms of a conversion of virtual quanta accompanying the particle to real quanta. Some recent experimental data on the PXR properties are analyzed and the asymmetry of PXR reflection is considered. Simple analytical expressions for conversion factors are obtained from experimentally confirmed data. The properties of the conversion factors for the parametric X-ray radiation are discussed.

  18. Peculiarities of gamma-quanta distribution at 20 TeV energy

    NASA Technical Reports Server (NTRS)

    Loktionov, A. A.; Ermakov, P. M.; Lukin, Y. T.; Sadykov, T. K.

    1985-01-01

    The angular distribution of protons from the fragmentational region is analyzed. The gamma-quanta families are generated in a dense target by cosmic ray particles at 20 Tev energy. Families were found which had dense groups (spikes) of gamma-quanta where the rapidity/density is 3 times more than the average value determined for all registered families. The experimental data is compared with the results of artificial families simulation.

  19. Contextual essay for integrated thematic unit: Kids, Quarks, and Quanta

    NASA Astrophysics Data System (ADS)

    Draeger, Vicki Lee

    This essay provides the research and rationale to support the theory that early adolescence is the best time to present an introduction to quantum mechanics. It supports the creation of an integrated thematic unit to be used with students ages 11--14 in an inclusion classroom without limiting the unit to only an inclusion setting. The first section sets forth five problems the unit was written to address. Citing The National Center for Education Statistics 2000 version of The Nation's Report Card, the problems with current practices in science education resulting in poor student performance are presented. References to Project 2061: Science for All Americans help to demonstrate that students with disabilities are seldom considered when physical science curriculum is being developed, supporting the position that equity in science education is necessary, while maintaining challenging subject matter. The problem of the poor quality of many physical science texts is addressed, with an emphasis on the importance of curricular connections. The poor quality of physical science teacher training in many university teacher training courses is discussed, and the nature of the integrated thematic unit as a curriculum design is examined with reference to what is considered the over-emphasis on "reality-based" content to the exclusion of abstract subject matter. Having presented the problems and supporting their validity, the essay then demonstrated how Kids, Quarks, and Quanta specifically addresses each problem. The two and a half year study of Dr. John Hubisz and the committee he formed under The David and Lucille Packard Foundation grant to review and critique the physical science textbooks currently used with early adolescents is often referenced to support both the problems of teacher training and the poor quality of many texts. Recent brain research conducted by researchers of the National Institute of Mental Health is used to support the presentation of more abstract

  20. Cooperative Two-Quanta Phase Transitions in Quantum Optics and Superconductivity

    NASA Astrophysics Data System (ADS)

    Enaki, Nicolae

    2010-09-01

    The behavior of an electronic subsystem in strong interaction with phonon subsystem, or quantified electromagnetic field (QEF) is discussed. In this case the correlation effect between first and second order electron-phonon interaction (or atom-QEF interaction) takes place. It is shown that the temperature dependence of two-quanta exchange between Fermi sub-system and thermal reservoir gives a non-linear behavior of the order parameter in superconductivity and super-radiance, accompanied by an increase of the electron correlations with increasing temperature. The same effect is considered for two-quanta scattering processes, in which one quantum is absorbed and another is emitted. It is demonstrated, that the order parameter in such a system firstly increases with temperature achieving the maximal value. After that it decreases as in traditional phase transition effects.

  1. Spectroscopic Line Shapes of Vibrational Quanta in the Presence of Molecular Resonances.

    PubMed

    Meierott, Stefan; Néel, Nicolas; Kröger, Jörg

    2016-07-01

    Line shapes of molecular vibrational quanta in inelastic electron tunneling spectroscopy may indicate the strength of electron-vibration coupling, the hybridization of the molecule with its environment, and the degree of vibrational damping by electron-hole pair excitation. Bare as well as C60-terminated Pb tips of a scanning tunneling microscope and clean as well as C60-covered Pb(111) surfaces were used in low-temperature experiments. Depending on the overlap of orbital and vibrational spectral ranges different spectroscopic line shapes of molecular vibrational quanta were observed. The energy range covered by the molecular resonance was altered by modifying the adsorption configuration of the molecule terminating the tip apex. Concomitantly, the line shapes of different vibrational modes were affected. The reported observations represent an experimental proof to theoretical predictions on the contribution from resonant processes to inelastic electron tunneling. PMID:27280313

  2. [The Gradual Formation of the Concept of ‘Light Quanta'].

    PubMed

    Hentschel, Klaus

    2015-06-01

    The Gradual Formation of the Concept of 'Light Quanta'. The complex concept of 'light quanta' which made its first appearance in Albert Einstein's 1905 paper on a "heuristic point of view" to cope with the photoelectric effect and other forms of interaction of light and matter, has a rich history both before and after 1905. Some of its semantic layers lead as far back as Newton and Kepler, others are only fully espoused several decades later, yet others initially increased, then diminished in importance and finally vanished. Two historiographic approaches are discussed and exemplified: a) my own model of conceptual development as a series of semantic accretions, and b) Mark Turner's model of 'conceptual blending'. Both of these models are shown to be useful and will be further explored in my own efforts to come to grips with the complex process of concept formation. PMID:26140625

  3. Simulation of generation of bremsstrahlung gamma quanta upon irradiation of thin metal films by ultra-intense femtosecond laser pulses

    SciTech Connect

    Andreev, Stepan N; Rukhadze, Anri A; Garanin, Sergey G; Yakutov, B P; Tarakanov, V P

    2010-06-23

    We report the results of simulations of generation of bremsstrahlung gamma quanta upon irradiation of a thin-film metal target by ultra-intense femtosecond laser pulses. It is shown by the example of a thin gold target that the mean electron energy is twenty five times higher than the mean energy of gamma quanta generated by them. A simple approximating formula is proposed, which establishes a one-to-one relation between these quantities. The angular distributions of electrons and gamma quanta are studied. It is shown that only the angular distribution of high-energy gamma quanta repeats the angular distribution of the electrons leaving the target. (interaction of laser radiation with matter. laser plasma)

  4. Light, rest mass and electric charge quanta all formed by neutrinos?

    NASA Astrophysics Data System (ADS)

    Chen, Shao-Guang

    In high energy physics experiments the electric charge and rest mass of particles can commonly transform into the photons, vice versa. Its reason QFT can only give a vague answer: based on the particle creation and annihilation operators. There are not more clear answers or conjecture? At least, light, electric charge and rest mass should have a collective structure component, if not, the transformation is unable understanding. An elementary answer is that neutrino and antineutrino as their collective structure component. In the paper ‘Chen Qiliang & Wang Bin, The formation and characteristics of Chen Shaoguang's formula, China Science &Technology Overview 127101-103 (2011)’, the lowest energy state vertical polarized left spin 1/2 neutrino and right spin 1/2 antineutrino are just the left, right advance unit quanta la _{0}nuυ, ra nuυ _{0} and left, right back unit quanta lb (0) nuυ, rb nuυ (0) , it again compose into spin 1 unit photon la-ra _{0}nuυnuυ _{0} and back-photon lb-rb (0) nuυnuυ (0) , spin 0 unit rest mass ra-rb nuυ _{0}nuυ (0) and anti-mass la-lb _{0}nuυ (0) nuυ, spin 0 unit positive charge la-rb _{0}nuυnuυ (0) and negative charge ra-lb nuυ _{0} (0) nuυ. The physical vacuum is the even collocation of non-combinational nuυ _{0} or _{0}nuυ. It accord to the high energy physics experimental results of the transformation among the photons, masses quanta and charges quanta. In my paper ‘Quanta turn-advance ism, China Science && Technology Overview 131 192-210 (2011)’, QFT four-dimensional uncertainty principle and momentum-energy conservation law had been generalized as a five-dimensional equations: de Broglie wavelength as a position vector \\underline{q}= (i c t, r, s), momentum \\underline{P} = (i E / c, P, U c), \\underline{q} = i h / \\underline{P}, \\underline{q} \\underline{q} = 0, \\underline{P} \\underline{P} = 0, Sigma∑ \\underline{P} = \\underline{P} (0) . The five-dimensional time-space-spin had been quantized as a

  5. Clinical Comparison of QUANTA Flash dsDNA Chemiluminescent Immunoassay with Four Current Assays for the Detection of Anti-dsDNA Autoantibodies

    PubMed Central

    Infantino, Maria; Meacci, Francesca; Bentow, Chelsea; Martis, Peter; Benucci, Maurizio; Afeltra, Antonella; Rigon, Amelia; Atzeni, Fabiola; Sarzi-Puttini, Piercarlo; Manfredi, Mariangela; Mahler, Michael

    2015-01-01

    Introduction. The objective of the present study was to compare QUANTA Flash dsDNA, a chemiluminescent immunoassay (CIA) on the BIO-FLASH, a rapid-response chemiluminescent analyzer, to three other anti-dsDNA antibody assays and to Crithidia luciliae indirect immunofluorescence test (CLIFT). Methods. In the first part of the study, 161 samples, 61 from patients suffering from systemic lupus erythematosus (SLE) and 100 from a disease control group, were tested by QUANTA Flash dsDNA CIA, QUANTA Lite dsDNA SC ELISA, BioPlex 2200 multiplex flow immunoassay (MFI), ImmuLisa dsDNA ELISA, and NOVA Lite CLIFT. A second cohort of 69 SLE patients was then tested by QUANTA Flash dsDNA and CLIFT to expand the study. Results. The overall qualitative agreements varied between 77.0% (NOVA Lite CLIFT versus QUANTA Lite) and 89.4% (ImmuLisa versus NOVA Lite CLIFT). The clinical sensitivities for the anti-dsDNA antibody tests varied from 8.2% (NOVA Lite CLIFT) to 54.1% (QUANTA Lite), while the clinical specificities varied from 88.0% (BioPlex 2200) to 100.0% (NOVA Lite CLIFT). Good correlation was found between QUANTA Flash dsDNA and NOVA Lite CLIFT. Conclusion. Significant variations among dsDNA methods were observed. QUANTA Flash dsDNA provides a good combination of sensitivity and specificity for the diagnosis of SLE and good agreement to CLIFT. PMID:25759849

  6. A Report on the Intellectual Development of Students in the QUANTA Learning Community at Daytona Beach Community College, 1989-1990.

    ERIC Educational Resources Information Center

    Avens, Cynthia; Zelley, Richard

    This report summarizes the results of a research study conducted to assess the intellectual development of students in the QUANTA Learning Community at Daytona Beach Community College (DBCC) (Florida) in the 1989-90 academic year. QUANTA is a freshman interdisciplinary program with 75 students and three faculty. Three courses--English, psychology,…

  7. Excitation of vibrational quanta in furfural by intermediate-energy electrons.

    PubMed

    Jones, D B; Neves, R F C; Lopes, M C A; da Costa, R F; Varella, M T do N; Bettega, M H F; Lima, M A P; García, G; Blanco, F; Brunger, M J

    2015-12-14

    We report cross sections for electron-impact excitation of vibrational quanta in furfural, at intermediate incident electron energies (20, 30, and 40 eV). The present differential cross sections are measured over the scattered electron angular range 10°-90°, with corresponding integral cross sections subsequently being determined. Furfural is a viable plant-derived alternative to petrochemicals, being produced via low-temperature plasma treatment of biomass. Current yields, however, need to be significantly improved, possibly through modelling, with the present cross sections being an important component of such simulations. To the best of our knowledge, there are no other cross sections for vibrational excitation of furfural available in the literature, so the present data are valuable for this important molecule. PMID:26671372

  8. Excitation of vibrational quanta in furfural by intermediate-energy electrons

    NASA Astrophysics Data System (ADS)

    Jones, D. B.; Neves, R. F. C.; Lopes, M. C. A.; da Costa, R. F.; Varella, M. T. do N.; Bettega, M. H. F.; Lima, M. A. P.; García, G.; Blanco, F.; Brunger, M. J.

    2015-12-01

    We report cross sections for electron-impact excitation of vibrational quanta in furfural, at intermediate incident electron energies (20, 30, and 40 eV). The present differential cross sections are measured over the scattered electron angular range 10°-90°, with corresponding integral cross sections subsequently being determined. Furfural is a viable plant-derived alternative to petrochemicals, being produced via low-temperature plasma treatment of biomass. Current yields, however, need to be significantly improved, possibly through modelling, with the present cross sections being an important component of such simulations. To the best of our knowledge, there are no other cross sections for vibrational excitation of furfural available in the literature, so the present data are valuable for this important molecule.

  9. Excitation of vibrational quanta in furfural by intermediate-energy electrons

    SciTech Connect

    Jones, D. B.; Neves, R. F. C.; Lopes, M. C. A.; Costa, R. F. da; Varella, M. T. do N.; Bettega, M. H. F.; Lima, M. A. P.; García, G.; and others

    2015-12-14

    We report cross sections for electron-impact excitation of vibrational quanta in furfural, at intermediate incident electron energies (20, 30, and 40 eV). The present differential cross sections are measured over the scattered electron angular range 10°–90°, with corresponding integral cross sections subsequently being determined. Furfural is a viable plant-derived alternative to petrochemicals, being produced via low-temperature plasma treatment of biomass. Current yields, however, need to be significantly improved, possibly through modelling, with the present cross sections being an important component of such simulations. To the best of our knowledge, there are no other cross sections for vibrational excitation of furfural available in the literature, so the present data are valuable for this important molecule.

  10. Nuclear cascades in electromagnetic showers produced by primary gamma-quanta in the atmosphere

    NASA Technical Reports Server (NTRS)

    Danilova, T. V.; Erlykin, A. D.; Mironov, A. V.; Tukish, E. I.

    1985-01-01

    Distributions were calculated for the number of electrons N sub e, number of muons with the energy above 5 GeV N sub mu and the energy of hadron component E sub h in electromagnetic showers, produced by primary gamma-quanta with energies theta approx. equals 30 deg and observed at the mountain level 700 g/square centimeters. The mean number of nuclear interactions of photos with the energy above 5 GeV is about 0.3 per each TeV of the primary energy and nuclear cascades take out in average about 2% of the total shower energy. The mean number of 5 GeV muons for the electromagnetic shower is (2 to 5)% from the number of muons in cosmic ray showers with the same number of electrons at the observation level. similar value for the total energy of hadron component is also (2 to 5)%. N sub mu and N sub e values as well as E sub h and n sub e don't correlate at the fixed primary energy E sug gamma (o). Between N sub mu and E sub h there is a positive correlation at the given E sub gamma.

  11. Clinical performance evaluation of a novel, automated chemiluminescent immunoassay, QUANTA Flash CTD Screen Plus.

    PubMed

    Bentow, Chelsea; Lakos, Gabriella; Rosenblum, Rachel; Bryant, Cassandra; Seaman, Andrea; Mahler, Michael

    2015-02-01

    The QUANTA Flash(®) CTD Screen Plus is a chemiluminescent immunoassay (CIA) for the detection of the major antinuclear antibodies (ANA) on the BIO-FLASH(®) platform. NOVA View(®) is an automated fluorescence microscope that acquires digital images of indirect immunofluorescent assay (IFA) slides. Our goal was to evaluate the clinical performance of the two automated systems and compare their performance to that of traditional IFA. Sera from patients with systemic autoimmune rheumatic diseases (SARD, n = 178), along with disease and healthy controls (n = 204), were tested with the CTD CIA and with NOVA Lite(®) HEp-2 ANA, using both the manual method of reading the IFA slides and the NOVA View instrument. The CTD CIA showed 78.1% sensitivity for SARD, coupled with 94.1% specificity. Manual IFA and NOVA View showed somewhat higher sensitivity (81.5 and 84.8% in SARD, respectively), but significantly lower specificity (79.4 and 64.7%, respectively). Both automated systems displayed somewhat different performance, due to the different principals of ANA detection: IFA with NOVA View digital image interpretation had higher sensitivity, while the CTD CIA showed higher specificity. With the added benefits of full automation, the new CTD CIA is an attractive alternative to traditional ANA screening. PMID:25420962

  12. Hanbury Brown-Twiss interferometry and second-order correlations of inflaton quanta

    SciTech Connect

    Giovannini, Massimo

    2011-01-15

    The quantum theory of optical coherence is applied to the scrutiny of the statistical properties of the relic inflaton quanta. After adapting the description of the quantized scalar and tensor modes of the geometry to the analysis of intensity correlations, the normalized degrees of first-order and second-order coherence are computed in the concordance paradigm and are shown to encode faithfully the statistical properties of the initial quantum state. The strongly bunched curvature phonons are not only super-Poissonian but also superchaotic. Testable inequalities are derived in the limit of large-angular scales and can be physically interpreted in the light of the tenets of Hanbury Brown-Twiss interferometry. The quantum mechanical results are compared and contrasted with different situations including the one where intensity correlations are the result of a classical stochastic process. The survival of second-order correlations (not necessarily related to the purity of the initial quantum state) is addressed by defining a generalized ensemble where super-Poissonian statistics is an intrinsic property of the density matrix and turns out to be associated with finite volume effects which are expected to vanish in the thermodynamic limit.

  13. Non-Gaussianities and the stimulated creation of quanta in the inflationary universe

    SciTech Connect

    Agullo, Ivan; Parker, Leonard

    2011-03-15

    Cosmological inflation generates a spectrum of density perturbations that can seed the cosmic structures we observe today. These perturbations are usually computed as the result of the gravitationally induced spontaneous creation of perturbations from an initial vacuum state. In this paper, we compute the perturbations arising from gravitationally induced stimulated creation when perturbations are already present in the initial state. The effect of these initial perturbations is not diluted by inflation and survives to its end, and beyond. We consider a generic statistical density operator {rho} describing an initial mixed state that includes probabilities for nonzero numbers of scalar perturbations to be present at early times during inflation. We analyze the primordial bispectrum for general configurations of the three different momentum vectors in its arguments. We find that the initial presence of quanta can significantly enhance non-Gaussianities in the so-called squeezed limit. Our results show that an observation of non-Gaussianities in the squeezed limit can occur for single-field inflation when the state in the very early inflationary Universe is not the vacuum, but instead contains early-time perturbations. Valuable information about the initial state can then be obtained from observations of those non-Gaussianities.

  14. Application of the Quanta image sensor concept to linear polarization imaging-a theoretical study.

    PubMed

    Anzagira, Leo; Fossum, Eric R

    2016-06-01

    Research efforts in linear polarization imaging have largely targeted the development of novel polarizing filters with improved performance and the monolithic integration of image sensors and polarization filter arrays. However, as pixel sizes in CMOS image sensors continue to decrease, the same limitations that have an impact on color and monochrome CMOS image sensors will undoubtedly affect polarization imagers. Issues of low signal capacity and dynamic range in small pixels will severely limit the useful polarization information that can be obtained. In this paper, we propose to leverage the benefits of the relatively new Quanta image sensor (QIS) concept to mitigate the anticipated limitations of linear polarization imaging as pixel sizes decrease. We address, by theoretical calculation and simulation, implementation issues such as alignment of polarization filters over extremely small pixels used in the QIS concept and polarization image formation from single-bit output of such pixels. We also present design innovations aimed at exploiting the benefits of this new imaging concept for simultaneous color and linear polarization imaging. PMID:27409443

  15. Left–right asymmetry in integral spectra of γ-quanta in the interaction of nuclei with polarized thermal neutrons

    SciTech Connect

    Vesna, V. A.; Gledenov, Yu. M.; Nesvizhevsky, V. V.; Sedyshev, P. V.; Shul’gina, E. V.

    2015-10-15

    The paper presents results of preliminarymeasurements of the left–right asymmetry in integral spectra of γ-quanta emitted in the interaction of polarized thermal neutrons with nuclei. These results indicate that for all cases of measured statistically significant P-odd asymmetry, the left–right asymmetry coefficient is much smaller than the P-odd asymmetry coefficient. This observation is not consistent with the predictions of theoretical calculations.

  16. DIGIT-PHYSICS: Digits Are Bosons Are Quanta Because (On Average) Quanta and Bosons Are and Always Were Digits!!! DIGITS?: For a Very Long Time Giving Us All The FINGER!!!

    NASA Astrophysics Data System (ADS)

    Siegel, Edward Carl-Ludwig; Newcomb, Simon; Strutt-Rayleigh, John William; Poincare, Henri; Weyl, Hermann; Benford, Frederick; Antonoff, Marvin

    2015-03-01

    DIGIT-PHYSICS: DIGITS?: For a Very Long Time Giving Us All The FINGER!!!: CONTRA Wigner,``On the Unreasonable Effectiveness of Physics in Mathematics!'' A Surprise in Theoretical/Experimental Physics and/or Ostensibly Pure-Mathematics: PHYSICS: Quantum-Mechanics/Statistical-.Mechanics. DIGITS-LAW(S); DIGITS' ostensibly ``pure-mathematics' 1:1-map onto the QUANTUM!!! [Google:''http://www.benfordonline.net/ list/ chronological'']: Newcomb[Am.J.Math.4,39(1881)]-Poincare[Calcul des Probabilité(1912)]-Weyl[Math.Ann., 77, 313(1916)-Benford[J.Am.Phil Soc,78,115 (1938)]-..-Antonoff/Siegel[AMS Joint-Mtg.,San Diego(2002)-abs.# 973-60-124] empirical inter-digit{on-ANY/ALL averageS) = log[base =10] (1 + 1/d) = log[base =10] ([d +1]/d) upon algebraic-inversion is d = 1/[10⌃[ ] -1] 1/[2.303..e⌃[ ] -1] 1/[2.303..e⌃[< ω>] -1] 1/[2.303..e⌃[ ω] -1]: Digits Are Bosons Are Quanta Because (On Average) Quanta and Bosons Are and Always Were Digits!!! (Ex: atom energy-levels numbering: 0,...,9) ANY/ALL QUANTUM-physics[Planck(1901)-Einstein(1905)-Bose(1924)-Einstein(1925)-vs.Fermi(1927)-Dirac(1927)-...] is and always was Newcomb(1881) DIGIT-physics!!!

  17. Imaging performance in differential phase contrast CT compared with the conventional CT-noise equivalent quanta NEQ(k)

    NASA Astrophysics Data System (ADS)

    Tang, Xiangyang; Yang, Yi; Tang, Shaojie

    2012-03-01

    The grating-based x-ray differential phase contrast (DPC) CT is emerging as a new technology with the potential for extensive preclinical and clinical applications. In general, the performance of an imaging system is jointly determined by its signal property (modulation transfer function-MTF(k)) and noise property (noise power spectrum-NPS(k)), which is characterized by its spectrum of noise equivalent quanta. As reported by us previously, owing to an adoption of the Hilbert filtering for image reconstruction in the fashion of filtered backprojection (FBP), the noise property of DPC-CT characterized by its NPS(k) differs drastically from that of the conventional attenuation-based CT (1/|k| trait vs. |k| trait). In this work, via system analysis, modeling and simulated phantom study, we initially investigate the signal property of DPC-CT characterized by its MTF(k) and compare it with that of the conventional CT. In addition, we investigate the DPC-CT's spectrum of noise equivalent quanta NEQ(k) - the most important figure of merit (FOM) in the assessment of an imaging system's performance - by taking the MTF(k) and NPS(k) jointly into account. Through such a thorough investigation into both the signal and noise properties, the imaging performance of DPC-CT and its potential over the conventional attenuation-based CT can be fully understood and appreciated.

  18. Gamma-quanta onboard identification in the GAMMA-400 experiment using the counting and triggers signals formation system.

    NASA Astrophysics Data System (ADS)

    Arkhangelskaja, I. V.; Arkhangelskiy, A. I.; Chasovikov, E. N.; Galper, A. M.; Kheymits, M. D.; Murchenko, A. E.; Yurkin, Y. T.

    2016-02-01

    GAMMA-400 (Gamma Astronomical Multifunctional Modular Apparatus) will be the new generation satellite gamma-observatory. Gamma-telescope GAMMA-400 consists of anticoincidence system (top and lateral sections - ACtop and AClat), the converter-tracker (C), time-of-flight system (2 sections S1 and S2), position-sensitive calorimeter CC1 makes of 2 strips layers and 2 layers of CsI(Tl) detectors, electromagnetic calorimeter CC2 composed of CsI(Tl) crystals, neutron detector ND, scintillation detectors of the calorimeter (S3 and S4) and lateral detectors of the calorimeter (LD). All detector systems ACtop, AClat, S1-S4, LD consist of two BC-408 based sensitive layers of 1 cm thickness each. Three apertures provide events registration both from upper and lateral directions. The main aperture provides the best angular (all strip layers information analysis) and energy (energy deposition in the all detectors studying) resolution. Gamma-telescope GAMMA-400 is optimized for the gamma-quanta and charged particles with energy 100 GeV detection with the best parameters in the main aperture. Triggers in the main aperture will be formed using information about particle direction provided by time of flight system and presence of charged particle or backsplash signal formed according to analysis of energy deposition in combination of both layers anticoincidence systems ACtop and AClat individual detectors. For double-layer ACtop taking into account both amplitude and temporal trigger marker onboard analysis only 2.8% photons will be wrongly recognized as electrons or protons for 100 GeV particles. The part of charged particles mistakenly identified as gammas is ∼10-5 using described algorithms. For E∼3 GeV less than 3% photons will be wrongly recognized as charged particles and fraction of wrongly identified charged particles will be also ∼10-5. In the additional aperture the particles identification is provided by analysis of signals corresponding to energy deposition in the

  19. Probabilistic secretion of quanta and the synaptosecretosome hypothesis: evoked release at active zones of varicosities, boutons, and endplates.

    PubMed Central

    Bennett, M R; Gibson, W G; Robinson, J

    1997-01-01

    A quantum of transmitter may be released upon the arrival of a nerve impulse if the influx of calcium ions through a nearby voltage-dependent calcium channel is sufficient to activate the vesicle-associated calcium sensor protein that triggers exocytosis. A synaptic vesicle, together with its calcium sensor protein, is often found complexed with the calcium channel in active zones to form what will be called a "synaptosecretosome." In the present work, a stochastic analysis is given of the conditions under which a quantum is released from the synaptosecretosome by a nerve impulse. The theoretical treatment considers the rise of calcium at the synaptosecretosome after the stochastic opening of a calcium channel at some time during the impulse, followed by the stochastic binding of calcium to the vesicle-associated protein and the probability of this leading to exocytosis. This allows determination of the probabilities that an impulse will release 0, 1, 2,... quanta from an active zone, whether this is in a varicosity, a bouton, or a motor endplate. A number of experimental observations of the release of transmitter at the active zones of sympathetic varicosities and boutons as well as somatic motor endplates are described by this analysis. These include the likelihood of the secretion of only one quantum at an active zone of endplates and of more than one quantum at an active zone of a sympathetic varicosity. The fourth-power relationship between the probability of transmitter release at the active zones of sympathetic varicosities and motor endplates and the external calcium concentration is also explained by this approach. So, too, is the fact that the time course of the increased rate of quantal secretion from a somatic active zone after an impulse is invariant with changes in the amount of calcium that enters through its calcium channel, whether due to changes consequent on the actions of autoreceptor agents such as adenosine or to facilitation. The increased

  20. Turing, ciphers and quanta.

    PubMed

    Ekert, Artur; Kay, Alastair; Pope, James

    2012-07-28

    Alan Turing has certainly contributed to a widespread belief that the quest for a perfect, unbreakable, cipher is a futile pursuit. The ancient art of concealing information has, in the past, been matched by the ingenuity of code-breakers, but no longer! With the advent of quantum cryptography, the hopes of would-be eavesdroppers have been dashed, perhaps for good. Moreover, recent research, building on schemes that were invented decades ago to perform quantum cryptography, shows that secure communication certified by a sufficient violation of a Bell inequality makes a seemingly insane scenario possible-devices of unknown or dubious provenance, even those that are manufactured by our enemies, can be safely used for secure communication, including key distribution. All that is needed to implement this bizarre and powerful form of cryptography is a loophole-free test of a Bell inequality, which is on the cusp of technological feasibility. We provide a brief overview of the intriguing connections between Bell inequalities and cryptography and describe how studies of quantum entanglement and the foundations of quantum theory influence the way we may protect information in the future. PMID:22711866

  1. Braiding light quanta

    NASA Astrophysics Data System (ADS)

    Iadecola, Thomas; Schuster, Thomas; Chamon, Claudio

    The possibility that anyons -- quantum particles other than fermions or bosons -- can emerge in condensed matter systems has motivated generations of physicists. In addition to being of fundamental scientific importance, so-called non-Abelian anyons are particularly sought-after for potential applications to quantum computing. However, experimental evidence of anyons in electronic systems remains inconclusive. We propose to demonstrate non-Abelian braiding by injecting coherent states of light into ``topological guided modes'' in specially-fabricated photonic waveguide arrays. These modes are photonic analogues of topological zero modes in electronic systems. Light traveling inside spatially well-separated topological guided modes can be braided, leading to the accumulation of non-Abelian phases. We propose an optical interference experiment to probe this non-Abelian braiding directly. T.I. is supported by a National Science Foundation Graduate Research Fellowship under Grant No. DGE-1247312.

  2. Vibrations, quanta and biology

    NASA Astrophysics Data System (ADS)

    Huelga, S. F.; Plenio, M. B.

    2013-07-01

    Quantum biology is an emerging field of research that concerns itself with the experimental and theoretical exploration of non-trivial quantum phenomena in biological systems. In this tutorial overview we aim to bring out fundamental assumptions and questions in the field, identify basic design principles and develop a key underlying theme - the dynamics of quantum dynamical networks in the presence of an environment and the fruitful interplay that the two may enter. At the hand of three biological phenomena whose understanding is held to require quantum mechanical processes, namely excitation and charge transfer in photosynthetic complexes, magneto-reception in birds and the olfactory sense, we demonstrate that this underlying theme encompasses them all, thus suggesting its wider relevance as an archetypical framework for quantum biology.

  3. Three-dimensional model of zeaxanthin binding PsbS protein associated with nonphotochemical quenching of excess quanta of light energy absorbed by the photosynthetic apparatus.

    PubMed

    Haripal, Prafulla K; Raval, Hemant K; Raval, Mukesh K; Rawal, Rakesh M; Biswal, Basanti; Biswal, Udaya C

    2006-09-01

    A three-dimensional model of the PsbS protein was built with the help of homology-modeling methods. This protein is also known as CP22 and is associated with the protection of photosystem II of thylakoid from excess quanta of light energy absorbed by the photosynthetic apparatus. PsbS is reported to bind two molecules of zeaxanthin at low pH (<5.0) and is believed to be essential for rapid nonphotochemical quenching (qE) of chlorophyll a fluorescence in photosystem II. An attempt was made to explain the pH modulation of the conformation of protein through salt-bridges Glu(-)(122)-Lys(+)(113) and Glu(-)(226)-Lys(+)(217). Binding of two molecules of zeaxanthin in the three-dimensional model of PsbS is postulated. The molecular mechanism of photoprotection by PsbS is explained through the model. PMID:16538483

  4. Characterization of imaging performance in differential phase contrast CT compared with the conventional CT: Spectrum of noise equivalent quanta NEQ(k)

    SciTech Connect

    Tang Xiangyang; Yang Yi; Tang Shaojie

    2012-07-15

    Purpose: Differential phase contrast CT (DPC-CT) is emerging as a new technology to improve the contrast sensitivity of conventional attenuation-based CT. The noise equivalent quanta as a function over spatial frequency, i.e., the spectrum of noise equivalent quanta NEQ(k), is a decisive indicator of the signal and noise transfer properties of an imaging system. In this work, we derive the functional form of NEQ(k) in DPC-CT. Via system modeling, analysis, and computer simulation, we evaluate and verify the derived NEQ(k) and compare it with that of the conventional attenuation-based CT. Methods: The DPC-CT is implemented with x-ray tube and gratings. The x-ray propagation and data acquisition are modeled and simulated through Fresnel and Fourier analysis. A monochromatic x-ray source (30 keV) is assumed to exclude any system imperfection and interference caused by scatter and beam hardening, while a 360 Degree-Sign full scan is carried out in data acquisition to avoid any weighting scheme that may disrupt noise randomness. Adequate upsampling is implemented to simulate the x-ray beam's propagation through the gratings G{sub 1} and G{sub 2} with periods 8 and 4 {mu}m, respectively, while the intergrating distance is 193.6 mm (1/16 of the Talbot distance). The dimensions of the detector cell for data acquisition are 32 Multiplication-Sign 32, 64 Multiplication-Sign 64, 96 Multiplication-Sign 96, and 128 Multiplication-Sign 128 {mu}m{sup 2}, respectively, corresponding to a 40.96 Multiplication-Sign 40.96 mm{sup 2} field of view in data acquisition. An air phantom is employed to obtain the noise power spectrum NPS(k), spectrum of noise equivalent quanta NEQ(k), and detective quantum efficiency DQE(k). A cylindrical water phantom at 5.1 mm diameter and complex refraction coefficient n= 1 -{delta}+i{beta}= 1 -2.5604 Multiplication-Sign 10{sup -7}+i1.2353 Multiplication-Sign 10{sup -10} is placed in air to measure the edge transfer function, line spread function and

  5. Characterization of imaging performance in differential phase contrast CT compared with the conventional CT: Spectrum of noise equivalent quanta NEQ(k)

    PubMed Central

    Tang, Xiangyang; Yang, Yi; Tang, Shaojie

    2012-01-01

    Purpose: Differential phase contrast CT (DPC-CT) is emerging as a new technology to improve the contrast sensitivity of conventional attenuation-based CT. The noise equivalent quanta as a function over spatial frequency, i.e., the spectrum of noise equivalent quanta NEQ(k), is a decisive indicator of the signal and noise transfer properties of an imaging system. In this work, we derive the functional form of NEQ(k) in DPC-CT. Via system modeling, analysis, and computer simulation, we evaluate and verify the derived NEQ(k) and compare it with that of the conventional attenuation-based CT. Methods: The DPC-CT is implemented with x-ray tube and gratings. The x-ray propagation and data acquisition are modeled and simulated through Fresnel and Fourier analysis. A monochromatic x-ray source (30 keV) is assumed to exclude any system imperfection and interference caused by scatter and beam hardening, while a 360° full scan is carried out in data acquisition to avoid any weighting scheme that may disrupt noise randomness. Adequate upsampling is implemented to simulate the x-ray beam's propagation through the gratings G1 and G2 with periods 8 and 4 μm, respectively, while the intergrating distance is 193.6 mm (1/16 of the Talbot distance). The dimensions of the detector cell for data acquisition are 32 × 32, 64 × 64, 96 × 96, and 128 × 128 μm2, respectively, corresponding to a 40.96 × 40.96 mm2 field of view in data acquisition. An air phantom is employed to obtain the noise power spectrum NPS(k), spectrum of noise equivalent quanta NEQ(k), and detective quantum efficiency DQE(k). A cylindrical water phantom at 5.1 mm diameter and complex refraction coefficient n = 1 − δ + iβ = 1 −2.5604 × 10−7 + i1.2353 × 10−10 is placed in air to measure the edge transfer function, line spread function and then modulation transfer function MTF(k), of both DPC-CT and the conventional attenuation-based CT. The x-ray flux is set at 5 × 106 photon/cm2 per projection and

  6. Extensive air showers generated by gamma-quanta from Geminga and Tycho's SNR at energy range 1 30 TeV

    NASA Astrophysics Data System (ADS)

    Sinitsyna, V. G.; Arsov, T. P.; Alaverdian, A. Y.; Borisov, S. S.; Musin, F. I.; Nikolsky, S. I.; Sinitsyna, V. Y.; Platonov, G. F.

    2006-01-01

    The gamma-quantum emitting objects in our Galaxy are supernova remnants and binary. The observed results of gamma-quantum sources Tycho Brahe and Geminga by the SHALON gamma-telescope are presented. The integral spectra of events from the source - k and background events, observing simultaneously with source's events - k, and the source image are presented. The energy spectra of Tycho's SNR and Geminga supernova remnant F(E>0.8TeV)˜E are harder than the Crab Nebula spectrum. Tycho's SNR has long been considered as a candidate cosmic ray source in Northern Hemisphere. A non-linear kinetic model of cosmic ray acceleration in supernova remnants was used for Tycho's SNR. The expected π°-decay gamma-quanta flux F˜Eγ-1 extends up to ˜30TeV, whereas the Inverse Compton gamma-ray flux has a cut-off above a few TeV. So, the detection of gamma-rays at energies of ˜10-30TeV by SHALON is evidence for hadron origin.

  7. Properties of carbon-based structures synthesized in nuclear reactions induced by bremsstrahlung γ quanta with threshold energy of 10 MeV at helium pressure of 1.1 kbar

    NASA Astrophysics Data System (ADS)

    Didyk, A. Yu.; Wiśniewski, R.

    2016-07-01

    Helium gas with an initial pressure of about 1.1 kbar inside a high-pressure chamber (HeHPC) has been irradiated by bremsstrahlung γ quanta with a threshold energy of 10 MeV for 1.0 × 105 s produced by an electron-beam current of 22-24 μA. After opening the HeHPC, the residual pressure of helium is equal to 430 bar. Synthesized black foils with a variety of other objects are found inside the HeHPC. They are located on the inner surfaces of the reaction chamber made of high-purity copper (99.99%), the entrance the window of γ quanta made of beryllium bronze and a copper container of nuclear and chemical reaction products. Elemental analysis with the use of scanning electron microscopy and X-ray microprobe analysis has revealed that the foils contain predominantly carbon and small quantities of other elements from carbon to iron. The results are in good agreement with the cycle of investigations of the authors devoted to the γ-quanta irradiation of dense hydrogen and helium gases in the presence (absence) of metals in a reaction chamber.

  8. Statistical physics of earthquakes: Comparison of distribution exponents for source area and potential energy and the dynamic emergence of log-periodic energy quanta

    NASA Astrophysics Data System (ADS)

    Main, Ian G.; O'Brien, Gareth; Henderson, Jeremy R.

    2000-03-01

    We investigate the relationship between the size distribution of earthquake rupture area and the underlying elastic potential energy distribution in a cellular automaton model for earthquake dynamics. The frequency-rupture area distribution has the form n(S) ˜Sτ exp (-S/So) and the system potential energy distribution from the elastic Hamiltonian has the form n(E) ˜Ev exp (-E/θ), both gamma distributions. Here n(S) reduces to the Gutenberg-Richter frequency-magnitude law, with slope b ˜τ, in the limit that the correlation length ξ, related to the characteristic source size So, tends to infinity. The form of the energy distribution is consistent with a statistical mechanical model with l degrees of freedom, where v = (l-2)/2 and θ is proportional to the mean energy per site ? . We examine the effect of the local energy conservation factor β and the degree of material heterogeneity (quenched disorder) on the distribution parameters, which vary systematically with the controlling variables. The inferred correlation length increases systematically with increasing material homogeneity and with increasing β. The thermal parameter θ varies systematically between the leaf springs and the connecting springs, and is proportional to ? as predicted. For heterogeneous faults, τ ˜1 stays relatively constant, consistent with field observation, and S0 increases with increasing β or decreasing heterogeneity. In contrast, smooth faults produce a systematic decrease in τ with respect to β and So remains relatively constant. For high β approximately log-periodic quanta emerge spontaneously from the dynamics in the form of modulations on the energy distribution. The output energy for both types of fault shows a transition from strongly quasi-periodic temporal fluctuations for strong dissipation, to more chaotic fluctuations for more conservative models. Only strongly heterogeneous faults show the small fluctuations in energy strictly required by models of self

  9. Effective detective quantum efficiency (eDQE) and effective noise equivalent quanta (eNEQ) for system optimization purposes in digital mammography

    NASA Astrophysics Data System (ADS)

    Salvagnini, Elena; Bosmans, Hilde; Struelens, Lara; Marshall, Nicholas W.

    2012-03-01

    Effective detective quantum efficiency (eDQE) and effective noise equivalent quanta (eNEQ) were recently introduced to broaden the notion of DQE and NEQ by including system parameters such as focus blurring and system scatter rejection methods. This work investigates eDQE and eNEQ normalized for mean glandular dose (eNEQMGD) as a means to characterize and select optimal exposure parameters for a digital mammographic system. The eDQE was measured for three anode/filter combinations, with and without anti-scatter grid and for four thicknesses of poly(methylmethacrylate) (PMMA). The modulation transfer function used to calculate eDQE and eNEQ was measured from an edge positioned at 20,40,60,70 mm above the table top without scattering material in the beam. The grid-in eDQE results for all A/F settings were generally larger than those for grid-out. Contrarily, the eNEQMGD results were higher for grid-out than gridin, with a maximum difference of 61% among all A/F combinations and PMMA thicknesses. The W/Rh combination gave the highest eNEQMGD for all PMMA thicknesses compared to the other A/F combinations (for grid-in and grid-out), supporting the results of alternative methods (e.g. the signal difference to noise ratio method). The eNEQMGD was then multiplied with the contrast obtained from a 0.2mm Al square, resulting in a normalized quantity that was higher for the W/Rh combination than for the other A/F combinations. In particular, the results for the W/Rh combination were greater for the grid-in case. Furthermore, these results showed close agreement with a non-prewhitened match filter with eye response model observer (d') normalized for MGD.

  10. Controlling the motion of magnetic flux quanta.

    PubMed

    Zhu, B Y; Marchesoni, F; Nori, Franco

    2004-05-01

    We study the transport of vortices in superconductors with triangular arrays of boomerang- or V-shaped asymmetric pinning wells, when applying an alternating electrical current. The asymmetry of the pinning landscape induces a very efficient "diode" effect, that allows the sculpting at will of the magnetic field profile inside the sample. We present the first quantitative study of magnetic "lensing" of fluxons inside superconductors. Our proposed vortex lens provides a near threefold increase of the vortex density at its "focus" regions. The main numerical features have been derived analytically. PMID:15169477

  11. Quantum correlations among optical and vibrational quanta

    NASA Astrophysics Data System (ADS)

    Carlig, Sergiu; Macovei, Mihai A.

    2014-05-01

    We investigate the feasibility of correlating an optical cavity field and a vibrational phonon mode. A laser pumped quantum dot fixed on a nanomechanical resonator beam interacts as a whole with the optical resonator mode. When the quantum dot variables are faster than the optical and phonon ones, we obtain a final master equation describing the involved modes only. Increasing the temperature, which directly affects the vibrational degrees of freedom, one can as well influence the cavity photon intensity, i.e., the optical and phonon modes are correlated. Furthermore, the corresponding Cauchy-Schwarz inequality is violated demonstrating the quantum nature of those correlations.

  12. Emergent behaviour in electrodiffusion: Planck's other quanta

    NASA Astrophysics Data System (ADS)

    Bass, L.; Bracken, A. J.

    2014-02-01

    A well-established nonlinear continuum model of time-independent electrodiffusion describes the migrational and diffusional transport of two ionic species, with equal and opposite valences, across a liquid junction. The ionic charge densities provide the source for a static electric field, which in turn feeds back on the charges to contribute the migrational component of the ionic transport. Underpinning the model is a form of the second Painlevé ordinary differential equation (PII). When Bäcklund transformations, extended from those known in the context of PII, are applied to an exact solution of the model first found by Planck, a sequence of exact solutions emerges. These are characterized by corresponding ionic flux and current densities that are found to be quantized in a particularly simple way. It is argued here that this flux quantization reflects the underlying quantization of charge at the ionic level: the nonlinear continuum model ‘remembers' its discrete roots, leading to this emergent phenomenon.

  13. Flux Quanta Driven by High-Density Currents in Low-Impurity V3Si and LuNi2B2C: Free Flux Flow and Fluxon-Core Size Effect

    SciTech Connect

    Gapud, Albert A.; Moraes, S.; Khadka, R. P.; Favreau, P.; Henderson, C.; Canfield, P. C.; Kogan, V. G.; Reyes, A. P.; Lumata, L. L.; Christen, David K; Thompson, James R

    2009-01-01

    High-density direct currents are used to drive flux quanta via the Lorentz force toward a highly ordered 'free flux flow' (FFF) dynamic state, made possible by the weak-pinning environment of high-quality, single-crystal samples of two low-T{sub c} superconducting compounds, V{sub 3}Si and LuNi{sub 2}B{sub 2}C. We report the effect of the magnetic field-dependent fluxon-core size on flux flow resistivity {rho}{sub f}. Much progress has been made in minimizing the technical challenges associated with the use of high currents. Attainment of a FFF phase is indicated by the saturation at highest currents of flux flow dissipation levels that are well below the normal-state resistance and have field-dependent values. The field dependence of the corresponding {rho}{sub f} is shown to be consistent with a prediction based on a model for the decrease of fluxon-core size at higher fields in weak-coupling BCS s-wave materials.

  14. From Quanta to the Continuum: Opportunities for Mesoscale Science

    SciTech Connect

    Crabtree, George; Sarrao, John; Alivisatos, Paul; Barletta, William; Bates, Frank; Brown, Gordon; French, Roger; Greene, Laura; Hemminger, John; Kastner, Marc; Kay, Bruce; Lewis, Jennifer; Ratner, Mark; Anthony, Rollett; Rubloff, Gary; Spence, John; Tobias, Douglas; Tranquada, John

    2012-09-01

    This report explores the opportunity and defines the research agenda for mesoscale science—discovering, understanding, and controlling interactions among disparate systems and phenomena to reach the full potential of materials complexity and functionality. The ability to predict and control mesoscale phenomena and architectures is essential if atomic and molecular knowledge is to blossom into a next generation of technology opportunities, societal benefits, and scientific advances.. The body of this report outlines the need, the opportunities, the challenges, and the benefits of mastering mesoscale science.

  15. [Photoeffects, Einstein's light quanta and the history of their acceptance].

    PubMed

    Wiederkehr, Karl Heinrich

    2006-01-01

    It is generally supposed, that the discovery of the efficacy-quantum by Planck was the impetus to Einstein's hypothesis of lightquanta. With its help Einstein could explain the external light-electrical effect. But even years before Einstein had worked at the photoeffect and already made experiments on it. For that reason the article gives a short survey about the history of the lightelectric effects. Lenard's basical work about the release of the photoelectrons is dealt with in detail, without which Einstein would scarcely have found his lightquanta. Furthermore it is shown how difficult it was for the physicists to give up--at least partially--the traditional view of the undulation-nature of light, and how they searched to explain the great energies of the photoelectrons. On the other side it is set forth how Einstein's formula of lightquanta was gradually confirmed. The tragical development of Einstein's personal relations with Johannes Stark and Philipp Lenard are briefly described. Stark was one of the few who supported Einstein's ideas at the beginning. Only with the Compton-effect, which could only be quantitatively interpreted by means of lightquanta and the special theory of relativity 1923, the way was free for the general acceptance of the lightquanta. Einstein did not agree to the obtained dualism of undulation and corpuscle; he had a different solution in mind about the fusion of the two forms of appearance of light. PMID:17338401

  16. From Quanta to the Continuum: Opportunities for Mesoscale Science

    SciTech Connect

    Hemminger, John; Crabtree, George; Sarrao, John

    2012-09-01

    We are at a time of unprecedented challenge and opportunity. Our economy is in need of a jump start, and our supply of clean energy needs to dramatically increase. Innovation through basic research is a key means for addressing both of these challenges. The great scientific advances of the last decade and more, especially at the nanoscale, are ripe for exploitation. Seizing this key opportunity requires mastering the mesoscale, where classical, quantum, and nanoscale science meet. It has become clear that—in many important areas—the functionality that is critical to macroscopic behavior begins to manifest itself not at the atomic or nanoscale but at the mesoscale, where defects, interfaces, and non-equilibrium structures are the norm. With our recently acquired knowledge of the rules of nature that govern the atomic and nanoscales, we are well positioned to unravel and control the complexity that determines functionality at the mesoscale. The reward for breakthroughs in our understanding at the mesoscale is the emergence of previously unrealized functionality. The present report explores the opportunity and defines the research agenda for mesoscale science—discovering, understanding, and controlling interactions among disparate systems and phenomena to reach the full potential of materials complexity and functionality. The ability to predict and control mesoscale phenomena and architectures is essential if atomic and molecular knowledge is to blossom into a next generation of technology opportunities, societal benefits, and scientific advances. Imagine the ability to manufacture at the mesoscale: that is, the directed assembly of mesoscale structures that possess unique functionality that yields faster, cheaper, higher performing, and longer lasting products, as well as products that have functionality that we have not yet imagined. Imagine the realization of biologically inspired complexity and functionality with inorganic earth-abundant materials to transform energy conversion, transmission, and storage. Imagine the transformation from top-down design of materials and systems with macroscopic building blocks to bottom-up design with nanoscale functional units producing next-generation technological innovation. This is the promise of mesoscale science. Mesoscale science and technology opportunities build on the enormous foundation of nanoscience that the scientific community has created over the last decade and continues to create. New features arise naturally in the transition to the mesoscale, including the emergence of collective behavior; the interaction of disparate electronic, mechanical, magnetic, and chemical phenomena; the appearance of defects, interfaces and statistical variation; and the self assembly of functional composite systems. The mesoscale represents a discovery laboratory for finding new science, a self-assembly foundry for creating new functional systems, and a design engine for new technologies. The last half-century and especially the last decade have witnessed a remarkable drive to ever smaller scales, exposing the atomic, molecular, and nanoscale structures that anchor the macroscopic materials and phenomena we deal with every day. Given this knowledge and capability, we are now starting the climb up from the atomic and nanoscale to the greater complexity and wider horizons of the mesoscale. The constructionist path up from atomic and nanoscale to mesoscale holds a different kind of promise than the reductionist path down: it allows us to re-arrange the nanoscale building blocks into new combinations, exploit the dynamics and kinetics of these new coupled interactions, and create qualitatively different mesoscale architectures and phenomena leading to new functionality and ultimately new technology. The reductionist journey to smaller length and time scales gave us sophisticated observational tools and intellectual understanding that we can now apply with great advantage to the wide opportunity of mesoscale science following a bottom-up approach. Realizing the mesoscale opportunity requires advances not only in our knowledge but also in our ability to observe, characterize, simulate, and ultimately control matter. Mastering mesoscale materials and phenomena requires the seamless integration of theory, modeling, and simulation with synthesis and characterization. The inherent complexity of mesoscale phenomena, often including many nanoscale structural or functional units, requires theory and simulation spanning multiple space and time scales. In mesoscale architectures the positions of individual atoms are often no longer relevant, requiring new simulation approaches beyond density functional theory and molecular dynamics that are so successful at atomic scales. New organizing principles that describe emergent mesoscale phenomena arising from many coupled and competing degrees of freedom wait to be discovered and applied. Measurements that are dynamic, in situ, and multimodal are needed to capture the sequential phenomena of composite mesoscale materials. Finally, the ability to design and realize the complex materials we imagine will require qualitative advances in how we synthesize and fabricate materials and how we manage their metastability and degradation over time. We must move from serendipitous to directed discovery, and we must master the art of assembling structural and functional nanoscale units into larger architectures that create a higher level of complex functional systems. While the challenge of discovering, controlling, and manipulating complex mesoscale architectures and phenomena to realize new functionality is immense, success in the pursuit of these research directions will have outcomes with the potential to transform society. The body of this report outlines the need, the opportunities, the challenges, and the benefits of mastering mesoscale science.

  17. On Einstein, Light Quanta, Radiation, and Relativity in 1905

    ERIC Educational Resources Information Center

    Miller, Arthur I.

    1976-01-01

    Analyzes section 8 of Einstein's relativity paper of 1905, "On the Electrodynamics of Moving Bodies," in its historical context. Relates this section to the rest of the relativity paper, to the genesis of relativity theory, and to contemporaneous work on radiation theory. (Author/MLH)

  18. Learning Quanta: Barriers to Stimulating Transitions in Student Understanding of Orbital Ideas

    ERIC Educational Resources Information Center

    Taber, Keith S.

    2005-01-01

    This paper reports the results of applying a particular analytical perspective to data from an interview study: a typology of learning impediments informed by research into learning and students' ideas in science. This typology is a heuristic tool that may help diagnose the origins of students' learning difficulties. Here it is applied to data…

  19. Moessbauer medium with a hidden nuclear population inversion and negative absorption of gamma quanta

    SciTech Connect

    Rivlin, Lev A

    2011-06-30

    We consider physical foundations of an eventual experiment aimed at observing stimulated gamma-photon emission of long-lived Moessbauer isomers through selective frequency modulation of gamma-resonances establishing hidden population inversion without exceeding the number of excited nuclei over unexcited ones and without additional pumping. The examples of suitable nuclei and numerical estimates of the parameters are presented. (active media)

  20. Analytic Methods for Predicting Significant Multi-Quanta Effects in Collisional Molecular Energy Transfer

    NASA Technical Reports Server (NTRS)

    Bieniek, Ronald J.

    1996-01-01

    Collision-induced transitions can significantly affect molecular vibrational-rotational populations and energy transfer in atmospheres and gaseous systems. This, in turn. can strongly influence convective heat transfer through dissociation and recombination of diatomics. and radiative heat transfer due to strong vibrational coupling. It is necessary to know state-to-state rates to predict engine performance and aerothermodynamic behavior of hypersonic flows, to analyze diagnostic radiative data obtained from experimental test facilities, and to design heat shields and other thermal protective systems. Furthermore, transfer rates between vibrational and translational modes can strongly influence energy flow in various 'disturbed' environments, particularly where the vibrational and translational temperatures are not equilibrated.

  1. The effect of atomic motion and two-quanta JCM on the information entropy

    NASA Astrophysics Data System (ADS)

    Abdel-Khalek, S.

    2008-02-01

    We study the interaction between a moving two-level atom and a single-mode field. The coupled atom-cavity system with atomic center-of-mass motion included is modeled by considering the dependence of the atomic motion along z-axis. At exact resonance between the internal atomic transition and the cavity eigenfrequency, an exact solution of the system is obtained and periodically modulated Rabi oscillations and regular translational motion are observed. We focused on the dynamics of both field Wehrl entropy and Wehrl phase distribution. The influence of the atomic motion on the evolution of von Neumann entropy and Wehrl entropy is examined. The results show that the atomic motion and the field-mode structure play important roles in the evolution of the von Neumann entropy, Wehrl entropy and Wehrl PD.

  2. Recovering hidden quanta of Cu2+-doped ZnS quantum dots in reductive environment

    NASA Astrophysics Data System (ADS)

    Begum, Raihana; Sahoo, Amaresh Kumar; Ghosh, Siddhartha Sankar; Chattopadhyay, Arun

    2013-12-01

    We report that photoluminescence of doped quantum dots (Qdots)--which was otherwise lost in the oxidized form of the dopant--could be recovered in chemical or cellular reducing environment. For example, as-synthesized Cu2+-doped zinc sulfide (ZnS) Qdots in water medium showed weak emission with a peak at 420 nm, following excitation with UV light (320 nm). However, addition of reducing agent led to the appearance of green emission with a peak at 540 nm and with quantum yield as high as 10%, in addition to the weak peak now appearing as a shoulder. The emission disappeared in the presence of an oxidizing agent or with time under ambient conditions. X-Ray photoelectron spectroscopic (XPS) and electron spin resonance (ESR) measurements suggested the presence of Cu2+ in the as-synthesized Qdots, while formation of its reduced form was indicated (by ESR results) following treatment with a reducing agent. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) studies confirmed the formation of ZnS nanocrystals, the size and shape of which did not undergo any change in the presence of a reducing or oxidizing agent. Nanoparticulate forms of the Qdots and chitosan (a biopolymer) composite exhibited similar emission characteristics. Interestingly, when mammalian cancer cells or non-cancerous cells were treated with the composite nanoparticles (NPs), characteristic green fluorescence was observed. Further, the intensity of the fluorescence diminished when the cells were treated later with pyrogallol--a known reactive oxygen species generator. Overall, the results indicated a new way of probing the reducing nature of mammalian cells using the emission properties of the Qdot based on the redox state of its dopant.We report that photoluminescence of doped quantum dots (Qdots)--which was otherwise lost in the oxidized form of the dopant--could be recovered in chemical or cellular reducing environment. For example, as-synthesized Cu2+-doped zinc sulfide (ZnS) Qdots in water medium showed weak emission with a peak at 420 nm, following excitation with UV light (320 nm). However, addition of reducing agent led to the appearance of green emission with a peak at 540 nm and with quantum yield as high as 10%, in addition to the weak peak now appearing as a shoulder. The emission disappeared in the presence of an oxidizing agent or with time under ambient conditions. X-Ray photoelectron spectroscopic (XPS) and electron spin resonance (ESR) measurements suggested the presence of Cu2+ in the as-synthesized Qdots, while formation of its reduced form was indicated (by ESR results) following treatment with a reducing agent. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) studies confirmed the formation of ZnS nanocrystals, the size and shape of which did not undergo any change in the presence of a reducing or oxidizing agent. Nanoparticulate forms of the Qdots and chitosan (a biopolymer) composite exhibited similar emission characteristics. Interestingly, when mammalian cancer cells or non-cancerous cells were treated with the composite nanoparticles (NPs), characteristic green fluorescence was observed. Further, the intensity of the fluorescence diminished when the cells were treated later with pyrogallol--a known reactive oxygen species generator. Overall, the results indicated a new way of probing the reducing nature of mammalian cells using the emission properties of the Qdot based on the redox state of its dopant. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr05280j

  3. Josephson fluxon pump: Theoretical aspects and experimental implementation of elementary flux quanta generator with BSCCO

    NASA Astrophysics Data System (ADS)

    Gulevich, D. R.; Gaifullin, M.; Kusmartseva, O. E.; Kusmartsev, F. V.; Hirata, K.

    2008-09-01

    We propose a device able to generate trains of Josephson fluxons without application of external magnetic field - fluxon pump. The pulses of individual fluxons are generated by cloning single fluxons trapped inside a reservoir. When an electric current is applied, a flow of fluxons is generated in the long attachment connected to the reservoir of fluxons. The role of a reservoir is played by Josephson junctions in the form of a loop where one or several fluxons are permanently trapped.

  4. PREFACE: Atoms, quanta and relativity—a century after Einstein's miraculous year

    NASA Astrophysics Data System (ADS)

    Hänsch, T. W.; Schmidt-Böcking, H.; Walther, H.

    2005-05-01

    In 2005 we celebrate the hundredth anniversary of the publication of five seminal papers by Albert Einstein establishing the basis of three fundamental fields of physics: the theory of relativity, quantum theory and the theory of Brownian motion. This happened at a time when the reality of atoms and molecules was still far from certain. The microscopic view Einstein took of molecular motion led to the calculation of Avogadro's number and the size of molecules by studying the motion of small particles in liquids. Combining kinetic theory and classical thermodynamics finally led Einstein to the conclusion that the displacement of a microparticle under Brownian motion varies as the square root of time. The experimental demonstration of this law three years later was considered as the striking proof that atoms and molecules are physically real. Today single atoms are probed directly in experiments, and we are able to observe the individual paths of colliding or dissociating particles. These new techniques are described in some of the papers of this issue in a very impressive way. An even more exciting development was initiated with the demonstration of Bose-Einstein condensation of dilute gases of ultracold atoms, a phenomenon first predicted by Einstein in papers published between 1916 and 1924. The first paper of Einstein's famous series of 1905, 'On an heuristic point of view about the creation and conversion of light', was an explanation of the photoelectric effect, demonstrated in several experiments over the previous few years. The explanation was based on the quantum hypothesis introduced by Max Planck five years earlier, and was considered as an additional and important proof of Planck's hypothesis. Today quantum theory and photons are the basis for much of modern science and technology. We have learned to experiment with single photons, and we have demonstrated the advantages of information transfer by single photons. Photons permit new and incredibly precise time and frequency standards. These are not only technically important, but may also lead to even more stringent tests of relativity and other fundamental laws and concepts of physics. Examples of these applications and many other uses of modern optics are discussed in this issue. Special relativity, the third of Einstein's 1905 topics, has always been closely connected with atomic, molecular and optical physics. Today atomic physics provides some of the most stringent tests of special relativity. Furthermore, fast electron beams are used in advanced light sources such as synchrotron radiation generators and free electron lasers. Those aspects and related applications are also discussed here. We hope that this special issue will be of great interest to the reader by highlighting recent advances in atomic, molecular and optical physics. This field continues to provide one of the most fertile areas for research one hundred years after it first emerged from the work of Einstein published in 1905, his 'miraculous year'.

  5. A voltage-clamp study of the permeability change induced by quanta of transmitter at the mouse end-plate.

    PubMed Central

    Linder, T M; Quastel, D M

    1978-01-01

    1. Miniature end-plate currents (m.e.p.c.s) were recorded from mouse diaphragm using a point voltage-clamp. The relation between m.e.p.c. amplitude and membrane potential was determined in bathing solutions of varied composition. 2. In solution containing normal sodium the relation between m.e.p.c. height and membrane potential (Im.e.p.c./Vm relation) was always linear, at least in the range +30 to -100 mV; the reversal potential (Vr) at which Im.e.p.c. was zero was close to 0. The slope of the Im.e.p.c./Vm line varied little between junctions (coefficient of variation about 20%) and was about 50 nS, or 1nA per 20 mV. The Im.e.p.c./Vm relation was not altered by withdrawal of Ca2+, addition of ethanol, or substitution of NO-3 or SO2-(4) for Cl-. 3. Alteration of K+ concentration in the bathing medium, in the range 10 to 1 mM, had no apparent effect on the Im.e.p.c./Vm relation. 4. Reduction of Na+ concentration, with isosmotic substitution of sucrose, caused rapid alteration of the Im.e.p.c./Vm relation, which became rectifying, with a slope at negative Vm less than at positive Vm. Vr was shifted in the negative direction. Quantitatively these changes were close to those predicted by the Goldman-Hodgkin-Katz formulation for permeation of monovalent ions through a membrane with constant field. 5. In solution with low Na+ (2 mM) and partial substitution of K+ for Na+, the Im.e.p.c./Vm relation was indistinguishable from that in solutions with Na" as the predominant extracellular cation. With complete substitution of K+ for Na+ the Im.e.p.c./Vm relation was a little less steep (at negative Vm) than in Na+ solution and Vr was shifted slightly in the negative direction. 6. With substitution of NH+4 for Na+, the Im.e.p.c./Vm relation was little changed (about 10% steeper at negative Vm). With substitution of Li+ for Na+, the Im.e.p.c./Vm relation remained linear, but was made less steep, at positive as well as negative Vm, and Vr was shifted slightly in the positive direction. 7. These results indicate that the permeability change associated with generation of the m.e.p.c. (i.e., evoked by a quantum of transmitter) corresponds to the opening of a single species of membrane channel that allows the free movement of K+, Na+, NH+4, AND Li+ ions along their electrochemical gradients. The channel discriminates little between these ions. The apparent order of permeability is Li+ greater than NH+4 greater than Na+ greater than or equal to K+. The apparent permeability per channel corresponds to that expected for channels of about 6.4 A diameter, 100 A length, and ionic mobility the same as in dilute solution. PMID:212556

  6. The puzzle of half-integral quanta in the application of the adiabatic hypothesis to rotational motion

    NASA Astrophysics Data System (ADS)

    Duncan, Anthony; Pérez, Enric

    2016-05-01

    We present and discuss an interesting and puzzling problem Ehrenfest found in his first application of the adiabatic hypothesis, in 1913. It arose when trying to extend Planck's quantization of the energy of harmonic oscillators to a rotating dipole within the frame of the old quantum theory. Such an extension seemed to lead unavoidably to half-integral values for the rotational angular momentum of a system (in units of ℏ). We present the problem in its original form along with the (few) responses we have found to Ehrenfest's treatment. After giving a brief account of the classical and quantum adiabatic theorem, we also describe how Quantum Mechanics provides an explanation for this difficulty.

  7. Discovery of Dozy Chaos and Discovery of Quanta: Analogy Being in Science and Perhaps in Human Progress

    NASA Astrophysics Data System (ADS)

    Egorov, Vladimir V.

    The concept of a dozy chaos in the theory of quantum transitions and its applications are discussed in a historical context. Conjectured that dozy chaos is of primary importance to the dynamic self-organization of any living organism and concentrated in its brain. A hypothesis of the physical origin of cancer is put forward. Surmised that dozy chaos is the physical origin of life and driving force of its evolution.

  8. Yield and cross section of {sup 232}Th and {sup 236}U fission induced by {gamma} quanta with energies up to 11 MeV

    SciTech Connect

    Soldatov, A.S.; Smirenkin, G.N.

    1995-02-01

    The results of relative measurements of photofission yields are presented for {sup 232}Th and {sup 236}U nuclei in the region 7-11 MeV of end-point bremsstrahlung energies. The cross section and yield of {sup 238}U photofission is taken as the standard. The photofission cross sections for the {sup 232}Th and {sup 236}U nuclei are reconstructed from these data. The experimental data processing is refined, and the information obtained is revised. This paper is a continuation of the earlier publication. 21 refs., 5 figs.

  9. Phenomenological nuclear-reaction description in deuterium-saturated palladium and synthesized structure in dense deuterium gas under γ-quanta irradiation

    NASA Astrophysics Data System (ADS)

    Didyk, A. Yu.; Wiśniewski, R.

    2013-05-01

    The observed phenomena of changes of chemical compositions in previous reports [1, 2] allowed us to develop a phenomenological nuclear fusion-fission model with taking into consideration the elastic and inelastic scattering of photoprotons and photoneutrons, heating of surrounding deuterium nuclei, following d-d fusion reactions and fission of middle-mass nuclei by "hot" protons, deuterons and various-energy neutrons. Such chain processes could produce the necessary number of neutrons, "hot" deuterons for explanation of observed experimental results [1, 2]. The developed approach can be a basis for creation of deuterated nuclear fission reactors (DNFR) with high-density deuterium gas and the so-called deuterated metals. Also, this approach can be used for the study of nuclear reactions in high-density deuterium or tritium gas and deuterated metals.

  10. ``Quantum-Computing''(Q-C) = Simple-Arithmetic Since Digits = Quanta/Bosons Via Algebraic-INVERSION 1881(<1901-05-25) of Digits On-Average Logarithmic-Law = ONLY BEQS!!!

    NASA Astrophysics Data System (ADS)

    Pi, E. I.; Siegel, Edward Carl-Ludwig

    2011-03-01

    Digits'(On Average) Newcomb(1881)-Weyl(1914)-Benford(1938) "NeWBe" Logarithmic-Law P > = log { base = 10 } (1 + 1 / d) = log { base = 10 } ([ d + 1 ] / d) Siegel [ Abs . 973 - 60 - 124 , AMSNat . Mtg . (2002) ] INVERSIONtoONLYBose - Einsteinquantum - statistics (BEQS) d = 1 / [ 10 (P >) - 1 ] 1 / [ exp (P >) - 1 ] 1 / [ exp (w >) - 1 ] { 1 / [ 1 + (w >) + . . . ] - 1 ] 1 / w > 1.000 . . . Archimedes ' Zipf - lawHYPERBOLICITY (noise generalized - susceptibility) power - spectrumINEVITABILITYwithgapFULBECtodigitd = 0 , P (0) > = oo , GAP = [ P (0) > = oo ] - [ P (1) > = 0.32 ] = oohasdeepmeaningfor (socalled) Q - C . Identificationofdigits (BCE) asquanta (1901 - 05 ACE) becausequantaare / alwaysweredigits : energy - levels : ground - stated = 0 , firstexcited - stated = 1 , . . . , withnointermediate / fractional - levels , separatedbyquantum : Q = (d = 1) - (d = 0) = 1 means (onaverageany / allsimplearithmeticcomputationswithdigitsareabinitiobydefinitionQ - C . Example : ablank - checkisaBECofdigitsd = 0 ; writingsomenon - zerodigitsd > 0 , thensigningcheck , isquantum - excitationfromd = 0 tod >0. Thus (so called) Q-C has existed since man learned to count/manipulate hand's digits. Simple arithmetic(except for: division; factoring with remainders) is/has been from time immemorial (on average) "Q-C"!!!

