Science.gov

Sample records for quanta

  1. 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

  2. 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

  3. QUANTA: An Interdisciplinary Learning Community (Four Studies).

    ERIC Educational Resources Information Center

    Avens, Cynthia; Zelley, Richard

    QUANTA is a year-long interdisciplinary program at Daytona Beach Community College (Florida) that seeks to establish a learning community of students and teachers. Three courses (English, Pyschology, and Humanities) are integrated around a common theme each semester of the freshman year, and are taught using a collaborative teaching model. This…

  4. 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.

  5. 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.

  6. 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.

  7. The Quanta Image Sensor: Every Photon Counts

    PubMed Central

    Fossum, Eric R.; Ma, Jiaju; Masoodian, Saleh; Anzagira, Leo; Zizza, Rachel

    2016-01-01

    The Quanta Image Sensor (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 1 Tb/s. Basically, we are trying to count photons as they arrive at the sensor. This paper reviews the QIS concept and its imaging characteristics. Recent progress towards realizing the QIS for commercial and scientific purposes is discussed. This includes implementation of a pump-gate jot device in a 65 nm CIS BSI process yielding read noise as low as 0.22 e− r.m.s. and conversion gain as high as 420 µV/e−, power efficient readout electronics, currently as low as 0.4 pJ/b in the same process, creating high dynamic range images from jot data, and understanding the imaging characteristics of single-bit and multi-bit QIS devices. The QIS represents a possible major paradigm shift in image capture. PMID:27517926

  8. The Quanta Image Sensor: Every Photon Counts.

    PubMed

    Fossum, Eric R; Ma, Jiaju; Masoodian, Saleh; Anzagira, Leo; Zizza, Rachel

    2016-01-01

    The Quanta Image Sensor (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 1 Tb/s. Basically, we are trying to count photons as they arrive at the sensor. This paper reviews the QIS concept and its imaging characteristics. Recent progress towards realizing the QIS for commercial and scientific purposes is discussed. This includes implementation of a pump-gate jot device in a 65 nm CIS BSI process yielding read noise as low as 0.22 e- r.m.s. and conversion gain as high as 420 µV/e-, power efficient readout electronics, currently as low as 0.4 pJ/b in the same process, creating high dynamic range images from jot data, and understanding the imaging characteristics of single-bit and multi-bit QIS devices. The QIS represents a possible major paradigm shift in image capture.

  9. Proving Light Quanta Exist in an Undergraduate Laboratory

    NASA Astrophysics Data System (ADS)

    Neel, M. S.; Thorn, J. J.; Davies, R. E.; Beck, M.

    2003-05-01

    While well known experiments involving phenomena such as the photoelectric effect and Compton scattering strongly suggest the existence of photons, they do not prove the existence of light quanta. For example, it is possible to explain both of the aforementioned effects using a semiclassical treatment in which the electromagnetic field is not quantized, and is instead treated as a classical wave. To prove the existence of light quanta one must perform an experiment whose results cannot be explained using classical waves. Here we have performed an experiment that cannot be explained with a classical wave theory, and which demonstrates the localization of light quanta. Namely, we prove that a single photon can only go one way when it leaves a beamsplitter. (P. Grangier, G. Roger and A. Aspect, Europhys. Lett. 1, 173 (1986).) The experimental apparatus is appropriate for an undergraduate teaching laboratory.

  10. Relativistic quantum channel of communication through field quanta

    SciTech Connect

    Cliche, M.; Kempf, A.

    2010-01-15

    Setups in which a system Alice emits field quanta that a system Bob receives are prototypical for wireless communication and have been extensively studied. In the most basic setup, Alice and Bob are modeled as Unruh-DeWitt detectors for scalar quanta, and the only noise in their communication is due to quantum fluctuations. For this basic setup, we construct the corresponding information-theoretic quantum channel. We calculate the classical channel capacity as a function of the spacetime separation, and we confirm that the classical as well as the quantum channel capacity are strictly zero for spacelike separations. We show that this channel can be used to entangle Alice and Bob instantaneously. Alice and Bob are shown to extract this entanglement from the vacuum through a Casimir-Polder effect.

  11. Bistability and chaos at low levels of quanta

    NASA Astrophysics Data System (ADS)

    Gevorgyan, T. V.; Shahinyan, A. R.; Chew, Lock Yue; Kryuchkyan, G. Yu.

    2013-08-01

    We study nonlinear phenomena of bistability and chaos at a level of few quanta. For this purpose, we consider a single-mode dissipative oscillator with strong Kerr nonlinearity with respect to the dissipation rate driven by a monochromatic force as well as by a train of Gaussian pulses. The quantum effects and decoherence in the oscillatory mode are investigated in the framework of the purity of states and the Wigner functions calculated from the master equation. We demonstrate the quantum chaotic regime by means of a comparison between the contour plots of the Wigner functions and the strange attractors on the classical Poincaré section. Considering bistability at a low limit of quanta, we analyze the minimal level of excitation numbers at which the bistable regime of the system is displayed. We also discuss the formation of an oscillatory chaotic regime by varying oscillatory excitation numbers at ranges of a few quanta. We demonstrate quantum-interference phenomena that are assisted hysteresis-cycle behavior and quantum chaos for the oscillator driven by a train of Gaussian pulses. We establish the border of quantum-classical correspondence for chaotic regimes in the case of strong nonlinearities.

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

    PubMed

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

    2016-06-29

    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.

  13. 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

  14. 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

  15. 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.

  16. 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

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

    NASA Astrophysics Data System (ADS)

    Sarrao, John

    2013-03-01

    Mesoscale science embraces the regime where atomic granularity and quantization of energy yield to continuous matter and energy, collective behavior reaches its full potential, defects, fluctuations and statistical variation emerge, interacting degrees of freedom create new phenomena, and homogeneous behavior gives way to heterogeneous structure and dynamics. Mesoscale architectures form a hierarchy extending from atoms and molecules through polymers, supramolecular assemblies, periodic lattices, multilayers, nanocrystal arrays and multiphase materials. Mesoscale science builds on the foundation of nanoscale knowledge and tools that the community has developed over the last decade and continues to develop. Mesoscale phenomena offer a new scientific opportunity: designing architectures and interactions among nanoscale units to create new macroscopic behavior and functionality. Examples of mesoscale successes, challenges and opportunities will be described. A more complete discussion of mesoscale science can be found in the BESAC report, From Quanta to the Continuum: Opportunities for Mesoscale Science, http://science.energy.gov/bes/news-and-resources/reports/basic-research-needs/ Innovative community input on opportunities for mesoscale science can be found on the Mesoscopic Materials and Chemistry website, http://www.meso2012.com/

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

    PubMed

    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

  19. 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

  20. 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

  1. Shot noise of large charge quanta in superconductor/semiconductor/superconductor junctions

    NASA Astrophysics Data System (ADS)

    Camino, F. E.; Kuznetsov, V. V.; Mendez, E. E.; Schäpers, Th.; Guzenko, V. A.; Hardtdegen, H.