  11. Experiment Pamir-3. Coplanar emission of high energy gamma-quanta at interaction of hadrons with nuclei of air atoms at energies above 10 to the 7th power GeV

    NASA Technical Reports Server (NTRS)

    Genina, L. E.; Asatiani, T. L.; Zatsepin, G. T.

    1985-01-01

    A systematic analysis of large gamma families, detected in X-ray emulsion chambers, cases of multicore halos have been observed, and among them five events in which the halo is divided into three of four separate cores with their alignment observed in the target diagram (coplanarity of axes of corresponding electron photon cascades). The halo alignment (tendency to the straight line) leads to the aximuthal asymmetry (thrust). The analysis of lateral and momentum distributions of particles in these families shows that they also have thrust that correlates with the direction of the halo core alignment.

  12. Detection of gamma quanta due to {pi}{sup 0} and {eta} decays by a modular electromagnetic calorimeter with a neutral trigger under a 40-GeV {pi}{sup -} beam

    SciTech Connect

    Barkov, B.P.; Katinov, Y.V.; Lisin, V.I.

    1994-11-01

    We have previously generated a YAC contig of the SMA region on chromosome 5q13 and initiated construction of a corresponding cosmid contig from these YAC clones and a chromosome 5 cosmid library. In order to screen for candidate genes from this area, a cosmid containing CATT1, a microsatellite marker, in linkage disequilibrium with SMA was used to screen a fetal brain library. The largest cDNA clone (2.2 Kb) isolated from this library, GA1, was mapped back to the original cosmid and then characterized. Screening of a spinal cord library with the GA1 cDNA identified a 700 bp clone. Hybridization to a zoo blot revealed cross-species conservation in pig, sheep, goat and horse. Sequencing of GA1 identified 2221 bp with no long open reading frame or poly A tail. Analysis of this sequence with `grail` showed a small potential coding region of 75 bp coding for 25 amino acids. A database search for homologous sequence using `blast` did not show any significant matches. Furthermore, no introns were identified in genomic subclones when compared to the cDNA sequence by using PCR and various combinations of GA1 sequence-derived primers. Experiments with RT-PCR on DNase-treated total mRNA from adult brain, fibroblasts and liver identified the anticipated GA1 product from fibroblast mRNA only. RACE extension of the cDNA clone revealed that we were dealing with the full-length transcript. Subsequent fine mapping with various combinations of GA1 PCR primers to PAC clones in this region identified 1 copy of a novel 300 bp sequence that has undergone a microduplication yielding several copies of this sequence in a 300 Kb segment of the SMA critical region. PCR-based mutational analysis has not revealed any alteration peculiar to SMA chromosomes. A search for polymorphisms with the GA1 sequence to use in SMA linkage analysis was also conducted.

  13. On quanta, mind, and matter: Hans Primas in Context. H. Atmanspacher, A. Amann, U. Müller-Herold (Eds), Kluwer, Boston, 1999, pp. 398 + viii, US192.00 £133.56 (hardback), ISBN 0-7923-5696-9

    NASA Astrophysics Data System (ADS)

    Halvorson, Hans

    This book consists of a collection of 18 articles by students, colleagues, and friends of the theoretical chemist/philosopher of science, Hans Primas. Although the articles are written in honor of Primas, the editors state that the collection is not a Festschrift, but that it simply 'takes up some of the discussions that Primas has initiated or inspired' (p. 2). Due to the breadth of Primas' intellectual interests, the result is a highly eclectic collection of articles, whose topics range through (i) the historical development of experimental NMR spectroscopy, (ii) Jungian psychology, (iii) a defense of determinism in the rationalistic tradition of Leibniz, to (iv) a mathematical exposition of 'operator trigonometry.' However, since our space-and my expertise-is limited, the following comments will be restricted to those articles that deal with the mathematical and conceptual foundations of physics, a subject to which Primas has made a large contribution.

  14. 75 FR 3895 - Yale University, et al.;

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-25

    ..., Quanta 3D Dual-Beam Focused Ion-Beam Tool. Manufacturer: FEI Company, Czech Republic. Intended Use: See notice at 74 FR 67851, December 21, 2009. Docket Number: 09-065. Applicant: U.S. Department of Homeland..., Quanta 200 FEG. Manufacturer: FEI Company, Czech Republic. Intended Use: See notice at 74 FR...

  15. The search for gamma radiation from supernova 1987A in an experiment aboard the Salut-7/Cosmos-1686 complex

    NASA Astrophysics Data System (ADS)

    Bachilova, R. N.; Bloch, G. M.; Pankov, V. M.; Prohin, V. L.; Rutkovsky, A. I.; Rumin, S. P.

    1988-07-01

    Gamma-quanta flux measurements were carried out during February-October 1987 in a search for radiation from SN 1987A. The time dependence of the mean monthly gamma-quanta flux measured with the Nega telescope at an altitude of 500 km in the equatorial region is analyzed. The upper limit of the gamma-quanta flux is determined to be 1.5 x 10 to the -6th/sq cm s keV on the 3-sigma level for the 1.5-4.4 MeV energy interval.

  16. Natural thermodynamics

    NASA Astrophysics Data System (ADS)

    Annila, Arto

    2016-02-01

    The principle of increasing entropy is derived from statistical physics of open systems assuming that quanta of actions, as undividable basic build blocks, embody everything. According to this tenet, all systems evolve from one state to another either by acquiring quanta from their surroundings or by discarding quanta to the surroundings in order to attain energetic balance in least time. These natural processes result in ubiquitous scale-free patterns: skewed distributions that accumulate in a sigmoid manner and hence span log-log scales mostly as straight lines. Moreover, the equation for least-time motions reveals that evolution is by nature a non-deterministic process. Although the obtained insight in thermodynamics from the notion of quanta in motion yields nothing new, it accentuates that contemporary comprehension is impaired when modeling evolution as a computable process by imposing conservation of energy and thereby ignoring that quantum of actions are the carriers of energy from the system to its surroundings.

  17. Hideki Yukawa and the meson theory

    SciTech Connect

    Brown, L.M.

    1986-12-01

    Some 50 years ago, in his first research contribution, a young Japanese theoretical physicist explained the strong, short-range force between neutrons and protons as due to an exchange of ''heavy quanta.''

  18. Optomechanics: Listening to quantum grains of sound

    NASA Astrophysics Data System (ADS)

    Favero, Ivan

    2015-04-01

    An optomechanical device has allowed quanta, or 'grains', of mechanical vibration to be counted by optical means. The system may open up new possibilities in acoustics and thermal engineering. See Letter p.522

  19. Not so special

    NASA Astrophysics Data System (ADS)

    Stancey, Gerald

    2015-10-01

    In reply to the Quanta article “Earth to the ISS - from a shed” (September p3), which described how Adrian Lane, a 52-year-old lorry driver, had contacted the International Space Station from his garden shed.

  20. Photon polarization version of the GHz-Mermin Gedanken

    NASA Technical Reports Server (NTRS)

    Kiess, Thomas E.

    1992-01-01

    We have defined a photon polarization analog of the Greenberger, Horne, and Zeilinger (GHZ) experiment that was initially proposed for spin-1/2 quanta. Analogs of the ket states and Pauli spin matrix operators are presented.

  1. Hawking's acting roles

    NASA Astrophysics Data System (ADS)

    Castell, Stephen

    2012-06-01

    In the wake of Stephen Hawking's appearance on the TV show The Big Bang Theory, last month's "Quanta" page (May p3), included a request: "If you think Hawking should appear in any other TV shows, then let us know".

  2. Light-dependency of growth and secondary metabolite production in the captive zooxanthellate soft coral Sinularia flexibilis.

    PubMed

    Khalesi, Mohammad K; Beeftink, H H; Wijffels, R H

    2009-01-01

    The branching zooxanthellate soft coral Sinularia flexibillis releases antimicrobial and toxic compounds with potential pharmaceutical importance. As photosynthesis by the symbiotic algae is vital to the host, the light-dependency of the coral, including its specific growth rate (micro day(-1)) and the physiological response to a range of light intensities (10-1,000 micromol quanta m(-2) s(-1)) was studied for 12 weeks. Although a range of irradiances from 100 to 400 micromol quanta m(-2) s(-1) was favorable for S. flexibilis, based on chlorophyll content, a light intensity around 100 micromol quanta m(-2) s(-1) was found to be optimal. The contents of both zooxanthellae and chlorophyll a were highest at 100 micromol quanta m(-2) s(-1). The specific budding rate showed almost the same pattern as the specific growth rate. The concentration of the terpene flexibilide, produced by this species, increased at high light intensities (200-600 micromol quanta m(-2) s(-1)). PMID:19048343

  3. Simulation of the Focal Spot of the Accelerator Bremsstrahlung Radiation

    NASA Astrophysics Data System (ADS)

    Sorokin, V.; Bespalov, V.

    2016-06-01

    Testing of thick-walled objects by bremsstrahlung radiation (BR) is primarily performed via high-energy quanta. The testing parameters are specified by the focal spot size of the high-energy bremsstrahlung radiation. In determining the focal spot size, the high- energy BR portion cannot be experimentally separated from the low-energy BR to use high- energy quanta only. The patterns of BR focal spot formation have been investigated via statistical modeling of the radiation transfer in the target material. The distributions of BR quanta emitted by the target for different energies and emission angles under normal distribution of the accelerated electrons bombarding the target have been obtained, and the ratio of the distribution parameters has been determined.

  4. Study of EUV and x-ray radiation hardness of silicon photodiodes

    NASA Astrophysics Data System (ADS)

    Zabrodsky, Vladimir V.; Aruev, Pavel; Filimonov, Vladimir V.; Sobolev, Nikolay A.; Sherstnev, Evgeniy V.; Belik, Viktor P.; Nikolenko, Anton D.; Ivlyushkin, Denis V.; Pindyurin, Valery F.; Shadrin, Nikita S.; Soldatov, Artem E.; Mashkovtsev, Mikhail R.

    2013-05-01

    This work presents the results of long-term observation of the silicon photodiodes spatial profile response and the silicon photodiodes dark current after their exposure to 10.2 eV quanta and in the spectral range of 150-300 eV. Exposure of the photodiodes to quanta of an energy of 10.2 eV was repeated. Several other photodiodes have been irradiated in the spectral range of 700-1800 eV with a dose of 8 J/cm2. The spatial profile of the irradiated photodiodes was studied with 3.49 eV, 10.2 eV and 100 eV quanta. The effect of the recovery of the response spatial profile has been proved for the p+-n diode. An additional useful method of visualization of irradiated photodiode area is also presented.

  5. Topological Growing of Laughlin States in Synthetic Gauge Fields

    NASA Astrophysics Data System (ADS)

    Grusdt, Fabian; Letscher, Fabian; Hafezi, Mohammad; Fleischhauer, Michael

    2014-10-01

    We suggest a scheme for the preparation of highly correlated Laughlin states in the presence of synthetic gauge fields, realizing an analogue of the fractional quantum Hall effect in photonic or atomic systems of interacting bosons. It is based on the idea of growing such states by adding weakly interacting composite fermions along with magnetic flux quanta one by one. The topologically protected Thouless pump ("Laughlin's argument") is used to create two localized flux quanta and the resulting hole excitation is subsequently filled by a single boson, which, together with one of the flux quanta, forms a composite fermion. Using our protocol, filling 1/2 Laughlin states can be grown with particle number N increasing linearly in time and strongly suppressed number fluctuations. To demonstrate the feasibility of our scheme, we consider two-dimensional lattices subject to effective magnetic fields and strong on-site interactions. We present numerical simulations of small lattice systems and also discuss the influence of losses.

  6. Lateral distribution on charged particles in EAS

    NASA Technical Reports Server (NTRS)

    Dedenko, L. G.; Sulakov, V. F.; Kulikov, G. V.; Solovjeva, V. I.

    1985-01-01

    Lateral distribution of charged particles which allow for the finiteness of energy gamma-quanta, the inhomogeneity of the atmosphere and the experimental selection of EAS are needed to interpret experimental data. The effects of finiteness of energy of gamma-quanta which produce the partial electron-photon cascades were considered by substituting K R sub m instead of R sub m in NKG approximation where K was found to be 0.56 from comparison with the experimental data. New results on the lateral distribution of electrons in the partial cascades from gamma-quanta were obtained. It is shown that the coefficient K can be regarded as a constant. The last approximation of K was found to be most adequate when compared with the experimental data. The inhomogeneity of the atmosphere, muons and experimental selection are considered. The calculation of Ne are extended from 100,000 to 10 million for sea level and for Akeno level.

  7. Analytical and Clinical Comparison of Two Fully Automated Immunoassay Systems for the Diagnosis of Celiac Disease

    PubMed Central

    Norman, Gary L.; Santora, Debby; Fasano, Alessio

    2014-01-01

    Objective. Here we compared analytical and clinical performance characteristics of two novel automated assay systems for the detection of celiac disease (CD) specific antibodies: QUANTA Flash (INOVA Diagnostics, Inc.) and EliA (Thermo Scientific). Methods. A total of 74 biopsy-proven CD patients (2 with IgA deficiency) and 138 controls were tested by both methods. Results. Sensitivities of QUANTA Flash assays ranged from 35.1% to 90.5% and specificities from 96.4% to 99.3%, while sensitivities for EliA assays ranged from 37.8% to 90.5% (equivocal considered positive) and specificities from 97.1% to 100.0%. Good qualitative agreement was found between all assays. Thirty-four (50.0%) of the 68 QUANTA Flash h-tTG IgA positive results were higher than 10 times the upper limit of normal (ULN). In contrast, only 22.8% of the EliA tTG IgA positive samples were >10x ULN. Seventy-three (98.6%) biopsy-proven CD patients were correctly identified with the QUANTA Flash h-tTG IgA+DGP IgG combination, while 64 (86.5%) and 72 (97.3%) (depending on equivocal range) were identified with the same combination of EliA assays. Conclusion. The QUANTA Flash CD assays have outstanding clinical performance. Of particular clinical significance, in light of proposals to decrease the absolute necessity of biopsy, was the demonstration that 50% of the QUANTA Flash h-tTG IgA results were >10x ULN. PMID:24741592

  8. Parallel cone bipolar pathways to a ganglion cell use different rates and amplitudes of quantal excitation.

    PubMed

    Freed, M A

    2000-06-01

    The cone signal reaches the cat's On-beta (X) ganglion cell via several parallel circuits (bipolar cell types b1, b2, and b3). These circuits might convey different regions of the cone's temporal bandwidth. To test this, I presented a step of light that elicited a transient depolarization followed by a sustained depolarization. The contribution of bipolar cells to these response components was isolated by blocking action potentials with tetrodotoxin and by blocking inhibitory synaptic potentials with bicuculline and strychnine. Stationary fluctuation analysis of the sustained depolarization gave the rate of quantal bombardment: approximately 5100 quanta sec(-1) for small central cells and approximately 45,000 quanta sec(-1) for large peripheral cells. Normalizing these rates for the vastly different numbers of bipolar synapses (150-370 per small cell vs 2000 per large cell), quantal rate was constant across the retina, approximately 22 quanta synapse(-1) sec(-1). Nonstationary fluctuation analysis gave the mean quantal EPSP amplitude: approximately 240 microV for the transient depolarization and 30 microV for the sustained depolarization. The b1 bipolar cell is known from noise analysis of the On-alpha ganglion cell to have a near-maximal sustained release of only approximately two quanta synapse(-1) sec(-1). This implies that the other bipolar types (b2 and b3) contribute many more quanta to the sustained depolarization (>/=46 synapse(-1) sec(-1)). Type b1 probably contributes large quanta to the transient depolarization. Thus, bipolar cell types b1 and b2/b3 apparently constitute parallel circuits that convey, respectively, high and low frequencies. PMID:10818130

  9. An ion trap built with photonic crystal fibre technology

    SciTech Connect

    Lindenfelser, F. Keitch, B.; Kienzler, D.; Home, J. P.; Bykov, D.; Uebel, P.; Russell, P. St. J.

    2015-03-15

    We demonstrate a surface-electrode ion trap fabricated using techniques transferred from the manufacture of photonic-crystal fibres. This provides a relatively straightforward route for realizing traps with an electrode structure on the 100 micron scale with high optical access. We demonstrate the basic functionality of the trap by cooling a single ion to the quantum ground state, allowing us to measure a heating rate from the ground state of 787 ± 24 quanta/s. Variation of the fabrication procedure used here may provide access to traps in this geometry with trap scales between 100 μm and 10 μm.

  10. On the biphoton excitation of the fluorescence of the bacteriochlorophyll molecules of purple photosynthetic bacteria by powerful near IR femto-picosecond pulses

    NASA Astrophysics Data System (ADS)

    Borisov, A. Yu.

    2011-11-01

    The authors of a number of experimental works detected nonresonance biphoton excitation of bacteriochlorophyll molecules, which represent the main pigment in the light-absorbing natural "antenna" complexes of photosynthesizing purple bacteria, by femtosecond IR pulses (1250-1500 nm). They believe that IR quanta excite hypothetic forbidden levels of the pigments of these bacteria in the double frequency range 625-750 nm. We propose and ground an alternative triplet mechanism to describe this phenomenon. According to our hypothesis, the mechanism of biphoton excitation of molecules by IR quanta can manifest itself specifically, through high triplet levels of molecules in the high fields induced by femtosecond-picosecond laser pulses.

  11. First observation of the competitive double-gamma (γγ/γ) decay process

    NASA Astrophysics Data System (ADS)

    Pietralla, N.; Walz, C.; Scheit, H.; Aumann, T.; Lefol, R.; Ponomarev, V. Yu

    2016-06-01

    First observation of the competitive double-γ decay process is presented. It is a second-order electromagnetic decay mode. The 662-keV transition from the 11/2‑ isomer of 137Ba to its ground state proceeds at a fraction of 2 x 10‑6 by simultaneous emission of two γ quanta instead of one. The angular correlation and energy distribution of coincident γ quanta are reproduced by a dominant M2-E2 and a minor E3-M1 contribution to the double-γ decay branch. The data are well accounted for by a calculation in the Quasiparticle Phonon Model.

  12. GASEOUS SCINTILLATION COUNTER

    DOEpatents

    Eggler, C.; Huddleston, C.M.

    1959-04-28

    A gaseous excitation counter for detecting the presence amd measuring the energy of subatomic particles and electromagnetic radiation is described. The counter includes a gas-tight chamber filled with an elemental gas capable of producing ultra-violet excitation quanta when irradiated with subatomic particles and electromagnetic radiation. The gas has less than one in a thousand parts ultra-violet absorbing contamination. When nuclear radiation ps present the ultra-violet light produced by the gas strikes a fluorescent material within the counter, responsive to produce visible excitation quanta, and photo-sensitive counting means detect the visible emission.

  13. Experimental search for the radiative capture reaction d + d {yields} {sup 4}He + {gamma} from the dd{mu} muonic molecule state J = 1

    SciTech Connect

    Baluev, V. V.; Bogdanova, L. N.; Bom, V. R.; Demin, D. L.; Eijk, C. W. E. van; Filchenkov, V. V.; Grafov, N. N.; Grishechkin, S. K.; Gritsaj, K. I.; Konin, A. D.; Mikhailyukov, K. L.; Rudenko, A. I.; Vinogradov, Yu. I.; Volnykh, V. P.; Yukhimchuk, A. A.; Yukhimchuk, S. A.

    2011-07-15

    A search for the muon-catalyzed fusion reaction d + d {yields} {sup 4}He + {gamma} in the dd{mu} muonic molecule was performed using the experimental installation TRITON with BGO detectors for {gamma}-quanta. A high-pressure target filled with deuterium was exposed to the negative muon beam of the JINR Phasotron to detect {gamma}-quanta with the energy 23.8 MeV. An experimental estimation for the yield of radiative deuteron capture from the dd{mu} state J = 1 was obtained at the level of {eta}{sub {gamma}} {<=} 8 Multiplication-Sign 10{sup -7} per fusion.

  14. An ion trap built with photonic crystal fibre technology.

    PubMed

    Lindenfelser, F; Keitch, B; Kienzler, D; Bykov, D; Uebel, P; Schmidt, M A; Russell, P St J; Home, J P

    2015-03-01

    We demonstrate a surface-electrode ion trap fabricated using techniques transferred from the manufacture of photonic-crystal fibres. This provides a relatively straightforward route for realizing traps with an electrode structure on the 100 micron scale with high optical access. We demonstrate the basic functionality of the trap by cooling a single ion to the quantum ground state, allowing us to measure a heating rate from the ground state of 787 ± 24 quanta/s. Variation of the fabrication procedure used here may provide access to traps in this geometry with trap scales between 100 μm and 10 μm. PMID:25832211

  15. Potential energy function for the hydroperoxyl radical

    SciTech Connect

    Lemon, W.J.; Hase, W.L.

    1987-03-12

    A switching function formalism is used to derive an analytic potential energy surface for the O + OH in equilibrium HO/sub 2/ in equilibrium H + O/sub 2/ reactive system. Both experimental and ab initio data are used to derive parameters for the potential energy surface. Trajectory calculations for highly excited HO/sub 2/ are performed on this surface. From these trajectories quasi-periodic eigentrajectories are found for vibrational levels near the HO/sub 2/ dissociation threshold with small amounts of quanta in the OH stretch mode and large amounts of quanta in the OO stretch mode.

  16. Experimental search for the radiative capture reaction d + d → 4He + γ from the ddμ muonic molecule state J = 1

    NASA Astrophysics Data System (ADS)

    Baluev, V. V.; Bogdanova, L. N.; Bom, V. R.; Demin, D. L.; van Eijk, C. W. E.; Filchenkov, V. V.; Grafov, N. N.; Grishechkin, S. K.; Gritsaj, K. I.; Konin, A. D.; Mikhailyukov, K. L.; Rudenko, A. I.; Vinogradov, Yu. I.; Volnykh, V. P.; Yukhimchuk, A. A.; Yukhimchuk, S. A.

    2011-07-01

    A search for the muon-catalyzed fusion reaction d + d → 4He + γ in the ddμ muonic molecule was performed using the experimental installation TRITON with BGO detectors for γ-quanta. A high-pressure target filled with deuterium was exposed to the negative muon beam of the JINR Phasotron to detect γ-quanta with the energy 23.8 MeV. An experimental estimation for the yield of radiative deuteron capture from the ddμ state J = 1 was obtained at the level of η γ ≤ 8 × 10-7 per fusion.

  17. On the biphoton excitation of the fluorescence of the bacteriochlorophyll molecules of purple photosynthetic bacteria by powerful near IR femto-picosecond pulses

    SciTech Connect

    Borisov, A. Yu.

    2011-11-15

    The authors of a number of experimental works detected nonresonance biphoton excitation of bacteriochlorophyll molecules, which represent the main pigment in the light-absorbing natural 'antenna' complexes of photosynthesizing purple bacteria, by femtosecond IR pulses (1250-1500 nm). They believe that IR quanta excite hypothetic forbidden levels of the pigments of these bacteria in the double frequency range 625-750 nm. We propose and ground an alternative triplet mechanism to describe this phenomenon. According to our hypothesis, the mechanism of biphoton excitation of molecules by IR quanta can manifest itself specifically, through high triplet levels of molecules in the high fields induced by femtosecond-picosecond laser pulses.

  18. Temporal and spatial variations in photosynthetic parameters in the South Sea and East/Japan Sea, Korea

    NASA Astrophysics Data System (ADS)

    Lee, J.

    2015-12-01

    Although the photosynthetic parameters are important factors for phytoplankton ecology and simulation models of ecological dynamics in marine ecosystems, very limited data for temporal and spatial variations in in situ photosynthetic parameters are available in Korean oceans. To obtain the photosynthetic parameters, we measured carbon fixation rates of phytoplankton from six light depths (100, 50, 30, 12, 5, and 1 %) at 2 sampling sites (Hupo-Pohang and Gwangyang bay, Korea) in 2013, using a stable carbon isotope (13C) tracer technique. Based on the results from this study, the ranges of α (photosynthetic efficiency), β (strength of the photoinhibition) and μ (growth rate) were 0.06-0.07 mg C h-1 (µmol quanta m-2 s-1) -1, 3.90-21.41 mg C h-1 (µmol quanta m-2 s-1) -1, and 0.18-0.19 d-1, respectively at Hupo-Pohang site in the East/Japan Sea. The values of α and β were higher in November (Average ± S.D = 0.07±0.02 mg C h-1 (µmol quanta m-2 s-1) -1 and 21.41±36.89 mg C h-1 (µmol quanta m-2 s-1) -1, respectvitly) than those (Average ± S.D = 0.06±0.05 mg C h-1 (µmol quanta m-2 s-1) -1 and 3.90±5.36 mg C h-1 (µmol quanta m-2 s-1) -1, respectively) in September, 2013. In contrast, μ value was higher in September (Average ± S.D = 0.19±0.15 d-1) than that (Average ± S.D = 0.18±0.14 d-1) in November. In comparison, the ranges of α, β and μ at Gwangyang bay site in the South Sea were 0.05-0.11 mg C h-1 mg C h-1 (µmol quanta m-2 s-1) -1 , 3.14-93.91 mg C h-1 (µmol quanta m-2 s-1) -1 and 0.14-0.34 d-1, respectively. The parameters of α and μ were highest in June (Average ± S.D = 0.11±0.05 mg C h-1 (µmol quanta m-2 s-1) -1, and 0.34±0.27 d-1), and β was highest value in January (Average ± S.D = 93.31±81.47 mg C h-1 (µmol quanta m-2 s-1) -1). The photosynthetic parameters obtained in this study are within the ranges of α (0.08 to 0.26 mg C h-1 (µmol quanta m-2 s-1) -1) and μ (0.42 to 1.31 d-1) in Bedford basin previously reported by Brenda

  19. The nonlinear effect of two-color light on bacterial viability

    NASA Astrophysics Data System (ADS)

    Lukyanovich, P. A.; Zon, B. A.; Grabovich, M. Yu; Shchelukhina, E. V.; Danilova, I. I.; Orlova, M. V.; Sapeltseva, I. O.; Sinugina, D. I.

    2016-01-01

    A bacterial (Escherichia coli) viability nonlinear effect is found experimentally after continuous irradiation by composite red and blue light. The dependence of bacterial viability on irradiance at equal specific doses is interpreted as possible two-photon absorption causing DNA damage that is similar to damage from the absorption of UV quanta.

  20. Fock space representation of differential calculus on the noncommutative quantum space

    SciTech Connect

    Mishra, A.K.; Rajasekaran, G.

    1997-01-01

    A complete Fock space representation of the covariant differential calculus on quantum space is constructed. The consistency criteria for the ensuing algebraic structure, mapping to the canonical fermions and bosons and the consequences of the new algebra for the statistics of quanta are analyzed and discussed. The concept of statistical transmutation between bosons and fermions is introduced. {copyright} {ital 1997 American Institute of Physics.}

  1. Comparison of high-MTF and reduced-noise radiographic imaging systems

    NASA Astrophysics Data System (ADS)

    Bunch, Phillip C.

    1995-05-01

    The objective imaging characteristics of a wide range of gandolinium oxysulfide-based, zero- crossover, screen-film combinations are presented and compared. It is shown that complex high-spatial frequency versus low-spatial frequency performance tradeoffs are found among these systems, when these systems are examined in terms of sensitometric response, modulation transfer function, noise equivalent quanta, and detective quantum efficiency.

  2. Missing energies at pair creation

    NASA Technical Reports Server (NTRS)

    El-Ela, A. A.; Bagge, E. R.; Hassan, S.

    1985-01-01

    Wilson cloud chamber measurements of the separated spectra of positrons and electrons produced by gamma quanta of 6.14 MeV differ considerably from the theoretically predicted spectra by BETHE and HEITLER, but are in good agreement with those of a modified theory of pair creation.

  3. Quantum origin of suppression for vacuum fluctuations of energy

    NASA Astrophysics Data System (ADS)

    Balitsky, Ja. V.; Kiselev, V. V.

    2014-12-01

    By using a model with a spatially global scalar field, we show that the energy density of zero-point modes is exponentially suppressed by an average number of field quanta in a finite volume with respect to the energy density in the stationary state of minimal energy. We describe cosmological implications of the mechanism.

  4. Theoretical estimates of photoproduction cross sections for neutral subthreshold pions in carbon-carbon collisions

    NASA Technical Reports Server (NTRS)

    Norbury, J. W.; Townsend, L. W.

    1986-01-01

    Using the Weizsacher-Williams method of virtual quanta, total cross section estimates for the photoproduction of neutral subthreshold pins in carbon-carbon collisions at incident energies below 300 MeV/nucleon are made. Comparisons with recent experimental data indicate that the photoproduction mechanism makes an insignificant contribution to these measured cross sections.

  5. Electromagnetic dissociation effects in galactic heavy-ion fragmentation

    NASA Technical Reports Server (NTRS)

    Norbury, J. W.; Townsend, L. W.

    1986-01-01

    Methods for calculating cross sections for the breakup of galactic heavy ions by the Coulomb fields of the interacting nuclei are presented. By using the Weizsacker-Williams method of virtual quanta, estimates of electromagnetic dissociation cross sections for a variety of reactions applicable to galactic cosmic ray shielding studies are presented and compared with other predictions and with available experimental data.

  6. Infrared Lasers in Chemistry.

    ERIC Educational Resources Information Center

    John, Phillip

    1982-01-01

    Selected infrared laser chemistry topics are discussed including carbon dioxide lasers, infrared quanta and molecules, laser-induced chemistry, structural isomerization (laser purification, sensitized reactions, and dielectric breakdown), and fundamental principles of laser isotope separation, focusing on uranium isotope separation. (JN)

  7. 77 FR 51573 - Certain Automated Media Library Devices; Determination To Review in Part a Final Initial...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-24

    ..., 2010, and supplemented on November 9, 2010. 75 FR 71735 (Nov. 24, 2010). The complaint alleged... disapprove the Commission's action. See Presidential Memorandum of July 21, 2005, 70 FR 43251 (July 26, 2005...., Quanta Computer, Inc. v. LG Elecs., Inc., 553 U.S. 617 (2008); LG Elecs., Inc. v. Bizcom Elecs.,...

  8. 78 FR 42976 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-International...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-18

    ... 28, 1996 (61 FR 33774). The last notification was filed with the Department on December 15, 2009. A... FR 2889). Patricia A. Brink, Director of Civil Enforcement, Antitrust Division. BILLING CODE 4410-11.... Also, Foxconn, Taipei Hsien, TAIWAN; and Quanta Computer, Tao Yuan Shine, TAIWAN, have withdrawn...

  9. The electromagnetic component of albedo from superhigh energy cascades in dense media

    NASA Technical Reports Server (NTRS)

    Golynskaya, R. M.; Hein, L. A.; Plyasheshnikov, A. V.; Vorobyev, K. V.

    1985-01-01

    Albedo from cascades induced in iron by high energy gamma quanta were Monte Carlo simulated. Thereafter the albedo electromagnetic component from proton induced cascades were calculated analytically. The calculations showed that the albedo electromagnetic component increases more rapidly than the nuclear active component and will dominate at sufficiently high energies.

  10. Teaching Quantum Physics without Paradoxes

    ERIC Educational Resources Information Center

    Hobson, Art

    2007-01-01

    Although the resolution to the wave-particle paradox has been known for 80 years, it is seldom presented. Briefly, the resolution is that material particles and photons are the quanta of extended spatially continuous but energetically quantized fields. But because the resolution resides in quantum field theory and is not usually spelled out in…

  11. Experimental study of the vidicon system for information recording using the wide-gap spark chamber of gamma - telescope gamma-I

    NASA Technical Reports Server (NTRS)

    Akimov, V. V.; Bazer-Bashv, R.; Voronov, S. A.; Galper, A. M.; Gro, M.; Kalinkin, L. F.; Kerl, P.; Kozlov, V. D.; Koten, F.; Kretol, D.

    1979-01-01

    The development of the gamma ray telescope is investigated. The wide gap spark chambers, used to identify the gamma quanta and to determine the directions of their arrival, are examined. Two systems of information recording with the spark chambers photographic and vidicon system are compared.

  12. The multiplicity and the spectra of secondaries correlated with the leading particle energy

    NASA Technical Reports Server (NTRS)

    Kruglov, N. A.; Proskuryakov, A. S.; Sarycheva, L. I.; Smirnova, L. N.

    1985-01-01

    The spectra of leading particles of different nature in pp-collisions at E sub 0 = 33 GeV are obtained. The multiplicities and the spectra of secondaries, mesons, gamma-quanta, lambda and lambda-hyperons and protons for different leading particle energy ranges are determined.

  13. 77 FR 70811 - Notice of Lodging of Proposed Consent Decree Under the Comprehensive Environmental Response...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-27

    ... between Plaintiff the United States of America, and the following Defendants: Honeywell International, Inc., Hudson River Associates, LLC, Metropolitan Consom, LLC, Quanta Resources Corporation, BASF Corporation, Beazer East, Inc., BFI Waste Systems of New Jersey, Inc., Borgwarner Inc., Buckeye Partners, LP,...

  14. Analysis of the detective quantum efficiency of coupling a CCD to a scintillating phosphor for x-ray microtomographic imaging

    NASA Astrophysics Data System (ADS)

    Westmore, Michael S.; Cunningham, Ian A.

    1993-09-01

    We are developing an x-ray microtomographic imaging system ((mu) CT) for imaging small objects at very high (approximately 25 micrometers ) spatial resolution. The detector for this system consists of a CCD array coupled to a phosphor screen through a fiber-optic faceplate. For the purposes of signal and noise analysis, this system is modeled as a multi-stage cascaded imaging system consisting of: (a) conversion of x-ray quanta to optical quanta in the phosphor; (b) collection and transfer of optical quanta from the phosphor to the CCD; and (c) detection of optical quanta by the CCD. We use the model of Rabbani et al. for cascaded systems to theoretically calculate the detective quantum efficiency (DQE) as a function of spatial frequency. We have developed the theoretical basis of a spatial-frequency dependent nomogram in terms of the system DQE. This approach is used to identify any sources of image degradation, and to make optimal design decisions of system parameters such as optical gains or numerical apertures. Using this approach, we show that the spreading of optical photons in the phosphor screen is the most significant factor degrading the MTF.

  15. Solitons in Josephson junctions

    NASA Astrophysics Data System (ADS)

    Ustinov, A. V.

    1998-11-01

    Magnetic flux quanta in Josephson junctions, often called fluxons, in many cases behave as solitons. A review of recent experiments and modelling of fluxon dynamics in Josephson circuits is presented. Classic quasi-one-dimensional junctions, stacked junctions (Josephson superlattices), and discrete Josephson transmission lines (JTLs) are discussed. Applications of fluxon devices as high-frequency oscillators and digital circuits are also addressed.

  16. Hawking radiation is corpuscular

    NASA Astrophysics Data System (ADS)

    Mück, Wolfgang

    2016-07-01

    The total number of Hawking quanta emitted during the evaporation of a Schwarzschild black hole is proportional to the square of the initial mass or, equivalently, to the Bekenstein entropy. This simple, but little appreciated, fact is interpreted in terms of the recent discovery of black hole soft hair.

  17. Quantum origin of suppression for vacuum fluctuations

    NASA Astrophysics Data System (ADS)

    Balitsky, Ja. V.; Kiselev, V. V.

    2016-03-01

    By example of a model with a spatially global scalar field, we show that the energy density of zero-point modes is exponentially suppressed by an average number of field quanta in a finite volume with respect to the energy density in the stationary state of minimal energy. We describe cosmological implications of mechanism.

  18. Illustrating Concepts of Quantal Analysis with an Intuitive Classroom Model

    ERIC Educational Resources Information Center

    Xu-Friedman, Matthew A.

    2013-01-01

    The quantal hypothesis is central to the modern understanding of how a neurotransmitter is released from synapses. This hypothesis expresses that a neurotransmitter is packaged together in quanta that are released probabilistically. The experiments that led to the quantal hypothesis are often related in introductory neuroscience textbooks, but…

  19. Harmonic oscillator states in aberration optics

    NASA Technical Reports Server (NTRS)

    Wolf, Kurt Bernardo

    1993-01-01

    The states of the three-dimensional quantum harmonic oscillator classify optical aberrations of axis-symmetric systems due to the isomorphism between the two mathematical structures. Cartesian quanta and angular momentum classifications have their corresponding aberration classifications. The operation of concatenation of optical elements introduces a new operation between harmonic oscillator states.

  20. Sum rules for M2 and other cases

    SciTech Connect

    Kurath, D.

    1995-08-01

    Sum rules were derived for parity-changing operators consisting of an odd-l spherical harmonic coupled to the spin operator sigma. The conditions are that the valence nucleons are in the oscillator shell with Q quanta and the shell with Q-1 quanta is full and the shell with Q+1 quanta is empty. Thus this applies to the 1p, 2sd and 3pf as valence shells, where the sum rules would be useful for inelastic electron scattering and other reactions. In particular a complete M2 sum rule was derived including the weak contribution from the orbital operator. The contribution from the spurious center-of-mass motion was also derived. The expression was tested by comparing to summations of transition strengths given by shell-model calculations. For nuclei with mass greater than {approximately}A = 70 one would need to include the effect of the intruding level with Q+1 quanta and J = Q+3/2. This problem will be considered in the coming year.

  1. Test of a single module of the J-PET scanner based on plastic scintillators

    NASA Astrophysics Data System (ADS)

    Moskal, P.; Niedźwiecki, Sz.; Bednarski, T.; Czerwiński, E.; Kapłon, Ł.; Kubicz, E.; Moskal, I.; Pawlik-Niedźwiecka, M.; Sharma, N. G.; Silarski, M.; Zieliński, M.; Zoń, N.; Białas, P.; Gajos, A.; Kochanowski, A.; Korcyl, G.; Kowal, J.; Kowalski, P.; Kozik, T.; Krzemień, W.; Molenda, M.; Pałka, M.; Raczyński, L.; Rudy, Z.; Salabura, P.; Słomski, A.; Smyrski, J.; Strzelecki, A.; Wieczorek, A.; Wiślicki, W.

    2014-11-01

    A Time of Flight Positron Emission Tomography scanner based on plastic scintillators is being developed at the Jagiellonian University by the J-PET collaboration. The main challenge of the conducted research lies in the elaboration of a method allowing application of plastic scintillators for the detection of low energy gamma quanta. In this paper we report on tests of a single detection module built out from the BC-420 plastic scintillator strip (with dimensions of 5×19×300 mm3) read out at two ends by Hamamatsu R5320 photomultipliers. The measurements were performed using collimated beam of annihilation quanta from the 68Ge isotope and applying the Serial Data Analyzer (Lecroy SDA6000A) which enabled sampling of signals with 50 ps intervals. The time resolution of the prototype module was established to be better than 80 ps (σ) for a single level discrimination. The spatial resolution of the determination of the hit position along the strip was determined to be about 0.93 cm (σ) for the annihilation quanta. The fractional energy resolution for the energy E deposited by the annihilation quanta via the Compton scattering amounts to σ(E) / E ≈ 0.044 /√{ E(MeV) } and corresponds to the σ(E) / E of 7.5% at the Compton edge.

  2. Phenomenology of Particle Production during Ination

    NASA Astrophysics Data System (ADS)

    Namba, Ryo

    This thesis is devoted to the study on particle production during the era of primordial inflation and its phenomenological impacts. The simplest models of inflation typically assume only one dynamical degree of freedom, inflaton, that is responsible for all the inflationary dynamics and predictions. Yet, it is a natural expectation that the inflaton should be coupled to some other fields, in need of successful reheating of the universe after inflation. We first consider the models in which the inflaton is coupled to a U(1) gauge field. For a pseudo-scalar inflaton, its natural coupling induces tachyonic growth of the gauge quanta, which then inverse-decay to the inflaton perturbations. This imprints non-Gaussianity in the cosmic microwave background (CMB) anisotropies. This non-Gaussianity has a nearly equilateral shape, and the fact that we have not observed it with Planck provides a bound on the axion decay constant, which is in the range naturally obtained in UV completed theories. The produced gauge quanta also source gravitational waves (GWs). Future GW interferometer experiments can improve over the CMB non-Gaussianity limits. We then study a different model characterized by a scalar inflaton coupled to gauge fields via a dilation-like interaction. This coupling can result in a nearly scale-invariant spectrum for the gauge field. Also in this case, the produced gauge quanta source inflaton perturbations, but the resulting non-Gaussianity now has a shape peaked for squeezed triangles, and which exhibits a peculiar angular dependence, that, if detected, would be a smoking gun of the higher-spin fields involved. In the above two models, the GW signals are always subdominant at the CMB scales, due to the non-Gaussianity bounds from the scalar perturbations (namely, from the perturbations generated by the inflaton quanta produced by the gauge fields). We study the radically different situation in which some field other than the inflaton produces the gauge quanta

  3. Characterization of SLUG microwave amplifiers

    NASA Astrophysics Data System (ADS)

    Hoi, I.-C.; Zhu, S.; Thorbeck, T.; McDermott, R.; Mutus, J.; Jeffrey, E.; Barends, R.; Chen, Y.; Roushan, P.; Fowler, A.; Sank, D.; White, T.; Campbell, B.; Chen, Z.; Chiaro, B.; Dunsworth, A.; Kelly, J.; Megrant, A.; Neill, C.; O'Malley, P. J. J.; Quintana, C.; Vainsencher, A.; Wenner, J.; Martinis, J. M.

    2015-03-01

    With the rapid growth of superconducting circuits quantum technology, a near quantum-limited amplifier at GHz frequency is needed to enable high fidelity measurements. We describe such an amplifier, the SQUID based, superconducting low inductance undulatory galvanometer (SLUG) amplifier. We measure the full scattering matrix of the SLUG. In particular, we measure both forward and reverse gain, as well as reflection. We see 15dB forward gain with added noise from one quanta to several quanta. The -1 dB compression point is around -95 dBm, about two orders of magnitude higher than that of typical Josephson parametric amplifiers. With these properties, SLUG is well suited for the high fidelity, simultaneous multiplexed readout of superconducting qubits.

  4. Quantum limited quasiparticle mixers at 100 GHz

    SciTech Connect

    Mears, C.A; Hu, Qing; Richards, P.L. ); Worsham, A.H.; Prober, D.E. . Dept. of Applied Physics); Raeisaenen, A.V. . Radio Lab.)

    1990-09-01

    We have made accurate measurements of the noise and gain of superconducting-insulating-superconducting (SIS) mixers employing small area (1{mu}m{sup 2}) Ta/Ta{sub 2}O{sub 5}/Pb{sub 0.9}Bi{sub 0.1} tunnel junctions. We have measured an added mixer noise of 0.61 +/{minus} 0.31 quanta at 95.0 GHz, which is within 25 percent of the quantum limit of 0.5 quanta. We have carried out a detailed comparison between theoretical predictions of the quantum theory of mixing and experimentally measured noise and gain. We used the shapes of I-V curves pumped at the upper and lower sideband frequencies to deduce values of the embedding admittances at these frequencies. Using these admittances, the mixer noise and gain predicted by quantum theory are in excellent agreement with experiment. 21 refs., 9 figs.

  5. Endplate structure and parameters of neuromuscular transmission in sporadic centronuclear myopathy associated with myasthenia.

    PubMed

    Liewluck, Teerin; Shen, Xin-Ming; Milone, Margherita; Engel, Andrew G

    2011-06-01

    Centronuclear myopathy is a pathologically diagnosed congenital myopathy. The disease genes encode proteins with membrane modulating properties (MTM1, DNM2, and BIN1) or alter excitation-contraction coupling (RYR1). Some patients also have myasthenic symptoms but electrodiagnostic and endplate studies in these are limited. A sporadic patient had fatigable weakness and a decremental EMG response. Analysis of centronuclear myopathy disease- and candidate-genes identified no mutations. Quantitative endplate electron microscopy studies revealed simplified postsynaptic regions, endplate remodeling with normal nerve terminal size, normal synaptic vesicle density, and mild acetylcholine receptor deficiency. The amplitude of the miniature endplate potential was decreased to 60% of normal. Quantal release by nerve impulse was reduced to 40% of normal due to a decreased number of releasable quanta. The safety margin of neuromuscular transmission is compromised by decreased quantal release by nerve impulse and by a reduced postsynaptic response to the released quanta. PMID:21482111

  6. Absolute angle-differential vibrational excitation cross sections for electron collisions with diacetylene

    SciTech Connect

    Allan, M.; May, O.; Fedor, J.; Ibanescu, B. C.; Andric, L.

    2011-05-15

    Absolute vibrational excitation cross sections were measured for diacetylene (1,3-butadiyne). The selectivity of vibrational excitation reveals detailed information about the shape resonances. Excitation of the C{identical_to}C stretch and of double quanta of the C-H bend vibrations reveals a {sup 2}{Pi}{sub u} resonance at 1 eV (autodetachment width {approx}30 meV) and a {sup 2}{Pi}{sub g} resonance at 6.2 eV (autodetachment width 1-2 eV). There is a strong preference for excitation of even quanta of the bending vibration. Excitation of the C-H stretch vibration reveals {sigma}* resonances at 4.3, 6.8, and 9.8 eV, with autodetachment widths of {approx}2 eV. Detailed information about resonances permits conclusions about the mechanism of the dissociative electron attachment.

  7. Propagation of radiation in fluctuating multiscale plasmas. II. Kinetic simulations

    SciTech Connect

    Pal Singh, Kunwar; Robinson, P. A.; Cairns, Iver H.; Tyshetskiy, Yu.

    2012-11-15

    A numerical algorithm is developed and tested that implements the kinetic treatment of electromagnetic radiation propagating through plasmas whose properties have small scale fluctuations, which was developed in a companion paper. This method incorporates the effects of refraction, damping, mode structure, and other aspects of large-scale propagation of electromagnetic waves on the distribution function of quanta in position and wave vector, with small-scale effects of nonuniformities, including scattering and mode conversion approximated as causing drift and diffusion in wave vector. Numerical solution of the kinetic equation yields the distribution function of radiation quanta in space, time, and wave vector. Simulations verify the convergence, accuracy, and speed of the methods used to treat each term in the equation. The simulations also illustrate the main physical effects and place the results in a form that can be used in future applications.

  8. Operating Spin Echo in the Quantum Regime for an Atomic-Ensemble Quantum Memory.

    PubMed

    Rui, Jun; Jiang, Yan; Yang, Sheng-Jun; Zhao, Bo; Bao, Xiao-Hui; Pan, Jian-Wei

    2015-09-25

    Spin echo is a powerful technique to extend atomic or nuclear coherence times by overcoming the dephasing due to inhomogeneous broadenings. However, there are disputes about the feasibility of applying this technique to an ensemble-based quantum memory at the single-quanta level. In this experimental study, we find that noise due to imperfections of the rephasing pulses has both intense superradiant and weak isotropic parts. By properly arranging the beam directions and optimizing the pulse fidelities, we successfully manage to operate the spin echo technique in the quantum regime by observing nonclassical photon-photon correlations as well as the quantum behavior of retrieved photons. Our work for the first time demonstrates the feasibility of harnessing the spin echo method to extend the lifetime of ensemble-based quantum memories at the single-quanta level. PMID:26451551

  9. The New Physics

    NASA Astrophysics Data System (ADS)

    Fraser, Gordon

    2009-08-01

    Introduction Gordon Fraser; Part I. Matter and the Universe: 1. Cosmology Wendy Freedman and Rocky Kolb; 2. Gravity Ronald Adler; 3. Astrophysics Arnon Dar; 4. Particles and the standard model Chris Quigg; 5. Superstrings Michael Green; Part II. Quantum Matter: 6. Atoms and photons Claude Cohen-Tannoudji and Jean Dalibard; 7. The quantum world of ultra-cold atoms Christopher Foot and William Phillips; 8. Superfluidity Henry Hall; 9. Quantum phase transitions Subir Sachdev; Part III. Quanta in Action: 10. Quantum entanglement Anton Zeilinger; 11. Quanta, ciphers and computers Artur Ekert; 12. Small-scale structure and nanoscience Yoseph Imry; Part IV. Calculation and Computation: 13. Nonlinearity Henry Abarbanel; 14. Complexity Antonio Politi; 15. Collaborative physics, e-science and the grid Tony Hey and Anne Trefethen; Part V. Science in Action: 16. Biophysics Cyrus Safinya; 17. Medical physics Nicolaj Pavel; 18. Physics and materials Robert Cahn; 19. Physics and society Ugo Amaldi.

  10. The New Physics

    NASA Astrophysics Data System (ADS)

    Fraser, Gordon

    2006-04-01

    Introduction Gordon Fraser; Part I. Matter and the Universe: 1. Cosmology Wendy Freedman and Rocky Kolb; 2. Gravity Ronald Adler; 3. Astrophysics Arnon Dar; 4. Particles and the standard model Chris Quigg; 5. Superstrings Michael Green; Part II. Quantum Matter: 6. Atoms and photons Claude Cohen-Tannoudji and Jean Dalibard; 7. The quantum world of ultra-cold atoms Christopher Foot and William Phillips; 8. Superfluidity Henry Hall; 9. Quantum phase transitions Subir Sachdev; Part III. Quanta in Action: 10. Quantum entanglement Anton Zeilinger; 11. Quanta, ciphers and computers Artur Ekert; 12. Small-scale structure and nanoscience Yoseph Imry; Part IV. Calculation and Computation: 13. Nonlinearity Henry Abarbanel; 14. Complexity Antonio Politi; 15. Collaborative physics, e-science and the grid Tony Hey and Anne Trefethen; Part V. Science in Action: 16. Biophysics Cyrus Safinya; 17. Medical physics Nicolaj Pavel; 18. Physics and materials Robert Cahn; 19. Physics and society Ugo Amaldi.

  11. Hadronic Spectrum of a Holographic Dual of QCD

    SciTech Connect

    Teramond, Guy F. de; Brodsky, Stanley J.

    2005-05-27

    We compute the spectrum of light hadrons in a holographic dual of QCD defined on AdS{sub 5}xS{sup 5} which has conformal behavior at short distances and confinement at large interquark separation. Specific hadrons are identified by the correspondence of string modes with the dimension of the interpolating operator of the hadron's valence Fock state. Higher orbital excitations are matched quanta to quanta with fluctuations about the AdS background. Since only one parameter, the QCD scale {lambda}{sub QCD}, is used, the agreement with the pattern of physical states is remarkable. In particular, the ratio of delta to nucleon trajectories is determined by the ratio of zeros of Bessel functions.

  12. Photolysis of alkaline-earth nitrates

    NASA Astrophysics Data System (ADS)

    Kriger, L. D.; Miklin, M. B.; Dyagileva, E. P.; Anan'ev, V. A.

    2013-02-01

    Peroxynitrite and nitrite ions are the diamagnetic products of photolysis (with light at a wavelength of 253.7 nm) of alkaline-earth nitrates; the paramagnetic products and hydrogen peroxide were not found. The structural water in alkaline-earth nitrate crystals did not affect the qualitative composition of the photodecomposition products. The quantum yield of nitrite ions was 0.0012, 0.0038, 0.0078, and 0.0091 quanta-1 and that of peroxynitrite ions was 0.0070, 0.0107, 0.0286, and 0.0407 quanta-1 for Sr(NO3)2, Ba(NO3)2, Ca(NO3)2 · 4H2O, and Mg(NO3)2 · 6H2O, respectively.

  13. Vibration-rotation variational calculations - Precise results on HCN up to 25,000/cm

    NASA Astrophysics Data System (ADS)

    Carter, Stuart; Mills, Ian M.; Handy, Nicholas C.

    1993-09-01

    Variation calculations of the vibration-rotation energy levels of many isotopomers of HCN are reported, for J = 0, 1, and 2, extending up to approximately 8 quanta of each of the stretching vibrations and 14 quanta of the bending mode. The force field, which is represented as a polynomial expansion in Morse coordinates for the bond stretches and even powers of the angle bend, has been refined by least squares to fit simultaneously all observed data on the Sigma and Pi state vibrational energies, and the Sigma state rotational constants, for both HCN and DCN. The observed vibrational energies are fitted to roughly +/- 0.5/cm, and the rotational constants to roughly +/- 0.0001/cm. The force field has been used to predict the vibration rotation spectra of many isotopomers of HCN up to 25,000/cm.

  14. Micro-fabricated stylus ion trap.

    PubMed

    Arrington, Christian L; McKay, Kyle S; Baca, Ehren D; Coleman, Jonathan J; Colombe, Yves; Finnegan, Patrick; Hite, Dustin A; Hollowell, Andrew E; Jördens, Robert; Jost, John D; Leibfried, Dietrich; Rowen, Adam M; Warring, Ulrich; Weides, Martin; Wilson, Andrew C; Wineland, David J; Pappas, David P

    2013-08-01

    An electroformed, three-dimensional stylus Paul trap was designed to confine a single atomic ion for use as a sensor to probe the electric-field noise of proximate surfaces. The trap was microfabricated with the UV-LIGA technique to reduce the distance of the ion from the surface of interest. We detail the fabrication process used to produce a 150 μm tall stylus trap with feature sizes of 40 μm. We confined single, laser-cooled, (25)Mg(+) ions with lifetimes greater than 2 h above the stylus trap in an ultra-high-vacuum environment. After cooling a motional mode of the ion at 4 MHz close to its ground state ( = 0.34 ± 0.07), the heating rate of the trap was measured with Raman sideband spectroscopy to be 387 ± 15 quanta/s at an ion height of 62 μm above the stylus electrodes. PMID:24007096

  15. Quantum signature of discrete breathers in a nonlinear Klein-Gordon lattice with nearest and next-nearest neighbor interactions

    NASA Astrophysics Data System (ADS)

    Tang, Bing; Li, De-Jun

    2016-05-01

    A theoretical work on quantum breathers in a nonlinear Klein-Gordon lattice model with nearest and next-nearest neighbor interactions is presented. The semiclassical and the full quantum cases are respectively considered. For the semiclassical case, we obtain the analytical solution of discrete breather, and find that the wave number corresponding to the appearance of discrete breather changes when the ratio of the next-nearest- to -nearest - neighbor harmonic force constants is greater than 1/4. For the full quantum case, by calculating the energy spectrum of the system containing two quanta, we prove numerically the existence of quantum breathers (two-quanta bound states) and find the shape of energy spectrum changes dramatically as the value of next -nearest neighbor harmonic force constant increasing.

  16. Remnants, fuzzballs or wormholes?

    NASA Astrophysics Data System (ADS)

    Mathur, Samir D.

    2014-11-01

    The black hole information paradox has caused enormous confusion over four decades. But in recent years, the theorem of quantum strong-subadditivity has sorted out the possible resolutions into three sharp categories: (i) No new physics at r ≫ lp; this necessarily implies remnants/information loss. A realization of remnants is given by a baby universe attached near r 0. (ii) Violation of the "no-hair" theorem by nontrivial effects at the horizon r M. This possibility is realized by fuzzballs in string theory, and gives unitary evaporation. (iii) Having the vacuum at the horizon, but requiring that Hawking quanta at r M3 be somehow identified with degrees of freedom inside the black hole. A model for this "extreme nonlocality" is realized by conjecturing that wormholes connect the radiation quanta to the hole.

  17. Protocols and prospects for building a quantum repeater

    NASA Astrophysics Data System (ADS)

    van Loock, Peter

    2013-10-01

    An overview will be given of various approaches to implementing a quantum repeater for quantum communication over large distances. This includes a discussion of systems and protocols that are experimentally feasible and thus realizable in the midterm in order to go beyond the current limit of a few hundred km given by direct quantum-state transmissions. At the same time, these schemes should be, in principle, scalable to arbitrary distances. In this context, the influence of various elements and strategies in a quantum repeater protocol on the final fidelities and rates shall be addressed: initial entanglement distribution, Bell measurements, multiplexing, postselection, quantum memories, and quantum error detection/correction. Solely on the hardware side, the differences in using just single quanta or instead employing many quanta for the flying (photons) and the stationary (atoms) qubits will be pointed out.

  18. CH3D Near Infrared Cavity Ring-Down Spectrum Reanalysis and Ir-Ir Double Resonance

    NASA Astrophysics Data System (ADS)

    Yang, Shaoyue; Schwartz, George; Lehmann, Kevin

    2015-06-01

    As one of the most important hydrocarbon prototype molecules, CH3D's overtone band in near infrared region has not been well studied. Various methods were used to help identifying transitions from previous cavity ring down spectrum of CH3D in the near infrared region. Symmetric top molecules' Hamiltonian diagonal terms for the ground state, perpendicular state and parallel state were simulated by software PGopher. Combination differences were used to find possible pairs of transitions starting from adjacent ground state and ending in same excited states. Also we introduced our temperature controlled spectrum setup for ground state energy and rotational quanta prediction from temperature dependence, and proven to be working well for lower J levels for CH4. At last, we set up a double resonance system, using two lasers (3.3 and 1.65 μm, respectively) to excite transitions from the same ground state, to provide strong proof for the lower state quanta.

  19. Hawking radiation in the ghost condensate is nonthermal

    SciTech Connect

    Feldstein, Brian

    2008-09-15

    We consider a Schwarzschild black hole immersed in a ghost condensate background. It is shown that the Hawking radiation in the quanta of small perturbations around this background is highly suppressed - in particular, it is not given by a thermal spectrum. This result is in accord with observations that such black holes can be used to violate the generalized second law of thermodynamics, and thus cannot have a standard entropy/area relation.

  20. On-chip optical trapping for atomic applications

    NASA Astrophysics Data System (ADS)

    Perez, Maximillian A.; Salim, Evan; Farkas, Daniel; Duggan, Janet; Ivory, Megan; Anderson, Dana

    2014-09-01

    To simplify applications that rely on optical trapping of cold and ultracold atoms, ColdQuanta is developing techniques to incorporate miniature optical components onto in-vacuum atom chips. The result is a hybrid atom chip that combines an in-vacuum micro-optical bench for optical control with an atom chip for magnetic control. Placing optical components on a chip inside of the vacuum system produces a compact system that can be targeted to specific experiments, in this case the generation of optical lattices. Applications that can benefit from this technology include timekeeping, inertial sensing, gravimetry, quantum information, and emulation of quantum many-body systems. ColdQuanta's GlasSi atom chip technology incorporates glass windows in the plane of a silicon atom chip. In conjunction with the in-vacuum micro-optical bench, optical lattices can be generated within a few hundred microns of an atom chip window through which single atomic lattice sites can be imaged with sub-micron spatial resolution. The result is a quantum gas microscope that allows optical lattices to be studied at the level of single lattice sites. Similar to what ColdQuanta has achieved with magneto-optical traps (MOTs) in its miniMOT system and with Bose- Einstein condensates (BECs) in its RuBECi(R) system, ColdQuanta seeks to apply the on-chip optical bench technology to studies of optical lattices in a commercially available, turnkey system. These techniques are currently being considered for lattice experiments in NASA's Cold Atom Laboratory (CAL) slated for flight on the International Space Station.

  1. How accurately can we measure the hydrogen 2S→1S transition rate from the cosmological data?

    SciTech Connect

    Mukhanov, Viatcheslav; Kim, Jaiseung; Naselsky, Pavel; Trombetti, Tiziana; Burigana, Carlo E-mail: jkim@nbi.dk E-mail: trombetti@iasfbo.inaf.it

    2012-06-01

    Recent progress in observational cosmology, and especially the forthcoming PLANCK mission data, open new directions in so-called precision cosmology. In this paper we illustrate this statement considering the accuracy of cosmological determination of the two-quanta decay rate of 2s hydrogen atom state. We show that the PLANCK data will allow us to measure this decay rate significantly better than in the laboratory experiments.

  2. Mesoscopic Superposition States in Relativistic Landau Levels

    SciTech Connect

    Bermudez, A.; Martin-Delgado, M. A.; Solano, E.

    2007-09-21

    We show that a linear superposition of mesoscopic states in relativistic Landau levels can be built when an external magnetic field couples to a relativistic spin 1/2 charged particle. Under suitable initial conditions, the associated Dirac equation produces unitarily superpositions of coherent states involving the particle orbital quanta in a well-defined mesoscopic regime. We demonstrate that these mesoscopic superpositions have a purely relativistic origin and disappear in the nonrelativistic limit.

  3. Isotope-Identifying neutron reflectometry

    SciTech Connect

    Nikitenko, Yu. V. Petrenko, A. V.; Gundorin, N. A.; Gledenov, Yu. M.; Aksenov, V. L.

    2015-07-15

    The possibilities of an isotope-indentifying study of layered structures in different regimes of a neutron wave field are considered. The detection of specularly reflected neutrons and secondary radiation (caused by neutron capture) in the form of charged particles, γ quanta, and nuclear fission fragments, as well as neutrons spin-flipped in a noncollinear magnetic field and on nuclei of elements with spin, makes it possible to implement isotope-indentifying neutron reflectometry.

  4. New features of a single-mode nonlinear Stark shift in the presence of phase damping

    NASA Astrophysics Data System (ADS)

    Obada, A.-S. F.; Khalil, E. M.; Abdel-Khalek, S.; Ali, S. I.

    2012-05-01

    The influence of the nonlinear Stark shift, for the multi-quanta JCM in the presence of phase damping is studied. In particular the temporal evolution of the atomic inversion, the linear entropy and the entropy squeezing are investigated. The linear entropy is used as an indicator of the degree of entanglement between the atom and the field. The results indicate the sensitivity of these aspects to changes either in the decay parameter or the Stark shift parameter.

  5. Construction of a cosmic ray air shower telescope

    NASA Technical Reports Server (NTRS)

    Ng, L. K.; Chan, S. K.

    1985-01-01

    The telescope under construction is mainly for the purpose of locating the arrival directions of energetic particles and quanta which generate air showers of sizes 10 to the 5th power to 10 to the 6th power. Both fast timing method and visual track method are incorporated in determining the arrival directions. The telescope is composed of four stations using scintillators and neon flash tubes as detectors. The system directional resolution is better than 1.5 deg.

  6. An epitaph for all photons: a phoenix rising from its ashes

    NASA Astrophysics Data System (ADS)

    Rangacharyulu, C.

    2015-09-01

    It is argued that, unlike material particles, electromagnetic quanta are devoid of individual identities. Their birth and death are dictated by the conservation principles involving the interacting partners resulting in the emission or absorption. During their entire life, they restlessly propagate unnoticed by the media they pass through. An encounter with an interacting partner results in their demise. A photon lives and propagates as a phoenix with a successive photon arising from the ashes of its predecessor.

  7. Recording of relativistic particles in thin scintillators

    SciTech Connect

    Tolstukhin, I A.; Somov, Alexander S.; Somov, S. V.; Bolozdynya, A. I.

    2014-11-01

    Results of investigating an assembly of thin scintillators and silicon photomultipliers for registering relativistic particles with the minimum ionization are presented. A high efficiency of registering relativistic particles using an Ej-212 plastic scintillator, BSF-91A wavelength-shifting fiber (Saint-Gobain), and a silicon photomultiplier (Hamamtsu) is shown. The measurement results are used for creating a scintillation hodoscope of the magnetic spectrometer for registering γ quanta in the GlueX experiment.

  8. S Matrix Proof of Consistency Condition Derived from Mixed Anomaly

    NASA Astrophysics Data System (ADS)

    Bhansali, Vineer

    For a confining quantum field theory with conserved current J and stress tensor T, the and anomalies computed in terms of elementary quanta must be precisely equal to the same anomalies computed in terms of the exact physical spectrum if the conservation law corresponding to J is unbroken. These strongly constrain the allowed representations of the low energy spectrum. We present a proof of the latter consistency condition based on the proof by Coleman and Grossman of the former consistency condition.

  9. Acclimation to intense light implies changes at the level of trimeric subunits involved in the structural organization of the main light-harvesting complex of photosystem II (LHCII) and their isoforms.

    PubMed

    Timperio, Anna Maria; Gevi, Federica; Ceci, Luigi R; Zolla, Lello

    2012-01-01

    When plants are grown under stable light conditions their photosynthetic apparatus undergoes a long-term acclimation process. Acclimation to different light intensities involves changes in the organization and/or abundance of protein complexes in the thylakoid membranes. In this study, spinach plants were exposed to differing light intensities, and the structural organization of the major light-harvesting chlorophyll a/b-protein complex of photosystem II (LHCII) was investigated by analysing their trimeric subunits. Plants were exposed to three different light intensities, 100 μmol quanta m⁻² s⁻¹, 200 μmol quanta m⁻² s⁻¹ and an elevated light intensity, 400 μmol quanta m⁻² s⁻¹, sufficient to provoke a moderate stress response in the form of down regulation of PSII. "MicroRotofor" analysis showed the presence of LHCII with different pIs and revealed a clear decline in their abundance as light intensity increased from 100 to 400 μmol quanta m⁻² s⁻¹. The three subunits (Lhcb1, Lhcb2, Lhcb3) behaved differently from each other as: Lhcb1 decreased more significantly than Lhcb2, whereas Lhcb3 was reduced only at a light window at which Lhcb1 and Lhcb2 abundance has already been depleted under intense irradiation. Interestingly, we also found that isoforms of Lhcb1 subunit (Lhcb1.1; 1.2; 1.3) behaved differently in response to elevated light intensity, suggesting an essential role of these isoforms to light adaption and consequently explaining the presence of this multigenic family, often identified among higher plants. PMID:22099514

  10. The Measurement Of Conversion Noise In X-Ray Intensifying Screens

    NASA Astrophysics Data System (ADS)

    Trauernicht, David P.; Van Metter, Richard

    1988-06-01

    A significant source of noise in screen-film radiography results from the variation in light output of the screen for absorption of x-rays of equal energy. Two methods are described in the literature for measuring the statistics of the number of light quanta emitted for each absorbed x-ray. The coincidence method registers x-ray events by detecting temporally correlated light quanta. It is limited in its ability to see events having a small number of quanta and can be biased by non-Poisson photomultiplier dark events. The pulse height method uses pulse shaping to produce pulses whose height is proportional to the number of quanta. In this case small pulses may be lost in order to discriminate against photomultiplier dark counts. We present a new method, based on the synchronous detection of a chopped x-ray source, which has the potential to avoid these shortcomings. Analytical methods necessary to remove the effects of unwanted x-ray energy components (such as backscatter radiation from our x-ray fluorescent targets) are discussed which provide stable estimates of the first and second moments of the light emission statistics. The method is then used to obtain a new set of measurements of the light emission statistics (including the mean light output and Swank I factor) for samples of Kodak Lanex x-ray intensifying screens for mean incident x-ray energies of 14.4, 17.8, 27.9, 35.2, 42.1, 49.8, and 59.6 keV.

  11. Vibrationally highly excited molecules and intramolecular mode coupling through high-overtone spectroscopy

    SciTech Connect

    Wong, J.S.; Moore, C.B.

    1981-08-01

    High overtone spectra of organic molecules can be interpreted using the local mode model for absorptions by the inequivalent C-H bonds. The spectra can be assigned using either observed C-H bond lengths or isolated fundamental frequencies. The spectra of trihalomethanes indicate that the dominant intramolecular mode coupling for the C-H stretching overtones is Fermi resonance with combination states with one less C-H stretching quantum plus two quanta of the C-H bending vibrations.

  12. The relationship of CO2 assimilation pathways and photorespiration to the physiological quantum requirement of green plant photosynthesis.

    PubMed

    Campbell, W H; Black, C C

    1978-08-01

    The quantum requirement of green cells for CO2 fixation has been evaluated and discussed in view of the recent discovery of photorespiration and of multiple biochemical pathways for photosynthetic CO2 fixation. The reported quantum requirement of algae generally is near 9 quanta per CO2 fixed. It is suggested that the high CO2 concentrations and low O2 concentrations used for these algae experiments would have completely suppressed photorespiration and, therefore, the minimum number of quanta required to fix 1 CO2 molecule was correctly determined in these experiments. With higher plant leaves, when measurements are made under physiological environments, quantum requirements range from about 12 to 20 quanta per CO2 fixed. It is suggested that these physiological quantum requirements are higher because photorespiration is functional in these leaves and that photorespiration requires energy. The energy requirement of photorespiration was derived using biochemical models of leaf photosynthesis combining photorespiration with specific biochemical pathways for CO2 fixation. The calculated physiological quantum requirements for C3, C4 and CAM plant photosynthesis are 13, 15 and 17 respectively. The literature values on quantum requirements correspond well with these biochemical models of net photosynthesis. However, it was concluded that the biochemical models fail to give a complete description of photosynthesis in plants using the C4-dicarboxylic acid cycle. PMID:719139

  13. Topological growing of Laughlin states in synthetic gauge fields.

    PubMed

    Grusdt, Fabian; Letscher, Fabian; Hafezi, Mohammad; Fleischhauer, Michael

    2014-10-10

    We suggest a scheme for the preparation of highly correlated Laughlin states in the presence of synthetic gauge fields, realizing an analogue of the fractional quantum Hall effect in photonic or atomic systems of interacting bosons. It is based on the idea of growing such states by adding weakly interacting composite fermions along with magnetic flux quanta one by one. The topologically protected Thouless pump ("Laughlin's argument") is used to create two localized flux quanta and the resulting hole excitation is subsequently filled by a single boson, which, together with one of the flux quanta, forms a composite fermion. Using our protocol, filling 1/2 Laughlin states can be grown with particle number N increasing linearly in time and strongly suppressed number fluctuations. To demonstrate the feasibility of our scheme, we consider two-dimensional lattices subject to effective magnetic fields and strong on-site interactions. We present numerical simulations of small lattice systems and also discuss the influence of losses. PMID:25375718

  14. The quantal component of synaptic transmission from sensory hair cells to the vestibular calyx.

    PubMed

    Highstein, Stephen M; Mann, Mary Anne; Holstein, Gay R; Rabbitt, Richard D

    2015-06-01

    Spontaneous and stimulus-evoked excitatory postsynaptic currents (EPSCs) were recorded in calyx nerve terminals from the turtle vestibular lagena to quantify key attributes of quantal transmission at this synapse. On average, EPSC events had a magnitude of ∼ 42 pA, a rise time constant of τ(0) ∼ 229 μs, decayed to baseline with a time constant of τ(R) ∼ 690 μs, and carried ∼ 46 fC of charge. Individual EPSCs varied in magnitude and decay time constant. Variability in the EPSC decay time constant was hair cell dependent and due in part to a slow protraction of the EPSC in some cases. Variability in EPSC size was well described by an integer summation of unitary quanta, with each quanta of glutamate gating a unitary postsynaptic current of ∼ 23 pA. The unitary charge was ∼ 26 fC for EPSCs with a simple exponential decay and increased to ∼ 48 fC for EPSCs exhibiting a slow protraction. The EPSC magnitude and the number of simultaneous unitary quanta within each event increased with presynaptic stimulus intensity. During tonic hair cell depolarization, both the EPSC magnitude and event rate exhibited adaptive run down over time. Present data from a reptilian calyx are remarkably similar to noncalyceal vestibular synaptic terminals in diverse species, indicating that the skewed EPSC size distribution and multiquantal release might be an ancestral property of inner ear ribbon synapses. PMID:25878150

  15. Helical mode and supercurrent measured on the topological surface states of Bi2Te3 nanoribbon field effect devices

    NASA Astrophysics Data System (ADS)

    Jauregui, Luis A.; Pettes, Michael T.; Shi, Li; Rokhinson, Leonid P.; Chen, Yong P.

    2014-03-01

    Topological superconductivity can be proximity induced by coupling s-wave superconductors with spin-helical electron systems, such as the surface of 3D topological insulators (TIs), where the energy bands follow Dirac dispersion and the electronic states possess helical spin-momentum locking. We have grown Bi2Te3 nanoribbons (NRs) by vapor liquid solid method and characterized their crystalline structure by TEM and Raman spectroscopy. We fabricate backgated field effect devices where the chemical potential (μ) can be tuned from bulk bands to surface states and ambipolar field effect has been observed. The temperature dependence of the resistance and Shubnikov de Haas oscillations show suppressed bulk conduction with surface conduction dominating and a pi-Berry's phase. The Aharonov-Bohm oscillations (ABO), measured with a magnetic field parallel to the NR axis, have a period equal to one flux quanta with conductance maxima at half flux quanta (pi-ABO), for μ close to the charge neutrality point. Such pi-ABO is a direct evidence of the existence of 1D helical modes at half flux quanta. We have also fabricated Josephson junctions on our TI NR devices with inter-electrode separations up to 200 nm, and measured supercurrent with a proximity induced gap of 0.5meV at 0.25K.

  16. The quantal component of synaptic transmission from sensory hair cells to the vestibular calyx

    PubMed Central

    Highstein, Stephen M.; Mann, Mary Anne; Holstein, Gay R.

    2015-01-01

    Spontaneous and stimulus-evoked excitatory postsynaptic currents (EPSCs) were recorded in calyx nerve terminals from the turtle vestibular lagena to quantify key attributes of quantal transmission at this synapse. On average, EPSC events had a magnitude of ∼42 pA, a rise time constant of τ0 ∼229 μs, decayed to baseline with a time constant of τR ∼690 μs, and carried ∼46 fC of charge. Individual EPSCs varied in magnitude and decay time constant. Variability in the EPSC decay time constant was hair cell dependent and due in part to a slow protraction of the EPSC in some cases. Variability in EPSC size was well described by an integer summation of unitary quanta, with each quanta of glutamate gating a unitary postsynaptic current of ∼23 pA. The unitary charge was ∼26 fC for EPSCs with a simple exponential decay and increased to ∼48 fC for EPSCs exhibiting a slow protraction. The EPSC magnitude and the number of simultaneous unitary quanta within each event increased with presynaptic stimulus intensity. During tonic hair cell depolarization, both the EPSC magnitude and event rate exhibited adaptive run down over time. Present data from a reptilian calyx are remarkably similar to noncalyceal vestibular synaptic terminals in diverse species, indicating that the skewed EPSC size distribution and multiquantal release might be an ancestral property of inner ear ribbon synapses. PMID:25878150

  17. Some evidence for high energy gamma-ray sources at large galactic latitudes

    NASA Technical Reports Server (NTRS)

    Stamenov, J. N.; Karakula, S.; Tkaczyk, W.

    1985-01-01

    The arrival directions of the gamma-quanta with energies of about 10 to 15th power eV which were registrated by Tien Shan experiment were compared with COS-B observations. On the basis of the Monte Carlo simulations it was shown with low probability that arrival directions of Tien Shan gamma-quanta initiated showers are not uniformly distributed. It is shown that in the region not seen by COS-B mission, the high energy gamma-ray sources should be located at position of 90 deg. 1 sup 11 130 deg and b sup 11 or = 50 deg. The integral intensity of these sources should be I ( 10 to the 15th power eV) = 4.8 + or - 1.7).10 to the 13th power/sq cm/s/str. There is no coincidence between the gamma-quanta registrated by Tien Shan experiment with Geminga intense COS-B gamma source. So it is shown that the integral photon spectrum of Geminga (I(e) approx E sup-Beta, where Beta = 0.8 for E 1 GeV) becomes steeper (Beta 1.2) in high energy region with probability 99.9.%.

  18. Non-linear optical diagnostic studies of high pressure non-equilibrium plasmas

    NASA Astrophysics Data System (ADS)

    Lempert, Walter

    2012-10-01

    Picosecond Coherent Anti-Stokes Raman Spectroscopy (CARS) is used for study of vibrational energy loading and relaxation kinetics in high pressure nitrogen and air nsec pulsed non-equilibrium plasmas in a pin-to-pin geometry. It is found that ˜33% of total discharge energy in a single pulse in air at 100 torr couples directly to nitrogen vibration by electron impact, in good agreement with master equation modeling predictions. However in the afterglow the total quanta in vibrational levels 0 -- 9 is found to increase by a factor of approximately 2 and 4 in nitrogen and air, respectively, a result in direct contrast to modeling results which predict the total number of quanta to be essentially constant. More detailed comparison between experiment and model show that the VDF predicted by the model during, and directly after, the discharge pulse is in good agreement with that determined experimentally, however for time delays exceeding ˜10 μsec the experimental and predicted VDFs diverge rapidly, particularly for levels v = 2 and greater. Specifically modeling predicts a rapid drop in population of high levels due to net downward V-V energy transfer whereas the experiment shows an increase in population in levels 2 and 3 and approximately constant population for higher levels. It is concluded that a collisional process is feeding high vibrational levels at a rate which is comparable to the rate at which population of the high levels is lost due to net downward V-V. A likely candidate for the source of additional vibrational quanta is the quenching of metastable electronic states of nitrogen to highly excited vibrational levels of the ground electronic state. Recent progress in the development and application of psec coherent Raman electric field and spontaneous Thomson scattering diagnostics for study of high pressure nsec pulsed plasmas will also be presented.

  19. DNA copy number concentration measured by digital and droplet digital quantitative PCR using certified reference materials.

    PubMed

    Corbisier, Philippe; Pinheiro, Leonardo; Mazoua, Stéphane; Kortekaas, Anne-Marie; Chung, Pui Yan Jenny; Gerganova, Tsvetelina; Roebben, Gert; Emons, Hendrik; Emslie, Kerry

    2015-03-01

    The value assignment for properties of six certified reference materials (ERM-AD623a-f), each containing a plasmid DNA solution ranging from 1 million to 10 copies per μL, by using digital PCR (dPCR) with the BioMark™ HD System (Fluidigm) has been verified by applying droplet digital PCR (ddPCR) using the QX100 system (Bio-Rad). One of the critical factors in the measurement of copy number concentrations by digital PCR is the partition volume. Therefore, we determined the average droplet volume by optical microscopy, revealing an average droplet volume that is 8 % smaller than the droplet volume used as the defined parameter in the QuantaSoft software version 1.3.2.0 (Bio-Rad) to calculate the copy number concentration. This observation explains why copy number concentrations estimated with ddPCR and using an average droplet volume predefined in the QuantaSoft software were systematically lower than those measured by dPCR, creating a significant bias between the values obtained by these two techniques. The difference was not significant anymore when the measured droplet volume of 0.834 nL was used to estimate copy number concentrations. A new version of QuantaSoft software (version 1.6.6.0320), which has since been released with Bio-Rad's new QX200 systems and QX100 upgrades, uses a droplet volume of 0.85 nL as a defined parameter to calculate copy number concentration. PMID:25600685

  20. Response of chlorophyll d-containing cyanobacterium Acaryochloris marina to UV and visible irradiations.

    PubMed

    Hou, Xuejing; Raposo, Aaron; Hou, Harvey J M

    2013-11-01

    We have previously investigated the response mechanisms of photosystem II complexes from spinach to strong UV and visible irradiations (Wei et al J Photochem Photobiol B 104:118-125, 2011). In this work, we extend our study to the effects of strong light on the unusual cyanobacterium Acaryochloris marina, which is able to use chlorophyll d (Chl d) to harvest solar energy at a longer wavelength (740 nm). We found that ultraviolet (UV) or high level of visible and near-far red light is harmful to A. marina. Treatment with strong white light (1,200 μmol quanta m(-2) s(-1)) caused a parallel decrease in PSII oxygen evolution of intact cells and in extracted pigments Chl d, zeaxanthin, and α-carotene analyzed by high-performance liquid chromatography, with severe loss after 6 h. When cells were irradiated with 700 nm of light (100 μmol quanta m(-2) s(-1)) there was also bleaching of Chl d and loss of photosynthetic activity. Interestingly, UVB radiation (138 μmol quanta m(-2) s(-1)) caused a loss of photosynthetic activity without reduction in Chl d. Excess absorption of light by Chl d (visible or 700 nm) causes a reduction in photosynthesis and loss of pigments in light harvesting and photoprotection, likely by photoinhibition and inactivation of photosystem II, while inhibition of photosynthesis by UVB radiation may occur by release of Mn ion(s) in Mn4CaO5 center in photosystem II. PMID:24158260

  1. Energy budget for the cultured, zooxanthellate octocoral Sinularia flexibilis.

    PubMed

    Khalesi, Mohammad K; Beeftink, H H; Wijffels, R H

    2011-12-01

    The zooxanthellate octocoral Sinularia flexibilis is a producer of potential pharmaceutically important metabolites such as antimicrobial and cytotoxic substances. Controlled rearing of the coral, as an alternative for commercial exploitation of these compounds, requires the study of species-specific growth requirements. In this study, phototrophic vs. heterotrophic daily energy demands of S. flexibilis was investigated through light and Artemia feeding trials in the laboratory. Rate of photosynthetic oxygen by zooxanthellae in light (≈200 μmol quanta m⁻² s⁻¹) was measured for the coral colonies with and without feeding on Artemia nauplii. Respiratory oxygen was measured in the dark, again with and without Artemia nauplii. Photosynthesis-irradiance curve at light intensities of 0, 50, 100, 200, and 400 μmol quanta m⁻² s⁻¹ showed an increase in photosynthetic oxygen production up to a light intensity between 100 and 200 μmol quanta m⁻² s⁻¹. The photosynthesis to respiration ratio (P/R > 1) confirmed phototrophy of S. flexibilis. Both fed and non-fed colonies in the light showed high carbon contribution by zooxanthellae to animal (host) respiration values of 111-127%. Carbon energy equivalents allocated to the coral growth averaged 6-12% of total photosynthesis energy (mg C g⁻¹ buoyant weight day⁻¹ and about 0.02% of the total daily radiant energy. "Light utilization efficiency (ε)" estimated an average ε value of 75% 12 h⁻¹ for coral practical energetics. This study shows that besides a fundamental role of phototrophy vs. heterotrophy in daily energy budget of S. flexibilis, an efficient fraction of irradiance is converted to useable energy. PMID:21537947

  2. Einstein's Revolutionary Light-Quantum Hypothesis

    NASA Astrophysics Data System (ADS)

    Stuewer, Roger H.

    2005-05-01

    The paper in which Albert Einstein proposed his light-quantum hypothesis was the only one of his great papers of 1905 that he himself termed ``revolutionary.'' Contrary to widespread belief, Einstein did not propose his light-quantum hypothesis ``to explain the photoelectric effect.'' Instead, he based his argument for light quanta on the statistical interpretation of the second law of thermodynamics, with the photoelectric effect being only one of three phenomena that he offered as possible experimental support for it. I will discuss Einstein's light-quantum hypothesis of 1905 and his introduction of the wave-particle duality in 1909 and then turn to the reception of his work on light quanta by his contemporaries. We will examine the reasons that prominent physicists advanced to reject Einstein's light-quantum hypothesis in succeeding years. Those physicists included Robert A. Millikan, even though he provided convincing experimental proof of the validity of Einstein's equation of the photoelectric effect in 1915. The turning point came after Arthur Holly Compton discovered the Compton effect in late 1922, but even then Compton's discovery was contested both on experimental and on theoretical grounds. Niels Bohr, in particular, had never accepted the reality of light quanta and now, in 1924, proposed a theory, the Bohr-Kramers-Slater theory, which assumed that energy and momentum were conserved only statistically in microscopic interactions. Only after that theory was disproved experimentally in 1925 was Einstein's revolutionary light-quantum hypothesis generally accepted by physicists---a full two decades after Einstein had proposed it.

  3. Loss of quantum yield in extremely low light.

    PubMed

    Kirschbaum, Miko U F; Ohlemacher, Christian; Küppers, Manfred

    2004-04-01

    It has generally been assumed that the photosynthetic quantum yield of all C3 plants is essentially the same for all unstressed leaves at the same temperature and CO2 and O2 concentrations. However, some recent work by H.C. Timm et al. (2002, Trees 16:47-62) has shown that quantum yield can be reduced for some time after leaves have been exposed to darkness. To investigate under what light conditions quantum yield can be reduced, we carried out a number of experiments on leaves of a partial-shade (unlit greenhouse)-grown Coleus blumei Benth. hybrid. We found that after leaves had been exposed to complete darkness, quantum yield was reduced by about 60%. Only very low light levels were needed for quantum yield to be fully restored, with 5 micromol quanta m(-2) s(-1) being sufficient for 85% of the quantum yield of fully induced leaves to be achieved. Leaves regained higher quantum yields upon exposure to higher light levels with an estimated time constant of 130 s. It was concluded that the loss of quantum yield would be quantitatively important only for leaves growing in very dense understoreys where maximum light levels might not exceed 5 micromol quanta m(-2) s(-1) even in the middle of the day. Most leaves, even in understorey conditions, do, however, experience light levels in excess of 5 micromol quanta m(-2) s(-1) over periods where they obtain most of their carbon so that the loss of quantum yield would affect total carbon gain of those leaves only marginally. PMID:14722771

  4. Growth of the C4 dicot Flaveria bidentis: photosynthetic acclimation to low light through shifts in leaf anatomy and biochemistry

    PubMed Central

    Pengelly, Jasper J. L.; Sirault, Xavier R. R.; Tazoe, Youshi; Evans, John R.; Furbank, Robert T.; von Caemmerer, Susanne

    2010-01-01

    In C4 plants, acclimation to growth at low irradiance by means of anatomical and biochemical changes to leaf tissue is considered to be limited by the need for a close interaction and coordination between bundle sheath and mesophyll cells. Here differences in relative growth rate (RGR), gas exchange, carbon isotope discrimination, photosynthetic enzyme activity, and leaf anatomy in the C4 dicot Flaveria bidentis grown at a low (LI; 150 μmol quanta m2 s−1) and medium (MI; 500 μmol quanta m2 s−1) irradiance and with a 12 h photoperiod over 36 d were examined. RGRs measured using a 3D non-destructive imaging technique were consistently higher in MI plants. Rates of CO2 assimilation per leaf area measured at 1500 μmmol quanta m2 s−1 were higher for MI than LI plants but did not differ on a mass basis. LI plants had lower Rubisco and phosphoenolpyruvate carboxylase activities and chlorophyll content on a leaf area basis. Bundle sheath leakiness of CO2 (ϕ) calculated from real-time carbon isotope discrimination was similar for MI and LI plants at high irradiance. ϕ increased at lower irradiances, but more so in MI plants, reflecting acclimation to low growth irradiance. Leaf thickness and vein density were greater in MI plants, and mesophyll surface area exposed to intercellular airspace (Sm) and bundle sheath surface area per unit leaf area (Sb) measured from leaf cross-sections were also both significantly greater in MI compared with LI leaves. Both mesophyll and bundle sheath conductance to CO2 diffusion were greater in MI compared with LI plants. Despite being a C4 species, F. bidentis is very plastic with respect to growth irradiance. PMID:20693408

  5. Thermoelectric voltage measurements of atomic and molecular wires using microheater-embedded mechanically-controllable break junctions

    NASA Astrophysics Data System (ADS)

    Morikawa, Takanori; Arima, Akihide; Tsutsui, Makusu; Taniguchi, Masateru

    2014-06-01

    We developed a method for simultaneous measurements of conductance and thermopower of atomic and molecular junctions by using a microheater-embedded mechanically-controllable break junction. We find linear increase in the thermoelectric voltage of Au atomic junctions with the voltage added to the heater. We also detect thermopower oscillations at several conductance quanta reflecting the quantum confinement effects in the atomic wire. Under high heater voltage conditions, on the other hand, we observed a peculiar behaviour in the conductance dependent thermopower, which was ascribed to a disordered contact structure under elevated temperatures.

  6. Substantiation of the mechanism of biphoton nonresonance excitation of molecules of bacteriochlorophyll of purple bacteria by femtosecond pulses

    NASA Astrophysics Data System (ADS)

    Borisov, A. Yu.

    2010-11-01

    In a series of published experimental works, there has been observed nonresonance biphoton excitation, by femtosecond IR pulses (1250-1500 nm) of molecules of bacteriochlorophyll-a and the pigment in the composition of light-absorbing natural "antenna" complexes of photosynthesizing purple bacteria. The authors of these works believe that IR quanta excite hypothetical forbidden levels of pigments of these bacteria in the dual frequency range of 625-750 nm. In this study, an alternative mechanism of intramolecular electron transport apparently responsible for this phenomenon is suggested and substantiated. The mechanism should manifest itself in powerful electric fields, which are achieved in the pulses of picofemtosecond lasers.

  7. 6300 A quantum efficiency of the recombination mechanism in the night-time F layer.

    NASA Technical Reports Server (NTRS)

    Brown, W. E.; Steiger, W. R.

    1972-01-01

    Simultaneous airglow and electron content measurements made at Hawaii are used to infer the number of 6300 and 6364 A quanta produced per electron lost in the nighttime F layer of the ionosphere. The equation of continuity of electrons is then solved numerically to obtain the electron density profile, and the amount of quenching is estimated. This leads to the number of excitations of O(super-1 D) per O2(+) recombination (epsilon). We find, for an exospheric temperature of 1100 K, epsilon is equal to 1.1 plus or minus 0.6, in good agreement with Zipf's laboratory measurement at 300 K.

  8. Davydov solitons in polypeptides

    SciTech Connect

    Scott, A.

    1984-10-01

    The experimental evidence for self-trapping of amide-I (CO stretching) vibrational energy in crystalline acetanilide (a model protein) is reviewed and related to A. S. Davydov's theory of solitons as a mechanism for energy storage and transport in protein. Particular attention is paid to the construction of quantum states that contain N amide-I vibrational quanta. It is noted that the N = 2 state is almost exactly resonant with the free energy that is released upon hydrolysis of adenosine triphosphate. 30 references, 4 figures, 3 tables.

  9. Davydov Solitons in Polypeptides

    NASA Astrophysics Data System (ADS)

    Scott, A. C.

    1985-08-01

    The experimental evidence for self-trapping of amide-I (CO stretching) vibrational energy in crystalline acetanilide (a model protein) is reviewed and related to A. S. Davydov's theory of solitons as a mechanism for energy storage and transport in protein. Particular attention is paid to the construction of quantum states that contain N amide-I vibrational quanta. It is noted that the `N = 2' state is almost exactly resonant with the free energy that is released upon hydrolysis of adenosine triphosphate.

  10. Study of cluster structure in 13C with AMD+HON-constraint method

    NASA Astrophysics Data System (ADS)

    Chiba, Yohei; Kimura, Masaaki

    2014-12-01

    The 3α + n cluster states of 13C are discussed on the basis of antisymmetrized molecular dynamics with the constraint on the harmonic oscillator quanta. We predict two different kinds of the cluster states, the hoyle analogue state and the linear-chain state. The former is understood as the 0+2 state (Hoyle state) of 12C accompanied by a valence neutron occupying the s-wave. The latter constitute the parity doublet bands of Kπ = 1/2± owing to its parity asymmetric intrinsic structure.

  11. Families of solutions to the generalized Ginzburg-Landau equation and structural transitions between them

    SciTech Connect

    Ovchinnikov, Yu. N.

    2013-09-15

    Solutions to the generalized Ginzburg-Landau equations for superconductors are obtained for a Ginzburg-Landau parameter {kappa} close to unity. The families of solutions with arbitrary number n of flux quanta in a unit cell are analyzed. It is shown that under certain conditions, a cascade of phase transitions between different structures in a magnetic field appears near T{sub c}. Algebraic equations are derived for determining the boundaries of coexistence of different phases on the (T, H{sub 0}) plane.

  12. Search for resonant absorption of solar axions emitted in M1 transition in 57Fe nuclei

    NASA Astrophysics Data System (ADS)

    Derbin, A. V.; Egorov, A. I.; Mitropol'Sky, I. A.; Muratova, V. N.; Semenov, D. A.; Unzhakov, E. V.

    2009-08-01

    A search for resonant absorption of 14.4 keV solar axions by a 57Fe target was performed. The Si(Li) detector placed inside the low-background setup was used to detect the γ-quanta appearing in the deexcitation of the 14.4 keV nuclear level: A+57Fe→57Fe*→57Fe+ γ. The new upper limit for the hadronic axion mass has been obtained of m A ≤159 eV (95% c.l.) ( S=0.5, z=0.56).

  13. Higher Dimensional Spacetimes for Visualizing and Modeling Subluminal, Luminal and Superluminal Flight

    SciTech Connect

    Froning, H. David; Meholic, Gregory V.

    2010-01-28

    This paper briefly explores higher dimensional spacetimes that extend Meholic's visualizable, fluidic views of: subluminal-luminal-superluminal flight; gravity, inertia, light quanta, and electromagnetism from 2-D to 3-D representations. Although 3-D representations have the potential to better model features of Meholic's most fundamental entities (Transluminal Energy Quantum) and of the zero-point quantum vacuum that pervades all space, the more complex 3-D representations loose some of the clarity of Meholic's 2-D representations of subluminal and superlumimal realms. So, much new work would be needed to replace Meholic's 2-D views of reality with 3-D ones.

  14. Magnetic calorimeter with a SQUID for detecting weak radiations and recording the ultralow energy release

    SciTech Connect

    Golovashkin, Aleksander I; Zherikhina, L N; Kuleshova, G V; Tskhovrebov, A M; Izmailov, G N

    2006-12-31

    The scheme of a magnetic calorimeter for recording extremely low energy releases is developed. The calorimeter is activated by the method of adiabatic demagnetisation and its response to the energy release is measured with a superconducting quantum interference device (SQUID). The estimate of the ultimate sensitivity of the calorimeter with the SQUID demonstrates the possibilities of its application for detecting ultralow radiation intensity, recording single X-ray quanta in the proportional regime and other events with ultralow energy releases. The scheme of the calorimeter with the SQUID on matter waves in superfluid {sup 4}He is proposed. (radiation detectors)

  15. Calculation of the Coulomb Fission Cross Sections for Pb-Pb and Bi-Pb Interactions at 158 A GeV

    NASA Technical Reports Server (NTRS)

    Poyser, William J.; Ahern, Sean C.; Norbury, John W.; Tripathi, R. K.

    2002-01-01

    The Weizsacker-Williams (WW) method of virtual quanta is used to make approximate cross section calculations for peripheral relativistic heavy-ion collisions. We calculated the Coulomb fission cross sections for projectile ions of Pb-208 and Bi-209 with energies of 158 A GeV interacting with a Pb-208 target. We also calculated the electromagnetic absorption cross section for Pb-208 ion interacting as described. For comparison we use both the full WW method and a standard approximate WW method. The approximate WW method in larger cross sections compared to the more accurate full WW method.

  16. Examples of the Zeroth Theorem of the History of Science

    SciTech Connect

    Jackson, J.D.

    2007-08-24

    The zeroth theorem of the history of science, enunciated byE. P. Fischer, states that a discovery (rule,regularity, insight) namedafter someone (often) did not originate with that person. I present fiveexamples from physics: the Lorentz condition partial muAmu = 0 definingthe Lorentz gauge of the electromagnetic potentials; the Dirac deltafunction, delta(x); the Schumann resonances of the earth-ionospherecavity; the Weizsacker-Williams method of virtual quanta; the BMTequation of spin dynamics. I give illustrated thumbnail sketches of boththe true and reputed discoverers and quote from their "discovery"publications.

  17. Vibrationally resolved molecular-frame angular distribution of O 1s photoelectrons from CO{sub 2} molecules

    SciTech Connect

    Saito, N.; Morishita, Y.; Suzuki, I.H.; Liu, X-J.; Pruemper, G.; Ueda, K.; Machida, M.; Oura, M.; Yamaoka, H.; Tamenori, Y.; Koyano, I.

    2005-10-15

    Vibrationally resolved O 1s photoelectron angular distributions from CO{sub 2} molecules, aligned parallel and perpendicular to the electric vector of the incident light, have been measured in the 5{sigma}{sub g}* shape resonance region, with photon energies up to 2 eV above the O 1s ionization threshold, using multiple-coincidence electron-ion momentum imaging spectroscopy. The angular distributions depend on the vibrational quanta of the antisymmetric vibrations in the O 1s ionized state but do not vary significantly as a function of the photon energy across the 5{sigma}{sub g}* shape resonance.

  18. Hydrogenic Rydberg States of Molecular van der Waals Complexes: Resolved Rydberg Spectroscopy of DABCO-N2

    NASA Astrophysics Data System (ADS)

    Cockett, Martin C.; Watkins, Mark J.

    2004-01-01

    The complementary threshold ionization techniques of MATI and ZEKE spectroscopy have been used to reveal well-resolved, long-lived (>10 μs) hydrogenic Rydberg series (50≤n≤98) in a van der Waals complex formed between a polyatomic molecule and a diatomic molecule for the first time. The series are observed within 50 cm-1 of the adiabatic ionization threshold as well as two core-excited thresholds corresponding to excitation of up to two quanta in the van der Waals vibra­tional mode.

  19. Single Photon Counting Performance and Noise Analysis of CMOS SPAD-Based Image Sensors.

    PubMed

    Dutton, Neale A W; Gyongy, Istvan; Parmesan, Luca; Henderson, Robert K

    2016-01-01

    SPAD-based solid state CMOS image sensors utilising analogue integrators have attained deep sub-electron read noise (DSERN) permitting single photon counting (SPC) imaging. A new method is proposed to determine the read noise in DSERN image sensors by evaluating the peak separation and width (PSW) of single photon peaks in a photon counting histogram (PCH). The technique is used to identify and analyse cumulative noise in analogue integrating SPC SPAD-based pixels. The DSERN of our SPAD image sensor is exploited to confirm recent multi-photon threshold quanta image sensor (QIS) theory. Finally, various single and multiple photon spatio-temporal oversampling techniques are reviewed. PMID:27447643

  20. Role of fluctuations in the quantal description of damped motion

    SciTech Connect

    Hernandez, E.S.

    1980-01-01

    The construction of a frictional time-dependent Schroedinger equation is reviewed for harmonic motion in a restricted framework, i.e., demanding the conservation of the Gaussian shape of wave packets. The evolution of the quanta fluctuations is discussed in a time-independent model, and it is shown that such a situation does not correspond to damped harmonic oscillations. The role of fluctuations in providing dissipative behavior is discussed and the time evolution of arbitrary wave functions subject to damped motion as described by Schroedinger-Kostin equation is analyzed in detail.

  1. A Selenium-Based Detector System For Digital Slot-Radiography

    NASA Astrophysics Data System (ADS)

    Hillen, W.; Schiebel, U.; Zaengel, T.

    1988-06-01

    A research system for digital radiography is described, which is based on a selenium detector with capacitive probe readout. The detector, in which a selenium drum is used as the primary image receptor, is exposed by a scanning fan beam. Scatter reduction and primary transmission by slot-radiography as well as the imaging properties of the selenium detector are discussed. The spatial resolution and the noise behaviour of the detector are analysed. The signal-to-noise ratios expressed in terms of noise equivalent quanta and detective quantum efficiency are calculated and compared with competitive systems.

  2. Classical Physics and the Bounds of Quantum Correlations.

    PubMed

    Frustaglia, Diego; Baltanás, José P; Velázquez-Ahumada, María C; Fernández-Prieto, Armando; Lujambio, Aintzane; Losada, Vicente; Freire, Manuel J; Cabello, Adán

    2016-06-24

    A unifying principle explaining the numerical bounds of quantum correlations remains elusive, despite the efforts devoted to identifying it. Here, we show that these bounds are indeed not exclusive to quantum theory: for any abstract correlation scenario with compatible measurements, models based on classical waves produce probability distributions indistinguishable from those of quantum theory and, therefore, share the same bounds. We demonstrate this finding by implementing classical microwaves that propagate along meter-size transmission-line circuits and reproduce the probabilities of three emblematic quantum experiments. Our results show that the "quantum" bounds would also occur in a classical universe without quanta. The implications of this observation are discussed. PMID:27391707

  3. Zero-Area Single-Photon Pulses.

    PubMed

    Costanzo, L S; Coelho, A S; Pellegrino, D; Mendes, M S; Acioli, L; Cassemiro, K N; Felinto, D; Zavatta, A; Bellini, M

    2016-01-15

    Broadband single photons are usually considered not to couple efficiently to atomic gases because of the large mismatch in bandwidth. Contrary to this intuitive picture, here we demonstrate that the interaction of ultrashort single photons with a dense resonant atomic sample deeply modifies the temporal shape of their wave packet mode without degrading their nonclassical character, and effectively generates zero-area single-photon pulses. This is a clear signature of strong transient coupling between single broadband (THz-level) light quanta and atoms, with intriguing fundamental implications and possible new applications to the storage of quantum information. PMID:26824539

  4. Quantum random flip-flop and its applications in random frequency synthesis and true random number generation.

    PubMed

    Stipčević, Mario

    2016-03-01

    In this work, a new type of elementary logic circuit, named random flip-flop (RFF), is proposed, experimentally realized, and studied. Unlike conventional Boolean logic circuits whose action is deterministic and highly reproducible, the action of a RFF is intentionally made maximally unpredictable and, in the proposed realization, derived from a fundamentally random process of emission and detection of light quanta. We demonstrate novel applications of RFF in randomness preserving frequency division, random frequency synthesis, and random number generation. Possible usages of these applications in the information and communication technology, cryptographic hardware, and testing equipment are discussed. PMID:27036825

  5. Quantum random flip-flop and its applications in random frequency synthesis and true random number generation

    NASA Astrophysics Data System (ADS)

    Stipčević, Mario

    2016-03-01

    In this work, a new type of elementary logic circuit, named random flip-flop (RFF), is proposed, experimentally realized, and studied. Unlike conventional Boolean logic circuits whose action is deterministic and highly reproducible, the action of a RFF is intentionally made maximally unpredictable and, in the proposed realization, derived from a fundamentally random process of emission and detection of light quanta. We demonstrate novel applications of RFF in randomness preserving frequency division, random frequency synthesis, and random number generation. Possible usages of these applications in the information and communication technology, cryptographic hardware, and testing equipment are discussed.

  6. [Quantum processes in evolution of regulation of living system (mathematical modelling)].

    PubMed

    Menshutkin, V V; Natochin, Iu V

    2011-01-01

    We have developed an imitation model of the appearance of regulation of physiological functions of protocell at the initial stages of evolution of living system. It is based on suggestion of the appearance of signal function in spontaneously formed products of partial hydrolysis of the protocell polypeptides, based on which there appear the regulatory molecules--quanta of regulation. For construction of the model, the mathematical apparatus of final automats and of genetic algorithm is used. The model has demonstrated the positive role of involvement of regulatory peptides in the system of regulation of protocell functions to provide its viability under the changing envelopment conditions. PMID:21780648

  7. Control and readout of current-induced magnetic flux quantization in a superconducting transformer

    NASA Astrophysics Data System (ADS)

    Kerner, C.; Hackens, B.; Golubović, D. S.; Poli, S.; Faniel, S.; Magnus, W.; Schoenmaker, W.; Bayot, V.; Maes, H.

    2009-02-01

    We demonstrate a simple and robust method for inducing and detecting changes of magnetic flux quantization in the absence of an externally applied magnetic field. In our device, an isolated ring is interconnected with two access loops via permalloy cores, forming a superconducting transformer. By applying and tuning a direct current at the first access loop, the number of flux quanta trapped in the isolated ring is modified without the aid of an external field. The flux state of the isolated ring is simply detected by recording the evolution of the critical current of the second access loop.

  8. Einstein-Podolsky-Rosen-Bohm experiment and Bell inequality violation using Type 2 parametric down conversion

    NASA Technical Reports Server (NTRS)

    Kiess, Thomas E.; Shih, Yan-Hua; Sergienko, A. V.; Alley, Carroll O.

    1994-01-01

    We report a new two-photon polarization correlation experiment for realizing the Einstein-Podolsky-Rosen-Bohm (EPRB) state and for testing Bell-type inequalities. We use the pair of orthogonally-polarized light quanta generated in Type 2 parametric down conversion. Using 1 nm interference filters in front of our detectors, we observe from the output of a 0.5mm beta - BaB2O4 (BBO) crystal the EPRB correlations in coincidence counts, and measure an associated Bell inequality violation of 22 standard deviations. The quantum state of the photon pair is a polarization analog of the spin-1/2 singlet state.

  9. Trojan horse attack free fault-tolerant quantum key distribution protocols

    NASA Astrophysics Data System (ADS)

    Yang, Chun-Wei; Hwang, Tzonelih

    2013-11-01

    This work proposes two quantum key distribution (QKD) protocols—each of which is robust under one kind of collective noises—collective-dephasing noise and collective-rotation noise. Due to the use of a new coding function which produces error-robust codewords allowing one-time transmission of quanta, the proposed QKD schemes are fault-tolerant and congenitally free from Trojan horse attacks without having to use any extra hardware. Moreover, by adopting two Bell state measurements instead of a 4-GHZ state joint measurement for decoding, the proposed protocols are practical in combating collective noises.

  10. Splash, pop, sizzle: Information processing with phononic computing

    SciTech Connect

    Sklan, Sophia R.

    2015-05-15

    Phonons, the quanta of mechanical vibration, are important to the transport of heat and sound in solid materials. Recent advances in the fundamental control of phonons (phononics) have brought into prominence the potential role of phonons in information processing. In this review, the many directions of realizing phononic computing and information processing are examined. Given the relative similarity of vibrational transport at different length scales, the related fields of acoustic, phononic, and thermal information processing are all included, as are quantum and classical computer implementations. Connections are made between the fundamental questions in phonon transport and phononic control and the device level approach to diodes, transistors, memory, and logic. .

  11. Estimation of composition of cosmic rays with E sub zero approximately equals 10(17) - 10(18) eV

    NASA Technical Reports Server (NTRS)

    Glushkov, A. V.; Efimov, N. N.; Efremov, N. N.; Makarov, I. T.; Pravdin, M. I.; Dedenko, L. I.

    1985-01-01

    Fluctuations of the shower maximum depth obtained from analysis of electron and muon fluctuations and the extensive air showers (EAS) Cerenkov light on the Yakutsk array data and data of other arrays are considered. On the basis of these the estimation of composition of primaries with E sub 0 = 5.10 to the 17th power eV is received. Estimation of gamma-quanta flux with E sub 0 10 to the 17th power eV is given on the poor-muon showers.

  12. Atmospheric CO{sub 2} concentrations the CSIRO (Australia) monitoring program from aircraft 1972 - 1981

    SciTech Connect

    Beardsmore, D.J.; Pearman, G.I.

    1984-09-01

    Atmospheric CO{sub 2} concentrations were measured in the troposphere and lower stratosphere over the Australia-New Zealand region and as far south as Antarctica for the period 1972-1981. The samples were collected from aircraft over a large range of latitudes and altitudes. The sampling program has been based on the cooperation of the Australia Department of Transport, Quantas Airways, Trans Australia Airlines, the United States, New Zealand and Australian Air Forces and occasional chartering of light aircraft for special purposes.

  13. Model-based pulse shape correction for CdTe detectors

    NASA Astrophysics Data System (ADS)

    Bargholtz, Chr.; Fumero, E.; Mårtensson, L.

    1999-02-01

    We present a systematic method to improve energy resolution of CdTe-detector systems with full control of the efficiency. Sampled pulses and multiple amplifier data are fitted by a model of the pulse shape including the deposited energy and the interaction point within the detector as parameters. We show the decisive improvements of spectral resolution and photo-peak efficiency that is obtained without distortion of spectral shape. The information concerning the interaction depth of individual events can be used to discriminate between beta particles and gamma quanta.

  14. Classical Physics and the Bounds of Quantum Correlations

    NASA Astrophysics Data System (ADS)

    Frustaglia, Diego; Baltanás, José P.; Velázquez-Ahumada, María C.; Fernández-Prieto, Armando; Lujambio, Aintzane; Losada, Vicente; Freire, Manuel J.; Cabello, Adán

    2016-06-01

    A unifying principle explaining the numerical bounds of quantum correlations remains elusive, despite the efforts devoted to identifying it. Here, we show that these bounds are indeed not exclusive to quantum theory: for any abstract correlation scenario with compatible measurements, models based on classical waves produce probability distributions indistinguishable from those of quantum theory and, therefore, share the same bounds. We demonstrate this finding by implementing classical microwaves that propagate along meter-size transmission-line circuits and reproduce the probabilities of three emblematic quantum experiments. Our results show that the "quantum" bounds would also occur in a classical universe without quanta. The implications of this observation are discussed.

  15. Glutamate-induced long-term potentiation of the frequency of miniature synaptic currents in cultured hippocampal neurons

    NASA Astrophysics Data System (ADS)

    Malgaroli, Antonio; Tsien, Richard W.

    1992-05-01

    Glutamate application at synapses between hippocampal neurons in culture produces long-term potentiation of the frequency of spontaneous miniature synaptic currents, together with long-term potentiation of evoked synaptic currents. The mini frequency potentiation is initiated postsynaptically and requires activity of NMDA receptors. Although the frequency of unitary quanta! responses increases strongly, their amplitude remains little changed with potentiation. Tests of postsynaptic responsiveness rule out recruitment of latent glutamate receptor clusters. Thus, postsynaptic induction can lead to enhancement of presynaptic transmitter release. The sustained potentiation of mini frequency is expressed even in the absence of Ca2+ entry into presynaptic terminals.

  16. Measurement of the energy of horizontal cosmic ray muons

    NASA Astrophysics Data System (ADS)

    Gettert, Michael

    1993-03-01

    An experiment in which the energy of cosmic ray muons is determined by measuring the electron positron pairs that they radiate off when passing through matter is described. The detector is a stack of lead converters interspersed with ionization chambers for particle detection. The chambers use as active medium the liquid tetra methyl silane (TMS). The radiated quanta initiate electromagnetic cascades in the lead and are recognized due to the characteristic shower development. The energy spectrum of horizontal muons is presented and from this the primary cosmic ray spectrum is deduced.

  17. Multiplicity fluctuations in heavy-ion collisions using canonical and grand-canonical ensemble

    NASA Astrophysics Data System (ADS)

    Garg, P.; Mishra, D. K.; Netrakanti, P. K.; Mohanty, A. K.

    2016-02-01

    We report the higher-order cumulants and their ratios for baryon, charge and strangeness multiplicity in canonical and grand-canonical ensembles in ideal thermal model including all the resonances. When the number of conserved quanta is small, an explicit treatment of these conserved charges is required, which leads to a canonical description of the system and the fluctuations are significantly different from the grand-canonical ensemble. Cumulant ratios of total-charge and net-charge multiplicity as a function of collision energies are also compared in grand-canonical ensemble.

  18. Spontaneous and stimulated Raman studies of vibrational dephasing in condensed phases

    SciTech Connect

    Cornelius, P.A.

    1980-05-01

    Vibrational dephasing in condensed phases is studied from both a theoretical and experimental standpoint. A theory is presented which describes the dynamics of motional or exchange processes in weakly perturbed systems. This general formalism, which has been previously used to describe motional narrowing in magnetic resonance, is applied to vibrational spectroscopy. The model treats the case of a high frequency vibration anharmonically coupled to a low-frequency vibration. Intermolecular exchange of low frequency vibrational quanta results in a temperature dependent broadening and frequency shift of the high frequency vibration. Analysis of experimental data by this model yields both the exchange rates and the anharmonic couplings.

  19. The Mössbauer rotor experiment and the general theory of relativity

    NASA Astrophysics Data System (ADS)

    Corda, Christian

    2016-05-01

    In the recent paper Yarman et al. (2015), the authors claim that our general relativistic analysis in Corda (2015), with the additional effect due to clock synchronization, cannot explain the extra energy shift in the Mössbauer rotor experiment. In their opinion, the extra energy shift due to the clock synchronization is of order 10-13 and cannot be detected by the detectors of γ-quanta which are completely insensitive to such a very low order of energy shifts. In addition, they claim to have shown that the extra energy shift can be explained in the framework of the so-called YARK gravitational theory. They indeed claim that such a theory should replace the general theory of relativity (GTR) as the correct theory of gravity. In this paper we show that the authors Yarman et al. (2015) had a misunderstanding of our theoretical analysis in Corda (2015). In fact, in that paper we have shown that electromagnetic radiation launched by the central source of the apparatus is redshifted of a quantity 0 . 6 ¯ v2/c2 when arriving to the detector of γ-quanta. This holds independently by the issue that the original photons are detected by the resonant absorber which, in turns, triggers the γ-quanta which arrive to the final detector. In other words, the result in Corda (2015) was a purely theoretical result that is completely independent of the way the experiment is concretely realized. Now, we show that, with some clarification, the results of Corda (2015) hold also when one considers the various steps of the concrete detection. In that case, the resonant absorber detects the energy shift and the separated detector of γ-quanta merely measures the resulting intensity. In addition, we also show that the YARK gravitational theory is in macroscopic contrast with geodesic motion and, in turn, with the weak equivalence principle (WEP). This is in contrast with another claim of the authors of Yarman et al. (2015), i.e. that the YARK gravitational theory arises from the WEP

  20. Analytical Approximation of Spectrum for Pulse X-ray Tubes

    NASA Astrophysics Data System (ADS)

    Vavilov, S.; Koshkin, G.; Udod, V.; Fofanof, O.

    2016-01-01

    Among the main characteristics of the pulsed X-ray apparatuses the spectral energy characteristics are the most important ones: the spectral distribution of the photon energy, effective and maximum energy of quanta. Knowing the spectral characteristics of the radiation of pulse sources is very important for the practical use of them in non-destructive testing. We have attempted on the analytical approximation of the pulsed X-ray apparatuses spectra obtained in the different experimental papers. The results of the analytical approximation of energy spectrum for pulse X-ray tube are presented. Obtained formulas are adequate to experimental data and can be used by designing pulsed X-ray apparatuses.

  1. Probing Radiation Damage at the Molecular Level

    NASA Astrophysics Data System (ADS)

    Mason, N. J.; Smialek, M. A.; Moore, S. A.; Folkard, M.; Hoffmann, S. V.

    2006-12-01

    Radiation damage of DNA and other cellular components has traditionally been attributed to ionisation via direct impact of high-energy quanta or by complex radical chemistry. However recent research has shown that strand breaks in DNA may be initiated by secondary electrons and is strongly dependent upon the target DNA base identity. Such research provides the fascinating perspective that it is possible that radiation damage may be described and understood at an individual molecular level introducing new possibilites for therapy and perhaps providing an insight into the origins of life.

  2. Transfer of excitation energy from host's ions to active dopant ions in oxide single crystals, glasses, and fluorides

    NASA Astrophysics Data System (ADS)

    Kaczmarek, Slawomir M.; Drozdowski, Winicjusz; Swirkowicz, Marek; Majchrowski, Andrzej

    2000-10-01

    Results of absorption and radio luminescence measurements of YalO3, Y3Al5O12, LiTaO3, LiNbO3, YVO4 single crystals and Li2B4O7 single crystals and glasses doped with rare-earth and transition metal ions and LiF crystal were presented. Analysis of excitation energy transfer of x-rays from lattice sites to active ions was performed. Changes in absorption spectra were also analyzed due to (gamma) -quanta irradiation of Nd3+ doped LiYF4 single crystal with a dose of 105 Gy.

  3. S matrix proof of consistency condition derived from mixed anomaly

    SciTech Connect

    Bhansali, V. . Lyman Lab. of Physics)

    1990-06-20

    For a confining quantum field theory with conserved current J and stress tensor T, the {l angle}JJJ{r angle} and {l angle}JTT{r angle} anomalies computed in terms of elementary quanta must be precisely equal to the same anomalies computed in terms of the exact physical spectrum if the conservation law corresponding to J is unbroken. These strongly constrain the allowed representations of the low energy spectrum. The authors present a proof of the latter consistency condition based on the proof by Coleman and Grossman of the former consistency condition.

  4. Microfabricated Surface-Electrode Ion Trap for Scalable Quantum Information Processing

    SciTech Connect

    Seidelin, S.; Chiaverini, J.; Reichle, R.; Bollinger, J.J.; Leibfried, D.; Britton, J.; Wesenberg, J.H.; Blakestad, R.B.; Epstein, R.J.; Hume, D.B.; Itano, W.M.; Jost, J.D.; Langer, C.; Ozeri, R.; Shiga, N.; Wineland, D.J.

    2006-06-30

    Individual laser-cooled {sup 24}Mg{sup +} ions are confined in a linear Paul trap with a novel geometry where gold electrodes are located in a single plane and the ions are trapped 40 {mu}m above this plane. The relatively simple trap design and fabrication procedure are important for large-scale quantum information processing (QIP) using ions. Measured ion motional frequencies are compared to simulations. Measurements of ion recooling after cooling is temporarily suspended yield a heating rate of approximately 5 motional quanta per millisecond for a trap frequency of 2.83 MHz, sufficiently low to be useful for QIP.

  5. Bond-selected bimolecular chemistry: H+HOD(4. nu. sub OH ) r arrow OD+H sub 2

    SciTech Connect

    Sinha, A.; Hsiao, M.C.; Crim, F.F. )

    1990-05-15

    The reaction of HOD containing four quanta of O--H bond stretching vibration with H atoms produces OD fragments almost exclusively. Vibrational overtone excitation prepares HOD(4{nu}{sub OH}) that reacts with H atoms formed in a microwave discharge. The endothermic reaction of water with hydrogen atoms does not occur for ground vibrational state water but proceeds at roughly the gas kinetic collision rate for the vibrationally excited molecule. The production of OD fragments from HOD(4{nu}{sub OH}) in the reaction is at least two orders of magnitude more efficient than the production of OH, indicating very selective reaction of the vibrationally excited bond.

  6. Quantum field theory of classically unstable Hamiltonian dynamics

    SciTech Connect

    Strauss, Y.; Horwitz, L. P.; Levitan, J.; Yahalom, A.

    2015-07-15

    We study a class of dynamical systems for which the motions can be described in terms of geodesics on a manifold (ordinary potential models can be cast into this form by means of a conformal map). It is rigorously proven that the geodesic deviation equation of Jacobi, constructed with a second covariant derivative, is unitarily equivalent to that of a parametric harmonic oscillator, and we study the second quantization of this oscillator. The excitations of the Fock space modes correspond to the emission and absorption of quanta into the dynamical medium, thus associating unstable behavior of the dynamical system with calculable fluctuations in an ensemble with possible thermodynamic consequences.

  7. Phase locking and quantum statistics in a parametrically driven nonlinear resonator

    NASA Astrophysics Data System (ADS)

    Hovsepyan, G. H.; Shahinyan, A. R.; Chew, Lock Yue; Kryuchkyan, G. Yu.

    2016-04-01

    We discuss phase-locking phenomenon at low-level of quanta and quantum statistics for parametrically driven nonlinear Kerr resonator (PDNR). Oscillatory mode of PDNR is created in the process of a degenerate down-conversion of photons under interaction with a train of external Gaussian pulses. We calculate the distribution of photon-number states, the second-order correlation function of photons, the Wigner functions of cavity mode showing two-fold symmetry in phase space, and we analyze formation of phase-locked states in the regular as well as the quantum chaotic regime of the PDNR.

  8. Quantum phase slip noise

    NASA Astrophysics Data System (ADS)

    Semenov, Andrew G.; Zaikin, Andrei D.

    2016-07-01

    Quantum phase slips (QPSs) generate voltage fluctuations in superconducting nanowires. Employing the Keldysh technique and making use of the phase-charge duality arguments, we develop a theory of QPS-induced voltage noise in such nanowires. We demonstrate that quantum tunneling of the magnetic flux quanta across the wire yields quantum shot noise which obeys Poisson statistics and is characterized by a power-law dependence of its spectrum SΩ on the external bias. In long wires, SΩ decreases with increasing frequency Ω and vanishes beyond a threshold value of Ω at T →0 . The quantum coherent nature of QPS noise yields nonmonotonous dependence of SΩ on T at small Ω .

  9. Single Photon Counting Performance and Noise Analysis of CMOS SPAD-Based Image Sensors

    PubMed Central

    Dutton, Neale A. W.; Gyongy, Istvan; Parmesan, Luca; Henderson, Robert K.

    2016-01-01

    SPAD-based solid state CMOS image sensors utilising analogue integrators have attained deep sub-electron read noise (DSERN) permitting single photon counting (SPC) imaging. A new method is proposed to determine the read noise in DSERN image sensors by evaluating the peak separation and width (PSW) of single photon peaks in a photon counting histogram (PCH). The technique is used to identify and analyse cumulative noise in analogue integrating SPC SPAD-based pixels. The DSERN of our SPAD image sensor is exploited to confirm recent multi-photon threshold quanta image sensor (QIS) theory. Finally, various single and multiple photon spatio-temporal oversampling techniques are reviewed. PMID:27447643

  10. Measurements of light background at large depth in the ocean

    NASA Technical Reports Server (NTRS)

    Bannykh, A. E.; Beresnev, V. I.; Gaidash, V. A.; Gulkhandanyan, O. M.; Ivanov, V. I.; Markov, M. A.; Paka, V. T.; Shtranikh, I. V.; Surin, N. M.; Volkov, A. N.

    1985-01-01

    The mean intensity of Cerenkov emission from the products of K(40) decay and bioluminescence was measured at depths to 5 km. The intensity of ocean light background is found to depend upon depth and at the 5 km level is equal on averaged to 300 + or - 60 quanta/sq cms into spatial angle of 2 pi sterradian in transparency window. The amplitudes, duration and number of BL flashes were measured at various depths. The intensive flashes due to BL are shown to be observed rather seldom at depths over 4 km.

  11. Twisted fermionic oscillator algebra in κ-minkowski space-time

    NASA Astrophysics Data System (ADS)

    Verma, Ravikant

    2015-04-01

    In this paper, we investigate the twisted algebra of the fermionic oscillators associated with Dirac field defined in κ-Minkowski space-time. Starting from κ-deformed Dirac theory, which is invariant under the undeformed κ-Poincaré algebra, using the twisted flip operator, we derive the deformed algebra of the creation and annihilation operators corresponding to the Dirac field quanta in κ-Minkowski space-time. In the limit a → 0, the deformed algebra reduces to the commutative result.

  12. Hydrogen cluster/network in tobermorite as studied by multiple-quantum spin counting {sup 1}H NMR

    SciTech Connect

    Mogami, Yuuki; Yamazaki, Satoru; Matsuno, Shinya; Matsui, Kunio; Noda, Yasuto; Takegoshi, K.

    2014-12-15

    Proton multiple-quantum (MQ) spin-counting experiment has been employed to study arrangement of hydrogen atoms in 9 Å/11 Å natural/synthetic tobermorites. Even though all tobermorite samples give similar characterless, broad static-powder {sup 1}H NMR spectra, their MQ spin-counting spectra are markedly different; higher quanta in 11 Å tobermorite do not grow with the MQ excitation time, while those in 9 Å one do. A statistical analysis of the MQ results recently proposed [26] is applied to show that hydrogens align in 9 Å tobermorite one dimensionally, while in 11 Å tobermorite they exist as a cluster of 5–8 hydrogen atoms.

  13. Optical Pulse-Shaping for Internal Cooling of Molecular Ions

    NASA Astrophysics Data System (ADS)

    Lien, Chien-Yu; Williams, Scott R.; Odom, Brian

    2011-06-01

    We propose a scheme to use pulse-shaped femtosecond lasers to optically cool the internal degrees of freedom of molecular ions. Since this approach relies on cooling rotational and vibrational quanta by exciting an electronic transition, it is most straightforward for molecular ions with diagonal Frank-Condon-Factors. The scheme has the advantage of requiring only tens of microseconds to reach equilibrium without blackbody radiation to redistribute the population. For AlH+, a candidate species, a rate equation simulation shows equilibrium is achieved in 15 μs.

  14. Analytical model for electromagnetic cascades in rotating electric field

    SciTech Connect

    Nerush, E. N.; Bashmakov, V. F.; Kostyukov, I. Yu.

    2011-08-15

    Electromagnetic cascades attract a lot of attention as an important quantum electrodynamics effect that will reveal itself in various electromagnetic field configurations at ultrahigh intensities. We study cascade dynamics in rotating electric field analytically and numerically. The kinetic equations for the electron-positron plasma and gamma-quanta are formulated. The scaling laws are derived and analyzed. For the cascades arising far above the threshold the dependence of the cascade parameters on the field frequency is derived. The spectra of high-energy cascade particles are calculated. The analytical results are verified by numerical simulations.

  15. Multiple nucleon knockout by Coulomb dissociation in relativistic heavy-ion collisions

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Norbury, John W.; Townsend, Lawrence W.

    1988-01-01

    The Coulomb dissociation contributions to fragmentation cross sections in relativistic heavy ion collisions, where more than one nucleon is removed, are estimated using the Weizsacker-Williams method of virtual quanta. Photonuclear cross sections taken from experimental results were used to fold into target photon number spectra calculated with the Weizsacker-Williams method. Calculations for several projectile target combinations over a wide range of charge numbers, and a wide range of incident projectile energies, are reported. These results suggest that multiple nucleon knockout by the Coulomb field may be of negligible importance in galactic heavy ion studies for projectiles lighter than Fe-56.

  16. Quasi-polaritons in Bose-Einstein condensates induced by Casimir-Polder interaction with graphene.

    PubMed

    Terças, H; Ribeiro, S; Mendonça, J T

    2015-06-01

    We consider the mechanical coupling between a two-dimensional Bose-Einstein condensate and a graphene sheet via the vacuum fluctuations of the electromagnetic field which are at the origin of the so-called Casimir-Polder potential. By deriving a self-consistent set of equations governing the dynamics of the condensate and the flexural (out-of-plane) modes of the graphene, we can show the formation of a new type of purely acoustic quasi-particle excitation, a quasi-polariton resulting from the coherent superposition of quanta of flexural and Bogoliubov modes. PMID:25966318

  17. The readout of a GEM or Micromegas-equipped TPC by means of the Medipix2 CMOS sensor as direct anode

    NASA Astrophysics Data System (ADS)

    Colas, P.; Colijn, A. P.; Fornaini, A.; Giomataris, Y.; van der Graaf, H.; Heijne, E. H. M.; Llopart, X.; Schmitz, J.; Timmermans, J.; Visschers, J. L.

    2004-12-01

    We have applied the Medipix2 pixel CMOS chip as direct anode readout for a TPC. For the gas amplification two options have been investigated: (i) a three-stage GEM system and (ii) a Micromegas mesh. The structure of the cloud of primary electrons, left after interactions of 55Fe quanta with the gas is visible with unprecedented precision. This proof-of-principle is an essential step in our project to realize a monolithic pixel sensor with integrated Micromegas, to be developed specially for the readout of TPCs, and applicable for drift chambers in general.

  18. Spectral shifting by dyes to enhance algae growth.

    PubMed

    Prokop, A; Quinn, M F; Fekri, M; Murad, M; Ahmed, S A

    1984-11-01

    The photosynthetic growth action spectrum of a green alga at three bands of visible light (blue, orange, and red) at fixed quanta input and under light-limiting conditions was measured in a batch cultivation system. Quantum efficiencies (biomass dry weight increment per quanta absorbed) were better in the yellow-red region than in the blue region. Results served as a basis for the design and optimization of a dye system that would shift the energy of solar radiation to the required wavelength range by absorbing ultraviolet to blue radiation and emitting in the yellow-red, thus enhancing algae growth. Direct incorporation of dyes into the growth medium, although theoretically expected to enhance growth, in fact resulted in dye decomposition, toxicity to algae and consequently in growth inhibition. Indirect application of dyes in a double tubular reactor (algae inside and dye solution outside) demonstrated growth enhancement for certain dyes with high quantum yields and stability, which had suitable absorption/emission spectra for artificial light sources used. The maximum indirect growth enhancement was obtained using rhodamine 6G at a concentration of 3x10(-5)M with tungsten filament lamp sources. PMID:18551655

  19. Multitude of ion channels in the regulation of transmitter release.

    PubMed Central

    Rahamimoff, R; Butkevich, A; Duridanova, D; Ahdut, R; Harari, E; Kachalsky, S G

    1999-01-01

    The presynaptic nerve terminal is of key importance in communication in the nervous system. Its primary role is to release transmitter quanta on the arrival of an appropriate stimulus. The structural basis of these transmitter quanta are the synaptic vesicles that fuse with the surface membrane of the nerve terminal, to release their content of neurotransmitter molecules and other vesicular components. We subdivide the control of quantal release into two major classes: the processes that take place before the fusion of the synaptic vesicle with the surface membrane (the pre-fusion control) and the processes that occur after the fusion of the vesicle (the post-fusion control). The pre-fusion control is the main determinant of transmitter release. It is achieved by a wide variety of cellular components, among them the ion channels. There are reports of several hundred different ion channel molecules at the surface membrane of the nerve terminal, that for convenience can be grouped into eight major categories. They are the voltage-dependent calcium channels, the potassium channels, the calcium-gated potassium channels, the sodium channels, the chloride channels, the non-selective channels, the ligand gated channels and the stretch-activated channels. There are several categories of intracellular channels in the mitochondria, endoplasmic reticulum and the synaptic vesicles. We speculate that the vesicle channels may be of an importance in the post-fusion control of transmitter release. PMID:10212476

  20. Effective exposure level and diagnostic performance in endodontic radiography

    SciTech Connect

    Okano, T.; Wiebe, J.D.; Webber, R.L.; Wagner, R.F.

    1983-05-01

    Image quality is limited by the information capacity of the image-forming system and can be computed from three parameters: contrast, resolution, and noise. These parameters can be combined to yield a single measure which determines the maximum amount of information obtainable from any x-ray system and is called the noise-equivalent number of quanta (NEQ) per unit area. The effects of image quality, expressed as noise-equivalent number of quanta (NEQ) per unit area, on the radiographic performance by dentists reading the position of an endodontic file in a root canal were studied. Three different speed films were used in conjunction with a fixed screen. Components of variance associated with the position of the tooth apex and the tip of an endodontic file in a root canal were compared for the effect of different NEQs and observers. Results show that the standard deviation in locating a file tip and tooth apex may be a linear function of log NEQ. These findings indicate that a significant reduction in exposure would have a relatively small effect on the precision of endodontic distance measurements.

  1. Experimental evaluation of environmental scanning electron microscopes at high chamber pressure.

    PubMed

    Fitzek, H; Schroettner, H; Wagner, J; Hofer, F; Rattenberger, J

    2015-11-01

    In environmental scanning electron microscopy (ESEM) high pressure applications have become increasingly important. Wet or biological samples can be investigated without time-consuming sample preparation and potential artefacts from this preparation can be neglected. Unfortunately, the signal-to-noise ratio strongly decreases with increasing chamber pressure. To evaluate the high pressure performance of ESEM and to compare different electron microscopes, information about spatial resolution and detector type is not enough. On the one hand, the scattering of the primary electron beam increases, which vanishes the contrast in images; and on the other hand, the secondary electrons (SE) signal amplification decreases. The stagnation gas thickness (effective distance the beam has to travel through the imaging gas) as well as the SE detection system depend on the microscope and for a complete and serious evaluation of an ESEM or low vacuum SEM it is necessary to specify these two parameters. A method is presented to determine the fraction of scattered and unscattered electrons and to calculate the stagnation gas thickness (θ). To evaluate the high pressure performance of the SE detection system, a method is presented that allows for an analysis of a single image and the calculation of the signal-to-noise ratio of this image. All investigations are performed on an FEI ESEM Quanta 600 (field emission gun) and an FEI ESEM Quanta 200 (thermionic gun). These methods and measurements should represent opportunities for evaluating the high pressure performance of an ESEM. PMID:26173072

  2. Blue tensor spectrum from particle production during inflation

    SciTech Connect

    Mukohyama, Shinji; Namba, Ryo; Peloso, Marco; Shiu, Gary E-mail: ryo.namba@ipmu.jp E-mail: shiu@physics.wisc.edu

    2014-08-01

    We discuss a mechanism of particle production during inflation that can result in a blue gravitational wave (GW) spectrum, compatible with the BICEP2 result and with the r < 0.11 limit on the tensor-to-scalar ratio at the Planck pivot scale. The mechanism is based on the production of vector quanta from a rolling pseudo-scalar field. Both the vector and the pseudo-scalar are only gravitationally coupled to the inflaton, to keep the production of inflaton quanta at an unobservable level (the overproduction of non-gaussian scalar perturbations is a generic difficulty for mechanisms that aim to generate a visible GW signal from particle production during inflation). This mechanism can produce a detectable amount of GWs for any inflationary energy scale. The produced GWs are chiral and non-gaussian; both these aspects can be tested with large-scale polarization data (starting from Planck). We study how to reconstruct the pseudo-scalar potential from the GW spectrum.

  3. Quantum graviton creation in a model universe

    NASA Technical Reports Server (NTRS)

    Berger, B. K.

    1974-01-01

    Consideration of the mechanism of production of gravitons in the empty, anisotropic, spatially inhomogeneous Gowdy three-torus cosmology. The Gowdy cosmology is an exact solution of the vacuum Einstein equations and is obtained as a generalization of the homogeneous empty Bianchi Type I (Kasner) cosmology by permitting the metric components to depend on one of the space variables in addition to time. The Hamiltonian methods of Arnowitt, Deser, and Misner are employed to identify the dynamical variables which are to be quantized. The WKB regime solution is identical to that found by Doroshkevich, Zel'dovich, and Novikov (DZN) for a universe containing collisionless anisotropic radiation. Using a procedure similar to that of Parker (1971) or Zel'dovich and Starobinskii (1971) for defining quantum number, it is found that the DZN large-time radiation consists of quanta (gravitons) created from an initial vacuum. The quantum behavior is much like the semiclassical enhancement of quantum number with the added feature of creation of quanta from vacuum fluctuations.