    2005-01-01

    We have found experimentally that the noise of ballistic electron transport in a superconductor/semiconductor/superconductor junction is enhanced relative to the value given by the general relation, SV=2eIR2coth(eV/2kT) , for two voltage regions in which this expression reduces to its thermal and shot noise limits. The noise enhancement is explained by the presence of large charge quanta, with an effective charge q*=(1+2Δ/eV)e , that generate a noise spectrum SV=2q*IR2 , as predicted by Averin and Imam [Phys. Rev. Lett. 76, 3814 (1996)]. These charge quanta result from multiple Andreev reflections at each junction interface, which are also responsible for the subharmonic gap structure observed in the voltage dependence of the junction’s conductance.

  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. Orientation of fission fragments and anisotropy of {gamma}-Quanta emission

    SciTech Connect

    Barabanov, A.L.

    1994-07-01

    Experimental data on angular distributions of {gamma}-quanta emitted by fragments of binary and ternary spontaneous fission of {sup 252}Cf are analyzed. Their difference indicates that the fragment alignment is higher in ternary fission than that in binary fission. Consequences of a possible relation between the ternary fission mechanism and the excitation of collective modes at the stage of descent from the barrier to the scission point are discussed. 19 refs., 5 figs.

  4. Quantum-mechanical derivation of the Davydov equations for multi-quanta states

    SciTech Connect

    Kerr, W.C.; Lomdahl, P.S.

    1989-01-01

    Our purpose here is to present a derivation of the Davydov equations which employs only quantum-mechanical techniques. The derivation here is more general than our previous treatment of this problem because we use an Ansatz which has present several quanta of the high frequency oscillator system rather than just one quantum. Since some steps of the calculation are the same as those in our paper which treats the single quantum case, reference will be made to that paper for some of the those details. 9 refs.

  5. Stability of the GaAs based Hall sensors irradiated by gamma quanta

    NASA Astrophysics Data System (ADS)

    Gradoboev, A. V.; Karlova, G. F.

    2015-04-01

    The present work is aimed at investigation of the stability of the GaAsbased Hall sensors (pickups) to irradiation by gamma quanta. The examined objects are the gallium arsenide based Hall sensors manufactured on thin active layers by the methods of vaporphase epitaxy (VPE), molecular beam epitaxy, and ion implantation. Our research methodology involves measurements of the volt-ampere characteristics (VACs) of all sensors for different values of the supply voltage polarity and electron concentration and mobility by the Van-der- Pau method as well as investigations of the noise properties of the sensors before and after irradiation. The sensors are irradiated by gamma quanta of Co60 at room temperature in the passive mode, that is, without imposition of an electrical bias. As a result of investigations, it is established that a part of the active layer of finite thickness adjoining the substrate plays an important role in the charge carrier transmission process depending on the concentration of deep-level centers in the substrate. Irradiation by high doses leads to degradation of VACs and increase in the spectral density of the sensor noise. Low gamma radiation doses have a stabilization effect on the sensors. Periodic relaxation processes are observed for a part of the structures manufactured by the VPE method. The assumption is made that they can be caused by the deep-level centersin GaAs.

  6. Are there Mega Quanta of Action Playing a Part in Hubble Spheres?

    NASA Astrophysics Data System (ADS)

    Kostro, Ludwik

    Quanta of action (Planck's, Stoney's, Kittel's etc.) are related to the so-called units determined by universal constants: c - speed of light in vacuum, G - Newtonian gravitational constant and by the respective constant connected with the respective interaction. If we introduce Λ - units determined by c, G and Λ we obtain also the Λ- mega quantum of action. It will be shown that this quantum of action can be disclosed in the Lagrangian used to express the stationary action in General Relativity applied in cosmology in which the cosmological constant Λ appears. It will be discussed if this mega quantum is connected with the causally bounded zones in our universe, i.e. with the Hubble spheres. If we introduce Kittel's gravitational units determined by c, G and MG, where MG means the gravitational mass (of ordinary + and dark matter), embedded and causally bounded in a Hubble' sphere then we obtain also a Kittel mega quantum of action. The meaning of both mega quanta will be discussed.

  7. 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

  8. 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.

  9. 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.

  10. The Cosmic Rays and Gamma-Quanta Local Sources Spectra Distinction and Formation of Uniform Cosmic Ray Spectrum

    NASA Astrophysics Data System (ADS)

    Georgievna Sinitysna, Vera; Nikolsky, S. I.

    2003-07-01

    The obtained experimental data about local sources of gamma-quanta are characteristic by the following fact. Though the observed metagalactic sources (active galactic nuclei) are 106 - 107 times more powerful, unlike the galactic one, the gamma-quanta energy spectra from both galactic and metagalactic sources can be averaged with spectrum index F (> Eγ ) ˜ Eγ 1.3±0.15 . This result puts - under doubt the assumption about the galactic origin of observable cosmic ray flux. Uniform cosmic ray spectrum is forming in "infinite" number of elastic (or inelastic) collisions with relict photons in intergalactic space, where the cosmic rays are 0.999... part of their time as the common volume of extragalactic space exceeds more then thousand times the total galactic volume in Universe. Accordingly, the observable spectrum distribution has index of (2.72 ± 0.02) = 2.718..., that is Napier's number. The local sources of extra-high energy cosmic radiation search by the EAS flux excess at narrow angular interval at the direction on supposed sources did not give conformable results because of extremely low flux of showers generated by gamma-quanta, which is connected with the process of accumulation of charged particles in Metagalaxy, which includes intergalactic space. This was confirmed at experiments in the ionization calorimeter with Pb absorb ent of total EAS formed by gamma-quanta which have no muons and hadrons flux determination. The analysis of such showers showed that between EAS on observation level of 3760 m high above sea level the "no hadron" showers flux is slight 0.005 ± 0.001 of full EAS flux; "no muons" showers showed the same result at 0.004 ± 0.001 EAS with primary energy > (3 - 4)1014 eV not a single muon was observed (Fig. 1). As a consequence of small flux of EAS containing no hadrons and muons searching of high-energy gamma-quanta stellar sources it was advisable to concentrate on observations of probable high-energy gamma-quanta sources at narrow

  11. 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.

  12. 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

  13. 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.

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

    NASA Astrophysics Data System (ADS)

    Giovannini, Massimo

    2011-01-01

    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.

  15. 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.

  16. Presynaptic recording of quanta from midbrain dopamine neurons and modulation of the quantal size.

    PubMed

    Pothos, E N; Davila, V; Sulzer, D

    1998-06-01

    The observation of quantal release from central catecholamine neurons has proven elusive because of the absence of evoked rapid postsynaptic currents. We adapted amperometric methods to observe quantal release directly from axonal varicosities of midbrain dopamine neurons that predominantly contain small synaptic vesicles. Quantal events were elicited by high K+ or alpha-latrotoxin, required extracellular Ca2+, and were abolished by reserpine. The events indicated the release of 3000 molecules over 200 microsec, much smaller and faster events than quanta associated with large dense-core vesicles previously recorded in vertebrate preparations. The number of dopamine molecules per quantum increased as a population to 380% of controls after glial-derived neurotrophic factor (GDNF) exposure and to 350% of controls after exposure to the dopamine precursor L-dihydroxyphenylalanine (L-DOPA). These results introduce a means to measure directly the number of transmitter molecules released from small synaptic vesicles of CNS neurons. Moreover, quantal size was not an invariant parameter in CNS neurons but could be modulated by neurotrophic factors and altered neurotransmitter synthesis.

  17. 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.