  4. Bayesian analysis of the kinetics of quantal transmitter secretion at the neuromuscular junction.

    PubMed

    Saveliev, Anatoly; Khuzakhmetova, Venera; Samigullin, Dmitry; Skorinkin, Andrey; Kovyazina, Irina; Nikolsky, Eugeny; Bukharaeva, Ellya

    2015-10-01

    The timing of transmitter release from nerve endings is considered nowadays as one of the factors determining the plasticity and efficacy of synaptic transmission. In the neuromuscular junction, the moments of release of individual acetylcholine quanta are related to the synaptic delays of uniquantal endplate currents recorded under conditions of lowered extracellular calcium. Using Bayesian modelling, we performed a statistical analysis of synaptic delays in mouse neuromuscular junction with different patterns of rhythmic nerve stimulation and when the entry of calcium ions into the nerve terminal was modified. We have obtained a statistical model of the release timing which is represented as the summation of two independent statistical distributions. The first of these is the exponentially modified Gaussian distribution. The mixture of normal and exponential components in this distribution can be interpreted as a two-stage mechanism of early and late periods of phasic synchronous secretion. The parameters of this distribution depend on both the stimulation frequency of the motor nerve and the calcium ions' entry conditions. The second distribution was modelled as quasi-uniform, with parameters independent of nerve stimulation frequency and calcium entry. Two different probability density functions for the distribution of synaptic delays suggest at least two independent processes controlling the time course of secretion, one of them potentially involving two stages. The relative contribution of these processes to the total number of mediator quanta released depends differently on the motor nerve stimulation pattern and on calcium ion entry into nerve endings. PMID:26129670

  5. The origin of unequal bond lengths in the C̃ (1)B2 state of SO2: Signatures of high-lying potential energy surface crossings in the low-lying vibrational structure.

    PubMed

    Park, G Barratt; Jiang, Jun; Field, Robert W

    2016-04-14

    The C̃ (1)B2 state of SO2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. The asymmetry in the potential energy surface is expressed as a staggering in the energy levels of the ν3(') progression. We have recently made the first observation of low-lying levels with odd quanta of v3('), which allows us-in the current work-to characterize the origins of the level staggering. Our work demonstrates the usefulness of low-lying vibrational level structure, where the character of the wavefunctions can be relatively easily understood, to extract information about dynamically important potential energy surface crossings that occur at much higher energy. The measured staggering pattern is consistent with a vibronic coupling model for the double-minimum, which involves direct coupling to the bound 2 (1)A1 state and indirect coupling with the repulsive 3 (1)A1 state. The degree of staggering in the ν3(') levels increases with quanta of bending excitation, which is consistent with the approach along the C̃ state potential energy surface to a conical intersection with the 2 (1)A1 surface at a bond angle of ∼145°. PMID:27083727

  6. Mixed quantum/classical calculations of total and differential elastic and rotationally inelastic scattering cross sections for light and heavy reduced masses in a broad range of collision energies

    SciTech Connect

    Semenov, Alexander; Babikov, Dmitri

    2014-01-28

    The mixed quantum/classical theory (MQCT) for rotationally inelastic scattering developed recently [A. Semenov and D. Babikov, J. Chem. Phys. 139, 174108 (2013)] is benchmarked against the full quantum calculations for two molecular systems: He + H{sub 2} and Na + N{sub 2}. This allows testing new method in the cases of light and reasonably heavy reduced masses, for small and large rotational quanta, in a broad range of collision energies and rotational excitations. The resultant collision cross sections vary through ten-orders of magnitude range of values. Both inelastic and elastic channels are considered, as well as differential (over scattering angle) cross sections. In many cases results of the mixed quantum/classical method are hard to distinguish from the full quantum results. In less favorable cases (light masses, larger quanta, and small collision energies) some deviations are observed but, even in the worst cases, they are within 25% or so. The method is computationally cheap and particularly accurate at higher energies, heavier masses, and larger densities of states. At these conditions MQCT represents a useful alternative to the standard full-quantum scattering theory.

  7. Mixed quantum/classical calculations of total and differential elastic and rotationally inelastic scattering cross sections for light and heavy reduced masses in a broad range of collision energies

    NASA Astrophysics Data System (ADS)

    Semenov, Alexander; Babikov, Dmitri

    2014-01-01

    The mixed quantum/classical theory (MQCT) for rotationally inelastic scattering developed recently [A. Semenov and D. Babikov, J. Chem. Phys. 139, 174108 (2013)] is benchmarked against the full quantum calculations for two molecular systems: He + H2 and Na + N2. This allows testing new method in the cases of light and reasonably heavy reduced masses, for small and large rotational quanta, in a broad range of collision energies and rotational excitations. The resultant collision cross sections vary through ten-orders of magnitude range of values. Both inelastic and elastic channels are considered, as well as differential (over scattering angle) cross sections. In many cases results of the mixed quantum/classical method are hard to distinguish from the full quantum results. In less favorable cases (light masses, larger quanta, and small collision energies) some deviations are observed but, even in the worst cases, they are within 25% or so. The method is computationally cheap and particularly accurate at higher energies, heavier masses, and larger densities of states. At these conditions MQCT represents a useful alternative to the standard full-quantum scattering theory.

  8. A superconducting qubit coupled to propagating acoustic waves

    NASA Astrophysics Data System (ADS)

    Gustafsson, Martin V.; Aref, Thomas; Frisk Kockum, Anton; Ekström, Maria K.; Johansson, Göran; Delsing, Per

    2015-03-01

    Mechanical devices in the quantum regime have so far consisted mainly of suspended resonators, where standing modes can be populated with quanta of vibrational energy. We present a fundamentally different system, where the mechanical excitation is not restricted to a specific mode and location. Instead, we demonstrate strong non-classical coupling between propagating phonons and a superconducting qubit. The qubit is fabricated on a piezoelectric substrate, and is designed to interact with Surface Acoustic Waves (SAWs) in the gigahertz frequency range. A separate on-chip transducer allows us to launch SAWs toward the qubit from a distance and pick up SAW phonons that the qubit reflects and emits. In a series of experiments where the qubit is addressed both electrically and acoustically, we show that the qubit couples much more strongly to SAWs than to any electrical modes. The low speed of sound sets phonons apart from photons as a medium for transporting quantum information, and should enable real-time manipulation of propagating quanta. The short acoustic wavelength and strong piezoelectric coupling should also allows regimes of interaction to be explored which cannot be reached in photonic systems.

  9. Long Josephson tunnel junctions with doubly connected electrodes

    NASA Astrophysics Data System (ADS)

    Monaco, R.; Mygind, J.; Koshelets, V. P.

    2012-03-01

    In order to mimic the phase changes in the primordial Big Bang, several cosmological solid-state experiments have been conceived, during the last decade, to investigate the spontaneous symmetry breaking in superconductors and superfluids cooled through their transition temperature. In one of such experiments, the number of magnetic flux quanta spontaneously trapped in a superconducting loop was measured by means of a long Josephson tunnel junction built on top of the loop itself. We have analyzed this system and found a number of interesting features not occurring in the conventional case with simply connected electrodes. In particular, the fluxoid quantization results in a frustration of the Josephson phase, which, in turn, reduces the junction critical current. Further, the possible stable states of the system are obtained by a self-consistent application of the principle of minimum energy. The theoretical findings are supported by measurements on a number of samples having different geometrical configuration. The experiments demonstrate that a very large signal-to-noise ratio can be achieved in the flux quanta detection.

  10. Application of FEL technique for constructing high-intensity, monochromatic, polarized gamma-sources at storage rings

    SciTech Connect

    Saldin, E.L.; Schneidmiller, E.A.; Ulyanov, Yu.N.

    1995-12-31

    A possibility to construct high-intensity tunable monochromatic{gamma}-source at high energy storage rings is discussed. It is proposed to produce {gamma}-quanta by means of Compton backscattering of laser photons on electrons circulating in the storage. The laser light wavelength is chosen in such a way that after the scattering, the electron does not leave the separatrix. So as the probability of the scattering is rather small, energy oscillations are damped prior the next scattering. As a result, the proposed source can operate in {open_quotes}parasitic{close_quote} mode not interfering with the main mode of the storage ring operation. Analysis of parameters of existent storage rings (PETRA, ESRF, Spring-8, etc) shows that the laser light wavelength should be in infrared, {lambda}{approximately} 10 - 400 {mu}m, wavelength band. Installation at storage rings of tunable free-electron lasers with the peak and average output power {approximately} 10 MW and {approximately} 1 kW, respectively, will result in the intensity of the {gamma}-source up to {approximately} 10{sup 14}s{sup -1} with tunable {gamma}-quanta energy from several MeV up to several hundreds MeV. Such a {gamma}-source will reveal unique possibilities for precision investigations in nuclear physics.

  11. Analysis of autoantibodies to 3-hydroxy-3-methylglutaryl-coenzyme A reductase using different technologies.

    PubMed

    Musset, Lucile; Miyara, Makoto; Benveniste, Olivier; Charuel, Jean-Luc; Shikhman, Alexander; Boyer, Olivier; Fowler, Richard; Mammen, Andrew; Phillips, Joe; Mahler, Michael

    2014-01-01

    Diagnostic tests are needed to aid in the diagnosis of necrotizing myopathies associated with statin use. This study aimed to compare different technologies for the detection of anti-HMGCR antibodies and analyze the clinical phenotype and autoantibody profile of the patients. Twenty samples from myositis patients positive for anti-HMGCR antibodies using a research addressable laser bead assay and 20 negative controls were tested for autoantibodies to HMGCR: QUANTA Lite HMGCR ELISA and QUANTA Flash HMGCR CIA. All patients were also tested for antibodies to extractable nuclear antigens and myositis related antibodies. To verify the specificity of the ELISA, 824 controls were tested. All three assays showed qualitative agreements of 100% and levels of anti-HMGCR antibodies showed significant correlation: Spearman's rho > 0.8. The mean age of the anti-HMGCR antibody positive patients was 54.4 years, 16/20 were females, and 18/20 had necrotizing myopathy (two patients were not diagnosed). Nine out of 20 anti-HMGCR positive patients were on statin. All patients with anti-HMGCR antibodies were negative for all other autoantibodies tested. Testing various controls showed high specificity (99.3%). Anti-HMGCR antibodies are not always associated with the use of statin and appear to be the exclusive autoantibody specificity in patients with statin associated myopathies. PMID:24741598

  12. Analysis of Autoantibodies to 3-Hydroxy-3-methylglutaryl-coenzyme A Reductase Using Different Technologies

    PubMed Central

    Musset, Lucile; Miyara, Makoto; Benveniste, Olivier; Charuel, Jean-Luc; Boyer, Olivier; Fowler, Richard; Phillips, Joe

    2014-01-01

    Diagnostic tests are needed to aid in the diagnosis of necrotizing myopathies associated with statin use. This study aimed to compare different technologies for the detection of anti-HMGCR antibodies and analyze the clinical phenotype and autoantibody profile of the patients. Twenty samples from myositis patients positive for anti-HMGCR antibodies using a research addressable laser bead assay and 20 negative controls were tested for autoantibodies to HMGCR: QUANTA Lite HMGCR ELISA and QUANTA Flash HMGCR CIA. All patients were also tested for antibodies to extractable nuclear antigens and myositis related antibodies. To verify the specificity of the ELISA, 824 controls were tested. All three assays showed qualitative agreements of 100% and levels of anti-HMGCR antibodies showed significant correlation: Spearman's rho > 0.8. The mean age of the anti-HMGCR antibody positive patients was 54.4 years, 16/20 were females, and 18/20 had necrotizing myopathy (two patients were not diagnosed). Nine out of 20 anti-HMGCR positive patients were on statin. All patients with anti-HMGCR antibodies were negative for all other autoantibodies tested. Testing various controls showed high specificity (99.3%). Anti-HMGCR antibodies are not always associated with the use of statin and appear to be the exclusive autoantibody specificity in patients with statin associated myopathies. PMID:24741598

  13. The origin of unequal bond lengths in the C1B2 state of SO2: Signatures of high-lying potential energy surface crossings in the low-lying vibrational structure

    DOE PAGESBeta

    Park, G. Barratt; Jiang, Jun; Field, Robert W.

    2016-04-14

    Here the C1B2 state of SO2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. The asymmetry in the potential energy surface is expressed as a staggering in the energy levels of the v'3 progression. We have recently made the first observation of low-lying levels with odd quanta of v'3, which allows us--in the current work--to characterize the origins of the level staggering. Our work demonstrates the usefulness of low-lying vibrational level structure, where the character of the wavefunctions can be relatively easily understood, to extract information about dynamicallymore » important potential energy surface crossings that occur at much higher energy. The measured staggering pattern is consistent with a vibronic coupling model for the double-minimum, which involves direct coupling to the bound 2 1A1 state and indirect coupling with the repulsive 3 1A1 state. The degree of staggering in the v'3 levels increases with quanta of bending excitation, which is consistent with the approach along the C state potential energy surface to a conical intersection with the 2 1A1 surface at a bond angle of ~145°.« less

  14. Statistical simulation of multiple Compton backscattering process

    NASA Astrophysics Data System (ADS)

    Potylitsyn, A. P.; Kolchuzhkin, A. M.

    2014-09-01

    A number of laboratories are currently developing monochromatic sources of X-rays and gamma quanta based on the Compton backscattering (CBS) of laser photons by relativistic electrons. Modern technologies are capable of providing a concentration of electrons and photons in the interaction point such that each primary electron can emit several hard photons. In contrast to the well-known nonlinear CBS process, in which an initial electron "absorbs" a few laser photons and emits a single hard one, the above-mentioned process can be called a multiple CBS process and is characterized by a mean number of emitted photons. The present paper is devoted to simulating the parameters of a beam of back scattered quanta based on the Monte Carlo technique. It is shown that, even in the case of strong collimation of a resulting photon beam, the radiation monochromaticity may deteriorate because of the contribution coming from the multiple photon emission, which is something that must be considered while designing new CBS sources.

  15. Counting every quantum

    PubMed Central

    Sakitt, B.

    1972-01-01

    1. Human subjects were asked to rate both blanks and very dim flashes of light under conditions of complete dark adaptation at 7° in the periphery. The ratings used were 0, 1, 2, 3, 4, 5, and 6. 2. For one subject (B.S.) the distributions of ratings were approximately Poisson distributions. The data were consistent with each rating being the actual number of effective quantal absorptions plus the number of noise events. This subject was presumably able to count every rod signal (effective absorptions plus noise). 3. For two other subjects, the data were consistent with the ratings being one less (L.F.) and two less (K.D.) than the number of effective absorptions plus noise. They were able to count every rod signal beginning with 2 and 3 respectively. A fourth subject's erratic data could not be fitted. 4. The fraction of quanta incident at the cornea that resulted in a rod signal was estimated to be about 0·03 which is consistent with physical estimates of effective absorption for that retinal region. 5. A simulated forced choice experiment leads to an absolute threshold about 0·40 log units below the normal yes-no absolute threshold. This and other results indicate that subjects can use the sensory information they receive even when only 1, 2 or 3 quanta are effectively absorbed, depending on the individual. Humans may be able to count every action potential or every discrete burst of action potentials in some critical neurone. PMID:5046137

  16. Consequences of partitioning the photon into its electrical and magnetic vectors upon absorption by an electron

    NASA Astrophysics Data System (ADS)

    Szumski, Daniel S.

    2013-10-01

    This research uses classical arguments to develop a blackbody spectral equation that provides useful insights into heat processes. The theory unites in a single equation, the heat radiation theory of Planck and the heat of molecular motion theory of Maxwell and Boltzmann. Light absorption is considered a two-step process. The first is an adiabatic reversible step, wherein one-dimensional light energy is absorbed in a quantum amount, ! h" , by an electron. The absorbed quanta is still 1-dimensional(1-D), and remains within the domain of reversible thermodynamics. There is no recourse to the Second Law during this first step. The absorption process' second step is a dimensional restructuring wherein the electrical and magnetic vectors evolve separately. The 1-D electrical quanta transforms into its 3-D equivalent, electrical charge density. The resulting displacement of the generalized coordinates translates to 3-D motion, the evolution of Joule heat, and irreversible thermodynamics. The magnetic vector has no 3-D equivalent, and can only transform to 1-D paramagnetic spin. Accordingly, photon decoupling distorts time's fabric, giving rise to the characteristic blackbody spectral emittance. This study's spectral equation introduces a new quantity to physics, the radiation temperature. Where it is identical to the classical thermodynamic temperature, the blackbody spectral curves are consistent with Planck's. However, by separating these two temperatures in a stable far-from-equilibrium manner, new energy storage modes become possible at the atomic level, something that could have profound implications in understanding matter's living state.

  17. Investigation of X-ray lasers on the SOKOL-P facility at RFNC-VNIITF

    NASA Astrophysics Data System (ADS)

    Gavrilov, D. S.; Andriyash, A. V.; Vikhlyaev, D. A.; Gorokhov, S. A.; Dmitrov, D. A.; Zapysov, A. L.; Kakshin, A. G.; Kapustin, I. A.; Loboda, E. A.; Lykov, V. A.; Politov, V. Yu.; Potapov, A. V.; Pronin, V. A.; Rykovanov, G. N.; Sukhanov, V. N.; Tischenko, A. S.; Ugodenko, A. A.; Chefonov, O. V.

    2007-11-01

    The experiments [1] have demonstrated generation of the laser X-radiation (LXR) λ=326A on 3p-3s transitions of Ne-like Ti ions at sequential irradiation of the targets by two laser pulses, focused into a narrow line. The small signal gain equaled 30cm-1. The intensity was 0.5.10^12 W/cm^2 in the prepulse of 0.4ns and 10^14 W/cm^2 in the master pulse of 4ps (delay 1.5 ns). The dependence of LXR yield on the laser energy is demonstrated to have an exponential form. The traveling pumping wave mode was realized using the reflective echelon and the LXR yield is as great as 5-fold. The latest experiments have demonstrated the LXR generation on 4d-4p of Ni-like molybdenum λ=189A. The development of LXR generation model, and numerical codes which allow for the quanta delay effects, quanta refraction in plasma with heavy density gradient, and also the saturation effect have made it possible to describe the experimental dependence of the output LXR yield on the active medium length. Good quantitative agreement is also evident when estimating the output LXR yield on Ne-like Ti ions. [1]Andriyash Quantum Electronics 36 511

  18. Evidence for P-Glycoprotein Involvement in Cell Volume Regulation Using Coulter Sizing in Flow Cytometry.

    PubMed

    Pasquier, Jennifer; Rioult, Damien; Abu-Kaoud, Nadine; Hoarau-Véchot, Jessica; Marin, Matthieu; Le Foll, Frank

    2015-01-01

    The regulation of cell volume is an essential function that is coupled to a variety of physiological processes such as receptor recycling, excitability and contraction, cell proliferation, migration, and programmed cell death. Under stress, cells undergo emergency swelling and respond to such a phenomenon with a regulatory volume decrease (RVD) where they release cellular ions, and other osmolytes as well as a concomitant loss of water. The link between P-glycoprotein, a transmembrane transporter, and cell volume regulation is controversial, and changes in cells volume are measured using microscopy or electrophysiology. For instance, by using the patch-clamp method, our team demonstrated that chloride currents activated in the RVD were more intense and rapid in a breast cancer cell line overexpressing the P-glycoprotein (P-gp). The Cell Lab Quanta SC is a flow cytometry system that simultaneously measures electronic volume, side scatter and three fluorescent colors; altogether this provides unsurpassed population resolution and accurate cell counting. Therefore, here we propose a novel method to follow cellular volume. By using the Coulter-type channel of the cytometer Cell Lab Quanta SC MPL (multi-platform loading), we demonstrated a role for the P-gp during different osmotic treatments, but also a differential activity of the P-gp through the cell cycle. Altogether, our data strongly suggests a role of P-gp in cell volume regulation. PMID:26114386

  19. Increased resistance to oxidative stress in transgenic plants that overexpress chloroplastic Cu/Zn superoxide dismutase.

    PubMed Central

    Gupta, A S; Heinen, J L; Holaday, A S; Burke, J J; Allen, R D

    1993-01-01

    Transgenic tobacco plants that express a chimeric gene that encodes chloroplast-localized Cu/Zn superoxide dismutase (SOD) from pea have been developed. To investigate whether increased expression of chloroplast-targeted SOD could alter the resistance of photosynthesis to environmental stress, these plants were subjected to chilling temperatures and moderate (500 mumol of quanta per m2 per s) or high (1500 mumol of quanta per m2 per s) light intensity. During exposure to moderate stress, transgenic SOD plants retained rates of photosynthesis approximately 20% higher than untransformed tobacco plants, implicating active oxygen species in the reduction of photosynthesis during chilling. Unlike untransformed plants, transgenic SOD plants were capable of maintaining nearly 90% of their photosynthetic capacity (determined by their photosynthetic rates at 25 degrees C) following exposure to chilling at high light intensity for 4 hr. These plants also showed reduced levels of light-mediated cellular damage from the superoxide-generating herbicide methyl viologen. These results demonstrate that SOD is a critical component of the active-oxygen-scavenging system of plant chloroplasts and indicate that modification of SOD expression in transgenic plants can improve plant stress tolerance. Images PMID:8434026

  20. De-pinning of disordered bosonic chains

    NASA Astrophysics Data System (ADS)

    Vogt, N.; Cole, J. H.; Shnirman, A.

    2016-05-01

    We consider onset of transport (de-pinning) in one-dimensional bosonic chains with a repulsive boson–boson interaction that decays exponentially on large length-scales. Our study is relevant for (i) de-pinning of Cooper-pairs in Josephson junction arrays; (ii) de-pinning of magnetic flux quanta in quantum-phase-slip ladders, i.e. arrays of superconducting wires in a ladder-configuration that allow for the coherent tunneling of flux quanta. In the low-frequency, long wave-length regime these chains can be mapped onto an effective model of a one-dimensional elastic field in a disordered potential. The standard de-pinning theories address infinitely long systems in two limiting cases: (a) of uncorrelated disorder (zero correlation length); (b) of long range power-law correlated disorder (infinite correlation length). In this paper we study numerically chains of finite length in the intermediate case of long but finite disorder correlation length. This regime is of relevance for, e.g., the experimental systems mentioned above. We study the interplay of three length scales: the system length, the interaction range, the correlation length of disorder. In particular, we observe the crossover between the solitonic onset of transport in arrays shorter than the disorder correlation length to onset of transport by de-pinning for longer arrays.

  1. Elevated CO2 alleviates high PAR and UV stress in the unicellular chlorophyte Dunaliella tertiolecta.

    PubMed

    García-Gómez, Candela; Gordillo, Francisco J L; Palma, Armando; Lorenzo, M Rosario; Segovia, María

    2014-09-01

    The effects of increased CO2 and irradiance on the physiological performance of the chlorophyte Dunaliella tertiolecta were studied at different PAR and UVR (UVA + UVB) irradiances, simulating the solar radiation at different depths, at present (390 ppmv, LC) and predicted CO2 levels for the year 2100 (1000 ppmv, HC). Elevated CO2 resulted in higher optimum and effective quantum yields (F(v)/F(m) and ϕPSII, respectively), electron transport rates (ETR) and specific growth rates (μ). Cell stress was alleviated in HC with respect to LC as evidenced by a decrease in reactive oxygen species (ROS) accumulation. DNA damage showed a 42-fold increase in cyclobutane-pyrimidine dimer (CPD) formation under the highest irradiance (1100 μmol quanta m(-2) s(-1)) in LC with respect to the lowest irradiance (200 μmol quanta m(-2) s(-1)). Photolyase (CII-PCD-PL) gene expression was upregulated under HC resulting in a drastic decrease in CPD accumulation to only 25% with respect to LC. Proliferating cell nuclear antigen (PCNA) accumulation was always higher in HC and the accumulation pattern indicated its involvement in repair or growth depending on the irradiance dose. The repressor of silencing (ROS1) was only marginally involved in the response, suggesting that photoreactivation was the most relevant mechanism to overcome UVR damage. Our results demonstrate that future scenarios of global change result in alleviation of irradiance stress by CO2-induced photoprotection in D. tertiolecta. PMID:25043601

  2. Sensing in the presence of an observed environment

    NASA Astrophysics Data System (ADS)

    Plenio, Martin B.; Huelga, Susana F.

    2016-03-01

    Sensing in the presence of environmental noise is a problem of increasing practical interest. In a master equation description, where the state of the environment is unobserved, the effect of the signal and noise is described by system operators only. In this context it is well known that noise that is orthogonal in an external signal can be corrected for without perturbing the signal, while similarly efficient strategies for nonorthogonal signal and noise operators are not known. Here we make use of the fact that system-environment interaction typically arises via local two-body interactions describing the exchange of quanta between system and environment, which are observable in principle. That two-body-interactions are usually orthogonal on system operators allows us to develop error-corrected sensing supported by the observation of the quanta that are emitted into the environment. We describe such schemes and outline possible proof-of-principle experiments in an ion trap setup and with color centers in diamond.

  3. Biotransformation of mycosporine like amino acids (MAAs) in the toxic dinoflagellate Alexandrium tamarense.

    PubMed

    Callone, Alan I; Carignan, Mario; Montoya, Nora G; Carreto, José I

    2006-09-01

    Changes in mycosporine-like amino acids (MAAs) induced by the increase of photosynthetically active radiation (PAR) were studied in the toxic dinoflagellate Alexandrium tamarense. Cultures of A. tamarense were maintained at exponential growth under low (25 micromol quanta m(-2)s(-1)) PAR irradiance. The cultures were nutrient enriched and one day later exposed to higher irradiance (150 micromol quanta m(-2)s(-1)). The content of MAAs was determined by means of high performance liquid chromatography (HPLC). Eleven MAAs, including some partially characterized compounds, were identified. The MAAs synthesis induction can be described as a two-stage process. The first one involves the net synthesis of the MAAs bi-substituted by amino acids. In the second stage these compounds were transformed into other secondary MAAs. The two most prominent changes were observed in the concentration of porphyra-334 and palythene. The cellular concentration of porphyra-334 increased during the first 2h of exposure to higher irradiance and then decreased rapidly. In contrast, the cellular concentration of palythene showed a continuous accumulation since the beginning of the exposure. In A. tamarense the main route of MAAs transformation has porphyra-334 as a precursor of a sequential conversion resulting in the accumulation of palythene. PMID:16697653

  4. Quantum fog and the degradation of information by the gravitational field

    SciTech Connect

    Sciffer, M. )

    1993-07-01

    In this paper the authors discuss how information transferred optically through a gravitational field is degraded as the quanta interact with the medium (vacuum state). The authors quantify information by means of Shannon's entropy, and consider information carriers that are quanta of some field. Next, the authors obtain the quantum noise ([open quote]quantum fog[close quote]) produced by the gravitational field and derive the appropriate [open quote]channel capacity[close quote] formula, which quantifies the maximum amount of information that can be transmitted per pulse, in the face of this noise. It is shown that the channel capacity formula vanishes if the source of information is a space-time singularity because a very intense noise is produced in the vicinity of the singularity. In other words, space-time singularities are hidden behind a very intense [open quote]quantum fog[close quote] and cannot be optically observed. A second consequence is that information is degraded as anisotropies (lumpiness) develop in the universe. 32 refs., 9 figs., 5 figs.

  5. MOPA FEL Scheme as a Source of Primary Photons for Gamma-Gamma Collider at TESLA and SBLC

    NASA Astrophysics Data System (ADS)

    Saldin, E. L.; Schneidmiller, E. A.; Yurkov, M. V.

    1997-05-01

    The project of a Linear Collider (TESLA and SBLC options) is developed by the international TESLA collaboration. This project includes the second interaction region for γ γ and γe collisions as an additional option. High energy gamma-quanta are produced in the process of Compton backscattering of the laser photons on the electrons of the main linear accelerator. In the present study of the Linear Collider Project it has been accepted to use Master Oscillator -- Power Amplifier (MOPA) free electron laser (FEL) scheme as a laser system. In this scheme the optical pulse from Nd glass laser (λ = 1 μm, 1 MW peak power) is amplified by FEL amplifier up to the power of about 500 GW. These parameters of the laser system allows one to obtain 70 % conversion efficiency of the electrons into high energy gamma-quanta. The driving beam for the FEL amplifier is produced by the linear rf accelerator identical to the main accelerator, but with lower accelerating gradient due to higher beam load. Such a choice fits well to both TESLA and SBLC options. It is important that the requirements to the parameters of the FEL driving electron beam are rather moderate and can be provided by injector consisting of gridded thermoionic gun and subharmonic buncher.

  6. Paramagnetic Meissner effect in high-temperature superconductors: Experiments and interpretation

    SciTech Connect

    He, Y.; Muirhead, C.M.; Vinen, W.F.

    1996-05-01

    The results are presented of experiments on the paramagnetic Meissner effect, the appearance of a net paramagnetic moment when some high-temperature superconductors (especially Bi-Sr-Ca-Cu-O) are cooled in a very small magnetic field. For ease of interpretation the experiments relate exclusively to Bi-Sr-Ca-Cu-O in finely powdered form. Attention is paid not only to the magnetic moment observed during a field cool, but also to the moment remaining during a subsequent zero-field warm and to the moment developed during a field warm following a zero-field cool. The moments observed during a field cool are similar to those reported by other authors. A tentative interpretation of the results is made in terms of a model in which there is a concentration within the material of small local moments that can be polarized during a field cool. Information about both the magnitudes of these local moments and their concentrations is deduced. Evidence is presented that the observed local moments are too small to be accounted for by half flux quanta trapped in loops or within grains, such half flux quanta being associated with {pi} junctions or {ital d}-wave pairing. This suggests that either the local moments originate in some other way or the model is incorrect. {copyright} {ital 1996 The American Physical Society.}

  7. Photoregulation of the Light-Harvesting Chlorophyll Protein Complex Associated with Photosystem II in Dunaliella tertiolecta1

    PubMed Central

    Mortain-Bertrand, Anne; Bennett, John; Falkowski, Paul G.

    1990-01-01

    The marine chlorophyte Dunaliella tertiolecta Butcher responds to a one-step transition from a high growth irradiance level (700 micromoles quanta per square meter per second) to a low growth irradiance level (70 micromoles quanta per square meter per second) by increasing the total amount of light-harvesting chlorophyll (Chl) a/b binding protein associated with photosystem II (LHC II), and by modifying the relative abundance of individual LHC II apoproteins. When high light-adapted cells were incubated with gabaculine, which inhibits Chl synthesis, and transferred to low light, the LHC II apoproteins were still synthesized and the 35S-labeled LHC II apoproteins remained stable after a 24 hour chase. These results suggest that Chl synthesis is not required for stability of the LHC II apoproteins in this alga. However, when the control cells are transferred from high light to low light, the amount of the four LHC II apoproteins per cell increases, whereas it does not in the presence of gabaculine. These results suggest that Chl synthesis is required for a photoadaptive increase in the cellular level of LHC II. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 PMID:16667702

  8. A feasibility study of ortho-positronium decays measurement with the J-PET scanner based on plastic scintillators

    NASA Astrophysics Data System (ADS)

    Kamińska, D.; Gajos, A.; Czerwiński, E.; Alfs, D.; Bednarski, T.; Białas, P.; Curceanu, C.; Dulski, K.; Głowacz, B.; Gupta-Sharma, N.; Gorgol, M.; Hiesmayr, B. C.; Jasińska, B.; Korcyl, G.; Kowalski, P.; Krzemień, W.; Krawczyk, N.; Kubicz, E.; Mohammed, M.; Niedźwiecki, Sz.; Pawlik-Niedźwiecka, M.; Raczyński, L.; Rudy, Z.; Silarski, M.; Wieczorek, A.; Wiślicki, W.; Zgardzińska, B.; Zieliński, M.; Moskal, P.

    2016-08-01

    We present a study of the application of the Jagiellonian positron emission tomograph (J-PET) for the registration of gamma quanta from decays of ortho-positronium (o-Ps). The J-PET is the first positron emission tomography scanner based on organic scintillators in contrast to all current PET scanners based on inorganic crystals. Monte Carlo simulations show that the J-PET as an axially symmetric and high acceptance scanner can be used as a multi-purpose detector well suited to pursue research including e.g. tests of discrete symmetries in decays of ortho-positronium in addition to the medical imaging. The gamma quanta originating from o-Ps decay interact in the plastic scintillators predominantly via the Compton effect, making the direct measurement of their energy impossible. Nevertheless, it is shown in this paper that the J-PET scanner will enable studies of the { o-Ps }→ 3γ decays with angular and energy resolution equal to σ (θ ) ≈ {0.4°} and σ (E) ≈ 4.1 {keV}, respectively. An order of magnitude shorter decay time of signals from plastic scintillators with respect to the inorganic crystals results not only in better timing properties crucial for the reduction of physical and instrumental background, but also suppresses significantly the pile-ups, thus enabling compensation of the lower efficiency of the plastic scintillators by performing measurements with higher positron source activities.

  9. Quantum breathers in Klein-Gordon lattice: Non-periodic boundary condition approach

    NASA Astrophysics Data System (ADS)

    Mandal, Subhra Jyoti; Choudhary, Kamal; Biswas, Arindam; Bandyopadhyay, A. K.; Bhattacharjee, A. K.; Mandal, D.

    2011-12-01

    The presence of classical breathers and two-phonon bound state (TPBS) or quantum breather (QB) state through detailed quantum calculations have already been shown in technologically important ferroelectric materials, such as lithium niobate with antisite niobium charge defects concerning pinning transition, its control, and application. The latter was done in a periodic boundary condition with Bloch function in terms of significant variations of TPBS parameters against impurity, which is related to nonlinearity. In further extension of this work, in a non-periodic boundary condition and number-conserving approach, apart from various techniques available, only the temporal evolution of the number of quanta (i.e., phonons) in more sites is detailed in this present investigation for a generalized Klein-Gordon system with applications in ferroelectrics, metamaterials, and DNA. The critical time of redistribution of quanta that is proportional to the QB's lifetime in these materials shows different types of behavior in the femtosecond range, which gives rise to the possibilities for making various devices.

  10. Gravitational constant is likely dependent on the absolute velocity of galaxy

    NASA Astrophysics Data System (ADS)

    Chen, Shao-Guang

    In my paper ‘Quanta turn-advance ism, China Science && Technology Overview 131 192-210 (2011)’, QFT four-dimensional uncertainty principle and momentum-energy conservation law had been generalized as a five-dimensional equations: de Broglie wavelength as a position vector \\underline{q}= (i c t, r, s), momentum \\underline{P} = (i E/c, P, U c), \\underline{q} = i h / \\underline{P}, \\underline{q} \\underline{q} = 0, \\underline{P} \\underline{P} = 0, Sigma∑\\underline{P} = \\underline{P} (0) . The five-dimensional time-space-spin had been quantized as a non-dot model basic cell, the lowest energy state vertical polarized left spin 1/2 neutrino and right spin 1/2 antineutrino are just the left, right advance unit quanta _{0}nuυ, nuυ _{0} and left, right back unit quanta (0) nuυ, nuυ (0) , it again compose into spin 1 unit advance photon _{0}nuυnuυ _{0} and back (0) nuυnuυ (0) , spin 0 unit rest mass nuυ _{0}nuυ (0) and anti-mass _{0}nuυ (0) nuυ, spin 0 unit positive charge _{0}nuυnuυ (0) and negative charge nuυ _{0} (0) nuυ. It accord to the high energy physics experiment results of the transformation among the photons, masses quanta and charges quanta. The physical vacuum is the even collocation of non-combinational nuυ _{0} or _{0}nuυ. It is mathematically easy that from five-dimensional equations deduce out the Dirac, Klein-Gordan, Maxwell equations and Lorentz force formula, but appear some new results. The interactions between _{0}nuυ, nuυ _{0}, (0) nuυ, nuυ (0) , i.e., force f = ± ( h c / 2 r (3) ) r cos thetaθ for r not equal to 0 and f = 0 for r = 0, f as the magnetic force makes the photons, rest mass and charge quanta automatically come into being and stabilize. QFT no longer with divergence difficulty by the non-dot model. The explanation of abnormal magnetic moment and Lamb shift is more natural and simple only with the spin — the conjunction between turn and advance. Many testable results had been obtained. In the

  11. Combined effects of temperature, irradiance and salinity on growth of diatom Skeletonema costatum

    NASA Astrophysics Data System (ADS)

    Yan, Tian; Zhou, Mingjiang; Qian, Peiyuan

    2002-09-01

    3-factor experiment was used to study the combined effects of temperature, irradiance and salinity on the growth of an HAB species diatom Skeletonema costatum (Grev.) Cleve. The results showed that temperature (12, 19, 25, 32 °C), irradiance (0.02, 0.08, 0.3, 1.6)×1016 quanta/(s·cm2)) and salinity (10, 18, 25, 30, 35) significantly influenced the growth of this species. There were interactive effects between any two of and among all three physical factors on the growth. In the experiment, the most optimal growth condition for S. costatum was temperature of 25°C, salinity of 18 35 and irradiance of 1.6×1016 quanta/(s·cm2). The results indicated S. costatum could divide at higher rate and were more likely to bloom under high temperature and high illumination from spring to fall. It was able to distribute widely in ocean and estuary due to its adaptation to a wide range of salinities.

  12. Detection of autoantibodies using chemiluminescence technologies

    PubMed Central

    Mahler, Michael; Bentow, Chelsea; Serra, Josep; Fritzler, Marvin J.

    2016-01-01

    Abstract Context: Although autoantibody detection methods such as indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assays (ELISAs) have been available for many years and are still in use the innovation of fast, fully automated instruments using chemiluminescence technology in recent years has led to rapid adoption in autoimmune disease diagnostics. In 2009, BIO-FLASH, a fully automated, random access chemiluminescent analyzer, was introduced, proceeded by the development of the QUANTA Flash chemiluminescent immunoassays (CIA) for autoimmune diagnostics. Objective: To summarize the evolution of CIAs for the detection of autoantibodies and to review their performance characteristics. Methods: Pubmed was screened for publications evaluating novel QUANTA Flash assays and how they compare to traditional methods for the detection of autoantibodies. In addition, comparative studies presented at scientific meetings were summarized. Results: Several studies were identified that compared the novel CIAs with conventional methods for autoantibody detection. The agreements ranged from moderate to excellent depending on the assay. The studies show how the CIA technology has enhanced the analytical and clinical performance characteristics of many autoantibody assays supporting both diagnosis and follow-up testing. Conclusion: CIA has started to improve the diagnostic testing of autoantibodies as an aid in the diagnosis of a broad range of autoimmune diseases. PMID:26525648

  13. High-quality imaging in environmental scanning electron microscopy - optimizing the pressure limiting system and the secondary electron detection of a commercially available ESEM.

    PubMed

    Fitzek, H; Schroettner, H; Wagner, J; Hofer, F; Rattenberger, J

    2016-04-01

    In environmental scanning electron microscopy applications in the kPa regime are of increasing interest for the investigation of wet and biological samples, because neither sample preparation nor extensive cooling are necessary. Unfortunately, the applications are limited by poor image quality. In this work the image quality at high pressures of a FEI Quanta 600 (field emission gun) and a FEI Quanta 200 (thermionic gun) is greatly improved by optimizing the pressure limiting system and the secondary electron (SE) detection system. The scattering of the primary electron beam strongly increases with pressure and thus the image quality vanishes. The key to high-image quality at high pressures is to reduce scattering as far as possible while maintaining ideal operation conditions for the SE-detector. The amount of scattering is reduced by reducing both the additional stagnation gas thickness (aSGT) and the environmental distance (ED). A new aperture holder is presented that significantly reduces the aSGT while maintaining the same field-of-view (FOV) as the original design. With this aperture holder it is also possible to make the aSGT even smaller at the expense of a smaller FOV. A new blade-shaped SE-detector is presented yielding better image quality than usual flat SE-detectors. The electrode of the new SE detector is positioned on the sample table, which allows the SE-detector to operate at ideal conditions regardless of pressure and ED. PMID:26540292

  14. Kinetics of retrograde signalling initiation in the high light response of Arabidopsis thaliana.

    PubMed

    Alsharafa, Khalid; Vogel, Marc Oliver; Oelze, Marie-Luise; Moore, Marten; Stingl, Nadja; König, Katharina; Friedman, Haya; Mueller, Martin J; Dietz, Karl-Josef

    2014-04-19

    High light acclimation depends on retrograde control of nuclear gene expression. Retrograde regulation uses multiple signalling pathways and thus exploits signal patterns. To maximally challenge the acclimation system, Arabidopsis thaliana plants were either adapted to 8 (low light (L-light)) or 80 µmol quanta m(-2) s(-1) (normal light (N-light)) and subsequently exposed to a 100- and 10-fold light intensity increase, respectively, to high light (H-light, 800 µmol quanta m(-2) s(-1)), for up to 6 h. Both L → H- and N → H-light plants efficiently regulated CO2 assimilation to a constant level without apparent damage and inhibition. This experimental set-up was scrutinized for time-dependent regulation and efficiency of adjustment. Transcriptome profiles revealed that N-light and L-light plants differentially accumulated 2119 transcripts. After 6 h in H-light, only 205 remained differently regulated between the L → H- and N → H-light plants, indicating efficient regulation allowing the plants to reach a similar transcriptome state. Time-dependent analysis of transcripts as markers for signalling pathways, and of metabolites and hormones as possibly involved transmitters, suggests that oxylipins such as oxophytodienoic acid and jasmonic acid, metabolites and redox cues predominantly control the acclimation response, whereas abscisic acid, salicylic acid and auxins play an insignificant or minor role. PMID:24591725

  15. Second law considerations on the third law: From Boltzmann and Loschmidt paradox to non equilibrium temperature

    NASA Astrophysics Data System (ADS)

    Lucia, Umberto

    2016-02-01

    The balance of forces and processes between the system and the environment and the processes inside the system are the result of the flows of the quanta. Moreover, the transition between two thermodynamic states is the consequence of absorption or emission of quanta, but, during the transition, the entropy variation due to the irreversibility occurs and it breaks any symmetry of time. Consequently, the irreversibility is the result of a transition, a process, an interaction between the system and its environment. This interaction results completely time-irreversible for any real process because of irreversibility. As a consequence, a proof of the third law is obtained proving that the zero temperature state can be achieved only for an infinite work lost for dissipation or in an infinite time. The fundamental role of time both in equilibrium and in non equilibrium analysis is pointed out. Moreover, the non equilibrium temperature is related to the entropy generation and its fluctuation rate; indeed, non-stationary temperature means that the system has not yet attained free energy minimum state, i.e., the maximum entropy state; the consequence is that the zero temperature state can be achieved only for an infinite work lost for dissipation or in an infinite time. In engineering thermodynamics the efficiency is always obtained without any consideration on time, while, here, just the time is introduced as a fundamental quantity of the analysis of non equilibrium states.

  16. Use of effective detective quantum efficiency to optimise radiographic exposures for chest imaging with computed radiography

    NASA Astrophysics Data System (ADS)

    Ertan, Ferihan; Mackenzie, Alistair; Urbanczyk, Hannah J.; Ranger, Nicole T.; Samei, Ehsan

    2009-02-01

    The purpose of the work was to test if effective detective quantum efficiency (eDQE) could be useful for optimisation of radiographic factors for computed radiography (CR) for adult chest examinations. The eDQE was therefore measured across a range of kilovoltage, with and without an anti-scatter grid. The modulation transfer function, noise power spectra, transmission factor and scatter fraction were measured with a phantom made of sheets of Aluminum and Acrylic. The entrance air kerma was selected to give an effective dose of 4.9 μSv. The effective noise equivalent quanta (eNEQ) is introduced in this work. eNEQ can be considered equal to the number of X-ray quanta equivalent in the image corrected for the amount of scatter and the blurring processes. The eNEQ was then normalised to account for slight differences in the effective dose (eNEQED). The peak eNEQED was largest at 80 kV and 100 kV with no grid and with grid respectively. At each kilovoltage, the eNEQED and eDQE were between 10% and 70% larger when the grid was not used. The results show that 80 kV without grid is the most suitable exposure conditions for CR in chest. This is consistent with clinical practice in the UK and previous publications recommending a low kV technique for CR for average sized adult chest imaging.

  17. Nonvacuum initial states for cosmological perturbations of quantum-mechanical origin

    NASA Astrophysics Data System (ADS)

    Martin, Jérôme; Riazuelo, Alain; Sakellariadou, Mairi

    2000-04-01

    In the context of inflation, nonvacuum initial states for cosmological perturbations that possess a built in scale are studied. It is demonstrated that this assumption leads to a falsifiable class of models. The question of whether they lead to conflicts with the available observations is addressed. For this purpose, the power spectrum of the Bardeen potential operator is calculated and compared with the CMBR anisotropies measurements and the redshift surveys of galaxies and clusters of galaxies. Generic predictions of the model are a high first acoustic peak, the presence of a bump in the matter power spectrum and non-Gaussian statistics. The details are controlled by the number of quanta in the nonvacuum initial state. Comparisons with observations show that there exists a window for the free parameters such that good agreement between the data and theoretical predictions is possible. However, in the case where the initial state is a state with a fixed number of quanta, it is shown that this number cannot be greater than a few. On the other hand, if the initial state is a quantum superposition, then a larger class of initial states could account for the observations, even though the state cannot be too different from the vacuum. Planned missions such as the MAP and Planck satellites and the Sloan Survey will demonstrate whether the new class of models proposed here represents a viable alternative to the standard theory.

  18. Effective exposure level and diagnostic performance in endodontic radiography.

    PubMed

    Okano, T; Wiebe, J D; Webber, R L; Wagner, R F

    1983-05-01

    Image quality is limited by the information capacity of the image-forming system and can be computed from three parameters: contrast, resolution, and noise. These parameters can be combined to yield a single measure which determines the maximum amount of information obtainable from any x-ray system and is called the noise-equivalent number of quanta (NEQ) per unit area. The effects of image quality, expressed as noise-equivalent number of quanta (NEQ) per unit area, on the radiographic performance by dentists reading the position of an endodontic file in a root canal were studied. Three different speed films were used in conjunction with a fixed screen. NEQ values ranged between 0.64 x 10(4) and 14.3 x 10(4) per square millimeter. Components of variance associated with the position of the tooth apex and the tip of an endodontic file in a root canal were compared for the effect of different NEQs and observers. Results show that the standard deviation in locating a file tip and tooth apex may be a linear function of log NEQ. The estimated standard deviation associated with changes in NEQ was found to be relatively small compared to that observed among dentists. These findings indicate that a significant reduction in exposure would have a relatively small effect on the precision of endodontic distance measurements. PMID:6575345

  19. Magnetic orientation in birds: non-compass responses under monochromatic light of increased intensity.

    PubMed

    Wiltschko, Wolfgang; Munro, Ursula; Ford, Hugh; Wiltschko, Roswitha

    2003-10-22

    Migratory Australian silvereyes (Zosterops lateralis) were tested under monochromatic light at wavelengths of 424 nm blue and 565 nm green. At a low light level of 7 x 10(15) quanta m(-2) s(-1) in the local geomagnetic field, the birds preferred their seasonally appropriate southern migratory direction under both wavelengths. Their reversal of headings when the vertical component of the magnetic field was inverted indicated normal use of the avian inclination compass. A higher light intensity of 43 x 10(15) quanta m(-2) s(-1), however, caused a fundamental change in behaviour: under bright blue, the silvereyes showed an axial tendency along the east-west axis; under bright green, they showed a unimodal preference of a west-northwesterly direction that followed a shift in magnetic north, but was not reversed by inverting the vertical component of the magnetic field. Hence it is not based on the inclination compass. The change in behaviour at higher light intensities suggests a complex interaction between at least two receptors. The polar nature of the response under bright green cannot be explained by the current models of light-dependent magnetoreception and will lead to new considerations on these receptive processes. PMID:14561276

  20. Characterization of the physiology and cell-mineral interactions of the marine anoxygenic phototrophic Fe(II) oxidizer Rhodovulum iodosum--implications for Precambrian Fe(II) oxidation.

    PubMed

    Wu, Wenfang; Swanner, Elizabeth D; Hao, Likai; Zeitvogel, Fabian; Obst, Martin; Pan, Yongxin; Kappler, Andreas

    2014-06-01

    Anoxygenic phototrophic Fe(II)-oxidizing bacteria (photoferrotrophs) are suggested to have contributed to the deposition of banded iron formations (BIFs) from oxygen-poor seawater. However, most studies evaluating the contribution of photoferrotrophs to Precambrian Fe(II) oxidation have used freshwater and not marine strains. Therefore, we investigated the physiology and mineral products of Fe(II) oxidation by the marine photoferrotroph Rhodovulum iodosum. Poorly crystalline Fe(III) minerals formed initially and transformed to more crystalline goethite over time. During Fe(II) oxidation, cell surfaces were largely free of minerals. Instead, the minerals were co-localized with EPS suggesting that EPS plays a critical role in preventing cell encrustation, likely by binding Fe(III) and directing precipitation away from cell surfaces. Fe(II) oxidation rates increased with increasing initial Fe(II) concentration (0.43-4.07 mM) under a light intensity of 12 μmol quanta m(-2) s(-1). Rates also increased as light intensity increased (from 3 to 20 μmol quanta m(-2) s(-1)), while the addition of Si did not significantly change Fe(II) oxidation rates. These results elaborate on how the physical and chemical conditions present in the Precambrian ocean controlled the activity of marine photoferrotrophs and confirm the possibility that such microorganisms could have oxidized Fe(II), generating the primary Fe(III) minerals that were then deposited to some Precambrian BIFs. PMID:24606418

  1. Experimental Study of Spectral Properties of a Frenkel-Kontorova System.

    PubMed

    Lucci, M; Badoni, D; Merlo, V; Ottaviani, I; Salina, G; Cirillo, M; Ustinov, A V; Winkler, D

    2015-09-01

    We report on microwave emission from linear parallel arrays of underdamped Josephson junctions, which are described by the Frenkel-Kontorova (FK) model. Electromagnetic radiation is detected from the arrays when biased on current singularities (steps) appearing at voltages V(n)=Φ(0)(nc̅/L), where Φ(0)=2.07×10(-15)  Wb is the magnetic flux quantum, and c̅, L, and n are, respectively, the speed of light in the transmission line embedding the array, L its physical length, and n an integer. The radiation, detected at fundamental frequency c̅/2L when biased on different singularities, indicates shuttling of bunched 2π kinks (magnetic flux quanta). Resonance of flux-quanta motion with the small-amplitude oscillations induced in the arrays gives rise to fine structures in the radiation spectrum, which are interpreted on the basis of the FK model describing the resonance. The impact of our results on design and performances of new digital circuit families is discussed. PMID:26382697

  2. Energy requirements for quantum data compression and 1-1 coding

    SciTech Connect

    Rallan, Luke; Vedral, Vlatko

    2003-10-01

    By looking at quantum data compression in the second quantization, we present a model for the efficient generation and use of variable length codes. In this picture, lossless data compression can be seen as the minimum energy required to faithfully represent or transmit classical information contained within a quantum state. In order to represent information, we create quanta in some predefined modes (i.e., frequencies) prepared in one of the two possible internal states (the information carrying degrees of freedom). Data compression is now seen as the selective annihilation of these quanta, the energy of which is effectively dissipated into the environment. As any increase in the energy of the environment is intricately linked to any information loss and is subject to Landauer's erasure principle, we use this principle to distinguish lossless and lossy schemes and to suggest bounds on the efficiency of our lossless compression protocol. In line with the work of Bostroem and Felbinger [Phys. Rev. A 65, 032313 (2002)], we also show that when using variable length codes the classical notions of prefix or uniquely decipherable codes are unnecessarily restrictive given the structure of quantum mechanics and that a 1-1 mapping is sufficient. In the absence of this restraint, we translate existing classical results on 1-1 coding to the quantum domain to derive a new upper bound on the compression of quantum information. Finally, we present a simple quantum circuit to implement our scheme.

  3. Toward Quantum Plasmonics with Plasmon Drag Effect. Theory and Experiment

    NASA Astrophysics Data System (ADS)

    Durach, Maxim; Lepain, Matthew; Mapes, Zoe; Rono, Vincent; Noginova, Natalia

    Giant plasmon drag effect observed in plasmonic metal films and nanostructures brings new fundamental insights into ways in which light-matter interaction occurs. We demonstrate analytically, numerically and experimentally that rectified drag forces acting upon electrons in plasmonic metals are intimately related to the absorption of plasmonic excitations. The plasmon energy quanta absorbed by the metal plasma are associated with momentum quanta, which are also transferred to electrons upon energy absorption. We show that this picture directly applies to plasmon drag effect in a variety of systems, and, to our knowledge for the first time, is capable to explain and predict the magnitude of the effect not only qualitatively, but with close quantitative agreement. The plasmon drag effect opens new avenues for plasmonic-based electronics providing opportunities for incorporation of plasmonic circuits into electronic devices, and for optical sensing offering a new operational principle and an opportunity to substitute the bulky optical set-ups with diffraction limited sensing by electronics. Our work not only adds more clarity into the mechanism behind the plasmon drag effect but also contributes to the emerging field of quantum plasmonics.

  4. A statistical representation of the cosmological constant from finite size effects at the apparent horizon

    NASA Astrophysics Data System (ADS)

    Viaggiu, Stefano

    2016-07-01

    In this paper we present a statistical description of the cosmological constant in terms of massless bosons (gravitons). To this purpose, we use our recent results implying a non vanishing temperature {T_{Λ }} for the cosmological constant. In particular, we found that a non vanishing T_{Λ } allows us to depict the cosmological constant Λ as composed of elementary oscillations of massless bosons of energy hbar ω by means of the Bose-Einstein distribution. In this context, as happens for photons in a medium, the effective phase velocity v_g of these massless excitations is not given by the speed of light c but it is suppressed by a factor depending on the number of quanta present in the universe at the apparent horizon. We found interesting formulas relating the cosmological constant, the number of quanta N and the mean value overline{λ } of the wavelength of the gravitons. In this context, we study the possibility to look to the gravitons system so obtained as being very near to be a Bose-Einstein condensate. Finally, an attempt is done to write down the Friedmann flat equations in terms of N and overline{λ }.

  5. Infrared Spectra of the CO_2-H_2O, CO_2-(H_2O)2, and (CO_2)2-H_2O Complexes Isolated in Solid Neon Between 90 and 5300 wn

    NASA Astrophysics Data System (ADS)

    Tremblay, Benoît; Soulard, Pascale

    2015-06-01

    The van der Waals complex of H_2O with CO_2 has attracted considerable theoretical interest since it is a typical example of a weak binding complex (less than 3 kcal/mol), but a very few IR data are available in gas. For these reasons, we have studied in solid neon hydrogen bonded complexes involving carbon dioxide and water molecules. Evidence for the existence of at least three (CO_2)m(H_2O)n, or m:n, complexes has been obtained from the appearance of many new absorptions near the well-know monomers fundamental transitions. Concentration effects and detailed vibrational analysis allowed identification of fifteen, eleven and four transitions for the 1:1, 1:2, and 2:1 complexes, respectively. Careful examination of the far infrared allows the assignment of several 1:1 and 1:2 intermolecular modes, confirmed by the observation of combinations of intra+intermolecular transitions. All of these results significantly increase the number of one and, especially, two quanta vibrational transitions observed for these complexes, and anharmonic coupling constants have been derived. This study shows the high sensibility of the solid neon isolation for the spectroscopy of the hydrogen-bonded complexes since two quanta transitions can't be easily observed in gas phase.

  6. Experimental Study of Spectral Properties of a Frenkel-Kontorova System

    NASA Astrophysics Data System (ADS)

    Lucci, M.; Badoni, D.; Merlo, V.; Ottaviani, I.; Salina, G.; Cirillo, M.; Ustinov, A. V.; Winkler, D.

    2015-09-01

    We report on microwave emission from linear parallel arrays of underdamped Josephson junctions, which are described by the Frenkel-Kontorova (FK) model. Electromagnetic radiation is detected from the arrays when biased on current singularities (steps) appearing at voltages Vn=Φ0(n c ¯ /L ) , where Φ0=2.07 ×10-15 Wb is the magnetic flux quantum, and c ¯, L , and n are, respectively, the speed of light in the transmission line embedding the array, L its physical length, and n an integer. The radiation, detected at fundamental frequency c ¯ /2 L when biased on different singularities, indicates shuttling of bunched 2 π kinks (magnetic flux quanta). Resonance of flux-quanta motion with the small-amplitude oscillations induced in the arrays gives rise to fine structures in the radiation spectrum, which are interpreted on the basis of the FK model describing the resonance. The impact of our results on design and performances of new digital circuit families is discussed.

  7. Non-destructive NIR-FT-raman analyses in practice. Part II. Analyses of 'jumping' crystals, photosensitive crystals and gems.

    PubMed

    Andreev, G N; Schrader, B; Boese, R; Rademacher, P; von Cranach, L

    2001-12-01

    Using an improved sampling arrangement we observed the FT Raman spectra of the different phases of a 'jumping crystal', an inositol derivative. The phase transition produced--as consequences of large changes of the unit cell constants--changes in frequency and intensity mainly of CH deformation vibrations. Photochemical reactions, usually produced with light quanta in the visible range, are not activated with the quanta from the Nd:YAG laser at 1064 nm. The Raman spectra of the 'dark' form of a dinitrobenzyl pyridine and afterwards the 'light' form, the product of its illumination in the visible range, were recorded. We could not observe changes of most bands, especially not of the NO2-vibrations; however, a new strong band appeared at 1253 cm(-1), which may be due to the expected NH-photo-isomer. Genuine gemstones and fakes can be unambiguously identified by FT Raman spectroscopy. This is especially useful for the stones whose physical properties are quite similar to those of diamonds--moissanite and zirconia. The quality of diamonds can be estimated from relative band intensities; however, this is not in complete agreement with the internationally accepted visual qualification. Synthetic diamonds produced by CVD (chemical vapor deposition) show remarkable differences from natural ones in their FT-Raman spectra. PMID:11769791

  8. A Scalable Microfabricated Ion Trap for Quantum Information Processing

    NASA Astrophysics Data System (ADS)

    Maunz, Peter; Haltli, Raymond; Hollowell, Andrew; Lobser, Daniel; Mizrahi, Jonathan; Rembetski, John; Resnick, Paul; Sterk, Jonathan D.; Stick, Daniel L.; Blain, Matthew G.

    2016-05-01

    Trapped Ion Quantum Information Processing (QIP) relies on complex microfabricated trap structures to enable scaling of the number of quantum bits. Building on previous demonstrations of surface-electrode ion traps, we have designed and characterized the Sandia high-optical-access (HOA-2) microfabricated ion trap. This trap features high optical access, high trap frequencies, low heating rates, and negligible charging of dielectric trap components. We have observed trap lifetimes of more than 100h, measured trap heating rates for ytterbium of less than 40quanta/s, and demonstrated shuttling of ions from a slotted to an above surface region and through a Y-junction. Furthermore, we summarize demonstrations of high-fidelity single and two-qubit gates realized in this trap. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000. This work was supported by the Intelligence Advanced Research Projects Activity (IARPA).

  9. The detective quantum efficiency of photon-counting x-ray detectors using cascaded-systems analyses

    SciTech Connect

    Tanguay, Jesse; Yun, Seungman; Kim, Ho Kyung; Cunningham, Ian A.

    2013-04-15

    Purpose: Single-photon counting (SPC) x-ray imaging has the potential to improve image quality and enable new advanced energy-dependent methods. The purpose of this study is to extend cascaded-systems analyses (CSA) to the description of image quality and the detective quantum efficiency (DQE) of SPC systems. Methods: Point-process theory is used to develop a method of propagating the mean signal and Wiener noise-power spectrum through a thresholding stage (required to identify x-ray interaction events). The new transfer relationships are used to describe the zero-frequency DQE of a hypothetical SPC detector including the effects of stochastic conversion of incident photons to secondary quanta, secondary quantum sinks, additive noise, and threshold level. Theoretical results are compared with Monte Carlo calculations assuming the same detector model. Results: Under certain conditions, the CSA approach can be applied to SPC systems with the additional requirement of propagating the probability density function describing the total number of image-forming quanta through each stage of a cascaded model. Theoretical results including DQE show excellent agreement with Monte Carlo calculations under all conditions considered. Conclusions: Application of the CSA method shows that false counts due to additive electronic noise results in both a nonlinear image signal and increased image noise. There is a window of allowable threshold values to achieve a high DQE that depends on conversion gain, secondary quantum sinks, and additive noise.

  10. The origin of unequal bond lengths in the C ˜ 1B2 state of SO2: Signatures of high-lying potential energy surface crossings in the low-lying vibrational structure

    NASA Astrophysics Data System (ADS)

    Park, G. Barratt; Jiang, Jun; Field, Robert W.

    2016-04-01

    The C ˜ 1B2 state of SO2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. The asymmetry in the potential energy surface is expressed as a staggering in the energy levels of the ν3' progression. We have recently made the first observation of low-lying levels with odd quanta of v3', which allows us—in the current work—to characterize the origins of the level staggering. Our work demonstrates the usefulness of low-lying vibrational level structure, where the character of the wavefunctions can be relatively easily understood, to extract information about dynamically important potential energy surface crossings that occur at much higher energy. The measured staggering pattern is consistent with a vibronic coupling model for the double-minimum, which involves direct coupling to the bound 2 1A1 state and indirect coupling with the repulsive 3 1A1 state. The degree of staggering in the ν3' levels increases with quanta of bending excitation, which is consistent with the approach along the C ˜ state potential energy surface to a conical intersection with the 2 1A1 surface at a bond angle of ˜145°.

  11. HOTB: High precision parallel code for calculation of four-particle harmonic oscillator transformation brackets

    NASA Astrophysics Data System (ADS)

    Stepšys, A.; Mickevicius, S.; Germanas, D.; Kalinauskas, R. K.

    2014-11-01

    effective way, which allows us to calculate matrix of the brackets up to a few hundred times more rapidly and more accurate than in a previous version. Solution method: Using external parallelization libraries and mutable precision we created a pack of numerical codes based on the methods of compact expressions of the three and four-particle harmonics oscillator brackets 3HOB, 4HOB, presented in [3]. Restrictions: For double precision version calculations can be done up to harmonic oscillator (HO) energy quanta e=28. For quadruple precision mantissa is equal to approximately 34 decimal digits, therefore calculations can be done up to HO energy quanta to e=52. Running time: The running time depends on the harmonic oscillator energy quanta, cluster size and the precision of intermediate calculations. More information on Table 1 for 3HOB and Table 2 for 4HOB. Reasons for a new version: The new program version expands the limits of harmonic oscillator energy quanta and gives shorter calculation time. Extend the limits of calculation of HOB First version was able to produce harmonic oscillator transformation brackets for three and four particles if E≤HO energy quanta. With this version of our program, if quadruple or arbitrary precision functions are being used, it is possible to calculate three and four particle harmonic oscillator transformation brackets for greater values of energy and momenta, while sustaining tolerable margin of error. Calculation time As the code of previous version of program was redone using parallelism paradigma, it is now possible to reduce the calculation time of transformation matrices significantly, depending on the size of computing cluster, as the dimensions of matrices are growing very rapidly according to the energy and momenta values. subroutinematrix_4HOB_dimensionCalculates the dimension of 4HOB matrix. subroutinematrix_3HOB_dimensionCalculates the dimension of 3HOB matrix, subroutinematrix_3HOBCalculates the global state array which is

  12. Picosecond CARS measurements of nitrogen vibrational loading and rotational/translational temperature in non-equilibrium discharges

    NASA Astrophysics Data System (ADS)

    Montello, A.; Yin, Z.; Burnette, D.; Adamovich, I. V.; Lempert, W. R.

    2013-11-01

    Picosecond coherent anti-Stokes Raman spectroscopy (CARS) is used to study vibrational energy loading and relaxation kinetics in nitrogen and air ns pulsed non-equilibrium plasmas, in both plane-to-plane and pin-to-pin geometries. In 10 kHz repetitively pulsed plane-to-plane plasmas, up to ˜50% of coupled discharge power is found to load vibrations, in good agreement with a master equation kinetic model. In the pin-to-pin geometry, ˜40% of total discharge energy in a single pulse in air at 100 Torr is found to couple directly to nitrogen vibrations by electron impact, also in good agreement with model predictions. Post-discharge, the total quanta in vibrational levels v = 0-9 is found to increase by ˜60% in air and by a factor of ˜3 in nitrogen, respectively, a result in direct contrast to modelling results which predict the total number of quanta to be essentially constant until ultimately decaying by V-T relaxation and mass diffusion. More detailed comparison between experiment and model show that the vibrational distribution function (VDF) predicted by the model during, and directly after, the discharge pulse is in good agreement with that determined experimentally. However, for time delays exceeding ˜1 µs, the experimental VDF shows populations of vibrational levels v ⩾ 2 greatly exceeding modelling results, which predict their predominant decay due to net downward V-V transfer and corresponding increase in v = 1 population. This is at variance with the experimental results, which show a significant monotonic increase in the populations of levels v = 2-9 at t ˜ 1-10 µs after the discharge pulse, both in nitrogen and air, before gradually switching to relaxation at t ˜ 10-100 µs. It is concluded that a collisional process is likely feeding high vibrational levels at a rate which is comparable to the rate at which population of the high levels is lost due to net downward V-V energy transfer. A likely candidate for the source of additional vibrational

  13. Gravitational Spacecraft Anomalies as well as the at Present Relatively large Uncertainty of Newton's Gravity Constant are Explained on the Basis of Force-Effects Due to a so-far Unknown Form of Space-like Matter

    NASA Astrophysics Data System (ADS)

    Volkamer, Klaus

    2009-09-01

    Recently, a so-far unkown form of invisible, space-like and field-like form of matter was detected with real, weighable mass content. The observed quanta of field-like matter exhibit in laboratory experiments Planck mass mp = ℏ.c/G = 21.77 μg. They show either a positive or negative sign, and can be understood as candidates for dark matter (field-like quanta with positive sign) and dark energy (field-like quanta with negative sign). Due to the observed gravitational as well as ``topological'' (i.e. form-specific at phase borders) interaction of space-like matter, celestial objects at various scales build up quantized fields of these forms of matter around their centers' of gravity of normal matter which reach far beyond the observable surface of such objects, respectively. From the description of he space-like matter fields of the Sun and the Earth a quantitative explanation of the reported NASA spacecraft anomalies of Pioneer 10 and 11 as well as of NEAR-Shoemaker at its fly-by maneuver on 01/23/1998 at Earth is given. The structure of such quantized subtle matter fields of stars allow in addition a description of the formation of ``normal'' and ``inverse'' planetary nebulae at the end of a star's life.-So-far unknown physical force-effects between subtle matter fields, bound, due to the topological interaction, at various metals were observed. The results allow an explanation of the at present relatively large uncertainty ΔG/G in the determination of Newton's constant of gravity. Devices for a more precise and reproducible determination of G (with an accuracy comparable to that of Planck's quantum of action, for example) should be made of beryllium or aluminium/berylUum alloy to eliminate subtle matter effects or such effects should be taken into account by a comprehensive theoretical modeling of their material and shape (and also to some extend time and place) depending force actions. Thus, both anomalies, the reported NASA spacecraft acceleration anomalies

  14. Mass-Boom Versus Big-Bang: An Alternative Model

    NASA Astrophysics Data System (ADS)

    Alfonso-Faus, Antonio

    2006-03-01

    In an effort to advance a first step in the long journey to harmonize Einstein's General Relativity with Quantum Mechanics, we interpret the gravitational field as a sea of gravity quanta. We calculate the value of the mass of these quanta by imposing the condition that their energy cannot be localized in the Universe (a General Relativity property of the gravitational field energy). These quanta have negative energy that is emitted in each quantum, one by one, from every fundamental particle with gravitational properties. It follows that the emitting positive masses increase their value linearly with cosmological time (this effect is what we call the Mass-Boom and is present in the entire Universe). In particular, it turns out that the mass of the Universe M is equivalent to its age t, and to its gravitational entropy S, (i.e. M = t = S), in a certain system of units that convert many fundamental laws to very simple relations. This is the Mass- Boom cosmological model, which we have published elsewhere under various points of view (all giving the same result). The Mass-Boom cosmological model is identical to the one that Einstein initially proposed: a static, finite, curved and unlimited model, that today we know is stable. The Hubble observation of the red shifts, as a possible indication of an expanding Universe, is here interpreted in a very different way: we consider our LAB systems not to be rigid, fixed in size. If the Universe is the static (rigid) general reference, as Einstein first saw, then the Hubble observations must be interpreted as a proof of a local shrinkage of the quantum world. Instead of an expanding Universe we get the picture of a contracting quantum world. This new view is very well justified because it explains many of the problems that have plagued the standard model (the big-bang). It also eliminates the need for additions/corrections to the standard model, like the addition of ``inflation'', to solve the inconsistencies of the model

  15. Investigation of TeV Gamma-Ray Emission from Cygnus X-3

    NASA Astrophysics Data System (ADS)

    Georgievna Sinitsyna, V.; Arsov, T.P.; Alaverdian, A.Y.; Borisov, S.S.; Musin, F.I.; Mirzafatikhov, R.M.; Nikolsky, S.I.; Kasparov, G.M.; Sinitsyna, V.Y.; Platonov, G.F.

    2003-07-01

    Cherenkov mirror telescope SHALON-1 created at Leb edev Physical Institute and stated at 1991-1992 y. at Tien-Shan mountains 3338 m high above the sea level with 11,2 m2 mirror area and image matrix consisting of 144 photomultipliers with total viewing angle of 8o during 1992-2003 y. was used for observations of galactic sources: Crab Nebula, Cygnus X-3 Ticho Brage, Geminga and metagalactic sources: Markarian 421, Markarian 501, NGC 1275, 3C454.3, 1739+522. Timing analysis show that the contribution of protons of cosmic rays in observable gamma-quanta with energy more than 0.8TeV from the point sources of gammaquanta very high energies do not exceed 10% 15%. The fluxes at energy above 0.8TeV of observation Cygnus X-3 (4.20 ± 0.70) • 10-13 cm-2 s-1 is and Crab Nebula (1.10 ± 0.13) • 10-12 cm-2 s-1 . The observable energy distribution of gamma quanta in an interval of energy 1012 - 5 • 1013 from the local sources in our Galaxy do not contradict with the spectrum of Cygnus X-3 dF /dEγ ˜ Eγ 2.20±0.14 ,- of Crab Nebula -dF /dEγ ˜ Eγ 2.45±0.04 . The observed spectra of the gamma- quanta including the 10%-15% contribution of the proton showers is for Cygnus dF /dE ˜ E -2.51±0.22 , for Crab Nebula dF /dE ˜ E -2.61±0.04 . The images of Cygnus X-3 and Crab Nebula are also presented. One of the basic science parts is nuclear physics, physics of elementary particles and connected with them astrophysics and cosmology, studied the matter structure on micro and macro scales. The gamma-astronomy is a unique experimental possibility of high-energy cosmic rays sources (1012 - 1014 eV) location now. Only neutrino-astronomy will complete search and investigation of galactic and metagalactic objects where the protons and nuclei acceleration processes, accompanying with generation of non scattering by Universal magnetic fields gammas and neutrinos. The cosmological processes, connecting the physic of matter structure with its superdense quasistable state in active

  16. NREL/SCE High Penetration PV Integration Project: FY13 Annual Report

    SciTech Connect

    Mather, B. A.; Shah, S.; Norris, B. L.; Dise, J. H.; Yu, L.; Paradis, D.; Katiraei, F.; Seguin, R.; Costyk, D.; Woyak, J.; Jung, J.; Russell, K.; Broadwater, R.

    2014-06-01

    In 2010, the National Renewable Energy Laboratory (NREL), Southern California Edison (SCE), Quanta Technology, Satcon Technology Corporation, Electrical Distribution Design (EDD), and Clean Power Research (CPR) teamed to analyze the impacts of high penetration levels of photovoltaic (PV) systems interconnected onto the SCE distribution system. This project was designed specifically to benefit from the experience that SCE and the project team would gain during the installation of 500 megawatts (MW) of utility-scale PV systems (with 1-5 MW typical ratings) starting in 2010 and completing in 2015 within SCE's service territory through a program approved by the California Public Utility Commission (CPUC). This report provides the findings of the research completed under the project to date.

  17. {phi}{phi} Back-to-Back Correlations in Finite Expanding Systems

    SciTech Connect

    Padula, S. S.; Krein, G.; Hama, Y.; Panda, P. K.; Csoergo, T.

    2006-04-11

    Back-to-Back Correlations (BBC) of particle-antiparticle pairs are predicted to appear if hot and dense hadronic matter is formed in high energy nucleus-nucleus collisions. The BBC are related to in-medium mass-modification and squeezing of the quanta involved. Although the suppression of finite emission times were already known, the effects of finite system sizes and of collective phenomena had not been studied yet. Thus, for testing the survival and magnitude of the effect in more realistic situations, we study the BBC when mass-modification occurs in a finite sized, thermalized medium, considering a non-relativistically expanding fireball with finite emission time, and evaluating the width of the back-to-back correlation function. We show that the BBC signal indeed survives the expansion and flow effects, with sufficient magnitude to be observed at RHIC.

  18. Back-to-back correlations for finite expanding fireballs

    SciTech Connect

    Padula, Sandra S.; Krein, G.; Csoergo'', T.; Hama, Y.; Panda, P.K.

    2006-04-15

    Back-to-back correlations of particle-antiparticle pairs are related to the in-medium mass-modification and squeezing of the quanta involved. They are predicted to appear when hot and dense hadronic matter is formed in high energy nucleus-nucleus collisions. The survival and magnitude of the back-to-back correlations (BBC) of boson-antiboson pairs generated by in-medium mass modifications are studied here in the case of a thermalized, finite-sized, spherically symmetric expanding medium. We show that the BBC signal indeed survives the finite-time emission, as well as the expansion and flow effects, with sufficient intensity to be observed at BNL Relativistic Heavy Ion Collider (RHIC)

  19. High resolution spectroscopy of the Ar-D2O and Ar-HDO molecular complexes in the near-infrared range.

    PubMed

    Didriche, K; Földes, T

    2013-03-14

    Three rovibrational bands of Ar-D2O and two rovibrational bands of Ar-HDO were observed in the 1.5 μm range by continuous wave cavity ringdown spectroscopy. Their analyses led to the determination of rotational constants for the upper states and vibrational shifts indicating that the potential energy surface is only slightly affected by the vibrational excitation. Some Coriolis couplings were identified. The observed lines were fitted to retrieve a 3.5 ns lifetime of the upper state, showing that even with a triple or double excitation quanta in the water subunit, the Ar-D2O and Ar-HDO complexes are long-lived species. PMID:23514489

  20. Strong vortex matching effects in YBCO films with periodic modulations of the superconducting order parameter fabricated by masked ion irradiation

    NASA Astrophysics Data System (ADS)

    Haag, L. T.; Zechner, G.; Lang, W.; Dosmailov, M.; Bodea, M. A.; Pedarnig, J. D.

    2014-08-01

    We report on measurements of the magnetoresistance and of the critical current in thin films of the high-temperature superconductor YBa2Cu3O7-δ (YBCO). A square array of regions with suppressed superconducting order parameter has been created in these films by introducing point defects via irradiation with He+ ions through a silicon stencil mask. In such a structure distinct peaks of the critical current can be observed at commensurate arrangements of magnetic flux quanta with the artificial defect lattice. Concurrently, the magnetoresistance shows pronounced minima. Both observations demonstrate that the strong intrinsic pinning in YBCO can be overcome by a periodic array of ion-damage columns with 300 nm spacing.

  1. Anisotropy of radiation emitted from planar wire arrays

    NASA Astrophysics Data System (ADS)

    Kantsyrev, V. L.; Chuvatin, A. S.; Esaulov, A. A.; Safronova, A. S.; Rudakov, L. I.; Velikovich, A.; Williamson, K. M.; Osborne, G. C.; Shrestha, I. K.; Weller, M. E.; Shlyaptseva, V. V.

    2013-07-01

    The planar wire array (PWA) is a promising load for new multi-source inertial confinement fusion (ICF) hohlraums [B. Jones et al., Phys. Rev. Lett. 104, 125001 (2010)]. The hohlraum radiation symmetry is an important issue for ICF. It was found that extreme ultraviolet and sub-keV photon emission from PWAs may have considerable anisotropy in the load azimuthal plane. This experimental result is obtained on the UNR 1-1.7 MA Zebra generator. The time-dependent anisotropy effect is detected. This feature is studied in 2D numerical simulations and can be explained by initial anisotropy of implosion of those non-cylindrical loads radiating essentially as surface sources in sub-keV quanta and also by radiation absorption in cold magnetized plasma tails forming in the direction of magnetic compression.

  2. Attractive Bose gas in two dimensions: An analytical study of its fragmentation and collapse

    NASA Astrophysics Data System (ADS)

    Tsatsos, Marios C.

    2014-04-01

    An attractive Bose-Einstein condensate in two spatial dimensions is expected to collapse for supercritical values of the interaction strength. Moreover, it is known that for nonzero quanta of angular momentum and infinitesimal attraction the gas prefers to fragment and distribute its angular momentum over different orbitals. In this work we examine the two-dimensional trapped Bose gas for finite values of attraction and describe the ground state in connection to its angular momentum by theoretical methods that go beyond the standard Gross-Pitaevskii theory. By applying the best-mean-field approach over a variational ansatz whose accuracy has been checked numerically, we derive analytical relations for the energy, the fragmentation of the ground states, and the critical (for collapse) value of the attraction strength as a function of the total angular momentum L.

  3. Shot Noise of 1,4-Benzenedithiol Single-Molecule Junctions.

    PubMed

    Karimi, M A; Bahoosh, S G; Herz, M; Hayakawa, R; Pauly, F; Scheer, E

    2016-03-01

    We report measurements of the shot noise on single-molecule Au-1,4-benzenedithiol-Au junctions, fabricated with the mechanically controllable break junction (MCBJ) technique at 4.2 K in a wide range of conductance values from 10(-2) to 0.24 conductance quanta. We introduce a simple measurement scheme using a current amplifier and a spectrum analyzer and that does not imply special requirements regarding the electrical leads. The experimental findings provide evidence that the current is carried by a single conduction channel throughout the whole conductance range. This observation suggests that the number of channels is limited by the Au-thiol bonds and that contributions due to direct tunneling from the Au to the π-system of the aromatic ring are negligible also for high conductance. The results are supported by quantum transport calculations using density functional theory. PMID:26859711

  4. Cosmological model with gravitational, electromagnetic, and scalar waves

    SciTech Connect

    Charach, C.; Malin, S.

    1980-06-15

    Following Gowdy, Berger, and Misner we construct a new exact solution of the Einstein--Maxwell--massless-scalar-field equations which corresponds to an inhomogeneous closed universe filled with scalar, gravitational, and electromagnetic waves. It is obtained as a result of homogeneity breaking in the corresponding Bianchi type-I universe. The combined effect of the scalar and vector fields on the dynamics of the evolution process and the interactions between the fields involved are systematically investigated. The structure of the initial singularity is studied in detail in both the homogeneous and inhomogeneous cases. The final stage of evolution is studied and interpreted in terms of the quanta of scalar, gravitational, and electromagnetic fields. Possible extensions of the present model to the conformally coupled scalar field and the Abelian solutions of the Yang-Mills field equations are pointed out.

  5. Manifestation of the Hofstadter butterfly in far-infrared absorption

    SciTech Connect

    Gudmundsson, V.; Gerhardts, R.R.

    1996-08-01

    The far-infrared absorption of a two-dimensional electron gas with a square-lattice modulation in a perpendicular constant magnetic field is calculated self-consistently within the Hartree approximation. For strong modulation and short period we obtain intrasubband and intersubband magnetoplasmon modes reflecting the subbands of the Hofstadter butterfly in two or more Landau bands. The character of the absorption and the correlation of the peaks to the number of flux quanta through each unit cell of the periodic potential depends strongly on the location of the chemical potential with respect to the subbands, or equivalently, on the density of electrons in the system. {copyright} {ital 1996 The American Physical Society.}

  6. Synthetic magnetic fluxes on the honeycomb lattice

    SciTech Connect

    Gorecka, Agnieszka; Gremaud, Benoit; Miniatura, Christian

    2011-08-15

    We devise experimental schemes that are able to mimic uniform and staggered magnetic fluxes acting on ultracold two-electron atoms, such as ytterbium atoms, propagating in a honeycomb lattice. The atoms are first trapped into two independent state-selective triangular lattices and then further exposed to a suitable configuration of resonant Raman laser beams. These beams induce hops between the two triangular lattices and make atoms move in a honeycomb lattice. Atoms traveling around each unit cell of this honeycomb lattice pick up a nonzero phase. In the uniform case, the artificial magnetic flux sustained by each cell can reach about two flux quanta, thereby realizing a cold-atom analog of the Harper model with its notorious Hofstadter's butterfly structure. Different condensed-matter phenomena such as the relativistic integer and fractional quantum Hall effects, as observed in graphene samples, could be targeted with this scheme.

  7. Perturbed Angular Correlation of the stretched cascade in the decay of 180mHf using a digital spectrometer

    NASA Astrophysics Data System (ADS)

    Jäger, Markus; Butz, Tilman

    2012-05-01

    We report on the measurement of the nuclear quadrupole interaction (NQI) at Hf sites using the nuclear probe 180mHf in HfF4·HF·2H2O at 300 K by exploiting all possible start quanta in the stretched cascade with a digital Time Differential Perturbed Angular Correlation (TDPAC) spectrometer. With conventional spectrometers, multiple prompt start signals would paralyze the router. The gain in coincidence rate is about a factor of 5 compared to a conventional spectrometer using a single start only. With multiple starts 180mHf is a promising new isomeric nuclear probe in TDPAC experiments. As an additional feature we implemented the possibility to measure up to four cascades simultaneously in order to save data collection time or to measure isobaric contaminations like 111mCd and 111In.

  8. Comparative analysis of shot noise in EUV and e-beam lithography

    NASA Astrophysics Data System (ADS)

    Bhattarai, Suchit; Chao, Weilun; Neureuther, Andrew R.; Naulleau, Patrick P.

    2014-04-01

    Gray-scale e-beam lithography has been performed to match the EUV and e-beam aerial image log slope for studying shot noise fundamentals in the two mechanisms through line-edge roughness (LER) measurements for 50 nm lines and spaces patterned on a leading chemically amplified EUV resist. The measured e-beam exposure latitude decreased from 0.4 with binary patterning to 0.28 with gray-scale e-beam exposure designed to match the EUV incident image profile, closely matching the EUV exposure latitude of 0.26. Calculations of absorption statistics with EUV and e-beam suggest that the shot noise with e-beam patterning is expected to be 10% larger than the shot noise with EUV patterning. However, despite the matched image gradients and close to identical absorbed quanta predictions, the e-beam patterned LER is 2.5× larger than the EUV patterned LER.

  9. Bremsstrahlung-induced fission and spallation of the pre-actinide nucleus 181Ta

    NASA Astrophysics Data System (ADS)

    Deppman, A.; Karapetyan, G. S.; Guimarães, V.; Gonzales, C.; Balabekyan, A. R.; Demekhina, N. A.

    2015-02-01

    A study of photofission on 181Ta induced by bremsstrahlung with endpoint energies of 50 and 3500 MeV has been performed. The fission yields have been measured by using the induced-activity method in an off-line analysis. The total photofission yields for the tantalum target at 50 and 3500 MeV are found to be 5.4 ±1.1 μ b / equivalent quanta per second (eq.q) and 0.77 ±0.11 mb/eq.q, respectively, and the corresponding deduced fissilities are (0.23 ±0.05 )×10-3 and (2.9 ±0.5 )×10-3 . Mass- and charge-yield distributions were derived from the data. The results were compared with the simulated results from the crisp code for multimodal fission by the assuming symmetrical fission mode.

  10. Table-top ultrafast x-ray microcalorimeter spectrometry for molecular structure.

    PubMed

    Uhlig, J; Fullagar, W; Ullom, J N; Doriese, W B; Fowler, J W; Swetz, D S; Gador, N; Canton, S E; Kinnunen, K; Maasilta, I J; Reintsema, C D; Bennett, D A; Vale, L R; Hilton, G C; Irwin, K D; Schmidt, D R; Sundström, V

    2013-03-29

    This work presents an x-ray absorption measurement by use of ionizing radiation generated by a femtosecond pulsed laser source. The spectrometer was a microcalorimetric array whose pixels are capable of accurately measuring energies of individual radiation quanta. An isotropic continuum x-ray spectrum in the few-keV range was generated from a laser plasma source with a water-jet target. X rays were transmitted through a ferrocene powder sample to the detector, whose pixels have average photon energy resolution ΔE=3.14  eV full-width-at-half-maximum at 5.9 keV. The bond distance of ferrocene was retrieved from this first hard-x-ray absorption fine-structure spectrum collected with an energy-dispersive detector. This technique will be broadly enabling for time-resolved observations of structural dynamics in photoactive systems. PMID:23581383

  11. The Construction of Spin Foam Vertex Amplitudes

    NASA Astrophysics Data System (ADS)

    Bianchi, Eugenio; Hellmann, Frank

    2013-01-01

    Spin foam vertex amplitudes are the key ingredient of spin foam models for quantum gravity. These fall into the realm of discretized path integral, and can be seen as generalized lattice gauge theories. They can be seen as an attempt at a 4-dimensional generalization of the Ponzano-Regge model for 3d quantum gravity. We motivate and review the construction of the vertex amplitudes of recent spin foam models, giving two different and complementary perspectives of this construction. The first proceeds by extracting geometric configurations from a topological theory of the BF type, and can be seen to be in the tradition of the work of Barrett, Crane, Freidel and Krasnov. The second keeps closer contact to the structure of Loop Quantum Gravity and tries to identify an appropriate set of constraints to define a Lorentz-invariant interaction of its quanta of space. This approach is in the tradition of the work of Smolin, Markopoulous, Engle, Pereira, Rovelli and Livine.

  12. Theoretical investigation of the relaxation of the bending mode of CH{sub 2}(X{sup ~}) by collisions with helium

    SciTech Connect

    Ma, Lifang; Dagdigian, Paul J.; Alexander, Millard H.

    2014-12-07

    We have earlier determined the dependence on the bending angle of the interaction of the methylene radical (CH{sub 2}) in its X{sup ~3}B{sub 1} state with He [L. Ma, P. J. Dagdigian, and M. H. Alexander, J. Chem. Phys. 136, 224306 (2012)]. By integration over products of the bending vibrational wave function, in a quantum close-coupled treatment we have calculated cross sections for the ro-vibrational relaxation of CH{sub 2}(X{sup ~}). Specifically, we find that cross sections for a loss of one vibrational quantum (v{sub b} = 2 → 1 and 1 → 0) are roughly two orders of magnitude smaller, and those for a loss of two vibrational quanta (v{sub b} = 2 → 0) four orders of magnitude smaller, than those for pure rotational relaxation. In addition, no clear cut dependence on the energy gap is seen.

  13. Physics of Gravitational Interaction: Geometry of Space or Quantum Field in Space

    NASA Astrophysics Data System (ADS)

    Baryshev, Yurij

    2006-03-01

    Thirring-Feynman's tensor field approach to gravitation opens new understanding on the physics of gravitational interaction and stimulates novel experiments on the nature of gravity. According to Field Gravity, the universal gravity force is caused by exchange of gravitons - the quanta of gravity field. Energy of this field is well-defined and excludes the singularity. All classical relativistic effects are the same as in General Relativity. The intrinsic scalar (spin 0) part of gravity field corresponds to ``antigravity'' and only together with the pure tensor (spin 2) part gives the usual Newtonian force. Laboratory and astrophysical experiments which may test the predictions of FG, will be performed in near future. In particular, observations at gravity observatories with bar and interferometric detectors, like Explorer, Nautilus, LIGO and VIRGO, will check the predicted scalar gravitational waves from supernova explosions. New types of cosmological models in Minkowski space are possible too.

  14. Spectrometer for new gravitational experiment with UCN

    NASA Astrophysics Data System (ADS)

    Kulin, G. V.; Frank, A. I.; Goryunov, S. V.; Kustov, D. V.; Geltenbort, P.; Jentschel, M.; Strepetov, A. N.; Bushuev, V. A.

    2015-08-01

    We describe an experimental installation for a new test of the weak equivalence principle for neutron. The device is a sensitive gravitational spectrometer for ultracold neutrons allowing to precisely compare the gain in kinetic energy of free falling neutrons to quanta of energy ℏΩ transferred to the neutron via a non stationary device, i.e. a quantum modulator. The results of first test experiments indicate a collection rate allowing measurements of the factor of equivalence γ with a statistical uncertainty in the order of 5×10-3 per day. A number of systematic effects were found, which partially can be easily corrected. For the elimination of others more detailed investigations and analysis are needed. Some possibilities to improve the device are also discussed.

  15. Mapping quantum state dynamics in spontaneous emission.

    PubMed

    Naghiloo, M; Foroozani, N; Tan, D; Jadbabaie, A; Murch, K W

    2016-01-01

    The evolution of a quantum state undergoing radiative decay depends on how its emission is detected. If the emission is detected in the form of energy quanta, the evolution is characterized by a quantum jump to a lower energy state. In contrast, detection of the wave nature of the emitted radiation leads to different dynamics. Here, we investigate the diffusive dynamics of a superconducting artificial atom under continuous homodyne detection of its spontaneous emission. Using quantum state tomography, we characterize the correlation between the detected homodyne signal and the emitter's state, and map out the conditional back-action of homodyne measurement. By tracking the diffusive quantum trajectories of the state as it decays, we characterize selective stochastic excitation induced by the choice of measurement basis. Our results demonstrate dramatic differences from the quantum jump evolution associated with photodetection and highlight how continuous field detection can be harnessed to control quantum evolution. PMID:27167893

  16. Topics in the theory of heavy-quark systems

    SciTech Connect

    Flory, C.A.

    1981-04-01

    Due to the kinematic and dynamic simplifications possible because of the large mass of heavy quark bound states, certain properties of these systems can be quantitatively analyzed within the framework of quantum chromodynamics. It is clear that dimensionally the size of the bound state is proportional to the inverse quark mass, and for very heavy quarkonia the radius of the system should become smaller than that of normal hadrons. When this small system interacts with external long wavelength field quanta, the natural expansion that results is of a multipole type, analogous to the familiar multipole expansion in electrodynamics. This multipole expansion has better convergence properties than the standard perturbative treatment in certain kinematic regimes, which opens up a new area for strong interaction physics calculations. More specifically, it is ideally suited to investigate soft non-perturbative effects in QCD which appear to be so crucial to present day phenomenology and the conjectured confinement mechanism.

  17. Plasmons and surfaces

    NASA Astrophysics Data System (ADS)

    Ferrell, T. L.; Callcott, T. A.; Warmack, R. J.

    1985-08-01

    Plasmons, energy quanta related to electrical charge oscillations in condensed matter (such as metals), were first observed in 1955 by passing an electron beam through Al foil and measuring the resulting energy peaks of electrons which made it through. The energy, as predicted by quantum mechanics, is proportional to the associated frequency of the longitudinal waves set up as the oscillations propagate from electron to electron, and is a function of the free electron density. Plasmon data aid in characterizing the electronic state of matter under study. Performing spectroscopy of electrons bouncing off the surface permits characterizations of the electronic states of the surfaces. Plasmons can lose energy by emitting light. The wavelength of the light can be controlled by specifying the composition of a specimen. Techniques for coupling beam photons with surface plasmons to achieve excited states are discussed, along with emerging applications such as diffraction gratings for spectroscopy, holographic cameras and Raman scattering applied to biochemical studies.

  18. Cesium Chloride Density Gradient Study of Some Modifications Induced by Ultraviolet Radiation on the Denatured DNA Molecule of Phage T2

    PubMed Central

    Cremonese, M.; Giampaoli, C.; Matzeu, M.; Onori, G.

    1969-01-01

    The behaviour of the modifications due to ultraviolet (UV) radiation on denatured phagic DNA has been investigated by looking at the changes of density in CsCl gradient, after irradiation with increasing doses of monochromatic light. The spectral range studied is 2300-2900 A, with a wavelength resolution Δλ = ±20 A. The observed effect is a gradual shift toward higher densities as the UV absorbed dose increases. The experimental results show an exponential law and the analysis of the action spectra indicates that thymine is the main factor responsible for the observed effect. An evaluation of the quantum yield for the thymine-dimers formation gives a constant value of (18 ± 3) × 10-3 quanta-1. PMID:5352227

  19. Axion inflation with gauge field production and primordial black holes

    NASA Astrophysics Data System (ADS)

    Bugaev, Edgar; Klimai, Peter

    2014-11-01

    We study the process of primordial black hole (PBH) formation at the beginning of the radiation era for the cosmological scenario in which the inflaton is a pseudo-Nambu-Goldstone boson (axion) and there is a coupling of the inflaton with some gauge field. In this model inflation is accompanied by the gauge quanta production, and a strong rise of the curvature power spectrum amplitude at small scales (along with non-Gaussianity) is predicted. We show that data on PBH searches can be used for a derivation of essential constraints on the model parameters in such an axion inflation scenario. We compare our numerical results with the similar results published earlier, in the work [A. Linde, S. Mooij, and E. Pajer, Phys. Rev. D 87, 103506 (2013)].

  20. Photon Activation Analysis Of Light Elements Using 'Non-Gamma' Radiation Spectroscopy - The Instrumental Determination Of Phosphorus

    SciTech Connect

    Segebade, Christian; Goerner, Wolf

    2011-06-01

    Unlike metal determinations the analysis of light elements (e.g., carbon, oxygen, phosphorus) is frequently problematic, in particular if analysed instrumentally. In photon activation analysis (PAA) the respective activation products do not emit gamma radiation in the most cases. Usually, annihilation quanta counting and subsequent decay curve analysis have been used for determinations of C, N, O, and F. However, radiochemical separation of the respective radioisotopes mostly is indispensable. For several reasons, some of the light elements cannot be analysed following this procedure, e.g. phosphorus. In this contribution the instrumental PAA of phosphorus in organic matrix by activation with bremsstrahlung of an electron linear accelerator and subsequent beta spectroscopy is described. The accuracy of the results was excellent as obtained by analysis of a BCR Reference Material.

  1. Performance characteristics of asymmetric zero-crossover screen-film systems

    NASA Astrophysics Data System (ADS)

    Bunch, Phillip C.

    1992-05-01

    The development of specialized dyes that essentially prevent light from crossing the film base in duplitized screen-film systems has made it possible to design screen-film combinations with unusual performance characteristics. Specifically, by combining front and back screens with differing light emission and resolution properties with asymmetric films with differing front and back sensitometric characteristics, it is now possible to design screen-film systems that have some or all of the following features: (1) density-dependent image blur, (2) previously impractical sensitometric curve shapes, and (3) screen-dependent system contrast. Performance characteristics of two specific systems are summarized, including sensitometric data, contrast transfer functions, noise equivalent quanta, and detective quantum efficiency. Initial clinical applications of this technology are also described, with an emphasis on thoracic radiography.

  2. Performance characteristics of high-MTF screen-film systems

    NASA Astrophysics Data System (ADS)

    Bunch, Phillip C.

    1994-05-01

    The development of specialized dyes that essentially prevent light from crossing the film base in double-coated gadolinium oxysulfide (GOS) phosphor-based radiographic systems has made it possible to design screen-film combinations with significantly improved MTF characteristics. Specifically, by using GOS-based screens with reduced light diffusion properties in combination with near-zero-crossover radiographic films, significantly improved MTF can be obtained at competitive speed and effective x-ray attenuation levels. The basic performance characteristics of such screen-film systems are described in some detail, including x-ray attenuation properties, sensitivity to scattered x-radiation, sensitometric data, contrast transfer functions, noise equivalent quanta, and detective quantum efficiency. It is also shown that high-MTF GOS screens are available that meet or exceed the performance characteristics of comparable UV-emitting yttrium tantalate phosphor-based materials.

  3. Mapping quantum state dynamics in spontaneous emission

    NASA Astrophysics Data System (ADS)

    Naghiloo, M.; Foroozani, N.; Tan, D.; Jadbabaie, A.; Murch, K. W.

    2016-05-01

    The evolution of a quantum state undergoing radiative decay depends on how its emission is detected. If the emission is detected in the form of energy quanta, the evolution is characterized by a quantum jump to a lower energy state. In contrast, detection of the wave nature of the emitted radiation leads to different dynamics. Here, we investigate the diffusive dynamics of a superconducting artificial atom under continuous homodyne detection of its spontaneous emission. Using quantum state tomography, we characterize the correlation between the detected homodyne signal and the emitter's state, and map out the conditional back-action of homodyne measurement. By tracking the diffusive quantum trajectories of the state as it decays, we characterize selective stochastic excitation induced by the choice of measurement basis. Our results demonstrate dramatic differences from the quantum jump evolution associated with photodetection and highlight how continuous field detection can be harnessed to control quantum evolution.

  4. A search for double-electron capture of 74Se to excited levels using coincidence/anticoincidence gamma-ray spectrometry

    NASA Astrophysics Data System (ADS)

    Ješkovský, M.; Frekers, D.; Kováčik, A.; Povinec, P. P.; Puppe, P.; Staníček, J.; Sýkora, I.; Šimkovic, F.; Thies, J. H.

    2015-09-01

    Evaluation of single, coincidence and anticoincidence gamma-ray spectrometry methods has been carried out with the aim to search for double-electron capture of 74Se to excited states. This process is unique, because there is probability for transition to the 2+ excited state in 74Ge (1204 keV), and de-excitation through two gamma-quanta cascade with energies of 595.9 keV and 608.4 keV. Long-term measurements with an anticosmic shielded HPGe (high purity Ge) spectrometer and a coincidence HPGe-NaI(Tl) spectrometer did not show any evidence for the double-electron capture in 74Se. The best limit for the half-life of the double electron capture in 74Se (both for the neutrinoless and two neutrino processes) was estimated to be >1.5×1019 yr.

  5. Effect of vibrationally excited I{sub 2}(a{sup 1{Delta}}{sub g}) molecules on the parameters of the active medium of an oxygen - iodine laser

    SciTech Connect

    Azyazov, V N; Antonov, I O; Pichugin, S Yu; Ufimtsev, N I

    2004-12-31

    A comparison of the experimental and theoretical results shows that quenching of one singlet oxygen molecule leads to the formation of 4.5 vibrational quanta of the I{sub 2} molecule on the average in the active medium of an oxygen-iodine laser. The dependence of threshold yield of singlet oxygen and of the gain on the relative concentration of vibrationally excited I{sub 2}(a{sup 1{Delta}}{sub g}) molecules are studied. The threshold yield of singlet oxygen increases with the relative concentration of vibrationally excited I{sub 2} molecules and may be several percent higher than the value assumed earlier. The gain depends weakly on the relative concentration of vibrationally excited oxygen molecules. (active media)

  6. Single-trapped-ion vibronic Raman laser

    NASA Astrophysics Data System (ADS)

    di Fidio, C.; Vogel, W.; de Matos Filho, R. L.; Davidovich, L.

    2002-01-01

    We propose a model for a single-trapped-ion vibronic Raman laser and study its dynamics by using quantum-trajectory methods. In our treatment, it is essential that both the cavity field of the high-finesse optical cavity and the center-of-mass vibrational motion of the trapped ion be quantized. A transition from a super-Poissonian light source to a Poissonian lasing regime is obtained by increasing the Raman coupling constant. Furthermore, we demonstrate that a nonclassical regime can be realized, where the photon statistics becomes sub-Poissonian and the photons leak out of the cavity in an antibunched manner. This is achieved by exploiting nonlinear Stark shifts inherent in the model, which depend on both the number of cavity photons and the number of vibrational quanta.

  7. Multimodal Fission in Heavy-Ion Induced Reactions

    SciTech Connect

    Pokrovskiy, I. V.; Bogachev, A. A.; Iitkis, M. G.; Iitkis, J. M.; Kondratiev, N. A.; Kozulin, E. M.; Dorvaux, O.; Rowley, N.; Schmitt, Ch.; Stuttge, L.

    2006-08-14

    Mass, energy and folding angle distributions of the fission fragments as well as multiplicities of neutron and gamma-quanta emissions accompanying the fission process were measured for fission of 226Th, 227Pa and 234Pu compound nuclei produced in reactions with 18O and 26Mg projectiles over a wide energy range. Data were analyzed with respect to the presence of fission modes. Asymmetric fission was observed even at very high initial excitation for all the measured systems. The so-called fission mode S1 (caused by the proton shell Z{approx}50 and neutron shell N{approx}82 in heavy fragment) was found to be dominant in asymmetric fission of 234Pu. Reactions with not full linear momentum transfer were observed in the folding spectra for all the measured systems.

  8. Magnetic Property in Large Array Niobium Antidot Thin Films

    NASA Astrophysics Data System (ADS)

    Tinghui, Chen; Hsiang-Hsi, Kung; Wei-Li, Lee; Institute of Physics, Academia Sinica, Taipei, Taiwan Team

    2014-03-01

    In a superconducting ring, the total flux inside the ring is required to be an integer number of the flux quanta. Therefore, a supercurrent current can appear within the ring in order to satisfy this quantization rule, which gives rise to certain magnetic response. By using a special monolayer polymer/nanosphere hybrid we developed previously, we fabricated a series of superconducting niobium antidot thin films with different antidot diameters. The antidots form well-ordered triangular lattice with a lattice spacing about 200 nm and extend over an area larger than 1 cm2, which enables magnetic detections simply by a SQUID magnetometer. We observed magnetization oscillation with external magnetic field due to the supercurrent screening effect, where different features for large and small antidot thin films were found. Detailed size and temperature dependencies of the magnetization in niobium antidot nanostructures will be presented.

  9. Influence of damping on quantum interference - An exactly soluble model

    NASA Technical Reports Server (NTRS)

    Caldeira, A. O.; Leggett, A. J.

    1985-01-01

    This paper reports the result of a calculation which shows the effect of damping on the quantum interference of two Gaussian wave packets in a harmonic potential. The influence-functional method, which seems to be the most appropriate one for this kind of calculation, is used. It is shown that quantum-interference effects are severely diminished by the presence of damping even when its influence on the system is only light. The corrections to the undamped formulas are always expressible in terms of the phenomenological damping constant, the temperature (in the high-temperature limit), the cutoff frequency of the reservoir oscillators, and the mean number of quanta of energy intially present in the system. Both weakly and strongly damped systems are analyzed in the regime of low and high temperatures.

  10. Terahertz probing of local electron states in Pb1-xSnxTe(In)

    NASA Astrophysics Data System (ADS)

    Chernichkin, Vladimir; Ryabova, Ludmila; Nicorici, Andrey; Danilov, Sergey; Khokhlov, Dmitry

    2014-03-01

    A new type of semiconductor local states is revealed in lead-tin telluride solid solutions doped with indium. The energy position of these states is not linked to any specific location in the semiconductor energy spectrum, but follows the quasiFermi level position, which may be tuned by photoexcitation. The binding energy of these states is less than 10 meV providing appearance of photoresponse at wavelengths exceeding 100 μm. This conclusion is based on the results of experiments that use illumination of the samples by 100 ns - long pulses of an optically pumped NH3 terahertz laser with the wavelengths of 90, 148 and 280 μm corresponding to the quanta energies of 13.8, 8.4 and 4.4 meV, respectively.

  11. Giant vortex state in mesoscopic superconductors

    NASA Astrophysics Data System (ADS)

    Cobacy García, Luis; Giraldo, Jairo

    2005-08-01

    Using the self-consistent solution of the nonlinear Ginzburg-Landau equations, the superconducting state of a type II mesoscopic cylinder and of an infinite thin sheet with a circular hole (antidot), in the presence of an homogeneous magnetic field is studied. Close to the third critical field, the magnetic field penetrates the sample in the form of a vortex around the axis of the cylinder or of the antidot. This result has been found previously by other authors. The vortex, called a giant vortex, can carry several flux quanta. The giant vortex is persistent when the state is metastable and evolves to the so called paramagnetic Meissner effect (PME) within the cylinder. The behaviour of this effect as a function of the Ginzburg-Landau (GL) parameter is studied and the results are discussed. Gibbs free energy, order parameter and magnetic induccion as a function of the applied field and of the GL parameter are also studied.

  12. Cooperative Resonance Interaction Between One-and Two-Photon Super-fluorescences Trough the Vacuum Field

    NASA Astrophysics Data System (ADS)

    Enaki, Nicolae A.

    2012-02-01

    The theoretical approach takes in consideration the cooperative phenomena which appear between three particle in two-photon resonance in the process of single- and two- photon decay. This type of single- and two-quanta cooperative effect between three subsystems of radiators are described by master equation which takes into account three-particle cooperative resonance in the system. The resonance between the spontaneous emissions by two- and single photon transitions of three inverted radiators from the ensemble is proposed in order to accelerate the collective decay rate of the entangled photon pairs generated by the system. This effect is accompanied with the interferences between one-photon and two-quantum collective transitions of three inverted radiators from the ensemble. The three particle collective decay rate is defined in the description of three atomic correlation functions.

  13. Nonclassical-state generation in macroscopic systems via hybrid discrete-continuous quantum measurements

    NASA Astrophysics Data System (ADS)

    Milburn, T. J.; Kim, M. S.; Vanner, M. R.

    2016-05-01

    Nonclassical-state generation is an important component throughout experimental quantum science for quantum information applications and probing the fundamentals of physics. Here, we investigate permutations of quantum nondemolition quadrature measurements and single quanta addition or subtraction to prepare quantum superposition states in bosonic systems. The performance of each permutation is quantified and compared using several different nonclassicality criteria including Wigner negativity, nonclassical depth, and optimal fidelity with a coherent-state superposition. We also compare the performance of our protocol using squeezing instead of a quadrature measurement and find that the purification provided by the quadrature measurement can significantly increase the nonclassicality generated. Our approach is ideally suited for implementation in light-matter systems such as quantum optomechanics and atomic spin ensembles, and offers considerable robustness to initial thermal occupation.

  14. Constraints on just enough inflation preceded by a thermal era

    NASA Astrophysics Data System (ADS)

    Das, Suratna; Goswami, Gaurav; Prasad, Jayanti; Rangarajan, Raghavan

    2016-01-01

    If the inflationary era is preceded by a radiation-dominated era in which the inflaton too was in thermal equilibrium at some very early time, then the CMB data places an upper bound on the comoving temperature of the (decoupled) inflaton quanta. In addition, if one considers models of "just enough" inflation, where the number of e-foldings of inflation is just enough to solve the horizon and flatness problems, then we get a lower bound on the Hubble parameter during inflation, Hinf, which is in severe conflict with the upper bound from tensor perturbations. Alternatively, imposing the upper bound on Hinf implies that such scenarios are compatible with the data only if the number of relativistic degrees of freedom in the thermal bath in the preinflationary Universe is extremely large (greater than 109 or 1011 ). We are not aware of scenarios in which this can be satisfied.

  15. Medium-Induced QCD Cascade: Democratic Branching and Wave Turbulence

    NASA Astrophysics Data System (ADS)

    Blaizot, J.-P.; Iancu, E.; Mehtar-Tani, Y.

    2013-08-01

    We study the average properties of the gluon cascade generated by an energetic parton propagating through a quark-gluon plasma. We focus on the soft, medium-induced emissions which control the energy transport at large angles with respect to the leading parton. We show that the effect of multiple branchings is important. In contrast with what happens in a usual QCD cascade in vacuum, medium-induced branchings are quasidemocratic, with offspring gluons carrying sizable fractions of the energy of their parent gluon. This results in an efficient mechanism for the transport of energy toward the medium, which is akin to wave turbulence with a scaling spectrum ˜1/ω. We argue that the turbulent flow may be responsible for the excess energy carried by very soft quanta, as revealed by the analysis of the dijet asymmetry observed in Pb-Pb collisions at the LHC.

  16. Practical aspects of security certification for commercial quantum technologies

    NASA Astrophysics Data System (ADS)

    Walenta, Nino; Soucarros, Mathilde; Stucki, Damien; Caselunghe, Dario; Domergue, Mathias; Hagerman, Michael; Hart, Randall; Hayford, Don; Houlmann, Raphaël.; Legré, Matthieu; McCandlish, Todd; Page, Jean-Benoît; Tourville, Maurice; Wolterman, Richard

    2015-10-01

    Quantum random number generation (QRNG) and quantum key distribution (QKD) are the first applications of quantum physics at the level of individual quanta that have matured into commercial products. Both have been commercially available for over 10 years and increasingly adopted in information security systems. Current efforts focus on standardization and certification of QRNG and QKD devices and their components in order to validate the technology and enable more widespread adoption. Since no official certification scheme specific to quantum devices has been devised so far, alternative options must be investigated. This paper describes our approaches and efforts to enable compliance of commercial QRNG and QKD network devices with security standards such as AIS 20/311 and FIPS 140-2.2

  17. Pulsed H{sub 2} - F{sub 2} laser with simultaneous lasing on rotational and vibrational-rotational transitions

    SciTech Connect

    Molevich, N E; Pichugin, S Yu

    2011-05-31

    The possibility of operation of a pulsed chemical H{sub 2} - F{sub 2} laser on purely rotational transitions with simultaneous lasing on vibrational - rotational transitions is theoretically investigated. The lasing of a hydrogen-fluorine laser (mixture pressure 1.1 atm) on both v,j - 1 {yields} v - 1,j (j=2 - 20) and v,j {yields} v,j - 1 (j = 12 - 19) transitions has been modelled taking into account the resonant one- and two-quanta vibrational - rotational processes. The calculated specific energy extraction for purely rotational transitions reaches 0.3-0.5 J L{sup -1} at j=18 and 19 (wavelength 15.5-14 {mu}m) and 0.4-0.7 J L{sup -1} at j=13 and 14 (wavelength 21-19 {mu}m). (lasers)

  18. Silicon optomechanical crystal resonator at millikelvin temperatures

    NASA Astrophysics Data System (ADS)

    Meenehan, Seán M.; Cohen, Justin D.; Gröblacher, Simon; Hill, Jeff T.; Safavi-Naeini, Amir H.; Aspelmeyer, Markus; Painter, Oskar

    2014-07-01

    Optical measurements of a nanoscale silicon optomechanical crystal cavity with a mechanical resonance frequency of 3.6 GHz are performed at subkelvin temperatures. We infer optical-absorption-induced heating and damping of the mechanical resonator from measurements of phonon occupancy and motional sideband asymmetry. At the lowest probe power and lowest fridge temperature (Tf=10 mK), the localized mechanical resonance is found to couple at a rate of γi/2π=400 Hz (Qm=9×106) to a thermal bath of temperature Tb≈270 mK. These measurements indicate that silicon optomechanical crystals cooled to millikelvin temperatures should be suitable for a variety of experiments involving coherent coupling between photons and phonons at the single quanta level.

  19. Simultaneous observation of the quantization and the interference pattern of a plasmonic near-field

    DOE PAGESBeta

    Piazza, L.; Lummen, T. T. A.; Quiñonez, E.; Murooka, Y.; Reed, B. W.; Barwick, B.; Carbone, F.

    2015-03-02

    Surface plasmon polaritons can confine electromagnetic fields in subwavelength spaces and are of interest for photonics, optical data storage devices and biosensing applications. In analogy to photons, they exhibit wave–particle duality, whose different aspects have recently been observed in separate tailored experiments. Here we demonstrate the ability of ultrafast transmission electron microscopy to simultaneously image both the spatial interference and the quantization of such confined plasmonic fields. Our experiments are accomplished by spatiotemporally overlapping electron and light pulses on a single nanowire suspended on a graphene film. The resulting energy exchange between single electrons and the quanta of the photoinducedmore » near-field is imaged synchronously with its spatial interference pattern. In conclusion, this methodology enables the control and visualization of plasmonic fields at the nanoscale, providing a promising tool for understanding the fundamental properties of confined electromagnetic fields and the development of advanced photonic circuits.« less

  20. Simultaneous observation of the quantization and the interference pattern of a plasmonic near-field

    SciTech Connect

    Piazza, L.; Lummen, T. T. A.; Quiñonez, E.; Murooka, Y.; Reed, B. W.; Barwick, B.; Carbone, F.

    2015-03-02

    Surface plasmon polaritons can confine electromagnetic fields in subwavelength spaces and are of interest for photonics, optical data storage devices and biosensing applications. In analogy to photons, they exhibit wave–particle duality, whose different aspects have recently been observed in separate tailored experiments. Here we demonstrate the ability of ultrafast transmission electron microscopy to simultaneously image both the spatial interference and the quantization of such confined plasmonic fields. Our experiments are accomplished by spatiotemporally overlapping electron and light pulses on a single nanowire suspended on a graphene film. The resulting energy exchange between single electrons and the quanta of the photoinduced near-field is imaged synchronously with its spatial interference pattern. In conclusion, this methodology enables the control and visualization of plasmonic fields at the nanoscale, providing a promising tool for understanding the fundamental properties of confined electromagnetic fields and the development of advanced photonic circuits.

  1. [The pharmacology of humour -- a primer to quantum humourdynamics].

    PubMed

    Györfi, András

    2014-08-10

    A good word put in for someone during a medical consultation can alleviate the stress generated by the contact with the clinic. The superlative of "good word" in these situations could be a humorous phrase of the physician during the consultation, which can cause a cognitive shift in the patient's perception of her/his situation. This change of perspective will diminish the anxiety generated by the disease, can rebuild optimism and establish a good doctor-patient relationship, based on hope and collaboration. This paper analyzes the elements of humour and the neurological mechanisms involved in the emergence of mirth. The dosage of this genuine alternative medication is discussed based on a primer to quantum humor dynamics, observing the similarity between the behaviour of quantum mechanic's elementary particles with the quanta of humour called hilarion. Finally, laughter's psychological and physiological benefits are discussed, obtained through changes in circulation, respiration, muscular tonus and endorphin release. PMID:25087216

  2. Enigmatic electrons, photons, and ``empty`` waves

    SciTech Connect

    MacGregor, M.H.

    1995-08-22

    A spectroscopic analysis is made of electrons and photons from the standpoint of physical realism. In this conceptual framework, moving particles are portrayed as localized entities which are surrounded by ``empty`` waves. A spectroscopic model for the electron Stands as a guide for a somewhat similar, but in essential respects radically different, model for the photon. This leads in turn to a model for the ``zeron``. the quantum of the empty wave. The properties of these quanta mandate new basis states, and hence an extension of our customary framework for dealing with them. The zeron wave field of a photon differs in one important respect from the standard formalism for an electromagnetic wave. The vacuum state emerges as more than just a passive bystander. Its polarization properties provide wave stabilization, particle probability distributions, and orbit quantization. Questions with regard to special relativity are discussed.

  3. Mapping quantum state dynamics in spontaneous emission

    PubMed Central

    Naghiloo, M.; Foroozani, N.; Tan, D.; Jadbabaie, A.; Murch, K. W.

    2016-01-01

    The evolution of a quantum state undergoing radiative decay depends on how its emission is detected. If the emission is detected in the form of energy quanta, the evolution is characterized by a quantum jump to a lower energy state. In contrast, detection of the wave nature of the emitted radiation leads to different dynamics. Here, we investigate the diffusive dynamics of a superconducting artificial atom under continuous homodyne detection of its spontaneous emission. Using quantum state tomography, we characterize the correlation between the detected homodyne signal and the emitter's state, and map out the conditional back-action of homodyne measurement. By tracking the diffusive quantum trajectories of the state as it decays, we characterize selective stochastic excitation induced by the choice of measurement basis. Our results demonstrate dramatic differences from the quantum jump evolution associated with photodetection and highlight how continuous field detection can be harnessed to control quantum evolution. PMID:27167893

  4. High-Penetration PV Integration Handbook for Distribution Engineers

    SciTech Connect

    Seguin, Rich; Woyak, Jeremy; Costyk, David; Hambrick, Josh; Mather, Barry

    2016-01-01

    This handbook has been developed as part of a five-year research project which began in 2010. The National Renewable Energy Laboratory (NREL), Southern California Edison (SCE), Quanta Technology, Satcon Technology Corporation, Electrical Distribution Design (EDD), and Clean Power Research (CPR) teamed together to analyze the impacts of high-penetration levels of photovoltaic (PV) systems interconnected onto the SCE distribution system. This project was designed specifically to leverage the experience that SCE and the project team would gain during the significant installation of 500 MW of commercial scale PV systems (1-5 MW typically) starting in 2010 and completing in 2015 within SCE’s service territory through a program approved by the California Public Utility Commission (CPUC).

  5. Smooth and sharp creation of a Dirichlet wall in 1+1 quantum field theory: how singular is the sharp creation limit?

    NASA Astrophysics Data System (ADS)

    Brown, Eric G.; Louko, Jorma

    2015-08-01

    We present and utilize a simple formalism for the smooth creation of boundary conditions within relativistic quantum field theory. We consider a massless scalar field in (1 + 1)-dimensional flat spacetime and imagine smoothly transitioning from there being no boundary condition to there being a two-sided Dirichlet mirror. The act of doing this, expectantly, generates a flux of real quanta that emanates from the mirror as it is being created. We show that the local stress-energy tensor of the flux is finite only if an infrared cutoff is introduced, no matter how slowly the mirror is created, in agreement with the perturbative results of Obadia and Parentani. In the limit of instaneous mirror creation the total energy injected into the field becomes ultraviolet divergent, but the response of an Unruh-DeWitt particle detector passing through the infinite burst of energy nevertheless remains finite. Implications for vacuum entanglement extraction and for black hole firewalls are discussed.

  6. Origin of a signal detected with the LSD detector after the accident at the chernobyl nuclear power plant

    SciTech Connect

    Agafonova, N. Yu. Malgin, A. S.; Fulgione, W.

    2013-08-15

    A rare signal was detected at 23:53 Moscow time on April 27, 1986 with the LSD low-background scintillation detector located under Mont Blanc at a distance of 1820 km from Chernobyl. To reveal the origin of this signal, we discuss the results obtained with other instruments operating within a similar program, as well as analyze the characteristics of the pulses of the signal and facts referring to the explosion of the Chernobyl reactor. A hypothesis based on detection with the LSD of gamma-quanta from {beta} decays of {sup 135}I nuclei ejected into atmosphere by the reactor explosion and carried in the underground detector camera with air of positive ventilation is considered. The explosion origin of the LSD signal indicates a new technogenic source of the background in the search for neutrino bursts from cores of collapsing stars.

  7. Microfluidics with compound ``bubble-drops''

    NASA Astrophysics Data System (ADS)

    Khan, Saif A.; Duraiswamy, Suhanya

    2008-11-01

    ``Bubble-drops'' are compound fluid particles comprising a gas bubble and liquid drop that flow as a single fluid object through another immiscible liquid in a microchannel network. These fluid particles represent discrete multiphase `quanta', and expand the sphere of application of droplet microfluidics to inter-phase phenomena. We present here a simple method to generate monodisperse bubble-drop trains in microfabricated channel networks. The difference in drag force exerted on flowing bubbles and drops by the immiscible carrier liquid implies different translational speeds, thus providing the driving force for bubble-drop formation. We outline the criteria for stable generation and analyze factors influencing bubble-drop dynamics. We will also highlight several applications in chemical and biological synthesis and screening.

  8. Quantum origins of objectivity

    NASA Astrophysics Data System (ADS)

    Horodecki, R.; Korbicz, J. K.; Horodecki, P.

    2015-03-01

    In spite of all of its successes, quantum mechanics leaves us with a central problem: How does nature create a bridge from fragile quanta to the objective world of everyday experience? Here we find that a basic structure within quantum mechanics that leads to the perceived objectivity is a so-called spectrum broadcast structure. We uncover this based on minimal assumptions, without referring to any dynamical details or a concrete model. More specifically, working formally within the decoherence theory setting with multiple environments (called quantum Darwinism), we show how a crucial for quantum mechanics notion of nondisturbance due to Bohr [N. Bohr, Phys. Rev. 48, 696 (1935), 10.1103/PhysRev.48.696] and a natural definition of objectivity lead to a canonical structure of a quantum system-environment state, reflecting objective information records about the system stored in the environment.

  9. Chemical reactions of water molecules on Ru(0001) induced by selective excitation of vibrational modes

    SciTech Connect

    Mugarza, Aitor; Shimizu, Tomoko K.; Ogletree, D. Frank; Salmeron, Miquel

    2009-05-07

    Tunneling electrons in a scanning tunneling microscope were used to excite specific vibrational quantum states of adsorbed water and hydroxyl molecules on a Ru(0 0 0 1) surface. The excited molecules relaxed by transfer of energy to lower energy modes, resulting in diffusion, dissociation, desorption, and surface-tip transfer processes. Diffusion of H{sub 2}O molecules could be induced by excitation of the O-H stretch vibration mode at 445 meV. Isolated molecules required excitation of one single quantum while molecules bonded to a C atom required at least two quanta. Dissociation of single H{sub 2}O molecules into H and OH required electron energies of 1 eV or higher while dissociation of OH required at least 2 eV electrons. In contrast, water molecules forming part of a cluster could be dissociated with electron energies of 0.5 eV.

  10. EPR experiment and 2-photon interferometry: Report of a 2-photon interference experiment

    NASA Technical Reports Server (NTRS)

    Shih, Y. H.; Rubin, M. H.; Sergienko, A. V.

    1992-01-01

    After a very brief review of the historical Einstein, Podolsky, and Rosen (EPR) experiments, a new two-photon interference type EPR experiment is reported. A two-photon state was generated by optical parametric down conversion. Pairs of light quanta with degenerate frequency but divergent directions of propagation were sent to two independent Michelson interferometers. First and second order interference effectors were studied. Different than other reports, we observed that the second order interference visibility vanished when the optical path difference of the interferometers were much less than the coherence length of the pumping laser beam. However, we also observed that the second order interference behaved differently depending on whether the interferometers were set at equal or different optical path differences.

  11. In Search of the Ultimate Building Blocks

    NASA Astrophysics Data System (ADS)

    't Hooft, Gerard

    1996-12-01

    An apology; 1. The beginning of the journey to the small: cutting paper; 2. To molecules and atoms; 3. The magic mystery of the quanta; 4. Dazzling velocities; 5. The elementary particle zoo before 1970; 6. Life and death; 7. The crazy kaons; 8. The invisible quarks; 9. Fields or bootstraps?; 10. The Yang-Mills bonanza; 11. Superconducting empty space: the Higgs-Kibble machine; 12. Models; 13. Colouring in the strong forces; 14. The magnetic monopole; 15. Gypsy; 16. The brilliance of the standard model; 17. Anomalies; 18. Deceptive perfection; 19. Weighing neutrinos; 20. The great desert; 21. Technicolor; 22. Grand unification; 23. Supergravity; 24. Eleven dimensional space-time; 25. Attaching the super string; 26. Into the black hole; 27. Theories that do not yet exist … ; 28. Dominance of the rule of the smallest.

  12. The Unreasonable Effectiveness of Exponentially Suppressed Corrections in Preserving Information

    NASA Astrophysics Data System (ADS)

    Papadodimas, Kyriakos; Raju, Suvrat

    2013-11-01

    We point out that nonperturbative effects in quantum gravity are sufficient to reconcile the process of black hole evaporation with quantum mechanics. In ordinary processes, these corrections are unimportant because they are suppressed by e-S. However, they gain relevance in information-theoretic considerations because their small size is offset by the corresponding largeness of the Hilbert space. In particular, we show how such corrections can cause the von Neumann entropy of the emitted Hawking quanta to decrease after the Page time, without modifying the thermal nature of each emitted quantum. Second, we show that exponentially suppressed commutators between operators inside and outside the black hole are sufficient to resolve paradoxes associated with the strong subadditivity of entropy without any dramatic modifications of the geometry near the horizon.

  13. Electric fields and quantum wormholes

    NASA Astrophysics Data System (ADS)

    Engelhardt, Dalit; Freivogel, Ben; Iqbal, Nabil

    2015-09-01

    Electric fields can thread a classical Einstein-Rosen bridge. Maldacena and Susskind have recently suggested that in a theory of dynamical gravity the entanglement of ordinary perturbative quanta should be viewed as creating a quantum version of an Einstein-Rosen bridge between the particles, or a "quantum wormhole." We demonstrate within low-energy effective field theory that there is a precise sense in which electric fields can also thread such quantum wormholes. We define a nonperturbative "wormhole susceptibility" that measures the ease of passing an electric field through any sort of wormhole. The susceptibility of a quantum wormhole is suppressed by powers of the U (1 ) gauge coupling relative to that for a classical wormhole but can be made numerically equal with a sufficiently large amount of entangled matter.

  14. 'Nature and the Greeks' and 'Science and Humanism'

    NASA Astrophysics Data System (ADS)

    Schrödinger, Erwin

    2014-11-01

    Foreword; Part I. Nature and the Greeks: 1. The motives for returning to ancient thought; 2. The competition, reason v. senses; 3. The Pythagoreans; 4. The Ionian enlightenment; 5. The religion of Xenophanes, Heraclitus of Ephesus; 6. The atomists; 7. What are the special features?; Part II. Science and Humanism: 1. The spiritual bearing of science on life; 2. The practical achievements of science tending to obliterate its true import; 3. A radical change in our ideas of matter; 4. Form, not substance, the fundamental concept; 5. The nature of our 'models'; 6. Continuous descriptions and causality; 7. The intricacy of the continuum; 8. The makeshift of wave mechanics; 9. The alleged breakdown of the barrier between subject and object; 10. Atoms or quanta - the counter-spell of old standing, to escape the intricacy of the continuum; 11. Would physical indeterminacy give free will a chance?; 12. The bar to prediction, according to Niels Bohr; Literature.

  15. Tensile strength and the mining of black holes.

    PubMed

    Brown, Adam R

    2013-11-22

    There are a number of important thought experiments that involve raising and lowering boxes full of radiation in the vicinity of black hole horizons. This Letter looks at the limitations placed on these thought experiments by the null energy condition, which imposes a fundamental bound on the tensile-strength-to-weight ratio of the materials involved, makes it impossible to build a box near the horizon that is wider than a single wavelength of the Hawking quanta, and puts a severe constraint on the operation of "space elevators" near black holes. In particular, it is shown that proposals for mining black holes by lowering boxes near the horizon, collecting some Hawking radiation, and dragging it out to infinity cannot proceed nearly as rapidly as has previously been claimed. As a consequence of this limitation, the boxes and all the moving parts are superfluous and black holes can be destroyed equally rapidly by threading the horizon with strings. PMID:24313473

  16. Licht und Entwicklung — das Phytochromsystem der Pflanzen

    NASA Astrophysics Data System (ADS)

    Mohr, H.

    1981-04-01

    In photosynthetic green plants light is the decisive environmental factor. The terrestrial green plant is organized almost ideally in a way so as to absorb and process light quanta. The genetic adaptation to the factor, light, has taken place in the course of the genetic evolution (phylogeny) of terrestrial plants. However, light also affects the individual development (ontogeny) profoundly insofar as the genes which control normal development of a higher plant can only express themselves fully in the presence of light. Thus, the development of a higher plant (“photomorphogenesis”) is characterized by the obligatory interaction between genes and environment (light). The mechanisms of “transduction of light signals”, i.e. the biophysical and molecular events during photomorphogenesis, are described in the present article.

  17. Radiosensitivity of chromosomes in two successive mitotic cycles of human lymphocytes

    SciTech Connect

    Luchnik, N.V.; Poryadkova, N.A.

    1988-11-01

    A culture of human lymphocytes was irradiated with /gamma/-quanta in a dose of 0.5 Gy with different ratios of cells in first (M1) and second (M2) mitotic cycle and the frequency of aberrations induced at stage G2 was analyzed. With increase in interval of time between the start of culturing and irradiation, total yield of aberrations increased in a regular way. However, if the M1:M2 ratio is considered, then it turns out that in M2 chromosomes are /approximately/1.5 times more sensitive than in M1: within the limits of each cycle, radiosensitivity is constant and does not depend on its duration. It was established in accordance with data of other authors that 5-bromodeoxyuridine (5-BdU) increases radiosensitivity materially.

  18. Growing quantum states with topological order

    NASA Astrophysics Data System (ADS)

    Letscher, Fabian; Grusdt, Fabian; Fleischhauer, Michael

    2015-05-01

    We discuss a protocol for growing states with topological order in interacting many-body systems using a sequence of flux quanta and particle insertion. We first consider a simple toy model, the superlattice Bose-Hubbard model, to explain all required ingredients. Our protocol is then applied to fractional quantum Hall systems in both, continuum and lattice. We investigate in particular how the fidelity, with which a topologically ordered state can be grown, scales with increasing particle number N . For small systems, exact diagonalization methods are used. To treat large systems with many particles, we introduce an effective model based on the composite fermion description of the fractional quantum Hall effect. This model also allows to take into account the effects of dispersive bands and edges in the system, which will be discussed in detail.

  19. Quantum diffusion with drift and the Einstein relation. I

    SciTech Connect

    De Roeck, Wojciech; Fröhlich, Jürg; Schnelli, Kevin

    2014-07-15

    We study the dynamics of a quantum particle hopping on a simple cubic lattice and driven by a constant external force. It is coupled to an array of identical, independent thermal reservoirs consisting of free, massless Bose fields, one at each site of the lattice. When the particle visits a site x of the lattice it can emit or absorb field quanta of the reservoir at x. Under the assumption that the coupling between the particle and the reservoirs and the driving force are sufficiently small, we establish the following results: The ergodic average over time of the state of the particle approaches a non-equilibrium steady state describing a non-zero mean drift of the particle. Its motion around the mean drift is diffusive, and the diffusion constant and the drift velocity are related to one another by the Einstein relation.

  20. Optical and photoelectric properties of anodic oxide films on GaAs, GaP, and GaAs/sub 0. 6/P/sub 0. 4/

    SciTech Connect

    Kashkarov, P.K.; Obraztsov, A.N.; Sorokin, I.N.; Sosnovskikh, Yu.N.

    1987-03-01

    The authors investigate the optical absorption spectra and the photoconductivities of anodic oxide film based on GaAs, GaP, and GaAs/sub 0.6/P/sub 0.4/ in the range of light energy quanta 2-6.2 eV. Anodic oxide film (AOF) was studied on the surface of single crystals of GaAs and epitaxial layers of p-type Gap and AsAs/sub 0.6/P/sub 0.4/ of the n-type. The structures of the oxides were monitored by electron diffraction. The photoconductivity of the AOF was investigated. The absorption of the AOF in the visible and near-UV ranges was estimated by comparing the spectra of excitation of photoluminescence at 80 K for specimens coated with an AOF and specimens with the AOF removed by etching in HCl.

  1. Research on the new performance model for LLL TV imaging systems

    NASA Astrophysics Data System (ADS)

    Ai, Kecong; Zhou, Liwei; Zeng, Guilin; Liang, Yanxi; Wang, Chen; Li, Xudong

    2007-01-01

    Starting from threshold characteristics and night visual theory of the human eye the new quanta detector and linear filter integrated performance model, universal threshold detecting theory and synthesis detecting equations for LLL (low light level) TV imaging systems have been put foreword and established, which set up together active regularity and connection between photon noise fluctuation theory and linear filter theory. By using the new performance model and apparent distance detecting equations many specific properties of LLL TV imaging system, such as brightness intensified, visual angle enlarged, signal to noise ratio and contrast transferred and attenuated, can be correctly expressed, calculated and evaluated. The characteristics of the human eye can also be correctly reflected and described.

  2. Induced fermionic current by a magnetic flux in a cosmic string spacetime at finite temperature

    NASA Astrophysics Data System (ADS)

    Bezerra de Mello, Eugênio R.; Saharian, Aram A.; Mohammadi, Azadeh

    2016-01-01

    Here we analyze the finite temperature expectation values of the charge and current densities for a massive fermionic quantum field with nonzero chemical potential μ, induced by a magnetic flux running along the axis of an idealized cosmic string. These densities are decomposed into the vacuum expectation values and contributions coming from the particles and antiparticles. Specifically the charge density is an even periodic function of the magnetic flux with the period equal to the quantum flux and an odd function of the chemical potential. The only nonzero component of the current density corresponds to the azimuthal current and it is an odd periodic function of the magnetic flux and an even function of the chemical potential. Both analyzed are developed for the cases where |μ| is smaller than the mass of the field quanta m.

  3. Linewidth characteristics of Raman-shifted dye laser output at 720 and 940 nm

    NASA Technical Reports Server (NTRS)

    Grossmann, B. E.; Singh, U. N.; Cotnoir, L. J.; Wilkerson, T. D.; Higdon, N. S.; Browell, E. V.

    1986-01-01

    Raman conversion efficiency and line broadening are reported for Stokes operation at 720 and 940 nm, with hydrogen and deuterium as the Raman source, and using an Nd:YAG pumped Quanta-Ray PDL-2 dye laser. The dye laser linewidth is 0.2/cm (FWHM) with the grating alone as an intracavity element, and the conversion efficiency at 400 psi was found to be 40 and 20 percent for outputs of 720 and 940 nm, respectively. Pressure broadening coefficients of (9.2 + or - 0.9) x 10 to the -5th per cm/psi for hydrogen, and 7.7 x 10 to the -5th per cm/psi for deuterium, were obtained in good agreement with previous results. The linewidth at the first Stokes wavelength was shown to be determined by pressure broadening in the Raman medium.

  4. The information paradox: Conflicts and resolutions

    NASA Astrophysics Data System (ADS)

    Mathur, Samir D.

    2012-11-01

    Many relativists have been long convinced that black hole evaporation leads to information loss or remnants. String theorists have however not been too worried about the issue, largely due to a belief that the Hawking argument for information loss is flawed in its details. A recently derived inequality shows that the Hawking argument for black holes with horizon can in fact be made rigorous. What happens instead is that in string theory black hole microstates have no horizons. Thus the evolution of radiation quanta with E ~ kT is modified by order unity at the horizon, and we resolve the information paradox. We discuss how it is still possible for E >> kT objects to see an approximate black hole like geometry. We also note some possible implications of this physics for the early Universe.

  5. Probing the quantum vacuum with an artificial atom in front of a mirror

    NASA Astrophysics Data System (ADS)

    Hoi, I.-C.; Kockum, A. F.; Tornberg, L.; Pourkabirian, A.; Johansson, G.; Delsing, P.; Wilson, C. M.

    2015-12-01

    Quantum fluctuations of the vacuum are both a surprising and fundamental phenomenon of nature. Understood as virtual photons, they still have a very real impact, for instance, in the Casimir effects and the lifetimes of atoms. Engineering vacuum fluctuations is therefore becoming increasingly important to emerging technologies. Here, we shape vacuum fluctuations using a superconducting circuit analogue of a mirror, creating regions in space where they are suppressed. Moving an artificial atom through these regions and measuring the spontaneous emission lifetime of the atom provides us with the spectral density of the vacuum fluctuations. Using the paradigm of waveguide quantum electrodynamics, we significantly improve over previous studies of the interaction of an atom with its mirror image, observing a spectral density as low as 0.02 quanta, a factor of 50 below the mirrorless result. This demonstrates that we can hide the atom from the vacuum, even though it is exposed in free space.