  18. [Laboratory-based evaluation of "INOVA/QUANTA Lite" to determine antinuclear antibodies (ANA) and autoantibodies to double-stranded DNA, SS-A and SS-B].

    PubMed

    Yamauchi, Megumi S; Shingaki, Naohiko; Yamane, Nobuhisa

    2012-05-01

    We evaluated QUANTA Lite reagent series (INOVA Diagnostics, CA, USA) to determine antinuclear antibodies (ANA) and autoantibodies to double-stranded (ds) DNA, SS-A and SS-B, in parallel with MESACUP (Medical & Biological Laboratories, Nagoya). Overall agreements between two reagents for qualitative interpretation ranged from 77.5% (ANA) to 99.0%(anti-SS-B antibodies). When we compared to the results by indirect fluorescent antibody (IFA) test on HEp-2 cells, QUANTA Lite ANA demonstrated better sensitivity and specificity; 92.2% versus 76.5% in sensitivity and 92.1% versus 86.8% in specificity. Also, determining anti-chromatin antibodies and IFA test onto Chrithidia luciliae demonstrated greater interpretive correlation to detect anti-ds DNA by QUANTA Lite than by MESACUP. All the discrepant sera to which QUANTA Lite SS-A gave positive interpretations were confirmed to contain the antibodies specific to SS-A 52kDa antigen, which is supplemented to QUANTA Lite capture-probes. With these results, we can conclude that QUANTA Lite has superiorities over MESACUP; (1) to detect a variety of autoantibodies consisting of ANA, (2) to have a better correlation with confirmatory tests to detect anti-ds DNA antibodies, (3)to detect additional autoantibodies specific to SS-A 52kDa antigen, and (4) to have an enough compatibility in determining anti-SS-B antibodies.

  19. Cyclotron resonance of composite fermions with two and four flux quanta

    NASA Astrophysics Data System (ADS)

    Kukushkin, I. V.; Smet, J. H.; von Klitzing, K.; Wegscheider, W.

    2003-12-01

    The application of quantum field theoretical methods to strongly interacting many-body problems has reaped rich rewards. Foremost, it has nurtured the quasi-particle notion. The introduction of suitable fictitious entities permits to cast otherwise notoriously difficult many-body systems in a single-particle form. We can then take the customary physical approach, using concepts and representations which formerly could only be applied to systems with weak interactions, and still capture the essential physics. A most notable recent example occurs in the conduction properties of a two-dimensional electron system, when exposed to a strong perpendicular magnetic field B. They are governed by electron-electron interactions, that bring about the Nobel prize winning fractional quantum Hall effect (FQHE) (Perspectives on Quantum Hall effects, Wiley, New York, 1996). Composite fermions (CFs), that do not experience the external magnetic field but a drastically reduced effective magnetic field B ∗, were identified as opposite quasi-particles that simplify enormously the understanding of the FQHE (Phys. Today (2000) 39; Phys. Rev. Lett. 63 (1989) 199). They behave as legitimate particles with well-defined charge, spin and statistics (Phys. Rev. B 47 (1993) 7312; Composite Fermions, World Scientific, Singapore, 1998; Phys. Rev. Lett. 70 (1993) 2944; 75 (1995) 3926; 71 (1993) 3846; 72 (1994) 2065; 77 (1996) 2272). They precess, like electrons, along circular orbits, with a diameter determined by B ∗ rather than B, and with a frequency that is hard to predict, since the effective mass remains enigmatic. Ever since their prediction, the demonstration of enhanced absorption of a microwave field that resonates with the frequency of their circular motion was considered the ultimate experiment to unravel this issue. Here, we report the observation of this cyclotron resonance of CFs with two and four flux quanta and extract their effective mass.

  20. 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!!!

  1. 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

  2. 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

  3. Extensive air showers generated by protons, nuclei, gamma-quanta and neutrinos at energy range 1 - 100 TeV

    NASA Astrophysics Data System (ADS)

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

    2003-07-01

    Basic science: nuclear physics, physics of elementary particles and connected with them astrophysics and cosmology, has studied the structure of matter on micro and macro scales. Gamma-astronomy and neutrino-astronomy, are unique experimental possibilities to search for high-energy cosmic ray sources (1012 - 1014 eV). Evidence has already been obtained of metagalactic sources exceeding by 106 - 1012 times the power of gamma-quanta galactic sources. This data puts into doubt the assumption about the galactic origin of the observed very high energy cosmic radiation. The energy spectrum of the majority of known gamma-sources with energy 1012 - 1014 eV is harder than the proton and cosmic ray nuclei spectrum. The problem of observing extensive air showers generated by neutrinos is connected with the extremely small effective cross-section of inelastic collisions of neutrinos with nuclei. However, two facts allow a search for showers generated by neutrinos. The hadron cascade with primary energy of more than 1012 eV leaves the ground to atmosphere from depth of ~ 300 g/cm2 without essential loss of total energy in the hadron cascade. The Cherenkov radiation in the atmosphere from such hadron cascades will be observed at distances from the telescope of 7.5 km over an area more than 7 . 105 m2. This partially compensates for the small cross-section of inelastic neutrino collisions. RFBR, FNP, GNTP

  4. Light quanta modulated characteristics of Ni uptake by Brassica juncea seedlings: the interdependence of plant metal concentration and biomass.

    PubMed

    Dasgupta-Schubert, N; Whelan, T; Reyes, M A; Lloren, C; Brandt, T T; Persans, M W

    2007-01-01

    The relationships between the concentration of metal in the growth medium, Cs, the concentration of metal absorbed by the plant, Cp, and the total biomass achieved, M, all of which are factors relevant to the efficiency of metal uptake and tolerance by the plant, have been investigated via the physiological response of Brassica juncea seedlings to Ni stress. The factorial growth experiments treated the Ni concentration in agar medium and the diurnal light quanta as independently variable parameters. Observations included the evidence of light enhancement of Ni toxicity in the root, as well as at the whole-plant level. The shoot mass index possibly is an indicator of the amount of shoot metal sequestration in B. juncea, as are the logarithmic variation of Cp with Cs and the power-law dependence of M on Cp. The sum total of these observations indicates that, for the Ni accumulating plant B. juncea, the overall metabolic allocation to either growth or metal tolerance of the plant is important. Neither a rapid biomass increase nor a high metal absorbed concentration favored the removal of high metal mass from the medium. Rather, the plants with a moderate rate of biomass growth and a moderate absorbed metal concentration demonstrated the ability to remove the maximum mass of metal from the medium. The implication of these results as related to the extant model of phyoextraction efficiency is discussed.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Effects of undersampling on the proper interpretation of modulation transfer function, noise power spectra, and noise equivalent quanta of digital imaging systems.

    PubMed

    Dobbins, J T

    1995-02-01

    The proper understanding of modulation transfer function (MTF), noise power spectra (NPS), and noise equivalent quanta (NEQ) in digital systems is significantly hampered when the systems are undersampled. Undersampling leads to three significant complications: (1) MTF and NPS do not behave as transfer amplitude and variance, respectively, of a single sinusoid, (2) the response of a digital system to a delta function is not spatially invariant and therefore does not fulfill certain technical requirements of classical analysis, and (3) NEQ loses its common meaning as maximum available SNR2 (signal-to-noise) at a particular frequency. These three complications cause the comparisons of MTF and NEQ between undersampled digital systems to depend on the frequency content of the images being evaluated. A tutorial of MTF, NPS, and NEQ concepts for digital systems is presented, along with a complete theoretical treatment of the above-mentioned complications from undersampling.

  10. The distinction between gamma-quanta spectra from both local sources and cosmic rays, and the formation of a uniform cosmic ray spectrum

    NASA Astrophysics Data System (ADS)

    Nikolsky, S. I.; Sinitsyna, V. G.

    2003-07-01

    The experimental data about gamma-quanta sources with energy > 1 TeV are characterised by the fact that the observed metagalactic sources (active galactic nuclei) are 106 - 107 times more powerful than the galactic ones, but they do not differ in energy spectrum (F(> Eγ)~Eγ-1.3+/-0.15). The power of metagalactic sources and their unlimited number puts into doubt the assumption about the galactic origin of the observable cosmic ray flux. It is possible to assume, that the uniform cosmic ray spectrum is formed (by ``braking'') in an ``infinite'' number of elastic (or inelastic) collisions with relict photons in intergalactic space. Thus, the observable spectral distribution of protons and cosmic ray nuclei with index of (2.72+/-0.02) = 2.718... (the Nipper's number) is the consequence of such ``braking'' warming up the relict photons. RFBR, FNP, GNTP

  11. 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.

  12. Action Potential-Independent and Nicotinic Receptor-Mediated Concerted Release of Multiple Quanta at Hippocampal CA3–Mossy Fiber Synapses

    PubMed Central

    Sharma, Geeta; Grybko, Michael; Vijayaraghavan, Sukumar

    2009-01-01

    Presynaptic action potential-independent transmitter release is a potential means of information transfer across synapses. We show that in the hippocampal mossy fiber boutons, activation of the α7-subtype of nicotinic acetylcholine receptors (α7-nAChRs) results in a large increase in the amplitude of spontaneous events, resulting from concerted release of multiple quanta from the mossy fiber boutons. This amplitude increase is abolished at low temperatures. Activation of α7-nAChRs causes a rise in intraterminal calcium at mossy fiber boutons, involving ryanodine receptors. Regulation of concerted release requires the subsequent activation of presynaptic calcium/calmodulin-dependent protein kinase II (CaMKII). Activation of CaMKII is required to drive presynaptic action potential-independent transmission at the mossy fiber–CA3 pyramidal cell synapse. The effects of α7-nAChR activation are mediated by biologically relevant doses of nicotine. Our results demonstrate a novel form of synaptic plasticity mediated by presynaptic α7-nAChRs and store calcium that is temporally different and might respond to a different history of synaptic activity than that mediated by incoming action potentials. PMID:18322100

  13. 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.

  14. Detection of metagalactic and galactic sources of very high-energy gamma-quanta and neutrinos with the mirror Cherenkov telescope SHALON

    NASA Astrophysics Data System (ADS)

    Sinitsyna, V. G.

    2006-08-01

    Gamma-astronomy and neutrino astronomy are unique experimental possibilities to search for sources of high-energy cosmic rays (10 10eV). Experimental data on sources of γ-quanta with the energy >1TeV are characterized by the fact that observed metagalactic sources (active galactic nuclei), being different in power from galactic sources by the factor of 10 10, do not differ in the energy spectrum, F(>E)∝Eγ-1.3±0.15. The power of the metagalactic sources and their unlimited number casts doubts on the assumption of a galactic origin of the observed cosmic-ray flux. It is possible to assume that the uniform cosmic-ray spectrum is formed by “braking” in multiple elastic or inelastic collisions with relict photons in intergalactic space. Thus, the observed distribution of protons and cosmic-ray nuclei with the spectral index 2.72±0.02 (=2.718…, the Napier's constant) may be a consequence of such a “braking” that warms up the relict photons. Problems in observation of extensive air showers generated by neutrinos are connected with an extremely small cross section of inelastic collisions of neutrinos with nuclei. However, two facts allow to search for showers generated by neutrinos: (1) a hadron cascade with the primary energy of more than 10eV leaves a mountain ridge to the atmosphere from the depth ˜300g/cm without an essential loss of the total energy in the hadron cascade, and (2) air Cherenkov radiation from such hadron cascades will be observed with a 7.5 km distant telescope over an area of more than 7×10m. This partially compensates the small cross section of inelastic neutrino collisions.

  15. 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.

  16. Chemical composition and structure of particles synthesized on the surface of HHPC in nuclear reactions induced by bremstrahlung γ quanta with threshold energy of 10 MeV in molecular hydrogen at a pressure of 0.5 kbar

    NASA Astrophysics Data System (ADS)

    Didyk, A. Yu.; Wiśniewski, R.

    2015-12-01

    A high-pressure chamber filled with molecular hydrogen (HHPC) at a pressure of 0.5 kbar with a Pd rod inside has been irradiated for 14 h with γ quanta with an energy of 9.7 kbar produced by an electron beam current of 20-21 μA. Postirradiation studies of the changes in the structure of the synthesized particle and other objects on the surface of a brass hub in the composition of HHPC revealed the presence of light elements from carbon to calcium. Multiple small particles of lead have also been found and studied. The detected synthesized particle has complex shape and composition. Also, thin-walled microtubes were detected on the inner surfaces inside HHPC. Based on fission reactions of intermediate mass nuclei (descending reactions), as well as the reactions of synthesis from hydrogen and heavier nuclei (ascending reactions), an attempt to explain the anomalies that were observed is made.

  17. 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.

  18. Optical manipulation of single flux quanta

    PubMed Central

    Veshchunov, I. S.; Magrini, W.; Mironov, S. V.; Godin, A. G.; Trebbia, J.-B.; Buzdin, A. I.; Tamarat, Ph.; Lounis, B.

    2016-01-01

    Magnetic field can penetrate into type II superconductors in the form of Abrikosov vortices, which are magnetic flux tubes surrounded by circulating supercurrents often trapped at defects referred to as pinning sites. Although the average properties of the vortex matter in superconductors can be tuned with magnetic fields, temperature or electric currents, handling of individual Abrikosov vortices remains challenging and has been demonstrated only with sophisticated scanning local probe microscopies. Here we introduce a far-field optical method based on local heating of the superconductor with a focused laser beam to realize a fast and precise manipulation of individual vortices, in the same way as with optical tweezers. This simple approach provides the perfect basis for sculpting the magnetic flux profile in superconducting devices like a vortex lens or a vortex cleaner, without resorting to static pinning or ratchet effects. PMID:27677835

  19. 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.

  20. Multiple-charge-quanta shot noise in superconducting atomic contacts.

    PubMed

    Cron, R; Goffman, M F; Esteve, D; Urbina, C

    2001-04-30

    We have measured shot noise in aluminum atomic point contacts containing a small number of conduction channels of known transmissions. In the normal state, we find that the noise power is reduced from its Poissonian value and reaches the partition limit, as calculated from the transmissions. In the superconducting state, the noise reveals the large effective charge associated with each elementary transfer process, in excellent agreement with the predictions of the quantum theory of multiple Andreev reflections.

  1. 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)

  2. 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.

  3. [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

  4. Beyond Planck-Einstein quanta: Amplitude-driven quantum excitation

    NASA Astrophysics Data System (ADS)

    Shen, Wen; Devereaux, T. P.; Freericks, J. K.