  6. Medium-induced QCD cascade: democratic branching and wave turbulence.

    PubMed

    Blaizot, J-P; Iancu, E; Mehtar-Tani, Y

    2013-08-01

    We study the average properties of the gluon cascade generated by an energetic parton propagating through a quark-gluon plasma. We focus on the soft, medium-induced emissions which control the energy transport at large angles with respect to the leading parton. We show that the effect of multiple branchings is important. In contrast with what happens in a usual QCD cascade in vacuum, medium-induced branchings are quasidemocratic, with offspring gluons carrying sizable fractions of the energy of their parent gluon. This results in an efficient mechanism for the transport of energy toward the medium, which is akin to wave turbulence with a scaling spectrum ~1/sqrt[ω]. We argue that the turbulent flow may be responsible for the excess energy carried by very soft quanta, as revealed by the analysis of the dijet asymmetry observed in Pb-Pb collisions at the LHC. PMID:23952386

  7. A Survey of Plasmas and Their Applications

    NASA Technical Reports Server (NTRS)

    Eastman, Timothy E.; Grabbe, C. (Editor)

    2006-01-01

    Plasmas are everywhere and relevant to everyone. We bath in a sea of photons, quanta of electromagnetic radiation, whose sources (natural and artificial) are dominantly plasma-based (stars, fluorescent lights, arc lamps.. .). Plasma surface modification and materials processing contribute increasingly to a wide array of modern artifacts; e.g., tiny plasma discharge elements constitute the pixel arrays of plasma televisions and plasma processing provides roughly one-third of the steps to produce semiconductors, essential elements of our networking and computing infrastructure. Finally, plasmas are central to many cutting edge technologies with high potential (compact high-energy particle accelerators; plasma-enhanced waste processors; high tolerance surface preparation and multifuel preprocessors for transportation systems; fusion for energy production).

  8. Interlayer coherence and entanglement in bilayer quantum Hall states at filling factor ν=2/λ.

    PubMed

    Calixto, M; Pérez-Romero, E

    2014-12-01

    We study coherence and entanglement properties of the state space of a composite bi-fermion (two electrons pierced by λ magnetic flux lines) at one Landau site of a bilayer quantum Hall system. In particular, interlayer imbalance and entanglement (and its fluctuations) are analyzed for a set of U(4) coherent (quasiclassical) states generalizing the standard pseudospin U(2) coherent states for the spin-frozen case. The interplay between spin and pseudospin degrees of freedom opens new possibilities with regard to the spin-frozen case. Actually, spin degrees of freedom make interlayer entanglement more effective and robust under perturbations than in the spin-frozen situation, mainly for a large number of flux quanta λ. Interlayer entanglement of an equilibrium thermal state and its dependence with temperature and bias voltage is also studied for a pseudo-Zeeman interaction. PMID:25351998

  9. A charge-driven molecular water pump.

    PubMed

    Gong, Xiaojing; Li, Jingyuan; Lu, Hangjun; Wan, Rongzheng; Li, Jichen; Hu, Jun; Fang, Haiping

    2007-11-01

    Understanding and controlling the transport of water across nanochannels is of great importance for designing novel molecular devices, machines and sensors and has wide applications, including the desalination of seawater. Nanopumps driven by electric or magnetic fields can transport ions and magnetic quanta, but water is charge-neutral and has no magnetic moment. On the basis of molecular dynamics simulations, we propose a design for a molecular water pump. The design uses a combination of charges positioned adjacent to a nanopore and is inspired by the structure of channels in the cellular membrane that conduct water in and out of the cell (aquaporins). The remarkable pumping ability is attributed to the charge dipole-induced ordering of water confined in the nanochannels, where water can be easily driven by external fields in a concerted fashion. These findings may provide possibilities for developing water transport devices that function without osmotic pressure or a hydrostatic pressure gradient. PMID:18654410

  10. Compact Gamma-Beam Source for Nuclear Security Technologies

    NASA Astrophysics Data System (ADS)

    Gladkikh, P.; Urakawa, J.

    2015-10-01

    A compact gamma-beam source dedicated to the development of the nuclear security technologies by use of the nuclear resonance fluorescence is described. Besides, such source is a very promising tool for novel technologies of the express cargoes inspection to prevent nuclear terrorism. Gamma-beam with the quanta energies from 0.3MeV to 7.2MeV is generated in the Compton scattering of the "green" laser photons on the electron beam with energies from 90MeV to 430MeV. The characteristic property of the proposed gammabeam source is a narrow spectrum (less than 1%) at high average gamma-yield (of 1013γ/s) due to special operation mode.

  11. Origin of a signal detected with the LSD detector after the accident at the chernobyl nuclear power plant

    NASA Astrophysics Data System (ADS)

    Agafonova, N. Yu.; Malgin, A. S.; Fulgione, W.

    2013-08-01

    A rare signal was detected at 23:53 Moscow time on April 27, 1986 with the LSD low-background scintillation detector located under Mont Blanc at a distance of 1820 km from Chernobyl. To reveal the origin of this signal, we discuss the results obtained with other instruments operating within a similar program, as well as analyze the characteristics of the pulses of the signal and facts referring to the explosion of the Chernobyl reactor. A hypothesis based on detection with the LSD of gamma-quanta from β decays of 135I nuclei ejected into atmosphere by the reactor explosion and carried in the underground detector camera with air of positive ventilation is considered. The explosion origin of the LSD signal indicates a new technogenic source of the background in the search for neutrino bursts from cores of collapsing stars.

  12. Energy transport mechanism in the form of proton soliton in a one-dimensional hydrogen-bonded polypeptide chain.

    PubMed

    Kavitha, L; Priya, R; Ayyappan, N; Gopi, D; Jayanthi, S

    2016-01-01

    The dynamics of protons in a one-dimensional hydrogen-bonded (HB) polypeptide chain (PC) is investigated theoretically. A new Hamiltonian is formulated with the inclusion of higher-order molecular interactions between peptide groups (PGs). The wave function of the excitation state of a single particle is replaced by a new wave function of a two-quanta quasi-coherent state. The dynamics is governed by a higher-order nonlinear Schrödinger equation and the energy transport is performed by the proton soliton. A nonlinear multiple-scale perturbation analysis has been performed and the evolution of soliton parameters such as velocity and amplitude is explored numerically. The proton soliton is thermally stable and very robust against these perturbations. The energy transport by the proton soliton is more appropriate to understand the mechanism of energy transfer in biological processes such as muscle contraction, DNA replication, and neuro-electric pulse transfer on biomembranes. PMID:26198375

  13. Micropixel avalanche photodiodes and the possibility for their application in positron-emission tomography

    NASA Astrophysics Data System (ADS)

    Anfimov, N. V.; Selyunin, A. S.

    2012-12-01

    Micropixel avalanche photodiodes (MAPDs) are new instruments for detecting low-intensity light. They consist of many microcounters (pixels integrated on a common silicon wafer). A unique design by the Joint Institute for Nuclear Research (JINR) (Z. Sadygov)—deep-microwell MAPD—provides an order of larger pixel densities without losses in photon-detection efficiency. These instruments are beginning to find use in precision electromagnetic calorimetry. MAPDs can be most widely applied as photodetectors in scanners for positron-emission tomographs (PETs), particularly the time-of-flight PETs becoming popular now. The possibility of using MAPDs in PETs is shown, and the time resolution of a pair of quanta detected by Lutetium Fine Silicate scintillation crystals with MAPD readout is obtained at the level of 400 ps.

  14. Dirac Sea and its Evolution

    NASA Astrophysics Data System (ADS)

    Volfson, Boris

    2013-09-01

    The hypothesis of transition from a chaotic Dirac Sea, via highly unstable positronium, into a Simhony Model of stable face-centered cubic lattice structure of electrons and positrons securely bound in vacuum space, is considered. 13.75 Billion years ago, the new lattice, which, unlike a Dirac Sea, is permeable by photons and phonons, made the Universe detectable. Many electrons and positrons ended up annihilating each other producing energy quanta and neutrino-antineutrino pairs. The weak force of the electron-positron crystal lattice, bombarded by the chirality-changing neutrinos, may have started capturing these neutrinos thus transforming from cubic crystals into a quasicrystal lattice. Unlike cubic crystal lattice, clusters of quasicrystals are "slippery" allowing the formation of centers of local torsion, where gravity condenses matter into galaxies, stars and planets. In the presence of quanta, in a quasicrystal lattice, the Majorana neutrinos' rotation flips to the opposite direction causing natural transformations in a category comprised of three components; two others being positron and electron. In other words, each particle-antiparticle pair "e-" and "e+", in an individual crystal unit, could become either a quasi- component "e- ve e+", or a quasi- component "e+ - ve e-". Five-to-six six billion years ago, a continuous stimulation of the quasicrystal aetherial lattice by the same, similar, or different, astronomical events, could have triggered Hebbian and anti-Hebbian learning processes. The Universe may have started writing script into its own aether in a code most appropriate for the quasicrystal aether "hardware": Eight three-dimensional "alphabet" characters, each corresponding to the individual quasi-crystal unit shape. They could be expressed as quantum Turing machine qubits, or, alternatively, in a binary code. The code numerals could contain terminal and nonterminal symbols of the Chomsky's hierarchy, wherein, the showers of quanta, forming the

  15. Multimode circuit optomechanics near the quantum limit

    PubMed Central

    Massel, Francesco; Cho, Sung Un; Pirkkalainen, Juha-Matti; Hakonen, Pertti J.; Heikkilä, Tero T.; Sillanpää, Mika A.

    2012-01-01

    The coupling of distinct systems underlies nearly all physical phenomena. A basic instance is that of interacting harmonic oscillators, giving rise to, for example, the phonon eigenmodes in a lattice. Of particular importance are the interactions in hybrid quantum systems, which can combine the benefits of each part in quantum technologies. Here we investigate a hybrid optomechanical system having three degrees of freedom, consisting of a microwave cavity and two micromechanical beams with closely spaced frequencies around 32 MHz and no direct interaction. We record the first evidence of tripartite optomechanical mixing, implying that the eigenmodes are combinations of one photonic and two phononic modes. We identify an asymmetric dark mode having a long lifetime. Simultaneously, we operate the nearly macroscopic mechanical modes close to the motional quantum ground state, down to 1.8 thermal quanta, achieved by back-action cooling. These results constitute an important advance towards engineering of entangled motional states. PMID:22871806

  16. Nature's Swiss Army Knife: The Diverse Protective Roles of Anthocyanins in Leaves

    PubMed Central

    Gould, Kevin S.

    2004-01-01

    Anthocyanins, the pigments responsible for spectacular displays of vermilion in the leaves of deciduous trees, have long been considered an extravagant waste of a plant's resources. Contemporary research, in contrast, has begun to show that the pigments can significantly influence the way a leaf responds to environmental stress. Anthocyanins have been implicated in tolerance to stressors as diverse as drought, UV-B, and heavy metals, as well as resistance to herbivores and pathogens. By absorbing high-energy quanta, anthocyanic cell vacuoles both protect chloroplasts from the photoinhibitory and photooxidative effects of strong light, and prevent the catabolism of photolabile defence compounds. Anthocyanins also mitigate photooxidative injury in leaves by efficiently scavenging free radicals and reactive oxygen species. Far from being a useless by-product of the flavonoid pathway, these red pigments may in some instances be critical for plant survival. PMID:15577195

  17. White LEDs with limit luminous efficacy

    NASA Astrophysics Data System (ADS)

    Lisitsyn, V. M.; Lukash, V. S.; Stepanov, S. A.; Yangyang, Ju

    2016-01-01

    In most promising widespread gallium nitride based LEDs emission is generated in the blue spectral region with a maximum at about 450 nm which is converted to visible light with the desired spectrum by means of phosphor. The thermal energy in the conversion is determined by the difference in the energies of excitation and emission quanta and the phosphor quantum yield. Heat losses manifest themselves as decrease in the luminous efficacy. LED heating significantly reduces its efficiency and life. In addition, while heating, the emission generation output and the efficiency of the emission conversion decrease. Therefore, the reduction of the energy losses caused by heating is crucial for LED development. In this paper, heat losses in phosphor-converted LEDs (hereinafter chips) during spectrum conversion are estimated. The limit values of the luminous efficacy for white LEDs are evaluated.

  18. Diffusion of sodium, potassium, calcium, manganese, and radon in tuff and clinoptilolite under leaching

    NASA Astrophysics Data System (ADS)

    Dikii, N. P.; Dovbnya, A. N.; Lyashko, Yu. V.; Medvedev, D. V.; Medvedeva, E. P.; Uvarov, V. L.; Achkasov, K. V.

    2011-07-01

    Nuclear physics methods are used to determine the diffusion coefficients of Na, Ca, Mn, K, and 222Rn in clinoptilolite (Sokirnitsa occurrence, Ukraine) and in natural tuff (Yucca Mountain, Nevada, United States) and in tuff irradiated by γ-quanta ( E max = 23 MeV) to a dose of 107 Gy at a leaching temperature of 37°C. The diffusion coefficients of sodium and potassium in clinoptilolite are found to differ considerably: 4 × 10-17 and 2 × 10-20 m2/s, respectively. This indicates the influence of aquacomplexes on the cation transfer. The diffusion coefficient of radon in these materials is determined: in clinoptilolite it equals 2.5 × 10-12 m2/s.

  19. Continuous monitoring of the dynamical Casimir effect with a damped detector

    NASA Astrophysics Data System (ADS)

    de Castro, A. S. M.; Dodonov, V. V.

    2014-06-01

    We consider the problem of photon creation from vacuum inside an ideal cavity with harmonically vibrating walls in the resonance case, taking into account the interaction between the resonant field mode and a detector, modeled by a quantum damped harmonic oscillator. The frequency of wall vibrations is chosen to be exactly twice the cavity normal frequency. The field and detector modes are supposed to be initially in thermal quantum states with different temperatures. We analyze different regimes of excitation, characterized by the competition of three parameters: the modulation depth of the time-dependent cavity eigenfrequency, the cavity-detector coupling strength, and the detector damping coefficient. We show that statistical properties of the detector quantum state (variances of the photon numbers, photon distribution function, and the degree of quadrature squeezing) can be quite different from that of the field mode. In addition, the mean number of quanta in the detector mode increases with some time delay, compared with the field mode.

  20. Observation of b2 symmetry vibrational levels of the SO2 C̃ (1)B2 state: Vibrational level staggering, Coriolis interactions, and rotation-vibration constants.

    PubMed

    Park, G Barratt; Jiang, Jun; Saladrigas, Catherine A; Field, Robert W

    2016-04-14

    The C̃ (1)B2 state of SO2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. However, low-lying levels with odd quanta of antisymmetric stretch (b2 vibrational symmetry) have not previously been observed because transitions into these levels from the zero-point level of the X̃ state are vibronically forbidden. We use IR-UV double resonance to observe the b2 vibrational levels of the C̃ state below 1600 cm(-1) of vibrational excitation. This enables a direct characterization of the vibrational level staggering that results from the double-minimum potential. In addition, it allows us to deperturb the strong c-axis Coriolis interactions between levels of a1 and b2 vibrational symmetry and to determine accurately the vibrational dependence of the rotational constants in the distorted C̃ electronic state. PMID:27083725

  1. Infinite number of MSSMs from heterotic line bundles?

    NASA Astrophysics Data System (ADS)

    Groot Nibbelink, Stefan; Loukas, Orestis; Ruehle, Fabian; Vaudrevange, Patrick K. S.

    2015-08-01

    We consider heterotic E8×E8 supergravity compactified on smooth Calabi-Yau manifolds with line bundle gauge backgrounds. Infinite sets of models that satisfy the Bianchi identities and flux quantization conditions can be constructed by letting their background flux quanta grow without bound. Even though we do not have a general proof, we find that all examples are at the boundary of the theory's validity: the Donaldson-Uhlenbeck-Yau equations, which can be thought of as vanishing D-term conditions, cannot be satisfied inside the Kähler cone unless a growing number of scalar vacuum expectation values is switched on. As they are charged under various line bundles simultaneously, the gauge background gets deformed by these VEVs to a non-Abelian bundle. In general, our physical expectation is that such infinite sets of models should be impossible, since they never seem to occur in exact conformal field theory constructions.

  2. From de novo mutations to personalized therapeutic interventions in autism.

    PubMed

    Brandler, William M; Sebat, Jonathan

    2015-01-01

    The high heritability, early age at onset, and reproductive disadvantages of autism spectrum disorders (ASDs) are consistent with an etiology composed of dominant-acting de novo (spontaneous) mutations. Mutation detection by microarray analysis and DNA sequencing has confirmed that de novo copy-number variants or point mutations in protein-coding regions of genes contribute to risk, and some of the underlying causal variants and genes have been identified. As our understanding of autism genes develops, the spectrum of autism is breaking up into quanta of many different genetic disorders. Given the diversity of etiologies and underlying biochemical pathways, personalized therapy for ASDs is logical, and clinical genetic testing is a prerequisite. PMID:25587659

  3. Enhancing light-harvesting power with coherent vibrational interactions: A quantum heat engine picture

    SciTech Connect

    Killoran, N.; Huelga, S. F.; Plenio, M. B.

    2015-10-21

    Recent evidence suggests that quantum effects may have functional importance in biological light-harvesting systems. Along with delocalized electronic excitations, it is now suspected that quantum coherent interactions with certain near-resonant vibrations may contribute to light-harvesting performance. However, the actual quantum advantage offered by such coherent vibrational interactions has not yet been established. We investigate a quantum design principle, whereby coherent exchange of single energy quanta between electronic and vibrational degrees of freedom can enhance a light-harvesting system’s power above what is possible by thermal mechanisms alone. We present a prototype quantum heat engine which cleanly illustrates this quantum design principle and quantifies its quantum advantage using thermodynamic measures of performance. We also demonstrate the principle’s relevance in parameter regimes connected to natural light-harvesting structures.

  4. Gabor: frequency, time, and memory.

    PubMed

    Korpel, A

    1982-10-15

    Dennis Gabor is well-known as the inventor of holography. Less well-known, perhaps, are his contributions to other areas. Yet they are important and, like holography, characteristic of his foresight. In the field of communications, Gabor investigated the classic dichotomy of time and frequency. Guided by analogies to quantum mechanics, he postulated a set of elementary signals and made brilliant use of time-frequency diagrams to analyze communication systems. Applying his theories to acoustics, he researched the mechanism of hearing, defining acoustical quanta in the process and inventing early prototype frequency compressors and expanders. In a completely different field, Gabor, inspired by some early work of Longuet-Higgins on models for holographic temporal recall in the brain, suggested novel approaches which contributed significantly to the understanding of associative memories. In this paper we describe Gabor's pioneering work in these areas and trace the subsequent development by himself and others. PMID:20396288

  5. An experimental and theoretical study of the bond selected photodissociation of HOD

    SciTech Connect

    Vander Wal, R.L.; Scott, J.L.; Crim, F.F. ); Weide, K.; Schinke, R. )

    1991-03-01

    Experimental and theoretical studies of the photodissociation of single vibrational states in HOD provide a qualitative and quantitative understanding of the dissociation dynamics and bond selectivity of this process. Vibrationally mediated photodissociation, in which one photon prepares a vibrational state that a second photon dissociates, can selectively cleave the O--H bond in HOD molecules containing four quanta of O--H stretching excitation. Dissociation of HOD(4{nu}{sub OH}) with 266 or 239.5-nm photons produces OD fragments in at least a 15 fold excess over OH, but photolysis of the same state with 218.5-nm photons produces comparable amounts of OH and OD. Wave packet propagation calculations on an {ital ab} {ital initio} potential energy surface reproduce these observations quantitatively. They show that the origin of the selectivity and its energy dependence is the communication of the initial vibrational state with different portions of the outgoing continuum wave function for different photolysis energies.

  6. Anisotropy of radiation emitted from planar wire arrays

    SciTech Connect

    Kantsyrev, V. L.; Esaulov, A. A.; Safronova, A. S.; Williamson, K. M.; Osborne, G. C.; Shrestha, I. K.; Weller, M. E.; Shlyaptseva, V. V.; Chuvatin, A. S.; Rudakov, L. I.; Velikovich, A.

    2013-07-15

    The planar wire array (PWA) is a promising load for new multi-source inertial confinement fusion (ICF) hohlraums [B. Jones et al., Phys. Rev. Lett. 104, 125001 (2010)]. The hohlraum radiation symmetry is an important issue for ICF. It was found that extreme ultraviolet and sub-keV photon emission from PWAs may have considerable anisotropy in the load azimuthal plane. This experimental result is obtained on the UNR 1–1.7 MA Zebra generator. The time-dependent anisotropy effect is detected. This feature is studied in 2D numerical simulations and can be explained by initial anisotropy of implosion of those non-cylindrical loads radiating essentially as surface sources in sub-keV quanta and also by radiation absorption in cold magnetized plasma tails forming in the direction of magnetic compression.

  7. Study for luminescence performance of three methyl xanthine derivatives

    NASA Astrophysics Data System (ADS)

    Wei, Yan-Li; Dong, Chuan; Shuang, Shao-Min; Liu, Dian-Sheng

    2005-09-01

    In this paper, the low-temperature phosphorescence (LTP), the low-temperature fluorescence (LTF), the paper substrate room-temperature phosphorescence (PS-RTP) and the room fluorescence (RTF) properties of caffeine (CF), theophylline (TP), and theobromine (TB) are investigated and compared, and some rules are found out: their maximal excitation wavelength and emission wavelength are in the range of 270-300 nm and 395-445 nm, respectively. And the PS-RTP characters of lifetime, polarization and quanta yield are also investigated and compared. It is found that their lifetimes of PS-RTP are all in the level of 0.1 s. They belong to long-life phosphorescence and their PS-RTP spectra are incompletely polarized.

  8. On the first Solvay Congress in 1911

    NASA Astrophysics Data System (ADS)

    Straumann, Norbert

    2011-11-01

    Late in October 1911, eighteen leading scientists from all over Europe met to the first of a famous sequence of Solvay conferences in Brussels. This historical meeting was mainly devoted to "The Theory of Radiation and the Quanta", at a time when the foundations of physics were totally shaken. Although "nothing positive came out" (Einstein), it is interesting to see the diverging attitudes of Europe's most famous scientists in the middle of the quantum revolution. After a few general remarks about the conference, I shall focus on some of the most interesting contributions and discussions. Einstein, at 32 the youngest, was clearly most aware of the profound nature of the crises. He gave the final talk entitled "The Present State of the Problem of Specific Heats", but he put his theme into the larger context of the quantum problem, and caused a barrage of challenges, in particular from Lorentz, Planck, Poincaré, and others.

  9. The vibrational spectrum of the water trimer: Comparison between anharmonic ab initio calculations and neon matrix infrared data between 11,000 and 90 cm -1

    NASA Astrophysics Data System (ADS)

    Tremblay, B.; Madebène, B.; Alikhani, M. E.; Perchard, J. P.

    2010-12-01

    The infrared spectrum of the water trimer trapped in solid neon has been identified. Eighteen groups of absorptions between 1600 and 11,000 cm -1 were assigned to one-, two- and three-quanta transitions of the intramolecular modes. Because of the near equivalence of the three molecules and their weak interactions most of these modes correspond to quasi degenerate vibrations involving the bending δ, free OH stretching (OH f) and bonded OH stretching (OH b) of the three subunits at 1608, 3725 and 3525-3473 cm -1, respectively. In the last case the 52 cm -1 splitting is due to the coupling between the OH b oscillators. Calculated anharmonic frequencies correctly agree with these observations and allow to propose a new assignment of the intermolecular modes. Finally combinations of intra + intermolecular transitions were identified and assigned on the basis of calculated anharmonicity coefficients.

  10. Observation of b2 symmetry vibrational levels of the SO2C 1B2 state: Vibrational level staggering, Coriolis interactions, and rotation-vibration constants

    DOE PAGESBeta

    Park, G. Barratt; Jiang, Jun; Saladrigas, Catherine A.; Field, Robert W.

    2016-04-14

    Here, the C 1B2 state of SO2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. However, low-lying levels with odd quanta of antisymmetric stretch (b2 vibrational symmetry) have not previously been observed because transitions into these levels from the zero-point level of the X~ state are vibronically forbidden. We use IR-UV double resonance to observe the b2 vibrational levels of the C state below 1600 cm–1 of vibrational excitation. This enables a direct characterization of the vibrational level staggering that results from the double-minimum potential. In addition, itmore » allows us to deperturb the strong c-axis Coriolis interactions between levels of a1 and b2 vibrational symmetry, and to determine accurately the vibrational dependence of the rotational constants in the distorted C electronic state.« less

  11. State-selective spectroscopy of water up to its first dissociation limit.

    PubMed

    Grechko, Maxim; Boyarkin, Oleg V; Rizzo, Thomas R; Maksyutenko, Pavlo; Zobov, Nikolay F; Shirin, Sergei V; Lodi, Lorenzo; Tennyson, Jonathan; Császár, Attila G; Polyansky, Oleg L

    2009-12-14

    A joint experimental and first-principles quantum chemical study of the vibration-rotation states of the water molecule up to its first dissociation limit is presented. Triple-resonance, quantum state-selective spectroscopy is used to probe the entire ladder of water's stretching vibrations up to 19 quanta of OH stretch, the last stretching state below dissociation. A new ground state potential energy surface of water is calculated using a large basis set and an all-electron, multireference configuration interaction procedure, which is augmented by relativistic corrections and fitted to a flexible functional form appropriate for a dissociating system. Variational nuclear motion calculations on this surface are used to give vibrational assignments. A total of 44 new vibrational states and 366 rotation-vibration energy levels are characterized; these span the region from 35,508 to 41,126 cm(-1) above the vibrational ground state. PMID:20001017

  12. Manipulating the Majorana qubit with Landau-Zener-Stückelberg interference

    NASA Astrophysics Data System (ADS)

    Huang, Wen-Chao; Liang, Qi-Feng; Yao, Dao-Xin; Wang, Zhi

    2015-07-01

    Constructing a universal operation scheme for Majorana qubits remains a central issue for the topological quantum computation. We study the Landau-Zener-Stückelberg interference in a Majorana qubit and show that this interference can be used to achieve controllable operations. The Majorana qubit consists of an rf superconducting quantum interference device (SQUID) with a topological nanowire Josephson junction which hosts Majorana bound states. In the SQUID, a magnetic flux pulse can drive the quantum evolution of the Majorana qubit. The qubit experiences two Landau-Zener transitions when the amplitude of the pulse is tuned around the superconducting flux quanta h /2 e . The Landau-Zener-Stückelberg interference between the two transitions rotates the Majorana qubit, with the angle controlled by the time scale of the pulse. This rotation operation implements a high-speed single-qubit gate on the Majorana qubit, which is a necessary ingredient for the topological quantum computation.

  13. Growth of dopamine crystals

    NASA Astrophysics Data System (ADS)

    Patil, Vidya; Patki, Mugdha

    2016-05-01

    Many nonlinear optical (NLO) crystals have been identified as potential candidates in optical and electro-optical devices. Use of NLO organic crystals is expected in photonic applications. Hence organic nonlinear optical materials have been intensely investigated due to their potentially high nonlinearities, and rapid response in electro-optic effect compared to inorganic NLO materials. There are many methods to grow organic crystals such as vapor growth method, melt growth method and solution growth method. Out of these methods, solution growth method is useful in providing constraint free crystal. Single crystals of Dopamine have been grown by evaporating the solvents from aqueous solution. Crystals obtained were of the size of orders of mm. The crystal structure of dopamine was determined using XRD technique. Images of crystals were obtained using FEG SEM Quanta Series under high vacuum and low KV.

  14. Observation of b2 symmetry vibrational levels of the SO2 C ˜ 1B2 state: Vibrational level staggering, Coriolis interactions, and rotation-vibration constants

    NASA Astrophysics Data System (ADS)

    Park, G. Barratt; Jiang, Jun; Saladrigas, Catherine A.; Field, Robert W.

    2016-04-01

    The C ˜ 1B2 state of SO2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. However, low-lying levels with odd quanta of antisymmetric stretch (b2 vibrational symmetry) have not previously been observed because transitions into these levels from the zero-point level of the X ˜ state are vibronically forbidden. We use IR-UV double resonance to observe the b2 vibrational levels of the C ˜ state below 1600 cm-1 of vibrational excitation. This enables a direct characterization of the vibrational level staggering that results from the double-minimum potential. In addition, it allows us to deperturb the strong c-axis Coriolis interactions between levels of a1 and b2 vibrational symmetry and to determine accurately the vibrational dependence of the rotational constants in the distorted C ˜ electronic state.

  15. Micro-Macro Duality and Space-Time Emergence

    SciTech Connect

    Ojima, Izumi

    2011-03-28

    The microscopic origin of space-time geometry is explained on the basis of an emergence process associated with the condensation of infinite number of microscopic quanta responsible for symmetry breakdown, which implements the basic essence of 'Quantum-Classical Correspondence' and of the forcing method in physical and mathematical contexts, respectively. From this viewpoint, the space-time dependence of physical quantities arises from the 'logical extension' to change 'constant objects' into 'variable objects' by tagging the order parameters associated with the condensation onto ''constant objects''; the logical direction here from a value y to a domain variable x(to materialize the basic mechanism behind the Gel'fand isomorphism) is just opposite to that common in the usual definition of a function f : x->f(x) from its domain variable x to a value y = f(x).

  16. Flux Exclusion Superconducting Quantum Metamaterial: Towards Quantum-level Switching

    PubMed Central

    Savinov, V.; Tsiatmas, A.; Buckingham, A. R.; Fedotov, V. A.; de Groot, P. A. J.; Zheludev, N. I.

    2012-01-01

    Nonlinear and switchable metamaterials achieved by artificial structuring on the subwavelength scale have become a central topic in photonics research. Switching with only a few quanta of excitation per metamolecule, metamaterial's elementary building block, is the ultimate goal, achieving which will open new opportunities for energy efficient signal handling and quantum information processing. Recently, arrays of Josephson junction devices have been proposed as a possible solution. However, they require extremely high levels of nanofabrication. Here we introduce a new quantum superconducting metamaterial which exploits the magnetic flux quantization for switching. It does not contain Josephson junctions, making it simple to fabricate and scale into large arrays. The metamaterial was manufactured from a high-temperature superconductor and characterized in the low intensity regime, providing the first observation of the quantum phenomenon of flux exclusion affecting the far-field electromagnetic properties of the metamaterial. PMID:22690319

  17. Kinetic Simulations of Ladder Climbing and Autoresonance of Plasma Waves

    NASA Astrophysics Data System (ADS)

    Kaminski, Erez; Barth, Ido; Fisch, Nat; Dodin, Ilya

    2015-11-01

    Quantum like Ladder Climbing and Autoresonance of classical Langmuir waves in bounded plasmas are numerically studied within a kinetic model and compared with earlier fluid model simulations. Both dynamical solutions are excited and controlled via chirped modulations of the background density that preserve the plasma wave quanta. Landau damping determines the system's maximal stable level, imposing a kinetic limit on the maximal level of the Ladder Climbing or Autoresonance dynamics. Vlasov simulations are employed to test the kinetic stability of both dynamics and to find the kinetic limit for different system's parameters. This work was Supported by NNSA grant DE274-FG52-08NA28553, DOE contract DE-AC02-09CH11466, and DTRA grant HDTRA1-11-1-0037.

  18. Do humans discount the illuminant?

    NASA Astrophysics Data System (ADS)

    McCann, John J.

    2005-03-01

    In constancy experiments, humans report very small changes in appearance with substantial illumination changes. Hermann von Helmholtz introduced the term "discounting the illuminant" to describe 19th century thinking about underlying mechanisms of constancy. It uses an indirect approach. Since observers see objects as constant, observers "must" be able to detect the spatial and spectral changes in illumination and automatically compensate by altering the signals from the quanta catches of retinal receptors. Instead of solving the problem directly by calculating an object"s reflectance from the array of scene radiances, Helmholtz chose to solve the problem of identifying the illumination. Twentieth century experiments by Hubel and Wiesel, Campbell, Land, and Gibson demonstrate the power of mechanisms using spatial comparisons. This paper analyses a series of different experiments looking for unequivocal evidence that either supports "discounting the illuminant" or supports spatial comparisons as the underlying mechanism of constancy.

  19. Magnetic flux disorder and superconductor-insulator transition in nanohole thin films

    NASA Astrophysics Data System (ADS)

    Granato, Enzo

    2016-08-01

    We study the superconductor-insulator transition in nanohole ultrathin films in a transverse magnetic field by numerical simulation of a Josephson-junction array model. Geometrical disorder due to the random location of nanoholes in the film corresponds to random flux in the array model. Monte Carlo simulation in the path-integral representation is used to determine the critical behavior and the universal resistivity at the transition as a function of disorder and average number of flux quanta per cell, fo. The resistivity increases with disorder for noninteger fo while it decreases for integer fo, and reaches a common constant value in a vortex-glass regime above a critical value of the flux disorder Dfc. The estimate of Dfc and the resistivity increase for noninteger fo are consistent with recent experiments on ultrathin superconducting films with positional disordered nanoholes.

  20. Vector vortex beam emission from organic semiconductor microlasers

    NASA Astrophysics Data System (ADS)

    Qian, H.; Markman, B. D.; Giebink, N. C.

    2013-10-01

    High order Bessel beams (HOBBs) carrying discrete orbital angular momentum (OAM) are currently being explored for use in applications ranging from optical trapping to high-speed communication, all of which would benefit from the availability of compact semiconductor lasers with direct HOBB output. Here, we use an organic semiconductor gain medium to demonstrate a bilayer microdisk laser architecture that yields cylindrical vector HOBB emission with OAM quanta per photon >400ℏ. These devices feature azimuthally polarized, few-mode lasing with optical pumping thresholds <100 μJ/cm2 and emission wavelengths that can be tuned over a range of ˜40 nm by varying the organic microdisk thickness. Our approach is generally applicable to organic and inorganic semiconductors alike and may therefore serve as a practical route for integrating HOBB functionality into a range of optoelectronic and photonic applications throughout the visible and near-infrared spectrum.

  1. Rainbow metric from quantum gravity

    NASA Astrophysics Data System (ADS)

    Assanioussi, Mehdi; Dapor, Andrea; Lewandowski, Jerzy

    2015-12-01

    In this Letter, we describe a general mechanism for emergence of a rainbow metric from a quantum cosmological model. This idea is based on QFT on a quantum spacetime. Under general assumptions, we discover that the quantum spacetime on which the field propagates can be replaced by a classical spacetime, whose metric depends explicitly on the energy of the field: as shown by an analysis of dispersion relations, quanta of different energy propagate on different metrics, similar to photons in a refractive material (hence the name "rainbow" used in the literature). In deriving this result, we do not consider any specific theory of quantum gravity: the qualitative behaviour of high-energy particles on quantum spacetime relies only on the assumption that the quantum spacetime is described by a wave-function Ψo in a Hilbert space HG.

  2. Complementarity, quantum erasure and delayed choice with modified Mach-Zehnder interferometers

    NASA Astrophysics Data System (ADS)

    Ataman, Stefan

    2014-10-01

    Often cited dictums in Quantum Mechanics include "observation disturbance causes loss of interference" and "ignorance is interference". In this paper we propose and describe a series of experiments with modified Mach-Zehnder interferometers showing that one has to be careful when applying such dictums. We are able to show that without interacting in any way with the light quantum (or quanta) expected to behave "wave-like", interference fringes can be lost by simply gaining (or having the potential to gain) the which-path knowledge. Erasing this information may revive the interference fringes. Delayed choice can be added, arriving to an experiment in line with Wheeler's original proposal. We also show that ignorance is not always synonym with having the interference fringes. The often-invoked "collapse of the wavefunction" is found to be a non-necessary ingredient to describe our experiments.

  3. CMB and the elementary particles structure deduced from QFT of non-dot model

    NASA Astrophysics Data System (ADS)

    Chen, Shao-Guang

    In my paper ‘Planck Constant Deduced from Metrical Results of Doppler Effect of Moving Particle —Uncertainty Principle Caused by Collision of a Particle with CMB Photons and Virtual Photons (H05-0036-10)’ the absolute velocity is decided by CMB which as a mark of the vacuum. CMB come from the thermal radiation of stars via gravitational redshift about 10 (13) year (E14- 0032-08). In my paper ‘Quanta turn-advance ism, China Science && Technology Overview 131 192-210 (2011)’, QFT four-dimensional uncertainty principle and momentum-energy conservation law had been generalized as a five-dimensional equations: de Broglie wavelength as a position vector \\underline{q}= (i c t, r, s), momentum \\underline{P} = (i E / c, P, U c), \\underline{q} = i h / \\underline{P}, \\underline{q} \\underline{q} = 0, \\underline{P} \\underline{P} = 0, Sigma∑ \\underline{P} = \\underline{P} (0) . The five-dimensional time-space-spin had been quantized as a non-dot model basic cell, the lowest energy state vertical polarized left spin 1/2 neutrino and right spin 1/2 antineutrino are just the left, right advance unit quanta _{0}nuυ, nuυ _{0} and left, right back unit quanta (0) nuυ, nuυ (0) , it again compose into spin 1 unit advance photons _{0}nuυnuυ _{0} and back (0) nuυnuυ (0) , spin 0 unit rest mass nuυ _{0}nuυ (0) and anti-mass _{0}nuυ (0) nuυ, spin 0 unit positive charge _{0}nuυnuυ (0) and negative charge nuυ _{0} (0) nuυ. It accord to the high energy physics experimental results of the transformation among the photons, masses quanta and charges quanta. The physical vacuum is the even collocation of non-combinational nuυ _{0} or _{0}nuυ. QFT is no longer with divergence difficulty by the non-dot model. It is mathematically easy that from five-dimensional equations deduce out the Dirac, Klein-Gordan, Maxwell equations and Lorentz force formula, but appear some new results. The interactions between _{0}nuυ, nuυ _{0}, (0) nuυ, nuυ (0) , i.e., force f

  4. Modified Bose-Einstein and Fermi-Dirac statistics if excitations are localized on an intermediate length scale: Applications to non-Debye specific heat

    NASA Astrophysics Data System (ADS)

    Chamberlin, Ralph V.; Davis, Bryce F.

    2013-10-01

    Disordered systems show deviations from the standard Debye theory of specific heat at low temperatures. These deviations are often attributed to two-level systems of uncertain origin. We find that a source of excess specific heat comes from correlations between quanta of energy if excitations are localized on an intermediate length scale. We use simulations of a simplified Creutz model for a system of Ising-like spins coupled to a thermal bath of Einstein-like oscillators. One feature of this model is that energy is quantized in both the system and its bath, ensuring conservation of energy at every step. Another feature is that the exact entropies of both the system and its bath are known at every step, so that their temperatures can be determined independently. We find that there is a mismatch in canonical temperature between the system and its bath. In addition to the usual finite-size effects in the Bose-Einstein and Fermi-Dirac distributions, if excitations in the heat bath are localized on an intermediate length scale, this mismatch is independent of system size up to at least 106 particles. We use a model for correlations between quanta of energy to adjust the statistical distributions and yield a thermodynamically consistent temperature. The model includes a chemical potential for units of energy, as is often used for other types of particles that are quantized and conserved. Experimental evidence for this model comes from its ability to characterize the excess specific heat of imperfect crystals at low temperatures.

  5. Modified Bose-Einstein and Fermi-Dirac statistics if excitations are localized on an intermediate length scale: applications to non-Debye specific heat.

    PubMed

    Chamberlin, Ralph V; Davis, Bryce F

    2013-10-01

    Disordered systems show deviations from the standard Debye theory of specific heat at low temperatures. These deviations are often attributed to two-level systems of uncertain origin. We find that a source of excess specific heat comes from correlations between quanta of energy if excitations are localized on an intermediate length scale. We use simulations of a simplified Creutz model for a system of Ising-like spins coupled to a thermal bath of Einstein-like oscillators. One feature of this model is that energy is quantized in both the system and its bath, ensuring conservation of energy at every step. Another feature is that the exact entropies of both the system and its bath are known at every step, so that their temperatures can be determined independently. We find that there is a mismatch in canonical temperature between the system and its bath. In addition to the usual finite-size effects in the Bose-Einstein and Fermi-Dirac distributions, if excitations in the heat bath are localized on an intermediate length scale, this mismatch is independent of system size up to at least 10(6) particles. We use a model for correlations between quanta of energy to adjust the statistical distributions and yield a thermodynamically consistent temperature. The model includes a chemical potential for units of energy, as is often used for other types of particles that are quantized and conserved. Experimental evidence for this model comes from its ability to characterize the excess specific heat of imperfect crystals at low temperatures. PMID:24229117

  6. Poincaré's proof of the quantum discontinuity of nature

    NASA Astrophysics Data System (ADS)

    Prentis, Jeffrey J.

    1995-04-01

    In his last memoir on mathematical physics, Henri Poincaré presented one of the most profound and compelling proofs of the hypothesis of quanta. This highly original proof, which is actually three separate proofs, is based on first principles and is full of physical insight, mathematical rigor, and elegant simplicity. The memoir is refreshingly uncluttered by some of the conventional, and more abstract concepts, such as temperature and entropy, that Planck and others relied on in their work. Poincaré's analysis is based on an ingenious physical model consisting of long-period resonators interacting with short-period resonators. A unique formulation of statistical mechanics, based on the calculus of probabilities, Fourier's integral, and complex analysis, logically unfolds throughout the memoir. Poincaré invents an ``inverse statistical mechanics'' that allows him to prove a crucial result that no one had proved before: The hypothesis of quanta is both a sufficient and a necessary condition to account for Planck's law of radiation. In a separate, more universal proof, Poincaré proves that the existence of a discontinuity in the motion of a resonator is necessary to explain any observed law of radiation. Given the significant impact of Poincaré's memoir on quantum theory and statistical physics, it is surprising that most physicists are not aware of its valuable mathematical and physical ideas. Poincaré's tour de force proofs are presented here in a form suitable for use in a standard course in quantum mechanics, statistical mechanics, or mathematical physics.

  7. A common fluence threshold for first positive and second positive phototropism in Arabidopsis thaliana

    NASA Technical Reports Server (NTRS)

    Janoudi, A.; Poff, K. L.

    1990-01-01

    The relationship between the amount of light and the amount of response for any photobiological process can be based on the number of incident quanta per unit time (fluence rate-response) or on the number of incident quanta during a given period of irradiation (fluence-response). Fluence-response and fluence rate-response relationships have been measured for second positive phototropism by seedlings of Arabidopsis thaliana. The fluence-response relationships exhibit a single limiting threshold at about 0.01 micromole per square meter when measured at fluence rates from 2.4 x 10(-5) to 6.5 x 10(-3) micromoles per square meter per second. The threshold values in the fluence rate-response curves decrease with increasing time of irradiation, but show a common fluence threshold at about 0.01 micromole per square meter. These thresholds are the same as the threshold of about 0.01 micromole per square meter measured for first positive phototropism. Based on these data, it is suggested that second positive curvature has a threshold in time of about 10 minutes. Moreover, if the times of irradiation exceed the time threshold, there is a single limiting fluence threshold at about 0.01 micromole per square meter. Thus, the limiting fluence threshold for second positive phototropism is the same as the fluence threshold for first positive phototropism. Based on these data, we suggest that this common fluence threshold for first positive and second positive phototropism is set by a single photoreceptor pigment system.

  8. Combination Bands of the Nonpolar OCS Dimer Involving Intermolecular Modes

    NASA Astrophysics Data System (ADS)

    Rezaei, M.; Oliaee, J. Norooz; Moazzen-Ahmadi, N.; McKellar, A. R. W.

    2012-06-01

    Spectra of the nonpolar carbonyl sulfide in the region of the OCS ν_1 fundamental band were observed in a supersonic slit-jet apparatus. The expansion gas was probed using radiation from a tunable diode laser employed in a rapid-scan signal averaging mode. Three bands centered at 2085.906, 2103.504, and 2114.979 cm-1 were observed and anlysed. The rotational assignment and fitting of the bands were made by fixing the lower state parameters to those for the ground state of nonpolar (OCS)_2, thus confirming that they were indeed combination bands of the of the most stable isomer of OCS dimer. The band centered at 2085.906 cm-1 is a combination of the forbidden A_g intramolecular mode plus the geared bend intermolecular mode and that centered at 2114.979 cm-1 is a combination of the allowed B_u intramolecular mode plus the intermolecular van der Waals stretch. The combination at 2103.504 cm-1 can be assigned as a band whose upper state involves four quanta of the intramolecular bend or the B_u intramolecular mode plus two quanta of the intermolecular torsional mode. Isotopic work is needed to conclusively identify the vibrational assignment of this band. Our experimental frequencies for the geared bend and van der Waals modes are in good agreement with a recent high level ab initio calculation by Brown et al. J. Brown, Xiao-Gang Wang, T. Carrington Jr. and Richard Dawes, Journal of Chemical Physics, submitted.

  9. Black holes and beyond

    SciTech Connect

    Mathur, Samir D.

    2012-11-15

    The black hole information paradox forces us into a strange situation: we must find a way to break the semiclassical approximation in a domain where no quantum gravity effects would normally be expected. Traditional quantizations of gravity do not exhibit any such breakdown, and this forces us into a difficult corner: either we must give up quantum mechanics or we must accept the existence of troublesome 'remnants'. In string theory, however, the fundamental quanta are extended objects, and it turns out that the bound states of such objects acquire a size that grows with the number of quanta in the bound state. The interior of the black hole gets completely altered to a 'fuzzball' structure, and information is able to escape in radiation from the hole. The semiclassical approximation can break at macroscopic scales due to the large entropy of the hole: the measure in the path integral competes with the classical action, instead of giving a subleading correction. Putting this picture of black hole microstates together with ideas about entangled states leads to a natural set of conjectures on many long-standing questions in gravity: the significance of Rindler and de Sitter entropies, the notion of black hole complementarity, and the fate of an observer falling into a black hole. - Highlights: Black-Right-Pointing-Pointer The information paradox is a serious problem. Black-Right-Pointing-Pointer To solve it we need to find 'hair' on black holes. Black-Right-Pointing-Pointer In string theory we find 'hair' by the fuzzball construction. Black-Right-Pointing-Pointer Fuzzballs help to resolve many other issues in gravity.

  10. Photoconductive properties of organic-inorganic hybrid films of layered perovskite-type niobate.

    PubMed

    Saruwatari, Kazuko; Sato, Hisako; Idei, Tomochika; Kameda, Jun; Yamagishi, Akihiko; Takagaki, Atsushi; Domen, Kazunari

    2005-06-30

    A hybrid film of layered niobate and an organic amphiphile was prepared by the Langmuir-Blodgett (LB) method. Trimethylammonium-exchanged perovskite-type niobates ((CH(3))(3)NHSr(2)Nb(3)O(10)) were exfoliative to form an aqueous suspension. A monolayer of octadecylamine was produced on such an aqueous dispersion as a template for a hybrid film. A hybrid film was transferred as a Y-type LB film onto a hydrophilic glass plate or an ITO substrate. The structure of a deposited film was investigated with X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and atomic force microscopy (AFM) measurements, indicating a layer-by-layer structure with a single or double sheet of niobate as an inorganic composite. From the cyclic voltammogram on an ITO electrode modified with the Y-type 10 layered film, the lower edge of the conduction band of a niobate layer was determined to be - 0.6 V (vs Ag/AgCl). ac impedance and dc measurements were carried out on 1, 5, and 10-layered LB films (2 mm (electrode spacing) x 8 mm (width)) with aluminum electrodes. The freshly deposited samples behaved as an insulator under the illumination of 280 nm light (2.04 x 10(16) quanta s(-1)). Photoconductivities appeared, however, when they were preirradiated with a 150 W Xe lamp (ca. 2 x 10(18) quanta s(-1)) for 0.5-8.5 h. The process was denoted as photomodification. From the FT-IR and XRD results, it was deduced that the photomodification of LB films caused the decomposition of organic templates (octadecylammonium) accompanied by the collapse of layer-by-layer structures. dc analyses on the 5- and 10-layered films after photomodification also showed that they behaved as a photosemiconductor under UV light illumination. PMID:16852536

  11. The Active and Periactive Zone Organization and the Functional Properties of Small and Large Synapses

    PubMed Central

    Cano, Raquel; Tabares, Lucia

    2016-01-01

    The arrival of an action potential (AP) at a synaptic terminal elicits highly synchronized quanta release. Repetitive APs produce successive synaptic vesicle (SV) fusions that require management of spent SV components in the presynaptic membrane with minimum disturbance of the secretory apparatus. To this end, the synaptic machinery is structured accordingly to the strength and the range of frequencies at which each particular synapse operates. This results in variations in the number and dimension of Active Zones (AZs), amount and distribution of SVs, and probably, in the primary endocytic mechanisms they use. Understanding better how these structural differences determine the functional response in each case has been a matter of long-term interest. Here we review the structural and functional properties of three distinct types of synapses: the neuromuscular junction (NMJ; a giant, highly reliable synapse that must exocytose a large number of quanta with each stimulus to guarantee excitation of the postsynaptic cell), the hippocampal excitatory small synapse (which most often has a single release site and a relatively small pool of vesicles), and the cerebellar mossy fiber-granule cell synapse (which possesses hundreds of release sites and is able to translocate, dock and prime vesicles at high speed). We will focus on how the release apparatus is organized in each case, the relative amount of vesicular membrane that needs to be accommodated within the periAZ upon stimulation, the different mechanisms for retrieving the excess of membrane and finally, how these factors may influence the functioning of the release sites. PMID:27252645

  12. A new approach to the phenomena at the interfaces of finely dispersed systems.

    PubMed

    Spasic, Aleksandar M; Lazarevic, Mihailo P

    2007-12-15

    A new idea has been applied for the elucidation of the electron and momentum transfer phenomena, at both rigid and deformable interfaces, in finely (micro-, nano-, atto-) dispersed systems. The electroviscoelastic behavior of, e.g., liquid/liquid interfaces (emulsions and double emulsions), is based on three forms of "instabilities"; these are rigid, elastic, and plastic. The events are understood as interactions between the internal (immanent) and external (incident) periodical physical fields. Since the events at the interfaces of finely dispersed systems must be considered at the molecular, atomic, and/or entities level it is inevitable to introduce the electron transfer phenomenon beside the classical heat, mass, and momentum transfer phenomena commonly used in chemical engineering. Therefore, an entity can be defined as the smallest indivisible element of matter that is related to the particular transfer phenomena. Hence, the entity can be either differential element of mass/demon, ion, phonon as quanta of acoustic energy, infon as quanta of information, photon, and electron. Three possible mathematical formalisms have been derived and discussed related to this physical formalism, i.e., to the developed theory of electroviscoelasticity. The first is the stretching tensor model, where the normal and tangential forces are considered, only in mathematical formalism, regardless of their origin (mechanical and/or electrical). The second is the classical integer-order van der Pol derivative model. Finally, the third model comprises an effort to generalize the previous van der Pol differential equations, both linear and nonlinear, where the ordinary time derivatives and integrals are replaced by corresponding fractional-order time derivatives and integrals of order p < 2 (p = n - delta, n = 1,2,delta < 1). In order to justify and corroborate a more general approach the obtained calculated results were compared to those experimentally measured using the representative

  13. Coupled-surface investigation of the photodissociation of NH{sub 3}(A-tilde): Effect of exciting the symmetric and antisymmetric stretching modes

    SciTech Connect

    Bonhommeau, David; Valero, Rosendo; Truhlar, Donald G.; Jasper, Ahren W.

    2009-06-21

    Using previously developed potential energy surfaces and their couplings, non-Born-Oppenheimer trajectory methods are used to study the state-selected photodissociation of ammonia, prepared with up to six quanta of vibrational excitation in the symmetric ({nu}{sub 1}) or antisymmetric ({nu}{sub 3}) stretching modes of NH{sub 3}(A-tilde). The predicted dynamics is mainly electronically nonadiabatic (that is, it produces ground electronic state amino radicals). The small probability of forming the excited-state amino radical is found, for low excitations, to increase with total energy and to be independent of whether the symmetric or antisymmetric stretch is excited; however some selectivity with respect to exciting the antisymmetric stretch is found when more than one quantum of excitation is added to the stretches, and more than 50% of the amino radical are found to be electronically excited when six quanta are placed in the antisymmetric stretch. These results are in contrast to the mechanism inferred in recent experimental work, where excitation of the antisymmetric stretch by a single quantum was found to produce significant amounts of excited-state products via adiabatic dissociation at total energies of about 7.0 eV. Both theory and experiment predict a broad range of translational energies for the departing H atoms when the symmetric stretch is excited, but the present simulations do not reproduce the experimental translational energy profiles when the antisymmetric stretch is excited. The sensitivity of the predicted results to several aspects of the calculation is considered in detail, and the analysis leads to insight into the nature of the dynamics that is responsible for mode selectivity.

  14. Riemann-Hypothesis Millennium-Problem(MP) Physics Proof via CATEGORY-SEMANTICS(C-S)/F =C Aristotle SQUARE-of-OPPOSITION(SoO) DEduction-LOGIC DichotomY

    NASA Astrophysics Data System (ADS)

    Baez, Joao-Joan; Lapidaryus, Michelle; Siegel, Edward Carl-Ludwig

    2013-03-01

    Riemann-hypothesis physics-proof combines: Siegel-Antono®-Smith[AMS Joint Mtg.(2002)- Abs.973-03-126] digits on-average statistics HIll[Am. J. Math 123, 3, 887(1996)] logarithm-function's (1,0)- xed-point base =units =scale-invariance proven Newcomb [Am. J. Math. 4, 39(1881)]-Weyl[Goett. Nachr.(1914); Math. Ann.7, 313(1916)]-Benford[Proc. Am. Phil. Soc. 78, 4, 51(1938)]-law [Kac,Math. of Stat.-Reasoning(1955); Raimi, Sci. Am. 221, 109(1969)] algebraic-inversion to ONLY Bose-Einstein quantum-statistics(BEQS) with digit d = 0 gapFUL Bose-Einstein Condensation(BEC) insight that digits are quanta are bosons because bosons are and always were quanta are and always were digits, via Siegel-Baez category-semantics tabular list-format matrix truth-table analytics in Plato-Aristotle classic ''square-of-opposition'' : FUZZYICS =CATEGORYICS/Category-Semantics, with Goodkind Bose-Einstein Condensation (BEC) ABOVE ground-state with/and Rayleigh(cut-limit of ''short-cut method''1870)-Polya(1922)-''Anderson''(1958) localization [Doyle and Snell,Random-Walks and Electrical-Networks, MAA(1981)-p.99-100!!!] in Brillouin[Wave-Propagation in Periodic-Structures(1946) Dover(1922)]-Hubbard-Beeby[J.Phys.C(1967)] Siegel[J.Nonxline-Sol.40,453(1980)] generalized-disorder collective-boson negative-dispersion mode-softening universality-principle(G...P) first use of the ``square-of-opposition'' in physics since Plato and Aristote!!!

  15. The Active and Periactive Zone Organization and the Functional Properties of Small and Large Synapses.

    PubMed

    Cano, Raquel; Tabares, Lucia

    2016-01-01

    The arrival of an action potential (AP) at a synaptic terminal elicits highly synchronized quanta release. Repetitive APs produce successive synaptic vesicle (SV) fusions that require management of spent SV components in the presynaptic membrane with minimum disturbance of the secretory apparatus. To this end, the synaptic machinery is structured accordingly to the strength and the range of frequencies at which each particular synapse operates. This results in variations in the number and dimension of Active Zones (AZs), amount and distribution of SVs, and probably, in the primary endocytic mechanisms they use. Understanding better how these structural differences determine the functional response in each case has been a matter of long-term interest. Here we review the structural and functional properties of three distinct types of synapses: the neuromuscular junction (NMJ; a giant, highly reliable synapse that must exocytose a large number of quanta with each stimulus to guarantee excitation of the postsynaptic cell), the hippocampal excitatory small synapse (which most often has a single release site and a relatively small pool of vesicles), and the cerebellar mossy fiber-granule cell synapse (which possesses hundreds of release sites and is able to translocate, dock and prime vesicles at high speed). We will focus on how the release apparatus is organized in each case, the relative amount of vesicular membrane that needs to be accommodated within the periAZ upon stimulation, the different mechanisms for retrieving the excess of membrane and finally, how these factors may influence the functioning of the release sites. PMID:27252645

  16. Comparative performance of modern digital mammography systems in a large breast screening program

    SciTech Connect

    Yaffe, Martin J. Bloomquist, Aili K.; Hunter, David M.; Mawdsley, Gordon E.; Chiarelli, Anna M.; Muradali, Derek; Mainprize, James G.

    2013-12-15

    Purpose: To compare physical measures pertaining to image quality among digital mammography systems utilized in a large breast screening program. To examine qualitatively differences in these measures and differences in clinical cancer detection rates between CR and DR among sites within that program. Methods: As part of the routine quality assurance program for screening, field measurements are made of several variables considered to correlate with the diagnostic quality of medical images including: modulation transfer function, noise equivalent quanta, d′ (an index of lesion detectability) and air kerma to allow estimation of mean glandular dose. In addition, images of the mammography accreditation phantom are evaluated. Results: It was found that overall there were marked differences between the performance measures of DR and CR mammography systems. In particular, the modulation transfer functions obtained with the DR systems were found to be higher, even for larger detector element sizes. Similarly, the noise equivalent quanta, d′, and the phantom scores were higher, while the failure rates associated with low signal-to-noise ratio and high dose were lower with DR. These results were consistent with previous findings in the authors’ program that the breast cancer detection rates at sites employing CR technology were, on average, 30.6% lower than those that used DR mammography. Conclusions: While the clinical study was not large enough to allow a statistically powered system-by-system assessment of cancer detection accuracy, the physical measures expressing spatial resolution, and signal-to-noise ratio are consistent with the published finding that sites employing CR systems had lower cancer detection rates than those using DR systems for screening mammography.

  17. Superconductor Digital Electronics: -- Current Status, Future Prospects

    NASA Astrophysics Data System (ADS)

    Mukhanov, Oleg

    2011-03-01

    Two major applications of superconductor electronics: communications and supercomputing will be presented. These areas hold a significant promise of a large impact on electronics state-of-the-art for the defense and commercial markets stemming from the fundamental advantages of superconductivity: simultaneous high speed and low power, lossless interconnect, natural quantization, and high sensitivity. The availability of relatively small cryocoolers lowered the foremost market barrier for cryogenically-cooled superconductor electronic systems. These fundamental advantages enabled a novel Digital-RF architecture - a disruptive technological approach changing wireless communications, radar, and surveillance system architectures dramatically. Practical results were achieved for Digital-RF systems in which wide-band, multi-band radio frequency signals are directly digitized and digital domain is expanded throughout the entire system. Digital-RF systems combine digital and mixed signal integrated circuits based on Rapid Single Flux Quantum (RSFQ) technology, superconductor analog filter circuits, and semiconductor post-processing circuits. The demonstrated cryocooled Digital-RF systems are the world's first and fastest directly digitizing receivers operating with live satellite signals, enabling multi-net data links, and performing signal acquisition from HF to L-band with 30 GHz clock frequencies. In supercomputing, superconductivity leads to the highest energy efficiencies per operation. Superconductor technology based on manipulation and ballistic transfer of magnetic flux quanta provides a superior low-power alternative to CMOS and other charge-transfer based device technologies. The fundamental energy consumption in SFQ circuits defined by flux quanta energy 2 x 10-19 J. Recently, a novel energy-efficient zero-static-power SFQ technology, eSFQ/ERSFQ was invented, which retains all advantages of standard RSFQ circuits: high-speed, dc power, internal memory. The

  18. Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph.

    PubMed

    Moskal, P; Rundel, O; Alfs, D; Bednarski, T; Białas, P; Czerwiński, E; Gajos, A; Giergiel, K; Gorgol, M; Jasińska, B; Kamińska, D; Kapłon, Ł; Korcyl, G; Kowalski, P; Kozik, T; Krzemień, W; Kubicz, E; Niedźwiecki, Sz; Pałka, M; Raczyński, L; Rudy, Z; Sharma, N G; Słomski, A; Silarski, M; Strzelecki, A; Wieczorek, A; Wiślicki, W; Witkowski, P; Zieliński, M; Zoń, N

    2016-03-01

    Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the [Formula: see text] configuration at two ends allowing to read twenty timestamps, constitutes an optimal solution. The conducted simulations accounted for the emission time distribution, photon transport and absorption inside the scintillator, as well as quantum efficiency and transit time spread of photosensors, and were checked based on the experimental results. Application of the [Formula: see text] matrix of SiPM allows for achieving the coincidence resolving time in positron emission tomography of [Formula: see text]0.170 ns for 15 cm axial field-of-view (AFOV) and [Formula: see text]0.365 ns for 100 cm AFOV. The results open perspectives for construction of a cost-effective TOF-PET scanner with significantly better TOF resolution and larger AFOV with respect to the current TOF-PET modalities. PMID:26895187

  19. Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph

    NASA Astrophysics Data System (ADS)

    Moskal, P.; Rundel, O.; Alfs, D.; Bednarski, T.; Białas, P.; Czerwiński, E.; Gajos, A.; Giergiel, K.; Gorgol, M.; Jasińska, B.; Kamińska, D.; Kapłon, Ł.; Korcyl, G.; Kowalski, P.; Kozik, T.; Krzemień, W.; Kubicz, E.; Niedźwiecki, Sz; Pałka, M.; Raczyński, L.; Rudy, Z.; Sharma, N. G.; Słomski, A.; Silarski, M.; Strzelecki, A.; Wieczorek, A.; Wiślicki, W.; Witkowski, P.; Zieliński, M.; Zoń, N.

    2016-03-01

    Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the 2× 5 configuration at two ends allowing to read twenty timestamps, constitutes an optimal solution. The conducted simulations accounted for the emission time distribution, photon transport and absorption inside the scintillator, as well as quantum efficiency and transit time spread of photosensors, and were checked based on the experimental results. Application of the 2× 5 matrix of SiPM allows for achieving the coincidence resolving time in positron emission tomography of ≈ 0.170 ns for 15 cm axial field-of-view (AFOV) and ≈ 0.365 ns for 100 cm AFOV. The results open perspectives for construction of a cost-effective TOF-PET scanner with significantly better TOF resolution and larger AFOV with respect to the current TOF-PET modalities.

  20. Flux tubes and the type-I/type-II transition in a superconductor coupled to a superfluid

    SciTech Connect

    Alford, Mark G.; Good, Gerald

    2008-07-01

    We analyze magnetic-flux tubes at zero temperature in a superconductor that is coupled to a superfluid via both density and gradient ('entrainment') interactions. The example we have in mind is high-density nuclear matter, which is a proton superconductor and a neutron superfluid, but our treatment is general and simple, modeling the interactions as a Ginzburg-Landau effective theory with four-fermion couplings, including only s-wave pairing. We numerically solve the field equations for flux tubes with an arbitrary number of flux quanta and compare their energies. This allows us to map the type-I/type-II transition in the superconductor, which occurs at the conventional {kappa}{identical_to}{lambda}/{xi}=1/{radical}(2) if the condensates are uncoupled. We find that a density coupling between the condensates raises the critical {kappa} and, for a sufficiently high neutron density, resolves the type-I/type-II transition line into an infinite number of bands corresponding to 'type-II(n)' phases, in which n, the number of quanta in the favored flux tube, steps from 1 to infinity. For lower neutron density, the coupling creates spinodal regions around the type-I/type-II boundary, in which metastable flux configurations are possible. We find that a gradient coupling between the condensates lowers the critical {kappa} and creates spinodal regions. These exotic phenomena may not occur in nuclear matter, which is thought to be deep in the type-II region but might be observed in condensed-matter systems.

  1. Detective quantum efficiency of photon-counting x-ray detectors

    SciTech Connect

    Tanguay, Jesse; Yun, Seungman; Kim, Ho Kyung; Cunningham, Ian A.

    2015-01-15

    Purpose: Single-photon-counting (SPC) x-ray imaging has the potential to improve image quality and enable novel energy-dependent imaging methods. Similar to conventional detectors, optimizing image SPC quality will require systems that produce the highest possible detective quantum efficiency (DQE). This paper builds on the cascaded-systems analysis (CSA) framework to develop a comprehensive description of the DQE of SPC detectors that implement adaptive binning. Methods: The DQE of SPC systems can be described using the CSA approach by propagating the probability density function (PDF) of the number of image-forming quanta through simple quantum processes. New relationships are developed to describe PDF transfer through serial and parallel cascades to accommodate scatter reabsorption. Results are applied to hypothetical silicon and selenium-based flat-panel SPC detectors including the effects of reabsorption of characteristic/scatter photons from photoelectric and Compton interactions, stochastic conversion of x-ray energy to secondary quanta, depth-dependent charge collection, and electronic noise. Results are compared with a Monte Carlo study. Results: Depth-dependent collection efficiency can result in substantial broadening of photopeaks that in turn may result in reduced DQE at lower x-ray energies (20–45 keV). Double-counting interaction events caused by reabsorption of characteristic/scatter photons may result in falsely inflated image signal-to-noise ratio and potential overestimation of the DQE. Conclusions: The CSA approach is extended to describe signal and noise propagation through photoelectric and Compton interactions in SPC detectors, including the effects of escape and reabsorption of emission/scatter photons. High-performance SPC systems can be achieved but only for certain combinations of secondary conversion gain, depth-dependent collection efficiency, electronic noise, and reabsorption characteristics.

  2. Vibrational relaxation of a triatomic molecular impurity: D{sub 2}O in vitreous As{sub 2}S{sub 3}

    SciTech Connect

    Rella, C.W.; Schwettman, H.A.; Engholm, J.R.

    1995-12-31

    Measurements of the relaxation of the D{sub 2}O stretch mode in vitreous As{sub 2}S{sub 3} are presented. Because the bending mode of the molecule offers an intra-molecular decay channel for the stretch mode, the decay scheme of the D{sub 2}O molecule is more complex than that of diatomic molecules. The asymmetric stretch mode of D{sub 2}O has a frequency of 2680 cm{sup -1}. To study the relaxation of this mode we applied a pump-probe technique, using intense psec; pulses of the Stanford Free Electron Laser. Due to the small cross-section of the vibrational mode, successful efforts were made to improve the signal to noise ratio by using a laser stabilization system and a tightly focused beam to increase the intensity, by averaging the signal with a kHz repetition rate and by using samples with an optimized D{sub 2}O concentration. A rapid relaxation rate on the order of 5 x 10{sup 9} sec{sup -1} at low temperature is found that increases with temperature. Recalling that the bending mode of the D{sub 2}O molecule has a frequency of 1170 cm{sup -1}, one would expect a decay in a third order process, involving two quanta of the bending mode plus a vibrational host quanta with a frequency of 340 cm{sup -1}, which coincides with a fundamental frequency of the pyramidal building blocks of the glassy As{sub 2}S{sub 3} host. Instead, we find from the temperature dependence of the relaxation rate that the D{sub 2}O stretching mode relaxes in a higher order process. This indicates that the relaxation dynamics of small molecules is more complex than generally assumed.