    2014-11-01

    Linear-response quantum excitation is proportional to the amplitude of the field, with the energy of the excitation given by the driving frequency. As the amplitude is increased, there is a crossover, where the excitation energy is governed by the amplitude of the driving field, not its frequency. As the amplitude is increased even further, then complex quantum oscillations develop. We illustrate this phenomena with the exact solution of the simplest model of a charge-density-wave insulator driven by a spatially uniform time-dependent electric field. The driving by the field can be mapped onto a series of Landau-Zener problems, but with a complex, nonmonochromatic drive that varies for each momentum point in the reduced Brillouin zone.

  5. Skyrmions in quantum Hall ferromagnets as spin waves bound to unbalanced magnetic-flux quanta

    NASA Astrophysics Data System (ADS)

    Oaknin, J. H.; Paredes, B.; Tejedor, C.

    1998-11-01

    A microscopic description of (baby) skyrmions in quantum Hall ferromagnets is derived from a scattering theory of collective (neutral) spin modes by a bare quasiparticle. We start by mapping the low-lying spectrum of spin waves in the uniform ferromagnet onto that of freely moving spin excitons, and then we study their scattering by the charge defect. In the presence of this disturbance, the local spin stiffness varies in space, and we translate it into an inhomogeneous metric in the Hilbert space supporting the excitons. An attractive potential is then required to preserve the symmetry under global spin rotations, and it traps the excitons around the charged defect. The quasiparticle now carries a spin texture. Textures containing more than one exciton are described within a mean-field theory, the interaction among the excitons being taken into account through a new renormalization of the metric. The number of excitons actually bound depends on the Zeeman coupling, which plays the same role as a chemical potential. For small Zeeman energies, the defect binds many excitons that condensate. As the bound excitons have a unit of angular momentum, provided by the quantum of magnetic flux left unbalanced by the defect of charge, the resulting texture turns out to be a topological excitation of charge 1. Its energy is that given by the nonlinear σ model for the ground state in this topological sector, i.e., the texture is a skyrmion.

  6. Probabilistic secretion of quanta: spontaneous release at active zones of varicosities, boutons, and endplates.

    PubMed Central

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

    1995-01-01

    The amplitude-frequency histogram of spontaneous miniature endplate potentials follows a Gaussian distribution at mature endplates. This distribution gives the mean and variance of the quantum of transmitter. According to the vesicle hypothesis, this quantum is due to exocytosis of the contents of a single synaptic vesicle. Multimodal amplitude-frequency histograms are observed in varying degrees at developing endplates and at peripheral and central synapses, each of which has a specific active zone structure. These multimodal histograms may be due to the near synchronous exocytosis of more than one vesicle. In the present work, a theoretical treatment is given of the rise of intraterminal calcium after the stochastic opening of a calcium channel within a particular active zone geometry. The stochastic interaction of this calcium with the vesicle-associated proteins involved in exocytosis is then used to calculate the probability of quantal secretions from one or several vesicles at each active zone type. It is shown that this procedure can account for multiquantal spontaneous release that may occur at varicosities and boutons, compared with that at the active zones of motor nerve terminals. PMID:7669909

  7. 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.

  8. 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'.

  9. 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)

  10. Bose-Einstein condensation of spin wave quanta at room temperature.

    PubMed

    Dzyapko, O; Demidov, V E; Melkov, G A; Demokritov, S O

    2011-09-28

    Spin waves are delocalized excitations of magnetic media that mainly determine their magnetic dynamics and thermodynamics at temperatures far below the critical one. The quantum-mechanical counterparts of spin waves are magnons, which can be considered as a gas of weakly interacting bosonic quasi-particles. Here, we discuss the room-temperature kinetics and thermodynamics of the magnon gas in yttrium iron garnet films driven by parametric microwave pumping. We show that for high enough pumping powers, the thermalization of the driven gas results in a quasi-equilibrium state described by Bose-Einstein statistics with a non-zero chemical potential. Further increases of the pumping power cause a Bose-Einstein condensation documented by an observation of the magnon accumulation at the lowest energy level. Using the sensitivity of the Brillouin light scattering spectroscopy to the degree of coherence of the scattering magnons, we confirm the spontaneous emergence of coherence of the magnons accumulated at the bottom of the spectrum, occurring if their density exceeds a critical value.

  11. 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…

  12. Nonclassical correlations between terahertz-bandwidth photons mediated by rotational quanta in hydrogen molecules.

    PubMed

    Bustard, Philip J; Erskine, Jennifer; England, Duncan G; Nunn, Josh; Hockett, Paul; Lausten, Rune; Spanner, Michael; Sussman, Benjamin J

    2015-03-15

    Quantum photonics offers much promise for the development of new technologies. The ability to control the interaction of light and matter at the level of single quantum excitations is a prerequisite for the construction of potentially powerful devices. Here we use the rotational levels of a room temperature ensemble of hydrogen molecules to couple two distinct optical modes at the single photon level using femtosecond pulses with 2 THz bandwidth. We observe photon correlations that violate a Cauchy-Schwarz inequality, thereby verifying the creation of a nonclassical state. This work demonstrates the rich potential of molecules for use in ultrafast quantum photonic devices. PMID:25768147

  13. Nonclassical correlations between terahertz-bandwidth photons mediated by rotational quanta in hydrogen molecules.

    PubMed

    Bustard, Philip J; Erskine, Jennifer; England, Duncan G; Nunn, Josh; Hockett, Paul; Lausten, Rune; Spanner, Michael; Sussman, Benjamin J

    2015-03-15

    Quantum photonics offers much promise for the development of new technologies. The ability to control the interaction of light and matter at the level of single quantum excitations is a prerequisite for the construction of potentially powerful devices. Here we use the rotational levels of a room temperature ensemble of hydrogen molecules to couple two distinct optical modes at the single photon level using femtosecond pulses with 2 THz bandwidth. We observe photon correlations that violate a Cauchy-Schwarz inequality, thereby verifying the creation of a nonclassical state. This work demonstrates the rich potential of molecules for use in ultrafast quantum photonic devices.

  14. 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

  15. Quanta, quarks, and families: implications of quantum physics for family research.

    PubMed

    Doherty, W J

    1986-06-01

    This paper offers recommendations for family research in light of the scientific paradigm ushered in by quantum physics in the early twentieth century. After summarizing the basic discoveries of quantum physics, the author discusses philosophical implications of these discoveries, and then presents implications for conducting scientific research about families within a post-Newtonian paradigm that emphasizes relations, process, and dynamic causation. The author argues for using complementary research models, including linear and systemic, because no one theory or methodology can illuminate fully the inscrutable nature of family processes.

  16. Learning quanta: Barriers to stimulating transitions in student understanding of orbital ideas

    NASA Astrophysics Data System (ADS)

    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 from students interviewed about a problematic curriculum topic - the oribital model of atomic and molecular structures. Several specific features of learners' developing ideas about atomic and molecular structures were identified in published reports of the study. In this paper, interview data is examined through the analytical lens of the typology to explore possible explanations for students' learning difficulties in the topic. It is suggested that the typology provides a useful perspective for exploring some aspects of students' learning difficulties, but that the previously published form of the typology could be modified to include important additional types of learning impediments. The heuristic value of the typology is demonstrated in terms of the way that the analysis can both inform teaching, and suggest a focus for further research.

  17. 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.

  18. Even-odd flux quanta effect in the Fraunhofer oscillations of an edge-channel Josephson junction

    NASA Astrophysics Data System (ADS)

    Baxevanis, B.; Ostroukh, V. P.; Beenakker, C. W. J.

    2015-01-01

    We calculate the beating of h /2 e and h /e periodic oscillations of the flux-dependent critical supercurrent Ic(Φ ) through a quantum spin-Hall insulator between two superconducting electrodes. A conducting pathway along the superconductor connects the helical edge channels via a nonhelical channel, allowing an electron incident on the superconductor along one edge to be Andreev reflected along the opposite edge. In the limit of small Andreev reflection probability the resulting even-odd effect is described by Ic∝|cos(e Φ /ℏ ) +f | , with |f |≪1 proportional to the probability for phase-coherent interedge transmission. Because the sign of f depends on microscopic details, a sample-dependent inversion of the alternation of large and small peaks is a distinctive feature of the beating mechanism for the even-odd effect.

  19. 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

    ... the United States Environmental Protection Agency (``EPA'') for the Quanta Resources Superfund Site...., Hudson River Associates, LLC, Metropolitan Consom, LLC, Quanta Resources Corporation, BASF...

  20. 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.

  1. 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.

  2. On Bits and Quanta. Hoi-Kwong Lo, Sandu Popescu and Tim Spiller (eds), Introduction to Quantum Computation and Information (Singapore: World Scientific, 1998), xi+348 pp., ISBN 981-02-3399-X, £35, US52.

    NASA Astrophysics Data System (ADS)

    Delhôtel, Jean-Michel

    'Information is physical': the popular slogan (Landauer, 1991) recalls the fact that information, if it is to be stored, processed or communicated, must have a physical embodiment. Until recently, the physical systems used for representing information were all within the jurisdiction of classical laws. Since the early 1980s however, a growing band of theorists have been toying with the idea of extending such representations to the quantum realm. The computational or cryptographical advantages afforded by linear combinations of quantum states have been unveiled and quantified. Renewed interest in Hilbert space structure and properties of 'entangled' quantum systems have become cornerstones of a new discipline: 'quantum information theory' (QIT), to which we owe some of the most significant and intriguing results in mathematical physics over the last decade.

  3. 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)

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

  4. Synthesis of new structures on the surface of Pd rod and HHPC elements and their chemical composition in nuclear reactions induced by bremstrahlung γ quanta with threshold energy of 10 MeV in molecular hydrogen at a pressure of 0.5 kbar

    NASA Astrophysics Data System (ADS)

    Didyk, A. Yu.; Wiśhnewski, R.

    2015-07-01

    A high-pressure chamber filled with molecular hydrogen (HHPC) at a pressure of 0.5 kbar with Pd rod inside has been irradiated for 14 h with γ rays having a threshold energy of 10 MeV produced by an electron beam current of 20-21 μA. Postirradiation studies of the changes in the structure and elemental composition of Pd rod and irregularities of all internal surfaces of the HHPC elements, as well as the large synthetic structures detected, reveal the presence of light elements from carbon to calcium. Multiple small particles of lead have also been found and studied. The detected synthesized particles have complex shapes and compositions. Also, thin-walled microtubes are detected on the inner surfaces inside HHPC. Based on fission reactions of intermediate mass nuclei (descending reactions), as well as the reactions of synthesis from hydrogen and heavy nuclei (ascending reactions), an attempt to explain the anomalies that were observed is made.

  5. 76 FR 37319 - Application(s) for Duty-Free Entry of Scientific Instruments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-27

    ... instrument will simulate solar radiation for an existing vehicle and component testing cell, to evaluate... 01063. Instrument: Quanta 450 Electron Microscope. Manufacturer: FEI Company, Czech Republic....

  6. 75 FR 38125 - Fanuc Robotics America, Inc. Including On-Site Leased Workers From Right Angle Staffing, Inc...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-01

    ... on February 16, 2010 (75 FR 7034). The initial investigation resulted in a negative determination... Right Angle Staffing, Inc., Quanta, Inc., Reliance One, Inc., Populus Group, LLC, Citistaff,...

  7. 75 FR 3895 - Yale University, et al.;

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-25

    ..., Quanta 200 FEG. Manufacturer: FEI Company, Czech Republic. Intended Use: See notice at 74 FR 67851..., 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...

  8. A new method of differential structural analysis of gamma-family basic parameters

    NASA Technical Reports Server (NTRS)

    Melkumian, L. G.; Ter-Antonian, S. V.; Smorodin, Y. A.

    1985-01-01

    The maximum likelihood method is used for the first time to restore parameters of electron photon cascades registered on X-ray films. The method permits one to carry out a structural analysis of the gamma quanta family darkening spots independent of the gamma quanta overlapping degree, and to obtain maximum admissible accuracies in estimating the energies of the gamma quanta composing a family. The parameter estimation accuracy weakly depends on the value of the parameters themselves and exceeds by an order of the values obtained by integral methods.

  9. 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.

  10. 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.''

  11. 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.

  12. 75 FR 43562 - FANUC Robotics America, Inc., Including On-Site Leased Workers From Right Angle Staffing, Inc...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-26

    ... Notice of determination was published in the Federal Register on July 1, 2010 (75 FR 38125). The initial... Right Angle Staffing, Inc., Quanta, Inc., Reliance One, Inc., Populus Group, LLC, Citistaff,...

  13. 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".

  14. Intermediate quantum statistics for identical objects

    SciTech Connect

    Kuryshkin, V.V.

    1988-11-01

    Methods to construct various algebras of creation and annihilation operators of physical objects in complex quantum state spaces with a nonnegative metric are proposed. All allowed algebras for the cases of identical nonrelativistic systems in the second quantization of the Schrodinger equation, of identical quanta of relativistic tensor fields, and of identical quanta of relativistic spinor fields are constructed. A comparison of the obtained algebras with the well-known algebras of this type (Fermi, Bose, para-Fermi, and superalgebras) is given.

  15. Underwater radiant energy absorbed by phytoplankton, detritus, dissolved organic matter, and pure water

    SciTech Connect

    Kishino, M.; Booth, C.R.; Okami, N.

    1984-03-01

    The spectral irradiance distribution at five stations on lakes and at sea was measured with a portable underwater spectral irradiance meter. Chlorophyll a concentration and the absorption coefficient of the water were concurrently measured. From measured spectral irradiance distributions, radiant energy absorbed per unit volume was computed. At these stations, the effect of upward irradiance on total quanta absorbed by the water was negligibly small for all layers. The relative contributions of phytoplankton, detritus, dissolved organic matter, and pure water to the total absorbed quanta were also computed by taking into consideration the spectral dependency of each component: the contribution of quanta absorbed by the water was negligibly small for all layers. The relative contributions of phytoplankton, detritus, dissolved organic matter, and pure water to the total absorbed quanta were also computed by taking into consideration the spectral dependency of each component: the contribution of quanta absorbed by phytoplankton was about 3-10% in clear water and about 30-40% in the plankton-rich water.

  16. 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.