  3. Characterization of a scintillating GEM detector with low energy x-rays.

    PubMed

    Seravalli, E; de Boer, M R; Geurink, F; Huizenga, J; Kreuger, R; Schippers, J M; van Eijk, C W E

    2008-11-01

    A two-dimensional position-sensitive dosimetry system based on a scintillating gas detector is being developed with the aim of using it for pre-treatment verification of dose distributions in charged particle therapy. The dosimetry system consists of a chamber filled with an Ar/CF(4) scintillating gas mixture, inside which two cascaded gas electron multipliers (GEMs) are mounted. A GEM is a thin kapton foil with copper cladding structured with a regular pattern of sub-mm holes. In such a system, light quanta are emitted by the scintillating gas mixture during the electron avalanches in the GEM holes when radiation traverses the detector. The light intensity distribution is proportional to the energy deposited in the detector's sensitive volume by the beam. In the present work, we investigated the optimization of the scintillating GEM detector light yield. The light quanta are detected by means of a CCD camera or a photomultiplier tube coupled to a monochromator. The GEM charge signal is measured simultaneously. We have found that with 60 microm diameter double conical GEM holes, a brighter light signal and a higher electric signal are obtained than with 80 microm diameter holes. With an Ar + 8% CF(4) volume concentration, the highest voltage across the GEMs and the largest light and electric signals were reached. Moreover, we have found that the emission spectrum of Ar/CF(4) is independent of (1) the voltages applied across the GEMs, (2) the x-ray beam intensity and (3) the GEM hole diameter. On the other hand, the ratio of Ar to CF(4) peaks in the spectrum changes when the concentration of the latter gas is varied. PMID:18854612

  4. A Common Fluence Threshold for First Positive and Second Positive Phototropism in Arabidopsis thaliana1

    PubMed Central

    Janoudi, Abdul; Poff, Kenneth L.

    1990-01-01

    The relationship between the amount of light and the amount of response for any photobiological process can be based on the number of incident quanta per unit time (fluence rate-response) or on the number of incident quanta during a given period of irradiation (fluence-response). Fluence-response and fluence rate-response relationships have been measured for second positive phototropism by seedlings of Arabidopsis thaliana. The fluence-response relationships exhibit a single limiting threshold at about 0.01 micromole per square meter when measured at fluence rates from 2.4 × 10−5 to 6.5 × 10−3 micromoles per square meter per second. The threshold values in the fluence rateresponse curves decrease with increasing time of irradiation, but show a common fluence threshold at about 0.01 micromole per square meter. These thresholds are the same as the threshold of about 0.01 micromole per square meter measured for first positive phototropism. Based on these data, it is suggested that second positive curvature has a threshold in time of about 10 minutes. Moreover, if the times of irradiation exceed the time threshold, there is a single limiting fluence threshold at about 0.01 micromole per square meter. Thus, the limiting fluence threshold for second positive phototropism is the same as the fluence threshold for first positive phototropism. Based on these data, we suggest that this common fluence threshold for first positive and second positive phototropism is set by a single photoreceptor pigment system. PMID:11537470

  5. Action spectra of photosystems II and I and quantum yield of photosynthesis in leaves in State 1.

    PubMed

    Laisk, Agu; Oja, Vello; Eichelmann, Hillar; Dall'Osto, Luca

    2014-02-01

    The spectral global quantum yield (YII, electrons/photons absorbed) of photosystem II (PSII) was measured in sunflower leaves in State 1 using monochromatic light. The global quantum yield of PSI (YI) was measured using low-intensity monochromatic light flashes and the associated transmittance change at 810nm. The 810-nm signal change was calibrated based on the number of electrons generated by PSII during the flash (4·O2 evolution) which arrived at the PSI donor side after a delay of 2ms. The intrinsic quantum yield of PSI (yI, electrons per photon absorbed by PSI) was measured at 712nm, where photon absorption by PSII was small. The results were used to resolve the individual spectra of the excitation partitioning coefficients between PSI (aI) and PSII (aII) in leaves. For comparison, pigment-protein complexes for PSII and PSI were isolated, separated by sucrose density ultracentrifugation, and their optical density was measured. A good correlation was obtained for the spectral excitation partitioning coefficients measured by these different methods. The intrinsic yield of PSI was high (yI=0.88), but it absorbed only about 1/3 of quanta; consequently, about 2/3 of quanta were absorbed by PSII, but processed with the low intrinsic yield yII=0.63. In PSII, the quantum yield of charge separation was 0.89 as detected by variable fluorescence Fv/Fm, but 29% of separated charges recombined (Laisk A, Eichelmann H and Oja V, Photosynth. Res. 113, 145-155). At wavelengths less than 580nm about 30% of excitation is absorbed by pigments poorly connected to either photosystem, most likely carotenoids bound in pigment-protein complexes. PMID:24333386

  6. The quantum yield of CO2 fixation is reduced for several minutes after prior exposure to darkness. Exploration of the underlying causes.

    PubMed

    Kirschbaum, M U F; Oja, V; Laisk, A

    2005-01-01

    Previous work has shown that the apparent quantum yield of CO2 fixation can be reduced for up to several minutes after prior exposure to darkness. In the work reported here, we investigated this phenomenon more fully and have deduced information about the underlying processes. This was done mainly by concurrent measurements of O2 and CO2 exchange in an oxygen-free atmosphere. Measurements of O2 evolution indicated that photochemical efficiency was not lost through dark adaptation, and that O2 evolution could proceed immediately at high rates provided that there were reducible pools of photosynthetic intermediates. Part of the delay in reaching the full quantum yield of CO2 fixation could be attributed to the need to build up pools of photosynthetic intermediates to high enough levels to support steady rates of CO2 fixation. There was no evidence that Rubisco inactivation contributed towards delayed CO2 uptake (under measurement conditions of low light). However, we obtained evidence that an enzyme in the reaction path between triose phosphates and RuBP must become completely inactivated in the dark. As a consequence, in dark-adapted leaves, a large amount of triose phosphates were exported from the chloroplast over the first minute of light rather than being converted to RuBP for CO2 fixation. That pattern was not observed if the pre-incubation light level was increased to just 3-5 micromol quanta m(-2) s(-1). The findings from this work underscore that there are fundamental differences in enzyme activation between complete darkness and even a very low light level of only 3-5 micromol quanta m(-2) s(-1) which predispose leaves to different gas exchange patterns once leaves are transferred to higher light levels. PMID:15666215

  7. A novel method for the line-of-response and time-of-flight reconstruction in TOF-PET detectors based on a library of synchronized model signals

    NASA Astrophysics Data System (ADS)

    Moskal, P.; Zoń, N.; Bednarski, T.; Białas, P.; Czerwiński, E.; Gajos, A.; Kamińska, D.; Kapłon, Ł.; Kochanowski, A.; Korcyl, G.; Kowal, J.; Kowalski, P.; Kozik, T.; Krzemień, W.; Kubicz, E.; Niedźwiecki, Sz.; Pałka, M.; Raczyński, L.; Rudy, Z.; Rundel, O.; Salabura, P.; Sharma, N. G.; Silarski, M.; Słomski, A.; Smyrski, J.; Strzelecki, A.; Wieczorek, A.; Wiślicki, W.; Zieliński, M.

    2015-03-01

    A novel method of hit time and hit position reconstruction in scintillator detectors is described. The method is based on comparison of detector signals with results stored in a library of synchronized model signals registered for a set of well-defined positions of scintillation points. The hit position is reconstructed as the one corresponding to the signal from the library which is most similar to the measurement signal. The time of the interaction is determined as a relative time between the measured signal and the most similar one in the library. A degree of similarity of measured and model signals is defined as the distance between points representing the measurement- and model-signal in the multi-dimensional measurement space. Novelty of the method lies also in the proposed way of synchronization of model signals enabling direct determination of the difference between time-of-flights (TOF) of annihilation quanta from the annihilation point to the detectors. The introduced method was validated using experimental data obtained by means of the double strip prototype of the J-PET detector and 22Na sodium isotope as a source of annihilation gamma quanta. The detector was built out from plastic scintillator strips with dimensions of 5 mm×19 mm×300 mm, optically connected at both sides to photomultipliers, from which signals were sampled by means of the Serial Data Analyzer. Using the introduced method, the spatial and TOF resolution of about 1.3 cm (σ) and 125 ps (σ) were established, respectively.

  8. HOTB: High precision parallel code for calculation of four-particle harmonic oscillator transformation brackets

    NASA Astrophysics Data System (ADS)

    Stepšys, A.; Mickevicius, S.; Germanas, D.; Kalinauskas, R. K.

    2014-11-01

    effective way, which allows us to calculate matrix of the brackets up to a few hundred times more rapidly and more accurate than in a previous version. Solution method: Using external parallelization libraries and mutable precision we created a pack of numerical codes based on the methods of compact expressions of the three and four-particle harmonics oscillator brackets 3HOB, 4HOB, presented in [3]. Restrictions: For double precision version calculations can be done up to harmonic oscillator (HO) energy quanta e=28. For quadruple precision mantissa is equal to approximately 34 decimal digits, therefore calculations can be done up to HO energy quanta to e=52. Running time: The running time depends on the harmonic oscillator energy quanta, cluster size and the precision of intermediate calculations. More information on Table 1 for 3HOB and Table 2 for 4HOB. Reasons for a new version: The new program version expands the limits of harmonic oscillator energy quanta and gives shorter calculation time. Extend the limits of calculation of HOB First version was able to produce harmonic oscillator transformation brackets for three and four particles if E≤HO energy quanta. With this version of our program, if quadruple or arbitrary precision functions are being used, it is possible to calculate three and four particle harmonic oscillator transformation brackets for greater values of energy and momenta, while sustaining tolerable margin of error. Calculation time As the code of previous version of program was redone using parallelism paradigma, it is now possible to reduce the calculation time of transformation matrices significantly, depending on the size of computing cluster, as the dimensions of matrices are growing very rapidly according to the energy and momenta values. subroutinematrix_4HOB_dimensionCalculates the dimension of 4HOB matrix. subroutinematrix_3HOB_dimensionCalculates the dimension of 3HOB matrix, subroutinematrix_3HOBCalculates the global state array which is

  9. A comparative analysis of OTF, NPS, and DQE in energy integrating and photon counting digital x-ray detectors

    SciTech Connect

    Acciavatti, Raymond J.; Maidment, Andrew D. A.

    2010-12-15

    Purpose: One of the benefits of photon counting (PC) detectors over energy integrating (EI) detectors is the absence of many additive noise sources, such as electronic noise and secondary quantum noise. The purpose of this work is to demonstrate that thresholding voltage gains to detect individual x rays actually generates an unexpected source of white noise in photon counters. Methods: To distinguish the two detector types, their point spread function (PSF) is interpreted differently. The PSF of the energy integrating detector is treated as a weighting function for counting x rays, while the PSF of the photon counting detector is interpreted as a probability. Although this model ignores some subtleties of real imaging systems, such as scatter and the energy-dependent amplification of secondary quanta in indirect-converting detectors, it is useful for demonstrating fundamental differences between the two detector types. From first principles, the optical transfer function (OTF) is calculated as the continuous Fourier transform of the PSF, the noise power spectra (NPS) is determined by the discrete space Fourier transform (DSFT) of the autocovariance of signal intensity, and the detective quantum efficiency (DQE) is found from combined knowledge of the OTF and NPS. To illustrate the calculation of the transfer functions, the PSF is modeled as the convolution of a Gaussian with the product of rect functions. The Gaussian reflects the blurring of the x-ray converter, while the rect functions model the sampling of the detector. Results: The transfer functions are first calculated assuming outside noise sources such as electronic noise and secondary quantum noise are negligible. It is demonstrated that while OTF is the same for two detector types possessing an equivalent PSF, a frequency-independent (i.e., ''white'') difference in their NPS exists such that NPS{sub PC}{>=}NPS{sub EI} and hence DQE{sub PC}{<=}DQE{sub EI}. The necessary and sufficient condition for

  10. A comparative analysis of OTF, NPS, and DQE in energy integrating and photon counting digital x-ray detectors

    PubMed Central

    Acciavatti, Raymond J.; Maidment, Andrew D. A.

    2010-01-01

    Purpose: One of the benefits of photon counting (PC) detectors over energy integrating (EI) detectors is the absence of many additive noise sources, such as electronic noise and secondary quantum noise. The purpose of this work is to demonstrate that thresholding voltage gains to detect individual x rays actually generates an unexpected source of white noise in photon counters. Methods: To distinguish the two detector types, their point spread function (PSF) is interpreted differently. The PSF of the energy integrating detector is treated as a weighting function for counting x rays, while the PSF of the photon counting detector is interpreted as a probability. Although this model ignores some subtleties of real imaging systems, such as scatter and the energy-dependent amplification of secondary quanta in indirect-converting detectors, it is useful for demonstrating fundamental differences between the two detector types. From first principles, the optical transfer function (OTF) is calculated as the continuous Fourier transform of the PSF, the noise power spectra (NPS) is determined by the discrete space Fourier transform (DSFT) of the autocovariance of signal intensity, and the detective quantum efficiency (DQE) is found from combined knowledge of the OTF and NPS. To illustrate the calculation of the transfer functions, the PSF is modeled as the convolution of a Gaussian with the product of rect functions. The Gaussian reflects the blurring of the x-ray converter, while the rect functions model the sampling of the detector. Results: The transfer functions are first calculated assuming outside noise sources such as electronic noise and secondary quantum noise are negligible. It is demonstrated that while OTF is the same for two detector types possessing an equivalent PSF, a frequency-independent (i.e., “white”) difference in their NPS exists such that NPSPC≥NPSEI and hence DQEPC≤DQEEI. The necessary and sufficient condition for equality is that the PSF is a

  11. Gamma-telescopes Fermi/LAT and GAMMA-400 Trigger Systems Event Recognizing Methods Comparison

    NASA Astrophysics Data System (ADS)

    Arkhangelskaja, I. V.; Murchenko, A. E.; Chasovikov, E. N.; Arkhangelskiy, A. I.; Kheymits, M. D.

    Usually instruments for high-energy γ-quanta registration consists of converter (where γ-quanta produced pairs) and calorimeter for particles energy measurements surrounded by anticoincidence shield used to events identification (whether incident particle was charged or neutral). The influence of pair formation by γ-quanta in shield and the backsplash (moved in the opposite direction particles created due high energy γ-rays interact with calorimeter) should be taken into account. It leads to decrease both effective area and registration efficiency at E>10 GeV. In the presented article the event recognizing methods used in Fermi/LAT trigger system is considered in comparison with the ones applied in counting and triggers signals formation system of gamma-telescope GAMMA-400. The GAMMA-400 (Gamma Astronomical Multifunctional Modular Apparatus) will be the new high-apogee space γ-observatory. The GAMMA-400 consist of converter-tracker based on silicon-strip coordinate detectors interleaved with tungsten foils, imaging calorimeter make of 2 layers of double (x, y) silicon strip coordinate detectors interleaved with planes of CsI(Tl) crystals and the electromagnetic calorimeter CC2 consists only of CsI(Tl) crystals. Several plastics detections systems used as anticoincidence shield, for particles energy and moving direction estimations. The main differences of GAMMA-400 constructions from Fermi/LAT one are using the time-of-flight system with base of 50 cm and double layer structure of plastic detectors provides more effective particles direction definition and backsplash rejection. Also two calorimeters in GAMMA-400 composed the total absorbtion spectrometer with total thickness ∼ 25 X0 or ∼1.2 λ0 for vertical incident particles registration and 54 X0 or 2.5 λ0 for laterally incident ones (where λ0 is nuclear interaction length). It provides energy resolution 1-2% for 10 GeV-3.0×103 GeV events while the Fermi/LAT energy resolution does not reach such a

  12. Quantum field theory of interacting plasmon-photon-phonon system

    NASA Astrophysics Data System (ADS)

    Hieu Nguyen, Van; Nguyen, Bich Ha

    2015-09-01

    This work is devoted to the construction of the quantum field theory of the interacting system of plasmons, photons and phonons on the basis of general fundamental principles of electrodynamics and quantum field theory of many-body systems. Since a plasmon is a quasiparticle appearing as a resonance in the collective oscillation of the interacting electron gas in solids, the starting point is the total action functional of the interacting system comprising electron gas, electromagnetic field and phonon fields. By means of the powerful functional integral technique, this original total action is transformed into that of the system of the quantum fields describing plasmons, transverse photons, acoustic as well as optic longitudinal and transverse phonons. The collective oscillations of the electron gas is characterized by a real scalar field φ(x) called the collective oscillation field. This field is split into the static background field φ0(x) and the fluctuation field ζ(x). The longitudinal phonon fields {{{Q}}al}(x), {{{Q}}ol}(x) are also split into the background fields {Q}0al(x), {Q}0ol(x) and dynamical fields {{{q}}al}(x), {{{q}}ol}(x) while the transverse phonon fields {{{Q}}at}(x), {{{Q}}ot}(x) themselves are dynamical fields {{{q}}at}(x), {{{q}}ot}(x) without background fields. After the canonical quantization procedure, the background fields φ0(x), {Q}0al(x), {Q}0ol(x) remain the classical fields, while the fluctuation fields ζ(x) and dynamical phonon fields {{{q}}al}(x), {{{q}}at}(x), {{{q}}ol}(x), {{{q}}ot}(x) become quantum fields. In quantum theory, a plasmon is the quantum of Hermitian scalar field σ(x) called the plasmon field, longitudinal phonons as complex spinless quasiparticles are the quanta of the effective longitudinal phonon Hermitian scalar fields {{θ }a}(x), {{θ }0}(x), while transverse phonons are the quanta of the original Hermitian transverse phonon vector fields {{{q}}at}(x), {{{q}}ot}(x). By means of the functional integral

  13. Bio-optical characteristics along the Straits of Magallanes

    NASA Astrophysics Data System (ADS)

    Lutz, Vivian; Frouin, Robert; Negri, Rubén; Silva, Ricardo; Pompeu, Mayza; Rudorff, Natalia; Cabral, Anderson; Dogliotti, Ana; Martinez, Gustavo

    2016-05-01

    The Straits of Magallanes at the tip of South America connects the Atlantic and Pacific Oceans. The variability in the absorption characteristics by phytoplankton (aph(440)), non-pigmented particles, NPP (aNPP(440)), and chromophoric dissolved organic matter, CDOM (ay(440)), measured along the Straits in late summer 2011 (R/V Melville MV1102 cruise), was analyzed. Satellite-derived monthly PAR data showed that at the time of the cruise the western sector was exposed to a low-light environment (~ 16 mol quanta m-2d-1) while the eastern sector received higher irradiance (~ 28 mol quanta m-2d-1). In the Patagonian Shelf total absorption was dominated by phytoplankton (up to 76%; aph(440)=0.265 m-1), while in the Atlantic Sector of the Straits, the major contributor was NPP (up to 42%; aNPP(440)=0.138 m-1), and in the Pacific Sector of the Straits CDOM contributed up to 80% of the total absorption (ay(440)=0.232 m-1). These changes could be related in part to the input of fresh water from glacier melting and rain in the Pacific Sector (ay(440) vs salinity rs=-0.98). The carbon biomass (C) was composed in its majority by pico-phytoplankton and secondly by nano-phytoplankton, with exception of the Atlantic Sector where the micro-phytoplankton dominated. Carbon to chlorophyll-a ratios (C:Chla) were very low throughout the Straits (average of ~ 6) because of photoacclimation to the extremely low light. Complementary pigments data obtained in spring 2003 by the BEAGLE expedition indicated the predominance of diatoms all along the Straits, but the bio-optical trend resembled the one found in late summer 2011, i.e., NPP dominated the absorption in the well mixed Atlantic Sector, phytoplankton in the Middle Sector, and CDOM in the Pacific Sector. These results emphasize that underwater light is the major factor affecting phytoplankton growth and physiology, and that prevalent physical and geochemical conditions play an important role regulating the bio-optical properties in

  14. Dynamical Localization in Molecular Systems.

    NASA Astrophysics Data System (ADS)

    Wang, Xidi

    In the first four chapters of this thesis we concentrate on the Davydov model which describes the vibrational energy quanta of Amide I bonds (C=O bonds on the alpha -helix) coupled to the acoustic phonon modes of the alpha-helix backbone in the form of a Frohlich Hamiltonian. Following a brief introduction in chapter one, in chapter two we formulate the dynamics of vibrational quanta at finite temperature by using coherent state products. The fluctuation-dissipation relation is derived. At zero temperature, in the continuum limit, we recover the original results of Davydov. We also achieve good agreement with numerical simulations. In chapter three, the net contraction of the lattice is calculated exactly at any temperature, and its relation to the so -call "topological stability" of the Davydov soliton is discussed. In the second section of the chapter three we calculate the overtone spectra of crystalline acetanilide (according to some opinions ACN provides experimental evidence for the existence of Davydov solitons). Good agreement with experimental data has been obtained. In chapter four we study the self-trapped vibrational excitations by the Quantum Monte Carlo technique. For a single excitation, the temperature dependence of different physical observables is calculated. The quasi-particle which resembles the Davydov soliton has been found to be fairly narrow using the most commonly used data for the alpha -helix; at temperatures above a few Kelvin, the quasi-particle reaches its smallest limit (extends over three sites), which implies diffusive motion of the small polaron-like quasi-particle at high temperatures. For the multi-excitation case, bound pairs and clusters of excitations are found at low temperatures; they gradually dissociate when the temperature of the system is increased as calculated from the density-density correlation function. In the last chapter of this thesis, we study a more general model of dynamical local modes in molecular systems

  15. Optical amplifiers for coherent lidar

    NASA Technical Reports Server (NTRS)

    Fork, Richard

    1996-01-01

    We examine application of optical amplification to coherent lidar for the case of a weak return signal (a number of quanta of the return optical field close to unity). We consider the option that has been explored to date, namely, incorporation of an optical amplifier operated in a linear manner located after reception of the signal and immediately prior to heterodyning and photodetection. We also consider alternative strategies where the coherent interaction, the nonlinear processes, and the amplification are not necessarily constrained to occur in the manner investigated to date. We include the complications that occur because of mechanisms that occur at the level of a few, or one, quantum excitation. Two factors combine in the work to date that limit the value of the approach. These are: (1) the weak signal tends to require operation of the amplifier in the linear regime where the important advantages of nonlinear optical processing are not accessed, (2) the linear optical amplifier has a -3dB noise figure (SN(out)/SN(in)) that necessarily degrades the signal. Some improvement is gained because the gain provided by the optical amplifier can be used to overcome losses in the heterodyned process and photodetection. The result, however, is that introduction of an optical amplifier in a well optimized coherent lidar system results in, at best, a modest improvement in signal to noise. Some improvement may also be realized on incorporating more optical components in a coherent lidar system for purely practical reasons. For example, more compact, lighter weight, components, more robust alignment, or more rapid processing may be gained. We further find that there remain a number of potentially valuable, but unexplored options offered both by the rapidly expanding base of optical technology and the recent investigation of novel nonlinear coherent interference phenomena occurring at the single quantum excitation level. Key findings are: (1) insertion of linear optical

  16. Coherent inelastic Mössbauer scattering of synchrotron radiation (abstract)

    NASA Astrophysics Data System (ADS)

    Belyakov, V. A.

    2002-03-01

    Recent success of coherent elastic [Nuclear Resonant Scattering of Synchrotron Radiation, Part A edited by E. Gerdau and H. de Woard (Baltzer Science, 2000), Hyperfine Interact. 123/124, Chap. 4] and incoherent inelastic (Hyperfine Interact. 123/124, Chap. 5) Mössbauer scattering of synchrotron radiation (SR) in investigations of very delicate properties of the condensed matter also makes it urgent to perform experiments on coherent inelastic Mössbauer scattering (CIMS) of synchrotron radiation (the common meaning of the term CIMS is coherent inelastic Mössbauer scattering accompanied by creation or annihilation of phonons in the crystal lattice, i.e., by very low energy losses of SR quanta). However up to now there were no publications on experimental observation of CIMS so there is a need in theoretical investigations to reveal the most favorable conditions for CIMS observation. The theory of CIMS is presented below and applied to specific processes of CIMS such as forward scattering, scattering at grazing incidence angles, and scattering via a cascade of Mössbauer transitions. It is shown that the phase matching (between the incident and scattered beam) is very important for the angular and frequency distribution in CIMS and processes where phase matching can be reached, which the best candidates for CIMS experimental investigations. The performed analysis shows that because of the phase matching demands the forward CIMS is suppressed significantly in comparison with the coherent elastic Mössbauer scattering [V. A. Belyakov, JETP Lett. 67, 8 (1998)] and more favorable for observation is CIMS at a nonzero scattering angle. Some examples of CIMS specific geometries are discussed. In particular, it is shown that for the grazing CIMS at isotope interface (a plane interface between regions with different abundance of the Mössbauer isotope) there is enhancement of CIMS at the critical angle of total reflection and suppression of CIMS at angles below the critical

  17. Line shape parameters of PH3 transitions in the Pentad near 4–5 μm: Self-broadened widths, shifts, line mixing and speed dependence

    SciTech Connect

    Malathy Devi, V.; Benner, D. C.; Kleiner, Isabelle; Sams, Robert L.; Fletcher, Leigh N.

    2014-08-01

    Accurate knowledge of spectroscopic line parameters of PH3 is important for remote sensing of the outer planets, especially Jupiter and Saturn. In a recent study, line positions and intensities for the Pentad bands of PH3 have been reported from analysis of high-resolution, high signal-to noise room-temperature spectra recorded with two Fourier transform spectrometers (2014) [1]. The results presented in this study were obtained during the analysis of positions and intensities, but here we focus on the measurements of spectral line shapes (e.g. widths, shifts, line mixing) for the 2ν4, ν2 + ν4, ν1 and ν3 bands. A multispectrum nonlinear least squares curve fitting technique employing a non-Voigt line shape to include line mixing and speed dependence of the Lorentz width was employed to fit the spectra simultaneously. The least squares fittings were performed on five room-temperature spectra recorded at various PH3 pressures (~2–50 Torr) with the Bruker IFS-125HR Fourier transform spectrometer (FTS) located at the Pacific Northwest National Laboratory (PNNL), in Richland, Washington. Over 840 Lorentz self-broadened half-width coefficients, 620 self-shift coefficients and 185 speed dependence parameters were measured. Line mixing was detected for transitions in the 2ν4, ν1 and ν3 bands, and their values were quantified for 10 A+A- pairs of transitions via off-diagonal relaxation matrix element formalism. The dependences of the measured half-width coefficients on the J and K rotational quanta of the transitions are discussed. The self-width coefficients for the ν1 and ν3 bands from this study are compared to the self-width coefficients for transitions with the same rotational quanta (J, K) reported for the Dyad (ν2 and ν4) bands. The measurements from present study should be useful for the

  18. Line shape parameters of PH3 transitions in the Pentad near 4-5 μm: Self-broadened widths, shifts, line mixing and speed dependence

    NASA Astrophysics Data System (ADS)

    Malathy Devi, V.; Benner, D. Chris; Kleiner, Isabelle; Sams, Robert L.; Fletcher, Leigh N.

    2014-08-01

    Accurate knowledge of spectroscopic line parameters of PH3 is important for remote sensing of the outer planets, especially Jupiter and Saturn. In a recent study, line positions and intensities for the Pentad bands of PH3 have been reported from analysis of high-resolution, high signal-to noise room-temperature spectra recorded with two Fourier transform spectrometers (2014) [1]. The results presented in this study were obtained during the analysis of positions and intensities, but here we focus on the measurements of spectral line shapes (e.g. widths, shifts, line mixing) for the 2ν4, ν2 + ν4, ν1 and ν3 bands. A multispectrum nonlinear least squares curve fitting technique employing a non-Voigt line shape to include line mixing and speed dependence of the Lorentz width was employed to fit the spectra simultaneously. The least squares fittings were performed on five room-temperature spectra recorded at various PH3 pressures (∼2-50 Torr) with the Bruker IFS-125HR Fourier transform spectrometer (FTS) located at the Pacific Northwest National Laboratory (PNNL), in Richland, Washington. Over 840 Lorentz self-broadened half-width coefficients, 620 self-shift coefficients and 185 speed dependence parameters were measured. Line mixing was detected for transitions in the 2ν4, ν1 and ν3 bands, and their values were quantified for 10 A+A- pairs of transitions via off-diagonal relaxation matrix element formalism. The dependences of the measured half-width coefficients on the J and K rotational quanta of the transitions are discussed. The self-width coefficients for the ν1 and ν3 bands from this study are compared to the self-width coefficients for transitions with the same rotational quanta (J, K) reported for the Dyad (ν2 and ν4) bands. The measurements from present study should be useful for the development of a reliable theoretical modeling of pressure-broadened widths, shifts and line mixing in symmetric top molecules with C3v symmetry in general, and of PH3

  19. Registered particles onboard identification in the various apertures of GAMMA-400 space gamma-telescope

    NASA Astrophysics Data System (ADS)

    Arkhangelskaja, Irene

    2016-07-01

    GAMMA-400 (Gamma Astronomical Multifunctional Modular Apparatus) will be the gamma-telescope onboard international satellite gamma-observatory designed for particle registration in the wide energy band. Its parameters are optimized for detection of gamma-quanta with the energy ˜ 100 GeV in the main aperture. The main scientific goals of GAMMA-400 are to investigate fluxes of γ-rays and the electron-positron cosmic ray component possibly generated by dark matter particles decay or annihilation and to search for and study in detail discrete γ-ray sources, to investigate the energy spectra of Galactic and extragalactic diffuse γ-rays, and to study γ-ray bursts and γ-emission from the active Sun. This article presents analysis of detected events identification procedures and energy resolution in three apertures provide particles registration both from upper and lateral directions based on GAMMA-400 modeling due special designed software. Time and segmentation methods are used to reject backsplash (backscattering particles created when high energy γ-rays interact with the calorimeter's matter and move in the opposite direction) in the main aperture while only energy deposition analysis allows to reject this effect in the additional and lateral ones. The main aperture provides the best angular (all strip layers information analysis) and energy (energy deposition in the all detectors studying) resolution in the energy range 0.1 - 3 × 10^{3} GeV. The energy resolution in this band is 1%. Triggers in the main aperture will be formed using information about particle direction provided by time of flight system and presence of charged particle or backsplash signal formed according to analysis of energy deposition in combination of all two-layers anticoincidence systems individual detectors. In the additional aperture gamma-telescope allows to register events in the energy band 10 × 10^{-3} - 3 × 10^{3} GeV. The additional aperture energy resolution provides due to

  20. Coupling of Carbon Dioxide Stretch and Bend Vibrations Reveals Thermal Population Dynamics in an Ionic Liquid.

    PubMed

    Giammanco, Chiara H; Kramer, Patrick L; Yamada, Steven A; Nishida, Jun; Tamimi, Amr; Fayer, Michael D

    2016-01-28

    The population relaxation of carbon dioxide dissolved in the room temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EmimNTf2) was investigated using polarization-selective ultrafast infrared pump-probe spectroscopy and two-dimensional infrared (2D IR) spectroscopy. Due to the coupling of the bend with the asymmetric stretch, excitation of the asymmetric stretch of a molecule with a thermally populated bend leads to an additional peak, a hot band, which is red-shifted from the main asymmetric absorption band by the combination band shift. This hot band peak exchanges population with the main peak through the gain and loss of bend excitation quanta. The isotropic pump-probe signal originating from the unexcited bend state displays a fast, relatively small amplitude, initial growth followed by a longer time scale exponential decay. The signal is analyzed over its full time range using a kinetic model to determine both the vibrational lifetime (the final decay) and rate constant for the loss of the bend energy. This bend relaxation manifests as the fast initial growth of the stretch/no bend signal because the hot band (stretch with bend) is "over pumped" relative to the ground state equilibrium. The nonequilibrium pumping occurs because the hot band has a larger transition dipole moment than the stretch/no bend peak. The system is then prepared, utilizing an acousto-optic mid-infrared pulse shaper to cut a hole in the excitation pulse spectrum, such that the hot band is not pumped. The isotropic pump-probe signal from the stretch/no bend state is altered because the initial excited state population ratio has changed. Instead of a growth due to relaxation of bend quanta, a fast initial decay is observed because of thermal excitation of the bend. Fitting this curve gives the rate constant for thermal excitation of the bend and the lifetime, which agree with those determined in the pump-probe experiments without frequency

  1. Observations of terrestrial gamma-flashes by experiment «RELEC»

    NASA Astrophysics Data System (ADS)

    Iyudin, Anatoly

    2015-04-01

    catalogue of TGFs detected by «RELEC» during its first three months of operation. Events that are included in this catalogue were selected by selection creteria of having at least 5 hard X-ray, or gamma-ray quanta during the time interval of 1 ms, simultaneously in at least two DRGE detectors. TGFs included in this catalogue, do have a typical duration of about 400 microseconds, and in total contain from 10 to 40 gamma-quanta. For each selected for catalogue TGF candidate, we will show light curve and a correlating data of other instruments of «RELEC» on-board «Vernov» satellite.

  2. Laser cooling of solids

    NASA Astrophysics Data System (ADS)

    Nemova, Galina; Kashyap, Raman

    2010-08-01

    Laser cooling of solids, sometimes also known as optical refrigeration, is a fast developing area of optical science, investigating the interaction of light with condensed matter. Apart from being of fundamental scientific interest, this topic addresses a very important practical issue: design and construction of laser pumped solid-state cryocoolers, which are compact, free from mechanical vibrations, moving parts, fluids and can cause only low electromagnetic interference in the cooled area. The optical cryocooler has a broad area of applications such as in the development of magnetometers for geophysical sensors, in biomedical sensing and can be beneficial for satellite instrumentations and small sensors, where compactness and the lack of vibrations are very important. Simply, a laser cooler works on the conversion of low energy pump photons into high-energy anti-Stokes fluorescence photons by extracting some of the phonons (heat energy) in a material. That is, the process of laser cooling of solids is based on anti-Stokes fluorescence also known as luminescence upconversion, when light quanta in the red tail of the absorption spectrum are absorbed from a pump laser, and blue-shifted photons are spontaneously emitted. The extra energy extracted from the solid-state lattice in the form of the phonons is the quanta of vibrational energy which generates heat. The idea to cool solids with anti-Stokes fluorescence was proposed in 1929 by Peter Pringsheim and first demonstrated experimentally by Epstein's research team in 1995. In 1999, Steven Bowman proposed to use the optical refrigeration by anti-Stokes fluorescence within the laser medium to balance the heat generated by the Stokes shifted stimulated emission in a high-power solid-state bulk laser. Such a laser without internal heating named radiation-balanced or athermal laser was experimentally demonstrated for the first time in 2002. At the present time laser cooling of solids can be largely divided into three

  3. Signal formation and decay in CdTe x-ray detectors under intense irradiation.

    PubMed

    Jahnke, A; Matz, R

    1999-01-01

    The response of Cd(Zn)Te Schottky and resistive detectors to intense x-rays is investigated in a commercial computed tomography (CT) system to assess their potential for medical diagnostics. To describe their signal height, responsivity, signal-to-noise ratio (SNR), and detective quantum efficiency the devices are modeled as solid-state ionization chambers with spatially varying electric field and charge collection efficiency. The thicknesses and pixel areas of the discrete detector elements are 0.5-2 mm and a few mm2, respectively. The incident spectrum extends from 26 to 120 keV and comprises 10(10) quanta/s cm2. It photogenerates a carrier concentration in the semiconductor that is two to three orders of magnitude above the intrinsic concentration, but remains to a similar extent below the charge densities on the device electrodes. Stable linear operation is achieved with the Schottky-type devices under high bias. Their behavior can be modeled well if negatively charged near-midgap bulk defects with a concentration of 10(11)-10(13) cm-3 are assumed. The bulk defects explain the amount and time constant (about 100 ms) of the detrapping current measured after x-ray pulses (afterglow). To avoid screening by the trapped space charge the bias voltage should exceed 100(V) x [detector thickness/mm]2. Dark currents are of the order of the generation-recombination current, i.e., 300 pA/mm3 detector volume. With proper device design the signal height approaches the theoretical maximum of 0.2 A/W. This high responsivity, however, is not exploited in CT since the SNR is determined here by the incident quantum noise. As a consequence of the detrapping current, the response speed does not meet CT requirements. A medium-term effort for crystal growth appears necessary to achieve the required reduction of the trap density by an order of magnitude. Scintillation based detectors are, therefore, still preferred in fast operating medical diagnostic systems. PMID:9949396

  4. Oxygen evolution from single- and multiple-turnover light pulses: temporal kinetics of electron transport through PSII in sunflower leaves.

    PubMed

    Oja, Vello; Eichelmann, Hillar; Laisk, Agu

    2011-12-01

    Oxygen evolution per single-turnover flash (STF) or multiple-turnover pulse (MTP) was measured with a zirconium O(2) analyzer from sunflower leaves at 22 °C. STF were generated by Xe arc lamp, MTP by red LED light of up to 18000 μmol quanta m(-2) s(-1). Ambient O(2) concentration was 10-30 ppm, STF and MTP were superimposed on far-red background light in order to oxidize plastoquinone (PQ) and randomize S-states. Electron (e(-)) flow was calculated as 4 times O(2) evolution. Q (A) → Q (B) electron transport was investigated firing double STF with a delay of 0 to 2 ms between the two. Total O(2) evolution per two flashes equaled to that from a single flash when the delay was zero and doubled when the delay exceeded 2 ms. This trend was fitted with two exponentials with time constants of 0.25 and 0.95 ms, equal amplitudes. Illumination with MTP of increasing length resulted in increasing O(2) evolution per pulse, which was differentiated with an aim to find the time course of O(2) evolution with sub-millisecond resolution. At the highest pulse intensity of 2.9 photons ms(-1) per PSII, 3 e(-) initially accumulated inside PSII and the catalytic rate of PQ reduction was determined from the throughput rate of the fourth and fifth e(-). A light response curve for the reduction of completely oxidized PQ was a rectangular hyperbola with the initial slope of 1.2 PSII quanta per e(-) and V (m) of 0.6 e(-) ms(-1) per PSII. When PQ was gradually reduced during longer MTP, V (m) decreased proportionally with the fraction of oxidized PQ. It is suggested that the linear kinetics with respect to PQ are apparent, caused by strong product inhibition due to about equal binding constants of PQ and PQH(2) to the Q (B) site. The strong product inhibition is an appropriate mechanism for down-regulation of PSII electron transport in accordance with rate of PQH(2) oxidation by cytochrome b(6)f. PMID:22038184

  5. Research Into Characteristics of X-Ray Emission Laser Beams from Solid-State Cathode Medium of High-Current Glow Discharge

    NASA Astrophysics Data System (ADS)

    Karabut, Alexander B.

    2006-02-01

    X-ray emissions ranging 1.2-3.0 keV with dose rate up to 1.0 Gy/s have been registered in experiments with high-current Glow Discharge. The emissions energy and intensity depend on the cathode material, the kind of plasma-forming gas, and the discharge parameters. The experiments were carried out on the high-current glow discharge device using D2, H2, Kr, and Xe at pressure up to 10 Torr, as well as cathode samples made from Al, Sc, Ti, Ni, Nb, Zr, Mo, Pd, Ta, W, Pt, at current up to 500 mA, and discharge voltage of 500-2500 V. Two emission modes were revealed under the experiments: (1) Diffusion X-rays was observed as separate X-ray bursts (up to 5 × 105 bursts a second and up to 106 X-ray quanta in a burst), (2) X-rays in the form of laser microbeams (up to 104 beams a second and up to 1010 X-ray of quanta in a beam, angular divergence was up to 10-4, the duration of the separate laser beams must be τ = 3 × 10-13-3 × 10-14 s, the separate beam power must be 107-108 W). The emission of the X-ray laser beams occurred when the discharge occurred and within 100 ms after turning off the current. The results of experimental research into the characteristics of secondary penetrating radiation occurring when interacting primary X-ray beams from a solid-state cathode medium with targets made of various materials are reported. It was shown that the secondary radiation consisted of fast electrons. Secondary radiation of two types was observed: (1) The emission with a continuous temporal spectrum in the form of separate bursts with intensity up to 106 fast electrons a burst. (2) The emission with a discrete temporal spectrum and emission rate up to 1010 fast electrons a burst. A third type of the penetrating radiation was observed as well. This type was recorded directly by the photomultiplier placed behind of the target without the scintillator. The abnormal high penetrating ability of this radiation type requires additional research to explain. The obtained results

  6. Vibrational pooling and constrained equilibration on surfaces

    NASA Astrophysics Data System (ADS)

    Boney, E. T. D.

    In this thesis, we provide a statistical theory for the vibrational pooling and fluorescence time dependence observed in infrared laser excitation of CO on an NaCl surface. The pooling is seen in experiment and in computer simulations. In the theory, we assume a rapid equilibration of the quanta in the substrate and minimize the free energy subject to the constraint at any time t of a fixed number of vibrational quanta N(t). At low incident intensity, the distribution is limited to one-quantum exchanges with the solid and so the Debye frequency of the solid plays a key role in limiting the range of this one-quantum domain. The resulting inverted vibrational equilibrium population depends only on fundamental parameters of the oscillator (oe and oeχe) and the surface (oD and T). Possible applications and relation to the Treanor gas phase treatment are discussed. Unlike the solid phase system, the gas phase system has no Debye-constraining maximum. We discuss the possible distributions for arbitrary N-conserving diatom-surface pairs, and include application to H:Si(111) as an example. Computations are presented to describe and analyze the high levels of infrared laser induced vibrational excitation of a monolayer of absorbed 13CO on a NaCl(100) surface. The calculations confirm that, for situations where the Debye frequency limited n domain restriction approximately holds, the vibrational state population deviates from a Boltzmann population linearly in n, a result that we have derived earlier theoretically for a domain of n restricted to one-phonon transfers. This theoretically understood term, linear in n, dominates the Boltzmann term and is responsible for the inversion of the population of vibrational states, Pn We discuss the one-to-one relationship between N and gamma and the examine the state space of the new distribution function for varied gamma. We derive the Free Energy and effective chemical potential for the vibrational pool. We also find the anti

  7. Prevalence estimation of celiac disease in the general adult population of Latvia using serology and HLA genotyping

    PubMed Central

    Shums, Zakera; Nikitina-Zake, Liene; Gavars, Mikus; Kikuste, Ilze; Milo, Jay; Daugule, Ilva; Pahomova, Jelena; Pirags, Valdis; Dzerve, Vilnis; Klovins, Janis; Erglis, Andrejs; Norman, Gary L

    2015-01-01

    Background Prevalence estimates for celiac disease (CD) depend on the method used. The role of deamidated gliadin peptide (DGP) and genetic testing in epidemiological studies and diagnostic settings of celiac disease (CD) has still to be established. Objectives The objective of this article is to assess the prevalence of CD in Latvia by combining serological tests with DQ2.5/DQ8 testing. Methods A total of 1444 adults from a randomly selected cross-sectional general population sample were tested by ELISA for tTG IgA, DGP IgA and IgG antibodies (QUANTA Lite®, Inova Diagnostics Inc). Samples with tTG IgA ≥20U were tested for EMA IgA by indirect immunofluorescence assay, and all specimens with tTG IgA ≥15U were tested by QUANTA-Flash® chemiluminescent assays (CIA) (Inova Diagnostics Inc) for tTG IgA, DGP IgA and IgG. DQ2.5/8 was detected in individuals with any positive ELISA test and a subgroup of controls. Results Forty-three individuals (2.98%; 95% CI: 2.10–3.86%) tested positive by at least one ELISA test; 41.86% of the serology-positive individuals (any test above the cutoff) were DQ positive. Six individuals (0.42%; 95% CI: 0.09–0.75%) were triple ELISA positive, and DQ2.5 or DQ8 was positive in all; 0.35% (95% CI: 0.05–0.65%) were tTG IgA and EMA positive. Two tTG IgA-negative cases were both DGP IgG and IgA positive, both being DQ positive; including them in the “serology-positive” group would increase the prevalence to 0.49% (95% CI: 0.13–0.85%). CIA tests revealed 2 tTG IgA-positive and EMA-negative cases with a positive genotype. DQ2.5 or DQ8 genotype was positive in 28.6% of the serology-negative population. Conclusions Estimates of the prevalence of CD in Latvia based on the serogenetic testing approach range from 0.35% to 0.49% depending on the criteria used. There is a rationale for combining serological tests and DQ2.5/8 genotyping. PMID:25922680

  8. Novel iterative reconstruction method with optimal dose usage for partially redundant CT-acquisition

    NASA Astrophysics Data System (ADS)

    Bruder, H.; Raupach, R.; Sunnegardh, J.; Allmendinger, T.; Klotz, E.; Stierstorfer, K.; Flohr, T.

    2015-11-01

    In CT imaging, a variety of applications exist which are strongly SNR limited. However, in some cases redundant data of the same body region provide additional quanta. Examples: in dual energy CT, the spatial resolution has to be compromised to provide good SNR for material decomposition. However, the respective spectral dataset of the same body region provides additional quanta which might be utilized to improve SNR of each spectral component. Perfusion CT is a high dose application, and dose reduction is highly desirable. However, a meaningful evaluation of perfusion parameters might be impaired by noisy time frames. On the other hand, the SNR of the average of all time frames is extremely high. In redundant CT acquisitions, multiple image datasets can be reconstructed and averaged to composite image data. These composite image data, however, might be compromised with respect to contrast resolution and/or spatial resolution and/or temporal resolution. These observations bring us to the idea of transferring high SNR of composite image data to low SNR ‘source’ image data, while maintaining their resolution. It has been shown that the noise characteristics of CT image data can be improved by iterative reconstruction (Popescu et al 2012 Book of Abstracts, 2nd CT Meeting (Salt Lake City, UT) p 148). In case of data dependent Gaussian noise it can be modelled with image-based iterative reconstruction at least in an approximate manner (Bruder et al 2011 Proc. SPIE 7961 79610J). We present a generalized update equation in image space, consisting of a linear combination of the previous update, a correction term which is constrained by the source image data, and a regularization prior, which is initialized by the composite image data. This iterative reconstruction approach we call bimodal reconstruction (BMR). Based on simulation data it is shown that BMR can improve low contrast detectability, substantially reduces the noise power and has the potential to recover

  9. Novel iterative reconstruction method with optimal dose usage for partially redundant CT-acquisition.

    PubMed

    Bruder, H; Raupach, R; Sunnegardh, J; Allmendinger, T; Klotz, E; Stierstorfer, K; Flohr, T

    2015-11-01

    In CT imaging, a variety of applications exist which are strongly SNR limited. However, in some cases redundant data of the same body region provide additional quanta. Examples in dual energy CT, the spatial resolution has to be compromised to provide good SNR for material decomposition. However, the respective spectral dataset of the same body region provides additional quanta which might be utilized to improve SNR of each spectral component. Perfusion CT is a high dose application, and dose reduction is highly desirable. However, a meaningful evaluation of perfusion parameters might be impaired by noisy time frames. On the other hand, the SNR of the average of all time frames is extremely high.In redundant CT acquisitions, multiple image datasets can be reconstructed and averaged to composite image data. These composite image data, however, might be compromised with respect to contrast resolution and/or spatial resolution and/or temporal resolution. These observations bring us to the idea of transferring high SNR of composite image data to low SNR 'source' image data, while maintaining their resolution.It has been shown that the noise characteristics of CT image data can be improved by iterative reconstruction (Popescu et al 2012 Book of Abstracts, 2nd CT Meeting (Salt Lake City, UT) p 148). In case of data dependent Gaussian noise it can be modelled with image-based iterative reconstruction at least in an approximate manner (Bruder et al 2011 Proc. SPIE 7961 79610J). We present a generalized update equation in image space, consisting of a linear combination of the previous update, a correction term which is constrained by the source image data, and a regularization prior, which is initialized by the composite image data. This iterative reconstruction approach we call bimodal reconstruction (BMR). Based on simulation data it is shown that BMR can improve low contrast detectability, substantially reduces the noise power and has the potential to recover spatial

  10. Teaching Quantum Uncertainty1

    NASA Astrophysics Data System (ADS)

    Hobson, Art

    2011-10-01

    An earlier paper2 introduces quantum physics by means of four experiments: Youngs double-slit interference experiment using (1) a light beam, (2) a low-intensity light beam with time-lapse photography, (3) an electron beam, and (4) a low-intensity electron beam with time-lapse photography. It's ironic that, although these experiments demonstrate most of the quantum fundamentals, conventional pedagogy stresses their difficult and paradoxical nature. These paradoxes (i.e., logical contradictions) vanish, and understanding becomes simpler, if one takes seriously the fact that quantum mechanics is the nonrelativistic limit of our most accurate physical theory, namely quantum field theory, and treats the Schroedinger wave function, as well as the electromagnetic field, as quantized fields.2 Both the Schroedinger field, or "matter field," and the EM field are made of "quanta"—spatially extended but energetically discrete chunks or bundles of energy. Each quantum comes nonlocally from the entire space-filling field and interacts with macroscopic systems such as the viewing screen by collapsing into an atom instantaneously and randomly in accordance with the probability amplitude specified by the field. Thus, uncertainty and nonlocality are inherent in quantum physics. This paper is about quantum uncertainty. A planned later paper will take up quantum nonlocality.

  11. System Engineering for J-2X Development: The Simpler, the Better

    NASA Technical Reports Server (NTRS)

    Kelly, William M.; Greasley, Paul; Greene, William D.; Ackerman, Peter

    2008-01-01

    The Ares I and Ares V Vehicles will utilize the J-2X rocket engine developed for NASA by the Pratt and Whitney Rocketdyne Company (PWR) as the upper stage engine (USE). The J-2X is an improved higher power version of the original J-2 engine used for Apollo. System Engineering (SE) facilitates direct and open discussions of issues and problems. This simple idea is often overlooked in large, complex engineering development programs. Definition and distribution of requirements from the engine level to the component level is controlled by Allocation Reports which breaks down numerical design objectives (weight, reliability, etc.) into quanta goals for each component area. Linked databases of design and verification requirements help eliminate redundancy and potential mistakes inherent in separated systems. Another tool, the Architecture Design Description (ADD), is used to control J-2X system architecture and effectively communicate configuration changes to those involved in the design process. But the proof of an effective process is in successful program accomplishment. SE is the methodology being used to meet the challenge of completing J-2X engine certification 2 years ahead of any engine program ever developed at PWR. This paper describes the simple, better SE tools and techniques used to achieve this success.

  12. Simulation study on nitrogen vibrational kinetics in a single nanosecond pulse high voltage air discharge

    NASA Astrophysics Data System (ADS)

    Yang, Wei; Zhou, Qianhong; Dong, Zhiwei

    2016-05-01

    We report a simulation study on nitrogen vibrational kinetics N 2 ( X 1 Σg + , v = 0 - 12 ) in a single nanosecond pulse high voltage discharge in dry-air at a pressure of 100 Torr. Apart from the usual processes such as vibrational-vibrational exchange and vibrational-translational relaxation, the state-specific vibrational kinetics take into account the electronic-vibrational (E-V) process and chemical-vibrational process. The vibrational kinetics, coupled with electron Boltzmann equation solver, plasma chemical kinetics, and gas thermal balance are used to model the 100 ns discharge and its subsequent 10 ms afterglow. The self-consistent model shows good agreement with recent experimental results, with regard to time-resolved vibrational and translational temperature. According to the modeling results, The E-V mechanism has a small but non-negligible effect (about 2%) in rising of vibrational quanta in the early afterglow from 100 ns to 1μs. Another possible reason is the convective transport associated with the gas dynamic expansion in time delays around 1μs to 10 μs.

  13. Topical Delivery of Aceclofenac: Challenges and Promises of Novel Drug Delivery Systems

    PubMed Central

    Kumar, Manish; Kumar, Pramod; Malik, Ruchi; Sharma, Gajanand; Kaur, Manmeet; Katare, O. P.

    2014-01-01

    Osteoarthritis (OA), a common musculoskeletal disorder, is projected to affect about 60 million people of total world population by 2020. The associated pain and disability impair the quality of life and also pose economic burden to the patient. Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely prescribed in OA, while diclofenac is the most prescribed one. Oral NSAIDs are not very patient friendly, as they cause various gastrointestinal adverse effects like bleeding, ulceration, and perforation. To enhance the tolerability of diclofenac and decrease the common side effects, aceclofenac (ACE) was developed by its chemical modification. As expected, ACE is more well-tolerated than diclofenac and possesses superior efficacy but is not completely devoid of the NSAID-tagged side effects. A series of chemical modifications of already planned drug is unjustified as it consumes quanta of time, efforts, and money, and this approach will also pose stringent regulatory challenges. Therefore, it is justified to deliver ACE employing tools of drug delivery and nanotechnology to refine its safety profile. The present review highlights the constraints related to the topical delivery of ACE and the various attempts made so far for the safe and effective topical delivery employing the novel materials and methods. PMID:25045671

  14. BCS-BEC crossover and phase structure of relativistic systems: A variational approach

    SciTech Connect

    Chatterjee, Bhaswar; Mishra, Hiranmaya; Mishra, Amruta

    2009-01-01

    We investigate here the BCS-BEC crossover in relativistic systems using a variational construct for the ground state and the minimization of the thermodynamic potential. This is first studied in a four-fermion point interaction model and with a BCS type ansatz for the ground state with fermion pairs. It is shown that the antiparticle degrees of freedom play an important role in the BCS-BEC crossover physics, even when the ratio of Fermi momentum to the mass of the fermion is small. We also consider the phase structure for the case of fermion pairing with imbalanced populations. Within the ansatz, thermodynamically stable gapless modes for both fermions and antifermions are seen for strong coupling in the Bose-Einstein condensation (BEC) regime. We further investigate the effect of fluctuations of the condensate field by treating it as a dynamical field and generalize the BCS ansatz to include quanta of the condensate field also in a boson-fermion model with quartic self-interaction of the condensate field. It is seen that the critical temperature decreases with inclusion of fluctuations.

  15. Room temperature de Haas–van Alphen effect in silicon nanosandwiches

    NASA Astrophysics Data System (ADS)

    Bagraev, N. T.; Grigoryev, V. Yu.; Klyachkin, L. E.; Malyarenko, A. M.; Mashkov, V. A.; Romanov, V. V.

    2016-08-01

    The negative-U impurity stripes confining the edge channels of semiconductor quantum wells are shown to allow the effective cooling inside in the process of the spin-dependent transport. The aforesaid promotes also the creation of composite bosons and fermions by the capture of single magnetic flux quanta on the edge channels under the conditions of low sheet density of carriers, thus opening new opportunities for the registration of the quantum kinetic phenomena in weak magnetic fields at high temperatures up to the room temperature. As a certain version noted above we present the first findings of the high temperature de Haas-van Alphen, 300K, and quantum Hall, 77K, effects in the silicon sandwich structure that represents the ultra-narrow, 2 nm, p-type quantum well (Si-QW) confined by the delta barriers heavily doped with boron on the n-type Si (100) surface. These data appear to result from the low density of single holes that are of small effective mass in the edge channels of p-type Si-QW because of the impurity confinement by the stripes consisting of the negative-U dipole boron centers which seems to give rise to the efficiency reduction of the electron-electron interaction.

  16. Nanomagnonic devices based on the spin-transfer torque

    NASA Astrophysics Data System (ADS)

    Urazhdin, S.; Demidov, V. E.; Ulrichs, H.; Kendziorczyk, T.; Kuhn, T.; Leuthold, J.; Wilde, G.; Demokritov, S. O.

    2014-07-01

    Magnonics is based on signal transmission and processing by spin waves (or their quanta, called magnons) propagating in a magnetic medium. In the same way as nanoplasmonics makes use of metallic nanostructures to confine and guide optical-frequency plasmon-polaritons, nanomagnonics uses nanoscale magnetic waveguides to control the propagation of spin waves. Recent advances in the physics of nanomagnetism, such as the discovery of spin-transfer torque, have created possibilities for nanomagnonics. In particular, it was recently demonstrated that nanocontact spin-torque devices can radiate spin waves, serving as local nanoscale sources of signals for magnonic applications. However, the integration of spin-torque sources with nanoscale magnetic waveguides, which is necessary for the implementation of integrated spin-torque magnonic circuits, has not been achieved to date. Here, we suggest and experimentally demonstrate a new approach to this integration, utilizing dipolar field-induced magnonic nanowaveguides. The waveguides exhibit good spectral matching with spin-torque nano-oscillators and enable efficient directional transmission of spin waves. Our results provide a practical route for the implementation of integrated magnonic circuits utilizing spin transfer.

  17. Nanomagnonic devices based on the spin-transfer torque.

    PubMed

    Urazhdin, S; Demidov, V E; Ulrichs, H; Kendziorczyk, T; Kuhn, T; Leuthold, J; Wilde, G; Demokritov, S O

    2014-07-01

    Magnonics is based on signal transmission and processing by spin waves (or their quanta, called magnons) propagating in a magnetic medium. In the same way as nanoplasmonics makes use of metallic nanostructures to confine and guide optical-frequency plasmon-polaritons, nanomagnonics uses nanoscale magnetic waveguides to control the propagation of spin waves. Recent advances in the physics of nanomagnetism, such as the discovery of spin-transfer torque, have created possibilities for nanomagnonics. In particular, it was recently demonstrated that nanocontact spin-torque devices can radiate spin waves, serving as local nanoscale sources of signals for magnonic applications. However, the integration of spin-torque sources with nanoscale magnetic waveguides, which is necessary for the implementation of integrated spin-torque magnonic circuits, has not been achieved to date. Here, we suggest and experimentally demonstrate a new approach to this integration, utilizing dipolar field-induced magnonic nanowaveguides. The waveguides exhibit good spectral matching with spin-torque nano-oscillators and enable efficient directional transmission of spin waves. Our results provide a practical route for the implementation of integrated magnonic circuits utilizing spin transfer. PMID:24813697

  18. Spatial imaging in color and HDR: prometheus unchained

    NASA Astrophysics Data System (ADS)

    McCann, John J.

    2013-03-01

    The Human Vision and Electronic Imaging Conferences (HVEI) at the IS and T/SPIE Electronic Imaging meetings have brought together research in the fundamentals of both vision and digital technology. This conference has incorporated many color disciplines that have contributed to the theory and practice of today's imaging: color constancy, models of vision, digital output, high-dynamic-range imaging, and the understanding of perceptual mechanisms. Before digital imaging, silver halide color was a pixel-based mechanism. Color films are closely tied to colorimetry, the science of matching pixels in a black surround. The quanta catch of the sensitized silver salts determines the amount of colored dyes in the final print. The rapid expansion of digital imaging over the past 25 years has eliminated the limitations of using small local regions in forming images. Spatial interactions can now generate images more like vision. Since the 1950's, neurophysiology has shown that post-receptor neural processing is based on spatial interactions. These results reinforced the findings of 19th century experimental psychology. This paper reviews the role of HVEI in color, emphasizing the interaction of research on vision and the new algorithms and processes made possible by electronic imaging.

  19. Physical Realization of von Neumann Lattices in Rotating Bose Gases with Dipole Interatomic Interactions

    PubMed Central

    Cheng, Szu-Cheng; Jheng, Shih-Da

    2016-01-01

    This paper reports a novel type of vortex lattice, referred to as a bubble crystal, which was discovered in rapidly rotating Bose gases with long-range interactions. Bubble crystals differ from vortex lattices which possess a single quantum flux per unit cell, while atoms in bubble crystals are clustered periodically and surrounded by vortices. No existing model is able to describe the vortex structure of bubble crystals; however, we identified a mathematical lattice, which is a subset of coherent states and exists periodically in the physical space. This lattice is called a von Neumann lattice, and when it possesses a single vortex per unit cell, it presents the same geometrical structure as an Abrikosov lattice. In this report, we extend the von Neumann lattice to one with an integral number of flux quanta per unit cell and demonstrate that von Neumann lattices well reproduce the translational properties of bubble crystals. Numerical simulations confirm that, as a generalized vortex, a von Neumann lattice can be physically realized using vortex lattices in rapidly rotating Bose gases with dipole interatomic interactions. PMID:27545446

  20. Mammographic imaging with a small format CCD-based digital cassette: Physical characteristics of a clinical systema

    PubMed Central

    Vedantham, Srinivasan; Karellas, Andrew; Suryanarayanan, Sankararaman; Levis, Ilias; Sayag, Michel; Kleehammer, Robert; Heidsieck, Robert; D’Orsi, Carl J.

    2008-01-01

    The physical characteristics of a clinical charge coupled device (CCD)-based imager (Senovision, GE Medical Systems, Milwaukee, WI) for small-field digital mammography have been investigated. The imager employs a MinR 2000™ (Eastman Kodak Company, Rochester, NY) scintillator coupled by a 1:1 optical fiber to a front-illuminated 61×61 mm CCD operating at a pixel pitch of 30 microns. Objective criteria such as modulation transfer function (MTF), noise power spectrum (NPS), detective quantum efficiency (DQE), and noise equivalent quanta (NEQ) were employed for this evaluation. The results demonstrated a limiting spatial resolution (10% MTF) of 10 cy/mm. The measured DQE of the current prototype utilizing a 28 kVp, Mo–Mo spectrum beam hardened with 4.5 cm Lucite is ~40% at close to zero spatial frequency at an exposure of 8.2 mR, and decreases to ~28% at a low exposure of 1.1 mR. Detector element nonuniformity and electronic gain variations were not significant after appropriate calibration and software corrections. The response of the imager was linear and did not exhibit signal saturation under tested exposure conditions. PMID:10984230

  1. Dark matter from spacetime nonlocality

    NASA Astrophysics Data System (ADS)

    Saravani, Mehdi; Aslanbeigi, Siavash

    2015-11-01

    We propose that dark matter is not yet another new particle in nature, but that it is a remnant of quantum gravitational effects on known fields. We arrive at this possibility in an indirect and surprising manner: by considering retarded, nonlocal, and Lorentzian evolution for quantum fields. This is inspired by recent developments in causal set theory, where such an evolution shows up as the continuum limit of scalar field propagation on a background causal set. Concretely, we study the quantum theory of a massless scalar field whose evolution is given not by the the d'Alembertian □, but by an operator □˜ which is Lorentz invariant, reduces to □ at low energies, and defines an explicitly retarded evolution: (□˜ϕ )(x ) only depends on ϕ (y ), where y is in the causal past of x . This modification results in the existence of a continuum of massive particles, in addition to the usual massless ones, in the free theory. When interactions are introduced, these massive or off-shell quanta can be produced by the scattering of massless particles, but once produced, they no longer interact, which makes them a natural candidate for dark matter.

  2. Particle physics meets cosmology - The search for decaying neutrinos

    NASA Technical Reports Server (NTRS)

    Henry, R. C.

    1982-01-01

    The fundamental physical implications of the possible detection of massive neutrinos are discussed, with an emphasis on the Grand Unified Theories (GUTs) of matter. The Newtonian and general-relativistic pictures of the fundamental forces are compared, and the reduction of electromagnetic and weak forces to one force in the GUTs is explained. The cosmological consequences of the curved-spacetime gravitation concept are considered. Quarks, leptons, and neutrinos are characterized in a general treatment of elementary quantum mechanics. The universe is described in terms of quantized fields, the noninteractive 'particle' fields and the force fields, and cosmology becomes the study of the interaction of gravitation with the other fields, of the 'freezing out' of successive fields with the expansion and cooling of the universe. While the visible universe is the result of the clustering of the quark and electron fields, the distribution of the large number of quanta in neutrino field, like the mass of the neutrino, are unknown. Cosmological models which attribute anomalies in the observed motions of galaxies and stars to clusters or shells of massive neutrinos are shown to be consistent with a small but nonzero neutrino mass and a universe near the open/closed transition point, but direct detection of the presence of massive neutrinos by the UV emission of their decay is required to verify these hypotheses.

  3. Molecular modeling in the development of metal radiopharmaceuticals. Final progress report, July 15, 1989--July 14, 1993

    SciTech Connect

    Green, M.A.

    1993-10-01

    We began this project with a compilation of a structural library to serve as a data base containing descriptions of the molecular features of metal-labeled radiopharmaceuticals known to efficiently cross the blood-brain barrier. Such a data base is needed in order to identify structural features (size, shape, molecular surface areas and volumes) that are critical in allowing blood-brain barrier penetration. Nine metal complexes have been added to this structural library. We have completed a detailed comparison of four molecular mechanics computer programs QUANTA, SYBYL, BOYD, and MM2DREW to assess their applicability to modeling the structures of low molecular weight metal complexes. We tested the ability of each program to reproduce the crystallographic structures of 38 complexes between nickel(II) and saturated N-donor ligands. The programs were evaluated in terns of their ability to reproduce structural features such as bond lengths, bond angles, and torsion angles. Recently, we investigated the synthesis and characterization of lipophilic cationic gallium complexes with hexadentate bis(salicylaldimine) ligands. This work identified the first gallium-68 radiopharrnaceuticals that can be injected intravenously and that subsequently exhibit significant myocardial uptake followed by prolonged myocardial retention of {sup 68}Ga radioactivity. Tracers of this type remain under investigation as agents for evaluation of myocardial perfusion with positron emission tomography.

  4. Physical Realization of von Neumann Lattices in Rotating Bose Gases with Dipole Interatomic Interactions.

    PubMed

    Cheng, Szu-Cheng; Jheng, Shih-Da

    2016-01-01

    This paper reports a novel type of vortex lattice, referred to as a bubble crystal, which was discovered in rapidly rotating Bose gases with long-range interactions. Bubble crystals differ from vortex lattices which possess a single quantum flux per unit cell, while atoms in bubble crystals are clustered periodically and surrounded by vortices. No existing model is able to describe the vortex structure of bubble crystals; however, we identified a mathematical lattice, which is a subset of coherent states and exists periodically in the physical space. This lattice is called a von Neumann lattice, and when it possesses a single vortex per unit cell, it presents the same geometrical structure as an Abrikosov lattice. In this report, we extend the von Neumann lattice to one with an integral number of flux quanta per unit cell and demonstrate that von Neumann lattices well reproduce the translational properties of bubble crystals. Numerical simulations confirm that, as a generalized vortex, a von Neumann lattice can be physically realized using vortex lattices in rapidly rotating Bose gases with dipole interatomic interactions. PMID:27545446

  5. An unusual isotope effect in a high-transition-temperature superconductor

    SciTech Connect

    Gweon, G.-H.; Sasagawa, T.; Zhou, S.Y.; Graf, J.; Takagi, H.; Lee, D.-H.; Lanzara, A.

    2004-04-01

    In conventional superconductors, the electron pairing that allows superconductivity is caused by exchange of virtual phonons, which are quanta of lattice vibration. For high-transition-temperature (high-Tc) superconductors, it is far from clear that phonons are involved in the pairing at all. For example, the negligible change in Tc of optimally doped Bi2Sr2CaCu2O8 (Bi2212) upon oxygen isotope substitution (16O to 18O leads to Tc decreasing from 92 to 91 K) has often been taken to mean that phonons play an insignificant role in this material. Here we provide a detailed comparison of the electron dynamics of Bi2212 samples containing different oxygen isotopes, using angle-resolved photoemission spectroscopy. Our data show definite and strong isotope effects. Surprisingly, the effects mainly appear in broad high-energy humps, commonly referred to as ''incoherent peaks''. As a function of temperature and electron momentum, the magnitude of the isotope effect closely correlates with the superconducting gap--that is, the pair binding energy. We suggest that these results can be explained in a dynamic spin-Peierls picture, where the singlet pairing of electrons and the electron-lattice coupling mutually enhance each other.