  17. Black holes and the butterfly effect

    NASA Astrophysics Data System (ADS)

    Shenker, Stephen H.; Stanford, Douglas

    2014-03-01

    We use holography to study sensitive dependence on initial conditions in strongly coupled field theories. Specifically, we mildly perturb a thermofield double state by adding a small number of quanta on one side. If these quanta are released a scrambling time in the past, they destroy the local two-sided correlations present in the unperturbed state. The corresponding bulk geometry is a two-sided AdS black hole, and the key effect is the blueshift of the early infalling quanta relative to the t = 0 slice, creating a shock wave. We comment on string- and Planck-scale corrections to this setup, and discuss points that may be relevant to the firewall controversy.

  18. Teaching Quantum Physics: What Is An Electron?

    NASA Astrophysics Data System (ADS)

    Hobson, Art

    2008-04-01

    Quantum field theorists have understood for decades that electrons and other material ``particles'' are quanta of the electron-positron field and other fields, just as photons are quanta of the electromagnetic field, and that a field quantum is a discrete and irreducible portion (or ``chunk,'' or ``bundle'') of a field, occupying an extended spatial region. But this understanding has not seeped through to most teachers and textbook writers at the introductory or undergraduate levels. Hence, there is still much discussion, and perplexity, about the supposed wave-particle paradox. But there is no paradox. Electrons are field quanta, extending spatially throughout the delta-x of the uncertainty principle, not particles. I will present a simple experiment-based method of teaching these quantum fundamentals. The experiments are the double-slit experiment for light and for electrons using intense beams (demonstrating interference) and dim beams (demonstrating discrete interactions).

  19. 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

  20. Double-resonance studies of rotational autoionization of H2

    NASA Astrophysics Data System (ADS)

    O'Halloran, M. A.; Dehmer, P. M.; Pratt, S. T.; Dehmer, J. L.; Tomkins, F. S.

    1989-01-01

    The rotational autoionization of np Rydberg states of H2 near the first ionization threshold is investigated experimentally by means of two-color resonantly enhanced multiphoton ionization (REMPI) and photoelectron spectroscopy using the apparatus described by O'Halloran et al. (1988). The results are presented in extensive tables, graphs, and sample REMPI spectra and characterized in detail. It is found that the Rydberg-series members have large v-dependent half-widths, consistent with the predictions of quantum-defect theory, and that ionization involving the change of two quanta of rotational energy is significantly faster than that involving four quanta.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. LETTER TO THE EDITOR: Remarks on the construction of a Hermitian phase operator

    NASA Astrophysics Data System (ADS)

    Roy, P.; Roy, B.

    1997-12-01

    We consider an oscillator system (whose states are realized in the space of Kravchuk polynomials) in a finite-dimensional Hilbert space. A Hermitian phase operator and the phase quanta raising and lowering operator are constructed using this framework. Also, we have constructed phase coherent states and examined their squeezing property.

  6. Decay of 5H in a microscopic three-cluster model

    NASA Astrophysics Data System (ADS)

    Lashko, Yu. A.; Filippov, G. F.

    2008-12-01

    The Pauli-allowed states of a three-cluster model are shown to be orthonormal polynomials of a discrete variable, which become the Kravchuk polynomials as the number of oscillator quanta increases. Such asymptotic behavior corresponds to the subsequent decay of the 5H into the 4H and a neutron.

  7. Reducing Motional Decoherence in Ion Traps with Surface Science Methods

    NASA Astrophysics Data System (ADS)

    Haeffner, Hartmut

    2014-03-01

    Many trapped ions experiments ask for low motional heating rates while trapping the ions close to trapping electrodes. However, in practice small ion-electrode distances lead to unexpected high heating rates. While the mechanisms for the heating is still unclear, it is now evident that surface contamination of the metallic electrodes is at least partially responsible for the elevated heating rates. I will discuss heating rate measurements in a microfabricated surface trap complemented with basic surface science studies. We monitor the elemental surface composition of the Cu-Al alloy trap with an Auger spectrometer. After bake-out, we find a strong Carbon and Oxygen contamination and heating rates of 200 quanta/s at 1 MHz trap frequency. After removing most of the Carbon and Oxygen with Ar-Ion sputtering, the heating rates drop to 4 quanta/s. Interestingly, we still measure the decreased heating rate even after the surface oxidized from the background gas throughout a 40-day waiting time in UHV.

  8. Analytical approach to dynamics of transformed rotating-wave approximation with dephasing

    NASA Astrophysics Data System (ADS)

    Mirzaee, M.; Kamani, N.

    2013-09-01

    We study the dynamics of the Jaynes—Cummings model within transformed rotating-wave approximation (TRWA). We analyze this model coupled to a dephasing reservoir, through the Lindblad formalism in the master equation. Then, we examine the expectation value of the number operator. Finally, we investigate the validity of this model under dephasing using the Mandel parameter and the total number of quanta.

  9. Missing energies at pair creation

    NASA Technical Reports Server (NTRS)

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

    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.

  10. 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.

  11. Bothe's 1925 heuristic assumption in the dawn of quantum field theory

    NASA Astrophysics Data System (ADS)

    Fick, D.

    2013-01-01

    In an unpublished manuscript filed at the Archive of the Max-Planck Society in Berlin, Walther Bothe (1891-1957) put, with one heuristic assumption, the spontaneous and induced transitions of light quanta, on an equal footing, probably as early as 1925. In modern terms, he assumed that the probability for the creation of a light quantum in a phase space cell already containing s light quanta is proportional to s + 1 and not, as assumed at that time, proportional to s; that is proportional to the fraction of the total radiation density which belongs to s light quanta. For Bothe, the added +1 somehow replaced the spontaneous decay and allowed him to treat empty phase space cells in a black body as thermodynamically consistent. We describe in some detail Bothe's route to this heuristic trick. Finally we discuss why, both Bose's and Bothe's heuristic assumptions lead to an identical distribution law for light quanta in a black body and thus to Planck's law and Einstein's fluctuation formula.

  12. Limit on the energy density in the submillimetre background radiation.

    NASA Technical Reports Server (NTRS)

    Cowsik, R.

    1972-01-01

    An analysis is made which indicates that the energy density in the submillimeter quanta cannot exceed about 0.4 eV/cu cm averaged over the galactic dimensions, independent of the exact spectral distribution of this radiation. This corresponds to an upper limit of 3.4 K on the radiation temperature in the galactic neighborhood.

  13. 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.

  14. 75 FR 32790 - Discretionary Grant Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-09

    ... Resources and Services Administration (HRSA), HHS. ACTION: Notice of Noncompetitive Program Extension... by the extension. FOR FURTHER INFORMATION CONTACT: LaQuanta Person, Project Officer, Integrated.... Maine Parent Federation ME 95,700 31-May-11. Pacer Center Inc MN 95,700 31-May-11. University...

  15. 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.

  16. Inversion of Quantum Jumps in Quantum Optical Systems under Continuous Observation

    NASA Astrophysics Data System (ADS)

    Mabuchi, H.; Zoller, P.

    1996-04-01

    We formulate conditions for invertibility of quantum jumps in systems that decay by emission of quanta into a continuously monitored reservoir. We propose proof-of-principle experiments using techniques from cavity quantum electrodynamics and ion trapping, and briefly discuss the relevance of such methods for error correction in quantum computation.

  17. 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.

  18. 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.

  19. 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.