  6. Toward Fast Calibration of Global Drift in Scanning Electron Microscopes with Respect to Time and Magnification

    NASA Astrophysics Data System (ADS)

    Malti, Abed C.; Dembélé, Sounkalo; Piat, Nadine; Arnoult, Claire; Marturi, Naresh

    2012-01-01

    It is a well-known fact that scanning electron microscopic (SEM) image acquisition is mainly affected by nonlinearities and instabilities of the column and probe-specimen interaction; in turn, producing a shift in the image points with respect to many parameters and time, in particular. Even though this drift is comparatively less in modern SEMs, it is still an important factor to consider in most of the SEM-based applications. In this airticle, a simple and real-time method is proposed to estimate the global drift from a set of target images using image phase correlation, and to model its evolution by using the recursive equations of time and magnification. Based on the developed model, it is opted to use a Kalman filter in real time for accurate estimation and removal of the drift from the images. The developed method is tested using the images from a tungsten filament gun SEM (Jeol JSM 820) and a field effect gun SEM (FEI Quanta 200). The derived results show the effectiveness of the developed algorithm and also demonstrates its ability to be used in robotics as well as in material characterization under SEM.

  7. Quasi-ballistic thermal transport from nanoscale interfaces observed using ultrafast coherent soft X-ray beams

    NASA Astrophysics Data System (ADS)

    Siemens, Mark E.; Li, Qing; Yang, Ronggui; Nelson, Keith A.; Anderson, Erik H.; Murnane, Margaret M.; Kapteyn, Henry C.

    2010-01-01

    Fourier theory of thermal transport considers heat transport as a diffusive process where energy flow is driven by a temperature gradient. However, this is not valid at length scales smaller than the mean free path for the energy carriers in a material, which can be hundreds of nanometres in crystalline materials at room temperature. In this case, heat flow will become `ballistic'-driven by direct point-to-point transport of energy quanta . Past experiments have demonstrated size-dependent ballistic thermal transport through nanostructures such as thin films, superlattices, nanowires and carbon nanotubes. The Fourier law should also break down in the case of heat dissipation from a nanoscale heat source into the bulk. However, despite considerable theoretical discussion and direct application to thermal management in nanoelectronics, nano-enabled energy systems and nanomedicine, this non-Fourier heat dissipation has not been experimentally observed so far. Here, we report the first observation and quantitative measurements of this transition from diffusive to ballistic thermal transport from a nanoscale hotspot, finding a significant (as much as three times) decrease in energy transport away from the nanoscale heat source compared with Fourier-law predictions.

  8. Photon-induced near field electron microscopy

    NASA Astrophysics Data System (ADS)

    Park, Sang Tae; Zewail, Ahmed H.

    2013-09-01

    Ultrafast electron microscopy in the space and time domains utilizes a pulsed electron probe to directly map structural dynamics of nanomaterials initiated by an optical pump pulse, in imaging, di raction, spectroscopy, and their combinations. It has demonstrated its capability in the studies of phase transitions, mechanical vibrations, and chemical reactions. Moreover, electrons can directly interact with photons via the near eld component of light scattering by nanostructures, and either gain or lose light quanta discretely in energy. By energetically selecting those electrons that exchanged photon energies, we can map this photon-electron interaction, and the technique is termed photon-induced near eld electron microscopy (PINEM). Here, we give an account of the theoretical understanding of PINEM. Experimentally, nanostructures such as a sphere, cylinder, strip, and triangle have been investigated. Theoretically, time-dependent Schrodinger and Dirac equations for an electron under light are directly solved to obtain analytical solutions. The interaction probability is expressed by the mechanical work done by an optical wave on a traveling electron, which can be evaluated analytically by the near eld components of the Rayleigh scattering for small spheres and thin cylinders, and numerically by the discrete dipole approximation for other geometries. Application in visualization of plasmon elds is discussed.

  9. Arrangement Analysis of Leaves Optimized on Photon Flux Density or Photosynthetic Rate

    NASA Astrophysics Data System (ADS)

    Obara, Shin'ya; Tanno, Itaru

    By clarifying a plant evolutive process, useful information may be obtained on engineering. Consequently, an analysis algorithm that investigates the optimal arrangement of plant leaves was developed. In the developed algorithm, the Monte Carlo method is introduced and sunlight is simulated. Moreover, the arrangement optimization of leaves is analyzed using a Genetic Algorithm (GA). The number of light quanta (photon flux density) that reaches leaves, or the average photosynthetic rate of the same was set as the objective function, and leaf models of a dogwood and a ginkgo tree were analyzed. The number of leaf models was set between two to four, and the position of the leaf was expressed in terms of the angle of direction, elevation angle, rotation angle, and the representative length of the branch of a leaf. The chromosome model introduced into GA consists of information concerning the position of the leaf. Based on the analysis results, the characteristics of the leaf of an actual plant could be simulated by ensuring the algorithm had multiple constrained conditions. The optimal arrangement of leaves differs in maximization of the photon flux density, and that of the average value of a photosynthetic rate. Furthermore, the leaf form affecting the optimal arrangement of leave and also having a significant influence also on a photosynthetic rate was shown.

  10. Synchrophasor Based Tracking Three-Phase State Estimator and It's Applications

    SciTech Connect

    Phadke, A. G.; Thorp, James; Centeno, Virgilio; Gardner, Matthew; Novosel, Damir; Hu, Yi; Elizondo, David

    2013-08-31

    Electric power infrastructure is one of the critical resources of the nation. Its reliability in the face of natural or man-made catastrophes is of paramount importance for the economic and public health wellbeing of a modern society. Maintaining high levels of security for the high voltage transmission back bone of the electric supply network is a task requiring access to modern monitoring tools. These tools have been made particularly effective with the advent of synchronized phasor measurement units (PMUs) which became available in late 1990s, and have now become an indispensable for optimal monitoring, protection and control of the power grid. The present project was launched with an objective of demonstrating the value of the Wide Area Measurement System (WAMS) using PMUs and its applications on the Dominion Virginia Power High Voltage transmission grid. Virginia Tech is the birth place of PMUs, and was chosen to be the Principal Investigator of this project. In addition to Dominion Virginia Power, Quanta Technology of Raleigh, NC was selected to be co-Principal Investigators of this project.

  11. Cavity-Free Photon Blockade Induced by Many-Body Bound States

    NASA Astrophysics Data System (ADS)

    Zheng, Huaixiu; Gauthier, Daniel; Baranger, Harold

    2012-02-01

    We show theoretically that a variety of strong quantum nonlinear phenomena occur in a completely open one-dimensional waveguide coupled to an N-type four-level system. This system could be realized, for example, in experiments using superconducting circuits. We focus on photon blockade, photon-induced tunneling, bunching or anti-bunching, and the creation of single-photon states, all in the absence of a cavity. Many-body bound states appear due to the strong photon-photon correlation mediated by the four-level system. These bound states cause photon blockade, generating a sub-Poissonian single-photon source [1]. Such a source is crucial for quantum cryptography and distributed quantum networking; our work thus supports the notion that open quantum systems can play a critical role in the manipulation of individual, mobile quanta, a key goal of quantum communication. [1] H. Zheng, D. J. Gauthier, and H. U. Baranger, Phys. Rev. Lett. in press (2011), arXiv:1107.0309.

  12. On discrete symmetries for a whole Abelian model

    NASA Astrophysics Data System (ADS)

    Chauca, J.; Doria, R.

    2012-10-01

    Considering the whole concept applied to gauge theory a nonlinear abelian model is derived. A next step is to understand on the model properties. At this work, it will be devoted to discrete symmetries. For this, we will work based in two fields reference systems. This whole gauge symmetry allows to be analyzed through different sets which are the constructor basis {Dμ,Xiμ} and the physical basis {GμI}. Taking as fields reference system the diagonalized spin-1 sector, P, C, T and PCT symmetries are analyzed. They show that under this systemic model there are conservation laws driven for the parts and for the whole. It develops the meaning of whole-parity, field-parity and so on. However it is the whole symmetry that rules. This means that usually forbidden particles as pseudovector photons can be introduced through such whole abelian system. As result, one notices that the fields whole {GμI} manifest a quanta diversity. It involves particles with different spins, masses and discrete quantum numbers under a same gauge symmetry. It says that without violating PCT symmetry different possibilities on discrete symmetries can be accommodated.

  13. Black holes as self-sustained quantum states and Hawking radiation

    NASA Astrophysics Data System (ADS)

    Casadio, Roberto; Giugno, Andrea; Micu, Octavian; Orlandi, Alessio

    2014-10-01

    We employ the recently proposed formalism of the "horizon wave function" to investigate the emergence of a horizon in models of black holes as Bose-Einstein condensates of gravitons. We start from the Klein-Gordon equation for a massless scalar (toy graviton) field coupled to a static matter current. The (spherically symmetric) classical field reproduces the Newtonian potential generated by the matter source, and the corresponding quantum state is given by a coherent superposition of scalar modes with continuous occupation number. Assuming an attractive self-interaction that allows for bound states, one finds that (approximately) only one mode is allowed, and the system can be confined in a region the size of the Schwarzschild radius. This radius is then shown to correspond to a proper horizon, by means of the horizon wave function of the quantum system, with an uncertainty in size naturally related to the expected typical energy of Hawking modes. In particular, this uncertainty decreases for larger black hole mass (with a larger number of light scalar quanta), in agreement with semiclassical expectations, a result which does not hold for a single very massive particle. We finally speculate that a phase transition should occur during the gravitational collapse of a star (ideally represented by a static matter current and Newtonian potential) that leads to a black hole (again ideally represented by the condensate of toy gravitons), and suggest an effective order parameter that could be used to investigate this transition.

  14. Multi-Point Detection of the Elf Transient Caused by the Gamma Flare of December 27, 2004

    NASA Astrophysics Data System (ADS)

    Nickolaenko, A. P.; Schekotov, A. Yu.; Hayakawa, M.; Hobara, Y.; Sátori, G.; Bor, J.; Neska, M.

    2014-07-01

    We present the experimental records of the radio pulse related to the gamma burst that took place on December 27, 2004. The records, which are synchronized by GPS time marks, were obtained in the observatories at Moshiri and Onagawa (Japan), Esrange (Sweden), Karimshino (Kamchatka, Russia), Nagycenk (Hungary), and Hornsund (Polish Polar Station Spitzbergen). The data demonstrate exceptional similarity and contain characteristic pulses that correspond to the time of gamma-ray arrival. Processing of the signals shows that along with the time match, the following modeling predictions are confirmed: radio pulses contain a signal at the main frequency of the Schumann resonance, the field source has positive polarity (the current is directed from the ionosphere towards the Earth), the polarization of the horizontal magnetic field of the radio wave is almost linear, and the directions towards the source indicate the epicenter of the gamma-quanta flux collision with the ionosphere. These properties correspond to the concept of the parametric electromagnetic pulse that is produced due to a significant change in the current in the global electric circuit, which is caused by a cosmic gamma-ray flare.

  15. Failed CTL/NK cell killing and cytokine hypersecretion are directly linked through prolonged synapse time

    PubMed Central

    Rudd-Schmidt, Jesse A.; Lopez, Jamie A.; Ramsbottom, Kelly M.; Mannering, Stuart I.; Andrews, Daniel M.; Voskoboinik, Ilia

    2015-01-01

    Failure of cytotoxic T lymphocytes (CTLs) or natural killer (NK) cells to kill target cells by perforin (Prf)/granzyme (Gzm)-induced apoptosis causes severe immune dysregulation. In familial hemophagocytic lymphohistiocytosis, Prf-deficient infants suffer a fatal “cytokine storm” resulting from macrophage overactivation, but the link to failed target cell death is not understood. We show that prolonged target cell survival greatly amplifies the quanta of inflammatory cytokines secreted by CTLs/NK cells and that interferon-γ (IFN-γ) directly invokes the activation and secondary overproduction of proinflammatory IL-6 from naive macrophages. Furthermore, using live cell microscopy to visualize hundreds of synapses formed between wild-type, Prf-null, or GzmA/B-null CTLs/NK cells and their targets in real time, we show that hypersecretion of IL-2, TNF, IFN-γ, and various chemokines is linked to failed disengagement of Prf- or Gzm-deficient lymphocytes from their targets, with mean synapse time increased fivefold, from ∼8 to >40 min. Surprisingly, the signal for detachment arose from the dying target cell and was caspase dependent, as delaying target cell death with various forms of caspase blockade also prevented their disengagement from fully competent CTLs/NK cells and caused cytokine hypersecretion. Our findings provide the cellular mechanism through which failed killing by lymphocytes causes systemic inflammation involving recruitment and activation of myeloid cells. PMID:25732304

  16. Analog model for light propagation in semiclassical gravity

    NASA Astrophysics Data System (ADS)

    Bessa, C. H. G.; De Lorenci, V. A.; Ford, L. H.

    2014-07-01

    We treat a model based upon nonlinear optics for the semiclassical gravitational effects of quantum fields upon light propagation. Our model uses a nonlinear material with a nonzero third order polarizability. Here a probe light pulse satisfies a wave equation containing the expectation value of the squared electric field. This expectation value depends upon the presence of lower frequency quanta, the background field, and modifies the effective index of refraction, and hence the speed of the probe pulse. If the mean squared electric field is positive, then the pulse is slowed, which is analogous to the gravitational effects of ordinary matter. Such matter satisfies the null energy condition and produces gravitational lensing and time delay. If the mean squared field is negative, then the pulse has a higher speed than in the absence of the background field. This is analogous to the gravitational effects of exotic matter, such as stress tensor expectation values with locally negative energy densities, which lead to repulsive gravitational effects, such as defocusing and time advance. We give some estimates of the magnitude of the effects in our model and find that they may be large enough to be observable. We also briefly discuss the possibility that the mean squared electric field could be produced by the Casimir vacuum near a reflecting boundary.

  17. Gravity waves and non-Gaussian features from particle production in a sector gravitationally coupled to the inflaton

    NASA Astrophysics Data System (ADS)

    Barnaby, Neil; Moxon, Jordan; Namba, Ryo; Peloso, Marco; Shiu, Gary; Zhou, Peng

    2012-11-01

    We study the possibility that particle production during inflation could source observable gravity waves on scales relevant for cosmic microwave background experiments. A crucial constraint on such scenarios arises because particle production can also source inflaton perturbations and might ruin the usual predictions for a nearly scale-invariant spectrum of nearly Gaussian curvature fluctuations. To minimize this effect, we consider two models of particle production in a sector that is only gravitationally coupled to the inflaton. For a single instantaneous burst of massive particle production, we find that localized features in the scalar spectrum and bispectrum might be observable, but gravitational wave signatures are unlikely to be detectable (due to the suppressed quadrupole moment of nonrelativistic quanta) without invoking some additional effects. We also consider a model with a rolling pseudoscalar that leads to a continuous production of relativistic gauge field fluctuations during inflation. Here we find that gravitational waves from particle production can actually exceed the usual inflationary vacuum fluctuations in a regime where non-Gaussianity is consistent with observational limits. In this model observable B-mode polarization can be obtained for any choice of inflaton potential, and the amplitude of the signal is not necessarily correlated with the scale of inflation.

  18. Broadband Photoreceptors Are Involved in Violet Light Preference in the Parasitoid Fly Exorista Japonica

    PubMed Central

    Tokushima, Yoshiaki; Uehara, Takuya; Yamaguchi, Terumi; Arikawa, Kentaro; Kainoh, Yooichi

    2016-01-01

    Phototaxis has been described in many insects, which are often attracted to specific wavelengths of light. However, little is known about phototaxis in parasitoid insect species that are potentially useful for integrated pest management. In this study, we investigated the wavelength dependency of the phototactic behavior of the parasitoid fly Exorista japonica and its possible mechanism. Multiple-choice tests with six monochromatic stimuli revealed that the flies were specifically attracted to violet light peaking at 405 nm, which was unexpected because insects are generally attracted to ultraviolet or green light. We measured the spectral sensitivity of the compound eye, and found that the sensitivity peaked at 340 nm, as in other brachyceran flies. We used statistical modeling and optimization of the process parameters to predict the type of photoreceptor contributing to the violet preference. The analysis revealed that the wavelength preference could be explained by linear models of the quanta received by photoreceptors, including the R1-6 broadband receptors. The broadband receptors appear to contribute positively, whereas the R7-8 narrowband receptors contribute negatively to achieve the violet preference; i.e., spectral opponency might be involved. PMID:27532635

  19. Quantum information to the home

    NASA Astrophysics Data System (ADS)

    Choi, Iris; Young, Robert J.; Townsend, Paul D.

    2011-06-01

    Information encoded on individual quanta will play an important role in our future lives, much as classically encoded digital information does today. Combining quantum information carried by single photons with classical signals encoded on strong laser pulses in modern fibre-to-the-home (FTTH) networks is a significant challenge, the solution to which will facilitate the global distribution of quantum information to the home and with it a quantum internet [1]. In real-world networks, spontaneous Raman scattering in the optical fibre would induce crosstalk between the high-power classical channels and a single-photon quantum channel, such that the latter is unable to operate. Here, we show that the integration of quantum and classical information on an FTTH network is possible by performing quantum key distribution (QKD) on a network while simultaneously transferring realistic levels of classical data. Our novel scheme involves synchronously interleaving a channel of quantum data with the Raman scattered photons from a classical channel, exploiting the periodic minima in the instantaneous crosstalk and thereby enabling secure QKD to be performed.

  20. A compact digital time differential perturbed angular correlation-spectrometer using field programmable gate arrays and various timestamp algorithms.

    PubMed

    Jäger, Markus; Iwig, Kornelius; Butz, Tilman

    2011-06-01

    A user-friendly fully digital time differential perturbed angular correlation (TDPAC)-spectrometer with six detectors and fast digitizers using field programmable gate arrays (FPGA) is described and performance data are given. The new spectrometer has an online data analysis feature, a compact size, and a time resolution such as conventional analog spectrometers. Its calculation intensive part was implemented inside the digitizer. This gives the possibility to change parameters (energy windows, constant fraction trigger delay) and see their influence immediately in the γ-γ correlation diagrams. Tests were performed which showed that the time resolution using a (60)Co source with energy window set at 1.17 MeV and 1.33 MeV is 265 ps with LaBr(3)(Ce) scintillators and 254 ps with BaF(2) scintillators. A true constant fraction algorithm turned out to be slightly better than the constant fraction of amplitude method. The spectrometer performance was tested with a TDPAC measurement using a (44)Ti in rutile source and a positron lifetime measurement using (22)Na. The maximum possible data rate of the spectrometer is 1.1 × 10(6) γ quanta per detector and second. PMID:21721728

  1. A compact digital time differential perturbed angular correlation-spectrometer using field programmable gate arrays and various timestamp algorithms

    SciTech Connect

    Jaeger, Markus; Butz, Tilman; Iwig, Kornelius

    2011-06-15

    A user-friendly fully digital time differential perturbed angular correlation (TDPAC)-spectrometer with six detectors and fast digitizers using field programmable gate arrays (FPGA) is described and performance data are given. The new spectrometer has an online data analysis feature, a compact size, and a time resolution such as conventional analog spectrometers. Its calculation intensive part was implemented inside the digitizer. This gives the possibility to change parameters (energy windows, constant fraction trigger delay) and see their influence immediately in the {gamma}-{gamma} correlation diagrams. Tests were performed which showed that the time resolution using a {sup 60}Co source with energy window set at 1.17 MeV and 1.33 MeV is 265 ps with LaBr{sub 3}(Ce) scintillators and 254 ps with BaF{sub 2} scintillators. A true constant fraction algorithm turned out to be slightly better than the constant fraction of amplitude method. The spectrometer performance was tested with a TDPAC measurement using a {sup 44}Ti in rutile source and a positron lifetime measurement using {sup 22}Na. The maximum possible data rate of the spectrometer is 1.1 x 10{sup 6} {gamma} quanta per detector and second.

  2. Non-contact friction for ion-surface interactions

    NASA Astrophysics Data System (ADS)

    Jentschura, Ulrich D.; Lach, Grzegorz

    2015-05-01

    Non-contact friction forces are exerted on physical systems through dissipative processes, when the two systems are not in physical contact with each other, or, in quantum mechanical terms, when the overlap of their wave functions is negligible. Non-contact friction is mediated by the exchange of virtual quanta, with the additional requirement that the scattering process needs to have an inelastic component. For finite-temperature ion-surface interactions, the friction is essentially caused by Ohmic resistance due to the motion of the image charge moving in a dielectric material. A conceivable experiment is difficult because the friction force needs to be isolated from the interaction with the image charge, which significantly distorts the ion's flight path. We propose an experimental setup which is designed to minimize the influence of the image charge interaction though a compensation mechanism, and evaluate the energy loss due to non-contact friction for helium ions (He+) interacting with gold, vanadium, titanium and graphite surfaces. Interactions with the infinite series of mirror charges in the plates are summed in terms of the logarithmic derivatives of the Gamma function, and of the Hurwitz zeta function.

  3. Exploring Divisibility and Summability of 'Photon' Wave Packets in Nonlinear Optical Phenomena

    NASA Technical Reports Server (NTRS)

    Prasad, Narasimha; Roychoudhuri, Chandrasekhar

    2009-01-01

    Formulations for second and higher harmonic frequency up and down conversions, as well as multi photon processes directly assume summability and divisibility of photons. Quantum mechanical (QM) interpretations are completely congruent with these assumptions. However, for linear optical phenomena (interference, diffraction, refraction, material dispersion, spectral dispersion, etc.), we have a profound dichotomy. Most optical engineers innovate and analyze all optical instruments by propagating pure classical electromagnetic (EM) fields using Maxwell s equations and gives only lip-service to the concept "indivisible light quanta". Further, irrespective of linearity or nonlinearity of the phenomena, the final results are always registered through some photo-electric or photo-chemical effects. This is mathematically well modeled by a quadratic action (energy absorption) relation. Since QM does not preclude divisibility or summability of photons in nonlinear & multi-photon effects, it cannot have any foundational reason against these same possibilities in linear optical phenomena. It implies that we must carefully revisit the fundamental roots behind all light-matter interaction processes and understand the common origin of "graininess" and "discreteness" of light energy.

  4. Planar cone-beam computed tomography with a flat-panel detector

    NASA Astrophysics Data System (ADS)

    Kim, S. H.; Kim, D. W.; Youn, H.; Kim, D.; Kam, S.; Jeon, H.; Kim, H. K.

    2015-12-01

    For a dedicated x-ray inspection of printed-circuit boards (PCBs), a bench-top planar cone-beam computed tomography (pCT) system with a flat-panel detector has been built in the laboratory. The system adopts the tomosynthesis technique that can produce cross-sectional images parallel to the axis of rotation for a limited angular range. For the optimal operation of the system and further improvement in the next design, we have evaluated imaging performances, such as modulation-transfer function, noise-power spectrum, and noise-equivalent number of quanta. The performances are comparatively evaluated with the coventional cone-beam CT (CBCT) acquisition for various scanning angular ranges, applied tube voltages, and geometrical magnification factors. The pCT scan shows a poorer noise performance than the conventional CBCT scan because of less number of projection views used for reconstruction. However, the pCT shows a better spatial-resolution performance than the CBCT. Because the image noise can be compensated by an elevated exposure level during scanning, the pCT can be a useful modality for the PCB inspection that requires higher spatial-resolution performance.

  5. Logical operations with single x-ray photons via dynamically-controlled nuclear resonances

    PubMed Central

    Gunst, Jonas; Keitel, Christoph H.; Pálffy, Adriana

    2016-01-01

    Photonic qubits lie at the heart of quantum information technology, often encoding information in their polarization state. So far, only low-frequency optical and infrared photons have been employed as flying qubits, as the resources that are at present easiest to control. With their essentially different way of interacting with matter, x-ray qubits would bear however relevant advantages: they are extremely robust, penetrate deep through materials, and can be focused down to few-nm waveguides, allowing unprecedented miniaturization. Also, x-rays are resonant to nuclear transitions, which are very well isolated from the environment and present long coherence times. Here, we show theoretically that x-ray polarization qubits can be dynamically controlled by nuclear Mössbauer resonances. The control knob is played by nuclear hyperfine magnetic fields, that allow via fast rotations precise processing of single x-ray quanta polarization. With such rotations, single-qubit and binary logical operations such as a destructive C-NOT gate can be implemented. PMID:27118340

  6. On discrete symmetries for a whole Abelian model

    SciTech Connect

    Chauca, J.; Doria, R.

    2012-09-24

    Considering the whole concept applied to gauge theory a nonlinear abelian model is derived. A next step is to understand on the model properties. At this work, it will be devoted to discrete symmetries. For this, we will work based in two fields reference systems. This whole gauge symmetry allows to be analyzed through different sets which are the constructor basis {l_brace}D{sub {mu}},X{sup i}{sub {mu}}{r_brace} and the physical basis {l_brace}G{sub {mu}I}{r_brace}. Taking as fields reference system the diagonalized spin-1 sector, P, C, T and PCT symmetries are analyzed. They show that under this systemic model there are conservation laws driven for the parts and for the whole. It develops the meaning of whole-parity, field-parity and so on. However it is the whole symmetry that rules. This means that usually forbidden particles as pseudovector photons can be introduced through such whole abelian system. As result, one notices that the fields whole {l_brace}G{sub {mu}I}{r_brace} manifest a quanta diversity. It involves particles with different spins, masses and discrete quantum numbers under a same gauge symmetry. It says that without violating PCT symmetry different possibilities on discrete symmetries can be accommodated.

  7. High-energy limit of collision-induced false vacuum decay

    NASA Astrophysics Data System (ADS)

    Demidov, Sergei; Levkov, Dmitry

    2015-06-01

    We develop a consistent semiclassical description of field-theoretic collision-induced tunneling at arbitrary high collision energies. As a playground we consider a (1 + 1)-dimensional false vacuum decay initiated by a collision of N particles at energy E, paying special attention to the realistic case of N = 2 particles. We demonstrate that the cross section of this process is exponentially suppressed at all energies. Moreover, the respective suppressesion exponent F N ( E) exhibits a specific behavior which is significant for our semiclassical method and assumed to be general: it decreases with energy, reaches absolute minimum F = F min( N ) at a certain threshold energy E = E rt( N ), and stays constant at higher energies. We show that the minimal suppression F min( N ) and threshold energy can be evaluated using a special class of semiclassical solutions which describe exponentially suppressed transitions but nevertheless evolve in real time. Importantly, we argue that the cross section at energies above E rt( N ) is computed perturbatively in the background of the latter solutions, and the terms of this perturbative expansion stay bounded in the infinite-energy limit. Transitions in the high-energy regime proceed via emission of many soft quanta with total energy E rt; the energy excess E - E rt remains in the colliding particles till the end of the process.

  8. Optimization of LipL32 PCR assay for increased sensitivity in diagnosing leptospirosis.

    PubMed

    Galloway, Renee L; Hoffmaster, Alex R

    2015-07-01

    Early diagnosis of leptospirosis in humans is critical with regard to initiation of appropriate treatment; however, the gold standard serological test cannot detect antibodies until nearly a week after symptom onset. PCR has been shown to be sensitive and specific in the early phase of leptospirosis. Previously, we developed and validated a TaqMan PCR assay targeting lipL32. We reoptimized and validated this assay using PerfeCTa® qPCR ToughMix®, Low ROX™ (Quanta Biosciences, Gaithersburg, MD, USA). For optimization with the new mix, the final primer concentrations were increased from 0.5 μmol/L to 0.9 μmol/L compared to our previous assay, and the probe concentration increased from 0.1 μmol/L to 0.125 μmol/L. This newly optimized assay resulted in a lower limit of detection and increased diagnostic sensitivity. Here, we present the performance data of the improved assay and describe several clinical cases that were initially negative but tested positive using the optimized assay. PMID:25912810

  9. Vibrational ladder-climbing in surface-enhanced, ultrafast infrared spectroscopy.

    PubMed

    Kraack, Jan Philip; Hamm, Peter

    2016-06-28

    In a recent work (J. Phys. Chem. C 2016, 120, 3350-3359), we have introduced the concept of surface-enhanced, two-dimensional attenuated total reflectance (2D ATR IR) spectroscopy with modest enhancement factors (<50) using small plasmonic noble metal nanoparticles at solid-liquid interfaces. Here, we show that employment of almost continuous noble metal layers results in significantly stronger enhancement factors in 2D ATR IR signals (>450), which allows for multi-quantum IR excitation of adsorbed molecules, a process known as "vibrational ladder-climbing", even for weakly absorbing (ε < 200 M(-1) cm(-1)) nitrile IR labels. We show that it is possible to deposit up to four quanta of vibrational energy in the respective functional group. Based on these results, optical near-fields of plasmonic nanostructures may pave the way for future investigations involving ultrafast dynamics of highly excited vibrational states or surface-sensitive coherent control experiments of ground-state reactions at solid-liquid interfaces. PMID:27265518

  10. Nanostructures formed in pure quartz glass under irradiation in the reactor core

    NASA Astrophysics Data System (ADS)

    Ibragimova, E. M.; Mussaeva, M. A.; Kalanov, M. U.

    2014-04-01

    Optical spectroscopy and X-ray diffraction techniques were used for studying nanoscale particles grown in pure SiO2 glass under irradiation with fast neutron fluencies within 6×1016-5·1019 cm-2 and gamma-quanta ~1.8×1020 cm-2 in the reactor core in water. The neutron irradiation results in destroying of the initial α- and β-quartz mesoscopic order of 1.7 and 1.2 nm sizes and growing of cristobalite and tridymite nanocrystals of 16 and 8 nm sizes in the thermal peaks of displacements reapectively. The point defects (oxygen deficient E‧s, E'1, E'2 and non-bridging oxygen centers) induced by the γ-irradiation are accumulated in the nanocrystals shell of 0.65-0.85 nm thickness. Interaction of close point defects at the nanocrystal-glass interface causes the splitting of optical absorption bands into the intensive (D~2-4) resonances characteristic for local interband electron transitions, having the width of 10-15 nm close to the nanocrystals' sizes and the energy depending on their structure.

  11. First observation of {alpha} decay of {sup 190}Pt to the first excited level (E{sub exc}=137.2 keV) of {sup 186}Os

    SciTech Connect

    Belli, P.; Bernabei, R.; Cappella, F.; Cerulli, R.; Laubenstein, M.; Nisi, S.; Danevich, F. A.; Nagorny, S. S.; Polischuk, O. G.; Tretyak, V. I.; Incicchitti, A.

    2011-03-15

    The {alpha} decays of naturally occurring platinum isotopes, which are accompanied by the emission of {gamma} quanta, have been searched for deep underground (3600 m water equivalent) at the Gran Sasso National Laboratories of the INFN (Italy). A sample of Pt with a mass of 42.5 g and a natural isotopic composition has been measured with a low background HP Ge detector (468 cm{sup 3}) during 1815 h. The {alpha} decay of {sup 190}Pt to the first excited level of {sup 186}Os (J{sup {pi}}=2{sup +}, E{sub exc}=137.2 keV) has been observed for the first time, with the half-life determined as T{sub 1/2}=2.6{sub -0.3}{sup +0.4}(stat.){+-}0.6(syst.)x10{sup 14} yr. The T{sub 1/2} limits for the {alpha} decays of other Pt isotopes have been determined at the level of T{sub 1/2}{approx_equal}10{sup 16}-10{sup 20} yr. These limits have been set for the first time or they are better than those known from earlier experiments.

  12. Spontaneous emission effects in optically pumped x-ray FEL

    SciTech Connect

    Smetanin, I.V.; Grigor`ev, S.V.

    1995-12-31

    An effect of spontaneous emission in both quantum and classical regimes of the optically pumped X-ray free electron laser (FEL) in investigated. The quantum properties of an FEL are determined by the ratio of the separation {h_bar} between the absorption and emission lines (i.e. the quanta emitted) and their effective width {Delta}{epsilon} {eta}={h_bar}/{Delta}{epsilon}. In the conventional classical regime {eta} {much_lt} 1 an electron emits and absorbes a great number of shortwavelength photons over the interaction region, the gain in FEL being the result of these competitive processes. In the quantum limit {eta} {much_gt} 1 the emission and absorption lines are completely separated and thus the FEL becomes a two-level quantum oscillator with a completely inverted active medium. Spontaneous emission causes the electron to leave the range of energies where resonant interaction with the laser field occurs, thus effectively reducing the number of particles that take part in generating the induced X-ray signal. This effect is found to be crucial for lasing in optically pumped X-ray FEL. The characteristic relaxation times are calculated for both classical and quantum FEL regimes. It is shown that spontaneous emission results in FEL electron beam threshold current, which is of rather high value. An optimal range of pumping laser intensities is determined.

  13. Parallel adaptive wavelet collocation method for PDEs

    SciTech Connect

    Nejadmalayeri, Alireza; Vezolainen, Alexei; Brown-Dymkoski, Eric; Vasilyev, Oleg V.

    2015-10-01

    A parallel adaptive wavelet collocation method for solving a large class of Partial Differential Equations is presented. The parallelization is achieved by developing an asynchronous parallel wavelet transform, which allows one to perform parallel wavelet transform and derivative calculations with only one data synchronization at the highest level of resolution. The data are stored using tree-like structure with tree roots starting at a priori defined level of resolution. Both static and dynamic domain partitioning approaches are developed. For the dynamic domain partitioning, trees are considered to be the minimum quanta of data to be migrated between the processes. This allows fully automated and efficient handling of non-simply connected partitioning of a computational domain. Dynamic load balancing is achieved via domain repartitioning during the grid adaptation step and reassigning trees to the appropriate processes to ensure approximately the same number of grid points on each process. The parallel efficiency of the approach is discussed based on parallel adaptive wavelet-based Coherent Vortex Simulations of homogeneous turbulence with linear forcing at effective non-adaptive resolutions up to 2048{sup 3} using as many as 2048 CPU cores.

  14. Polarisation-based coincidence event discrimination: an in silico study towards a feasible scheme for Compton-PET

    NASA Astrophysics Data System (ADS)

    Toghyani, M.; Gillam, J. E.; McNamara, A. L.; Kuncic, Z.

    2016-08-01

    Current positron emission tomography (PET) systems use temporally localised coincidence events discriminated by energy and time-of-flight information. The two annihilation photons are in an entangled polarisation state and, in principle, additional information from the polarisation correlation of photon pairs could be used to improve the accuracy of coincidence classification. In a previous study, we demonstrated that in principle, the polarisation correlation information could be transferred to an angular correlation in the distribution of scattered photon pairs in a planar Compton camera system. In the present study, we model a source-phantom-detector system using Geant4 and we develop a coincidence classification scheme that exploits the angular correlation of scattered annihilation quanta to improve the accuracy of coincidence detection. We find a 22% image quality improvement in terms of the peak signal-to-noise ratio when scattered coincidence events are discriminated solely by their angular correlation, thus demonstrating the feasibility of this novel classification scheme. By integrating scatter events (both single-single and single-only) with unscattered coincidence events discriminated using conventional methods, our results suggest that Compton-PET may be a promising candidate for optimal emission tomographic imaging.

  15. The influence of translational and vibrational energy on the reaction of Cl with CH{sub 3}D

    SciTech Connect

    Berke, Andrew E.; Volpa, Ethan H.; Annesley, Christopher J.; Crim, F. Fleming

    2013-06-14

    The reaction of Cl atoms with CH{sub 3}D proceeds either by abstraction of hydrogen to produce HCl + CH{sub 2}D or by abstraction of deuterium to produce DCl + CH{sub 3}. Using Cl atoms with different amounts of translational energy, produced by photolysis of Cl{sub 2} with 309, 355, or 416 nm light, reveals the influence of translational energy on the relative reaction probability for the two channels. These measurements give an estimate of the energy barrier for the reaction for comparison to theory and indicate that tunneling is the dominant reaction mechanism at low collision energies. Adding two quanta of C-H stretching vibration causes the reaction to proceed readily at all collision energies. Detecting the vibrational state of the CH{sub 2}D product shows that vibrational energy initially in the surviving C-H bond appears as vibrational excitation of the product, an example of spectator behavior in the reaction. The reaction produces both stretch and stretch-bend excited products except at the lowest collision energy. A subtle variation in the reaction probability of the lowest energy rotational states with translational energy may reflect the presence of a van der Waals well in the entrance channel.

  16. Toward a scalable quantum computing architecture with mixed species ion chains

    NASA Astrophysics Data System (ADS)

    Wright, John; Auchter, Carolyn; Chou, Chen-Kuan; Graham, Richard D.; Noel, Thomas W.; Sakrejda, Tomasz; Zhou, Zichao; Blinov, Boris B.

    2016-01-01

    We report on progress toward implementing mixed ion species quantum information processing for a scalable ion-trap architecture. Mixed species chains may help solve several problems with scaling ion-trap quantum computation to large numbers of qubits. Initial temperature measurements of linear Coulomb crystals containing barium and ytterbium ions indicate that the mass difference does not significantly impede cooling at low ion numbers. Average motional occupation numbers are estimated to be bar{n} ≈ 130 quanta per mode for chains with small numbers of ions, which is within a factor of three of the Doppler limit for barium ions in our trap. We also discuss generation of ion-photon entanglement with barium ions with a fidelity of F ≥ 0.84 , which is an initial step towards remote ion-ion coupling in a more scalable quantum information architecture. Further, we are working to implement these techniques in surface traps in order to exercise greater control over ion chain ordering and positioning.

  17. Semiclassical S-matrix for black holes

    DOE PAGESBeta

    Bezrukov, Fedor; Levkov, Dmitry; Sibiryakov, Sergey

    2015-12-01

    In this study, we propose a semiclassical method to calculate S-matrix elements for two-stage gravitational transitions involving matter collapse into a black hole and evaporation of the latter. The method consistently incorporates back-reaction of the collapsing and emitted quanta on the metric. We illustrate the method in several toy models describing spherical self-gravitating shells in asymptotically flat and AdS space-times. We find that electrically neutral shells reflect via the above collapse-evaporation process with probability exp(–B), where B is the Bekenstein-Hawking entropy of the intermediate black hole. This is consistent with interpretation of exp(B) as the number of black hole states.more » The same expression for the probability is obtained in the case of charged shells if one takes into account instability of the Cauchy horizon of the intermediate Reissner-Nordström black hole. As a result, our semiclassical method opens a new systematic approach to the gravitational S-matrix in the non-perturbative regime.« less

  18. Holographic generation of highly twisted electron beams.

    PubMed

    Grillo, Vincenzo; Gazzadi, Gian Carlo; Mafakheri, Erfan; Frabboni, Stefano; Karimi, Ebrahim; Boyd, Robert W

    2015-01-23

    Free electrons can possess an intrinsic orbital angular momentum, similar to those in an electron cloud, upon free-space propagation. The wave front corresponding to the electron's wave function forms a helical structure with a number of twists given by the angular speed. Beams with a high number of twists are of particular interest because they carry a high magnetic moment about the propagation axis. Among several different techniques, electron holography seems to be a promising approach to shape a conventional electron beam into a helical form with large values of angular momentum. Here, we propose and manufacture a nanofabricated phase hologram for generating a beam of this kind with an orbital angular momentum up to 200ℏ. Based on a novel technique the value of orbital angular momentum of the generated beam is measured and then compared with simulations. Our work, apart from the technological achievements, may lead to a way of generating electron beams with a high quanta of magnetic moment along the propagation direction and, thus, may be used in the study of the magnetic properties of materials and for manipulating nanoparticles. PMID:25659003

  19. Could quantum gravity phenomenology be tested with high intensity lasers?

    SciTech Connect

    Magueijo, Joao

    2006-06-15

    In phenomenological quantum gravity theories, Planckian behavior is triggered by the energy of elementary particles approaching the Planck energy, E{sub P}, but it is also possible that anomalous behavior strikes systems of particles with total energy near E{sub P}. This is usually perceived to be pathological and has been labeled 'the soccer ball problem'. We point out that there is no obvious contradiction with experiment if coherent collections of particles with bulk energy of order E{sub P} do indeed display Planckian behavior, a possibility that would open a new experimental window. Unfortunately, field theory realizations of 'doubly' (or deformed) special relativity never exhibit a soccer ball problem; we present several formulations where this is undeniably true. Upon closer scrutiny we discover that the only chance for Planckian behavior to be triggered by large coherent energies involves the details of second quantization. We find a formulation where the quanta have their energy-momentum (mass-shell) relations deformed as a function of the bulk energy of the coherent packet to which they belong, rather than the frequency. Given ongoing developments in laser technology, such a possibility would be of great experimental interest.

  20. Generating and manipulating quantized vortices on-demand in a Bose-Einstein condensate: A numerical study

    NASA Astrophysics Data System (ADS)

    Gertjerenken, B.; Kevrekidis, P. G.; Carretero-González, R.; Anderson, B. P.

    2016-02-01

    We numerically investigate an experimentally viable method for generating and manipulating on-demand several vortices in a highly oblate atomic Bose-Einstein condensate (BEC) in order to initialize complex vortex distributions for studies of vortex dynamics. The method utilizes moving laser beams to generate, capture, and transport vortices inside and outside the BEC. We examine in detail this methodology and show a wide parameter range of applicability for the prototypical two-vortex case, as well as case examples of producing and manipulating several vortices for which there is no net circulation, corresponding to equal numbers of positive and negative circulation vortices, and cases for which there is one net quantum of circulation. We find that the presence of dissipation can help stabilize the pinning of the vortices on their respective laser beam pinning sites. Finally, we illustrate how to utilize laser beams as repositories that hold large numbers of vortices and how to deposit individual vortices in a sequential fashion in the repositories in order to construct superfluid flows about the repository beams with several quanta of circulation.

  1. Magnetic field-induced helical mode and topological transitions in a topological insulator nanoribbon.

    PubMed

    Jauregui, Luis A; Pettes, Michael T; Rokhinson, Leonid P; Shi, Li; Chen, Yong P

    2016-04-01

    The spin-helical Dirac fermion topological surface states in a topological insulator nanowire or nanoribbon promise novel topological devices and exotic physics such as Majorana fermions. Here, we report local and non-local transport measurements in Bi2Te3 topological insulator nanoribbons that exhibit quasi-ballistic transport over ∼2 μm. The conductance versus axial magnetic flux Φ exhibits Aharonov-Bohm oscillations with maxima occurring alternately at half-integer or integer flux quanta (Φ0 = h/e, where h is Planck's constant and e is the electron charge) depending periodically on the gate-tuned Fermi wavevector (kF) with period 2π/C (where C is the nanoribbon circumference). The conductance versus gate voltage also exhibits kF-periodic oscillations, anti-correlated between Φ = 0 and Φ0/2. These oscillations enable us to probe the Bi2Te3 band structure, and are consistent with the circumferentially quantized topological surface states forming a series of one-dimensional subbands, which undergo periodic magnetic field-induced topological transitions with the disappearance/appearance of the gapless Dirac point with a one-dimensional spin helical mode. PMID:26780658

  2. Minimum Energy Requirements for Sustained Microbial Activity in Anoxic Sediments

    NASA Technical Reports Server (NTRS)

    Hoehler, Tori M.; Alperin, Marc J.; Albert, Daniel B.; Martens, Christoper S.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    Currently understood mechanisms of biochemical energy conservation dictate that, in order to be biologically useful, energy must be available to organisms in "quanta" equal to, at minimum one-third to one-fifth of the energy required to synthesize ATP in vivo. The existence of this biological energy quantum means that a significant fraction of the chemical amp on Earth cannot be used to drive biological productivity, and places a fundamental thermodynamic constraint on the origins, evolution, and distribution of life. We examined the energy requirements of intact microbial assemblages in anoxic sediments from Cape Lookout Bight, NC, USA, using dissolved hydrogen concentrations as a non-invasive probe. In this system, the thermodynamics of metabolic processes occurring inside microbial cells is reflected quantitatively by H2 concentrations measured outside those cells. We find that methanogenic archaea are supported by energy yields as small as 10 kJ per mol, about half the quantity calculated from studies of microorganisms in culture. This finding implies that a significantly broader range of geologic and chemical niches might be exploited by microorganisms than would otherwise be expected.

  3. Surface Microstructure Modification in Square Extruded Al-Nb Powder Composites by Shot Peening

    NASA Astrophysics Data System (ADS)

    Brokmeier, Heinz-Günter; Avalos, Martina C.; Bolmaro, Raúl E.; Maawad, Emad

    2014-08-01

    75%Al-25%Nb powder composites, fabricated by square shape cold extrusion, were subject to shot peening treatment with full coverage. Shot peening results in a high number of intense local deformations, with a surface roughness in our case of about l6gm. Due to the high local deformation down to nano-scale surface grain refinement and strain accumulation was generated. Previous texture characterization was performed by neutron diffraction and laboratory X-rays (Cu Kα radiation). The first method took advantage of the high penetration power and averaging capabilities and the second method was further used taking advantage of the low penetration to characterize surface microstructure modification. Peak broadening, before and after shot peening, was analyzed by MAUD software and domain sizes and microstrains were calculated for both phases. Simultaneous EBSD and EDS scans, on 30 nm step sizes, were performed on a FESEM Quanta 200 + TSL-EDAX, showing the highly heterogeneous microstructure developed because of shot peening. Protrusions, due to particle impacts, are clearly seen on EBSD maps. Results mainly revealed that, for Al phase, domain sizes decrease, while microstrains and dislocation densities consistently increase after the materials have been subjected to SP. For Nb phase the visible effect of SP is an increment of microstrains, and related dislocation densities, but keeping the domain sizes almost constant.

  4. Magnon drag thermopile

    NASA Astrophysics Data System (ADS)

    Valenzuela, Sergio O.

    2013-03-01

    Thermoelectric effects in spintronics are gathering increasing attention as a means of controlling spin information by using heat flow. Thermal magnons (spin-wave quanta) are expected to play a major role, however, the coupling between electrons and magnons in ferromagnetic metals remains poorly understood. We demonstrate a conceptually new device that enables us to gather information on magnon-electron scattering and magnon-drag effects. The device resembles a thermopile formed by a large number of pairs of ferromagnetic wires placed between a hot and a cold source and connected thermally in parallel and electrically in series. By controlling the relative orientation of the magnetization in pairs of wires, the magnon drag can be studied independently of the electron and phonon drag thermoelectric effects. Measurements as a function of temperature reveal the effect on magnon drag following a variation of magnon and phonon populations. These results demonstrate the feasibility of directly converting magnon dynamics of nanomagnets into an electrical signal and could pave the way to novel thermoelectric devices for energy harvesting. This research was supported by the Spanish Ministerio de Ciencia e Innovación, MICINN (MAT2010-18065) and by the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement NANOFUNCTION no 257375.

  5. [Cytogenetic damage to the corneal epithelium of mice due to the in vivo exposure to ionizing radiation with different levels of linear energy transfer].

    PubMed

    Vorozhtsova, S V; Bulynina, T M; Molokanov, A G; Ivanov, A A

    2015-01-01

    Damages to corneal epithelium cells were studied in mice irradiated by protons with the energies of 10, 25, 50 and 645 MeV, 60Co γ-quanta and accelerated ions of boron, carbon and neon with the energies of 7.5; 2.5 and 6.0 MeV/nucleon, respectively. X-rays (180 keV) were used as a standard radiation. Animals were exposed to a single dose in the range from 25 to 760 cGy. The mitotic index and aberrant mitoses were counted in corneal preparations in 24 hrs after irradiation. No matter the type of radiation, the mitotic index had an inverse dose dependence, i.e. the higher the dose, the lower the mitotic index. Exposure to all types of radiation resulted in a sharp increase in the number of chromosomal aberrations in the corneal epithelium; frequency of aberrations was a function of dose and type of radiation. The number of chromosomal aberrations displayed a peculiar direct dose dependence irrespective of type of radiation; however, heavy ions of carbon and boron are the most damaging to the cytogenetic apparatus of epithelial cells. Protons at the Bragg peak and ensuing fall, and of 50 MeV also contribute to the production of chromosomal aberrations as compared with sparsely ionizing gamma- and X-rays and high-energy protons with low linear energy transfer. Coefficients of relative biological effectiveness were calculated based on the mitotic index and evidence of aberrant mitosis. PMID:25958467

  6. Threshold Electron-Molecule Attachment at Sub-meV Resolution

    NASA Astrophysics Data System (ADS)

    Kortyna, A.; Darrach, M.; Chutjian, A.

    1998-05-01

    The technique of rare-gas photoionization is used to study the attachment of electrons to SF6 at near-threshold energies. Tunable ultraviolet light ( ~ 276 nm), produced using standard pulsed laser and nonlinear mixing techniques, is frequency triple in a free jet of xenon. The resulting vacuum ultraviolet radiation ( ~ 92 nm) ionizes xenon near its ^2 P_1/2 threshold. Subsequent photoelectrons, characterized by a very narrow energy distribution of δ ɛ<0.5 meV with ɛ<100 meV, interact with SF6 in a 4 π steradian scattering arrangement. The Wigner threshold law is tested at low energies. As expected, the electron attachment cross section shows an approximate ɛ-1/2 dependence for 0< ɛ C 45 meV. At ɛ ≈ 45 meV, however, a steep drop in the attachment cross section reveals the opening of a previously unobserved inelastic channel associated with one quanta of the ω6 vibrational mode of SF6 predicted to occur at ɛ = 44 meV. Future investigations into the behavior of the electron attachment cross section near-threshold are planned. This work was carried out at JPL/Caltech and supported through agreement with NASA.

  7. The nerve-muscle synapse of the garter snake.

    PubMed

    Wilkinson, Robert S; Teng, Haibing

    2003-01-01

    Snake nerve-muscle preparations are well-suited for study of both motor innervation patterns at the systems level and NMJ function at the cellular level. Their small size ( approximately 100 myofibers) and thinness (one fiber) allows access to all NMJs in one muscle. Snake NMJs are of three types, two twitch subtypes and a single tonic type. Properties of the NMJs supplied by a particular motor neuron, and of the motor unit fibers they innervate, are precisely regulated by the motor neuron in a manner consistent with the Henneman Size Principle. Unlike its amphibian or mammalian cousins, the snake NMJ comprises approximately 50 (twitch) or approximately 20 (tonic) individual one-bouton synapses, similar to synapses found in the central nervous system. Each bouton releases a few quanta per stimulus. Larger fibers, which require more synaptic current to initiate contraction, receive nerve terminals that contain more boutons and express receptor patches with higher sensitivity to transmitter. Quantal analysis suggests that transmitter release sites in one bouton do not behave independently; rather, they may cooperate to reduce fluctuations and enhance reliability. After release, two mechanisms coexist for retrieval and reprocessing of spent vesicles-one involving clathrin-mediated endocytosis, the other macropinocytosis. Unanswered questions include how each mechanism is regulated in a use-dependent manner. PMID:15034251

  8. Computer Simulation Of Radiographic Screen-Film Images

    NASA Astrophysics Data System (ADS)

    Metter, Richard V.; Dillon, Peter L.; Huff, Kenneth E.; Rabbani, Majid

    1986-06-01

    A method is described for computer simulation of radiographic screen-film images. This method is based on a previously published model of the screen-film imaging process.l The x-ray transmittance of a test object is sampled at a pitch of 50 μm by scanning a high-resolution, low-noise direct-exposure radiograph. This transmittance is then used, along with the x-ray exposure incident upon the object, to determine the expected number of quanta per pixel incident upon the screen. The random nature of x-ray arrival and absorption, x-ray quantum to light photon conversion, and photon absorption by the film is simulated by appropriate random number generation. Standard FFT techniques are used for computing the effects of scattering. Finally, the computed film density for each pixel is produced on a high-resolution, low-noise output film by a scanning printer. The simulation allows independent specification of x-ray exposure, x-ray quantum absorption, light conversion statistics, light scattering, and film characteristics (sensitometry and gran-ularity). Each of these parameters is independently measured for radiographic systems of interest. The simulator is tested by comparing actual radiographic images with simulated images resulting from the independently measured parameters. Images are also shown illustrating the effects of changes in these parameters on image quality. Finally, comparison is made with a "perfect" imaging system where information content is only limited by the finite number of x-rays.

  9. Spectral transfers and zonal flow dynamics in the generalized Charney-Hasegawa-Mima model

    SciTech Connect

    Lashmore-Davies, C.N.; Thyagaraja, A.; McCarthy, D.R.

    2005-12-15

    The mechanism of four nonlinearly interacting drift or Rossby waves is used as the basic process underlying the turbulent evolution of both the Charney-Hasegawa-Mima-equation (CHME) and its generalized modification (GCHME). Hasegawa and Kodama's concept of equivalent action (or quanta) is applied to the four-wave system and shown to control the distribution of energy and enstrophy between the modes. A numerical study of the GCHME is described in which the initial state contains a single finite-amplitude drift wave (the pump wave), and all the modulationally unstable modes are present at the same low level (10{sup -6} times the pump amplitude). The simulation shows that at first the fastest-growing modulationally unstable modes dominate but reveals that at a later time, before pump depletion occurs, long- and short-wavelength modes, driven by pairs of fast-growing modes, grow at 2{gamma}{sub max}. The numerical simulation illustrates the development of a spectrum of turbulent modes from a finite-amplitude pump wave.

  10. Non-classical correlations between single photons and phonons from a mechanical oscillator.

    PubMed

    Riedinger, Ralf; Hong, Sungkun; Norte, Richard A; Slater, Joshua A; Shang, Juying; Krause, Alexander G; Anant, Vikas; Aspelmeyer, Markus; Gröblacher, Simon

    2016-02-18

    Interfacing a single photon with another quantum system is a key capability in modern quantum information science. It allows quantum states of matter, such as spin states of atoms, atomic ensembles or solids, to be prepared and manipulated by photon counting and, in particular, to be distributed over long distances. Such light-matter interfaces have become crucial to fundamental tests of quantum physics and realizations of quantum networks. Here we report non-classical correlations between single photons and phonons--the quanta of mechanical motion--from a nanomechanical resonator. We implement a full quantum protocol involving initialization of the resonator in its quantum ground state of motion and subsequent generation and read-out of correlated photon-phonon pairs. The observed violation of a Cauchy-Schwarz inequality is clear evidence for the non-classical nature of the mechanical state generated. Our results demonstrate the availability of on-chip solid-state mechanical resonators as light-matter quantum interfaces. The performance we achieved will enable studies of macroscopic quantum phenomena as well as applications in quantum communication, as quantum memories and as quantum transducers. PMID:26779950

  11. Figure of Image Quality and Information Capacity in Digital Mammography

    PubMed Central

    Michail, Christos M.; Kalyvas, Nektarios E.; Valais, Ioannis G.; Fudos, Ioannis P.; Fountos, George P.; Dimitropoulos, Nikos; Kandarakis, Ioannis S.

    2014-01-01

    Objectives. In this work, a simple technique to assess the image quality characteristics of the postprocessed image is developed and an easy to use figure of image quality (FIQ) is introduced. This FIQ characterizes images in terms of resolution and noise. In addition information capacity, defined within the context of Shannon's information theory, was used as an overall image quality index. Materials and Methods. A digital mammographic image was postprocessed with three digital filters. Resolution and noise were calculated via the Modulation Transfer Function (MTF), the coefficient of variation, and the figure of image quality. In addition, frequency dependent parameters such as the noise power spectrum (NPS) and noise equivalent quanta (NEQ) were estimated and used to assess information capacity. Results. FIQs for the “raw image” data and the image processed with the “sharpen edges” filter were found 907.3 and 1906.1, correspondingly. The information capacity values were 60.86 × 103 and 78.96 × 103 bits/mm2. Conclusion. It was found that, after the application of the postprocessing techniques (even commercial nondedicated software) on the raw digital mammograms, MTF, NPS, and NEQ are improved for medium to high spatial frequencies leading to resolving smaller structures in the final image. PMID:24895593

  12. Energy flow along the medium-induced parton cascade

    NASA Astrophysics Data System (ADS)

    Blaizot, J.-P.; Mehtar-Tani, Y.

    2016-05-01

    We discuss the dynamics of parton cascades that develop in dense QCD matter, and contrast their properties with those of similar cascades of gluon radiation in vacuum. We argue that such cascades belong to two distinct classes that are characterized respectively by an increasing or a constant (or decreasing) branching rate along the cascade. In the former class, of which the BDMPS, medium-induced, cascade constitutes a typical example, it takes a finite time to transport a finite amount of energy to very soft quanta, while this time is essentially infinite in the latter case, to which the DGLAP cascade belongs. The medium induced cascade is accompanied by a constant flow of energy towards arbitrary soft modes, leading eventually to the accumulation of the initial energy of the leading particle at zero energy. It also exhibits scaling properties akin to wave turbulence. These properties do not show up in the cascade that develops in vacuum. There, the energy accumulates in the spectrum at smaller and smaller energy as the cascade develops, but the energy never flows all the way down to zero energy. Our analysis suggests that the way the energy is shared among the offsprings of a splitting gluon has little impact on the qualitative properties of the cascades, provided the kernel that governs the splittings is not too singular.

  13. The Hawking cascade from a black hole is extremely sparse

    NASA Astrophysics Data System (ADS)

    Gray, Finnian; Schuster, Sebastian; Van–Brunt, Alexander; Visser, Matt

    2016-06-01

    The average time between emission of subsequent quanta in the Hawking process is extremely large. While this sparsity result has been known for a long time, it is neither well-known, nor do (semi-)analytic results currently exist, the prior focus being placed on numerical results. We define several ways of quantifying this sparsity, and starting from a black body approximation for the Schwarzschild case, we derive analytic expressions for a lower bound on this average time. We also check the validity of the results in presence of greybody factors by numerical analysis. Furthermore, we show how to separate the super-radiance in the low-frequency regime from the genuine Hawking effect itself. This enables us to extend the previous lower bounds to Reissner-Nordström, Kerr and dirty black holes in addition to different particle species. Lastly, we want to draw attention to some of the physical consequences of this under-appreciated fact of the Hawking process.

  14. The high-resolution visible overtone spectrum of CH4 and CD3H at 77 K

    NASA Astrophysics Data System (ADS)

    Scherer, G. J.; Lehmann, Kevin K.; Klemperer, W.

    1984-12-01

    We have obtained visible overtone spectra with Doppler-limited resolution of methane and trideuteromethane in the vicinity of six quanta of C-H stretch. At room temperature, the methane spectrum is unresolved. Upon cooling to 77 K in a specially designed photoacoustic cell, methane shows a complicated but rotationally resolved spectrum. The widths of all features in the spectrum are consistent with Doppler broadened linewidths at 77 K. Efforts to assign this spectrum are in progress. The overtone spectrum of CD3H has been recently studied by other workers at a resolution of 0.5 cm-1 [Perry, Moll, Kupperman, and Zewail (preprint)]. The spectrum in this region consists of two parallel bands, one at 16 156 cm-1 and another at 16 230 cm-1. These are assigned as arising from a Fermi resonance between the pure C-H overtone 6ν1 and a combination with the degenerate C-H bend, 5ν1+2ν5. A high resolution spectrum taken at 77 K shows nearly completely resolved K-subband structure for both bands. The rotational constants of both states cannot be rationalized purely on the basis of the above vibrational assignment, although it is the most reasonable explanation of the observed vibrational spectrum. Our rotational analysis of the bands indicates that both of these states are in Coriolis resonance with another state or states which are not seen in our spectrum.

  15. Could quantum gravity phenomenology be tested with high intensity lasers?

    NASA Astrophysics Data System (ADS)

    Magueijo, João

    2006-06-01

    In phenomenological quantum gravity theories, Planckian behavior is triggered by the energy of elementary particles approaching the Planck energy, EP, but it is also possible that anomalous behavior strikes systems of particles with total energy near EP. This is usually perceived to be pathological and has been labeled “the soccer ball problem.” We point out that there is no obvious contradiction with experiment if coherent collections of particles with bulk energy of order EP do indeed display Planckian behavior, a possibility that would open a new experimental window. Unfortunately, field theory realizations of “doubly” (or deformed) special relativity never exhibit a soccer ball problem; we present several formulations where this is undeniably true. Upon closer scrutiny we discover that the only chance for Planckian behavior to be triggered by large coherent energies involves the details of second quantization. We find a formulation where the quanta have their energy-momentum (mass-shell) relations deformed as a function of the bulk energy of the coherent packet to which they belong, rather than the frequency. Given ongoing developments in laser technology, such a possibility would be of great experimental interest.

  16. Monte-Carlo simulation of the kinetics of nuclear and radiative processes upon fast ignition of the fusion target in a `double liner' system

    NASA Astrophysics Data System (ADS)

    Andreev, Aleksandr A.; Gus'kov, Sergei Yu; Zakharov, S. V.; Il'in, Dmitrii V.; Levkovskii, Aleksei A.; Platonov, Konstantin Yu; Rozanov, Vladislav B.; Sherman, Vladimir E.

    2004-05-01

    A laser ignition scheme is considered for a fusion target placed in the cavity of a radiating plasma liner produced in a `double liner' system. It is shown that this scheme can be employed to realise an efficient thermonuclear burst. The precompression and heating of a deuterium — tritium target with an iron shell by a thermal radiation pulse was simulated using the TRITON mathematical code for the parameters of the Z-generator at the Sandia National Laboratories (USA). Laser and target parameters were optimised for the ignition of the deuterium — tritium fuel by protons accelerated by laser radiation. The propagation of the thermonuclear burning wave during the fast ignition was calculated employing the TERA mathematical code, which involves Monte-Carlo simulation of the kinetics of fast thermonuclear particles and hard gamma-ray quanta at each time step of hydrodynamic calculations. The dependence of the fusion energy gain G on the ignition energy is theoretically explained. The laser parameters required to obtain G gg 1 are determined.

  17. Nonequilibrium population of the first vibrational level of O{sub 2}({sup 1{Sigma}}) molecules in O{sub 2} - O{sub 2}({sup 1{Delta}}) - H{sub 2}O gas flow at the output of chemical singlet-oxygen generator

    SciTech Connect

    Zagidullin, M V

    2010-11-13

    The concentrations of electron-excited particles have been determined by measuring the absolute spectral irradiance in the range of 600 - 800 nm of O{sub 2} - O{sub 2}({sup 1{Delta}}) - H{sub 2}O gas mixture at the output of a chemical singlet-oxygen generator (SOG). A nonequilibrium population of the first vibrational level of O{sub 2}({sup 1{Sigma}}) molecules has been clearly observed and found to depend on the water vapour content. In correspondence with the results of these measurements and according to the analysis of kinetics processes in the O{sub 2} - O{sub 2}({sup 1{Delta}}) - H{sub 2}O mixture, the maximum number of vibrational quanta generated in the O{sub 2}({sup 1{Delta}}) + O{sub 2}({sup 1{Delta}}) {yields} O{sub 2}({sup 1{Sigma}}) + O{sub 2}({sup 3{Sigma}}) reaction is 0.05 {+-} 0.03. It is concluded that the vibrational population of O{sub 2}({sup 1{Delta}}) at the output of the SOG used in a chemical oxygen-iodine laser is close to thermal equilibrium value. (active media)

  18. Energy transfer efficiency in the chromophore network strongly coupled to a vibrational mode

    NASA Astrophysics Data System (ADS)

    Mourokh, Lev G.; Nori, Franco

    2015-11-01

    Using methods from condensed matter and statistical physics, we examine the transport of excitons through the photosynthetic complex from a receiving antenna to a reaction center. Writing the equations of motion for the exciton creation-annihilation operators, we are able to describe the exciton dynamics, even in the regime when the reorganization energy is of the order of the intrasystem couplings. We determine the exciton transfer efficiency in the presence of a quenching field and protein environment. While the majority of the protein vibrational modes are treated as a heat bath, we address the situation when specific modes are strongly coupled to excitons and examine the effects of these modes on the energy transfer efficiency in the steady-state regime. Using the structural parameters of the Fenna-Matthews-Olson complex, we find that, for vibrational frequencies below 16 meV, the exciton transfer is drastically suppressed. We attribute this effect to the formation of a "mixed exciton-vibrational mode" where the exciton is transferred back and forth between the two pigments with the absorption or emission of vibrational quanta, instead of proceeding to the reaction center. The same effect suppresses the quantum beating at the vibrational frequency of 25 meV. We also show that the efficiency of the energy transfer can be enhanced when the vibrational mode strongly couples to the third pigment only, instead of coupling to the entire system.

  19. Effect of hypertonicity on augmentation and potentiation and on corresponding quantal parameters of transmitter release.

    PubMed

    Cheng, H; Miyamoto, M D

    1999-03-01

    Augmentation and (posttetanic) potentiation are two of the four components comprising the enhanced release of transmitter following repetitive nerve stimulation. To examine the quantal basis of these components under isotonic and hypertonic conditions, we recorded miniature endplate potentials (MEPPs) from isolated frog (Rana pipiens) cutaneous pectoris muscles, before and after repetitive nerve stimulation (40 s at 80 Hz). Continuous recordings were made in low Ca2+ high Mg2+ isotonic Ringer solution, in Ringer that was made hypertonic with 100 mM sucrose, and in wash solution. Estimates were obtained of m (no. of quanta released), n (no. of functional release sites), p (mean probability of release), and vars p (spatial variance in p), using a method that employed MEPP counts. Hypertonicity abolished augmentation without affecting potentiation. There were prolonged poststimulation increases in m, n, and p and a marked but transient increase in vars p in the hypertonic solution. All effects were completely reversed with wash. The time constants of decay for potentiation and for vars p were virtually identical. The results are consistent with the notion that augmentation is caused by Ca2+ influx through voltage-gated calcium channels and that potentiation is due to Na+-induced Ca2+ release from mitochondria. The results also demonstrate the utility of this approach for analyzing the dynamics of quantal transmitter release. PMID:10085369

  20. Physics-based modeling of computed tomography systems

    NASA Astrophysics Data System (ADS)

    Youn, Hanbean; Kim, Ho Kyung; Kam, Soohwa; Kim, Seung Ho; Park, Ji Woong; Jeon, Hosang

    2015-03-01

    We present a theoretical framework describing projections obtained from computed tomography systems considering physics of each component consisting of the systems. The projection model mainly consists of the attenuation of x-ray photons through objects including x-ray scatter and the detection of attenuated/scattered x-ray photons at pixel detector arrays. X-ray photons are attenuated by the Beers-Lambert law and scattered by using the Klein-Nishina formula. The cascaded signal-transfer model for the detector includes x-ray photon detection and light photon conversion/spreading in scintillators, light photon detection in photodiodes, and the addition of electronic noise quanta. On the other hand, image noise is considered by re-distributing the pixel signals in pixel-by-pixel ways at each image formation stage using the proper distribution functions. Instead of iterating the ray tracing over each energy bin in the x-ray spectrum, we first perform the ray tracing for an object only considering the thickness of each component. Then, we assign energy-dependent linear attenuation coefficients to each component in the projected images. This approach reduces the computation time by a factor of the number of energy bins in the x-ray spectrum divided by the number of components in the object compared with the conventional ray-tracing method. All the methods developed in this study are validated in comparisons with the measurements or the Monte Carlo simulations.