  20. 75 FR 2889 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-International...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-19

    ... published a notice in the Federal Register pursuant to Section 6(b) of the Act on June 28, 1996 (61 FR 33774... Federal Register pursuant to Section 6(b) of the Act on December 12, 2008 (73 FR 75772). Patricia A. Brink... REPUBLIC OF CHINA; Lenovo, Quarry Bay, HONG KONG- CHINA; and Quanta Computer Inc., Tao Yuan Shien,...

  1. 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...

  2. 76 FR 37320 - Lawrence Technological University, et al.; Notice of Decision on Applications for Duty-Free Entry...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-27

    ... Technological University, 21000 W. 10 Mile Road, Southfield, MI 48075. Instrument: FEI Quanta 450 FEG Electron Microscope. Manufacturer: FEI Company, Brno, Czech Republic. Intended Use: See notice at 76 FR 29725, May 23... Lasertechnik, LLC, Marburg, Germany. Intended Use: See notice at 76 FR 29725, May 23, 2011. Reasons:...

  3. 76 FR 60867 - Certain Electronic Imaging Devices; Notice of Commission Determination To Review-in-Part a Final...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-30

    ... Flashpoint Technology, Inc. (``Flashpoint'') of Peterborough, New Hampshire. 75 FR 39971 (Jul. 8, 2010). The... FR 43251 (July 26, 2005). During this period, the subject articles would be entitled to enter the... ``substantially embodies'' the '716 patent and the '816 patent? See Quanta Computer, Inc. v. LG Elec., Inc., 128...

  4. 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…

  5. 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…

  6. 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.

  7. 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)

  8. CAISYS-8- A CAI Language Developed For A Minicomputer.

    ERIC Educational Resources Information Center

    Holm, Cheryl; And Others

    The University of Texas Medical Branch developed a minicomputer-based computer-assisted instruction (CAI) system which employed a teacher oriented software package called CAISYS-8, consisting of a highly modularized teaching compiler and operating system. CAISYS-8 used instructional quanta which generalized the flow of information to and from the…

  9. Correlation between quantal secretion and vesicle loss at the frog neuromuscular junction.

    PubMed

    Hurlbut, W P; Iezzi, N; Fesce, R; Ceccarelli, B

    1990-06-01

    1. We measured the rate of occurrence of miniature endplate potentials (MEPPs) at identified endplates in frog cutaneous pectoris muscles treated with crude black widow spider venom (BWSV) or purified alpha-latrotoxin (alpha-LTX) in calcium-free solutions, and we examined the relationship between the length of the nerve terminal and the total number of quanta secreted, and the relationship between the number of quanta secreted and the number of vesicles remaining at different times. 2. The venom, or toxin, was applied in a modified Ringer solution with tetrodotoxin, 1 mM-EGTA and no divalent cations, and quantal secretion was started by applying Ca2(+)-free solutions with Mg2+. This was done to synchronize the quantal discharge at the various junctions in a muscle. Ringer solution was applied after the MEPP rate had declined to low levels, and then the muscle fibre was injected with Lucifer Yellow, the endplate stained for acetylcholinesterase and the length of the nerve terminal and the length of a sarcomere were measured on the fluorescent fibre. 3. The total number of quanta secreted by a terminal was measured under a wide variety of experimental conditions: the weights of the frogs ranged from 13 to 68 g, the temperature from 9 to 28 degrees C, and the concentration of Mg2+ from 2 to 10 mM. In one series of experiments the Mg2+ was withdrawn after 3-4 min and reapplied 35-40 min later in order to divide the total output of quanta into two approximately equal bouts of secretion that were well separated in time. 4. The total number of MEPPs recorded at a junction was loosely correlated with the length of its nerve terminal, but it was not affected by the temperature, the concentration of Mg2+ or the division of secretion into well-separated bouts of quantal release. The average total secretion per unit length was about 3700 quanta/sarcomere or about 1200 quanta/microns. 5. The average time course of quantal secretion per micrometre of terminal was determined at

  10. Correlation between quantal secretion and vesicle loss at the frog neuromuscular junction.

    PubMed Central

    Hurlbut, W P; Iezzi, N; Fesce, R; Ceccarelli, B

    1990-01-01

    1. We measured the rate of occurrence of miniature endplate potentials (MEPPs) at identified endplates in frog cutaneous pectoris muscles treated with crude black widow spider venom (BWSV) or purified alpha-latrotoxin (alpha-LTX) in calcium-free solutions, and we examined the relationship between the length of the nerve terminal and the total number of quanta secreted, and the relationship between the number of quanta secreted and the number of vesicles remaining at different times. 2. The venom, or toxin, was applied in a modified Ringer solution with tetrodotoxin, 1 mM-EGTA and no divalent cations, and quantal secretion was started by applying Ca2(+)-free solutions with Mg2+. This was done to synchronize the quantal discharge at the various junctions in a muscle. Ringer solution was applied after the MEPP rate had declined to low levels, and then the muscle fibre was injected with Lucifer Yellow, the endplate stained for acetylcholinesterase and the length of the nerve terminal and the length of a sarcomere were measured on the fluorescent fibre. 3. The total number of quanta secreted by a terminal was measured under a wide variety of experimental conditions: the weights of the frogs ranged from 13 to 68 g, the temperature from 9 to 28 degrees C, and the concentration of Mg2+ from 2 to 10 mM. In one series of experiments the Mg2+ was withdrawn after 3-4 min and reapplied 35-40 min later in order to divide the total output of quanta into two approximately equal bouts of secretion that were well separated in time. 4. The total number of MEPPs recorded at a junction was loosely correlated with the length of its nerve terminal, but it was not affected by the temperature, the concentration of Mg2+ or the division of secretion into well-separated bouts of quantal release. The average total secretion per unit length was about 3700 quanta/sarcomere or about 1200 quanta/microns. 5. The average time course of quantal secretion per micrometre of terminal was determined at

  11. 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.

  12. 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.

  13. 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.

  14. Decoherence and the fate of an infalling wave packet: Is Alice burning or fuzzing?

    NASA Astrophysics Data System (ADS)

    Chowdhury, Borun D.; Puhm, Andrea

    2013-09-01

    Recently, Almheiri, Marolf, Polchinski, and Sully have suggested a Gedankenexperiment to test black hole complementarity. They claim that the postulates of black hole complementarity are mutually inconsistent and choose to give up the “absence of drama” for an infalling observer. According to them, the black hole is shielded by a firewall no later than Page time. This has generated some controversy. We find that an interesting picture emerges when we take into account objections from the advocates of fuzzballs. We reformulate Almheiri, Marolf, Polchinski, and Sully’s Gedankenexperiment in the decoherence picture of quantum mechanics and find that low energy wave packets interact with the radiation quanta rather violently while high energy wave packets do not. This is consistent with Mathur’s recent proposal of fuzzball complementarity for high energy quanta falling into fuzzballs.

  15. Energy sources, self-organization, and the origin of life.

    PubMed

    Boiteau, Laurent; Pascal, Robert

    2011-02-01

    The emergence and early developments of life are considered from the point of view that contingent events that inevitably marked evolution were accompanied by deterministic driving forces governing the selection between different alternatives. Accordingly, potential energy sources are considered for their propensity to induce self-organization within the scope of the chemical approach to the origin of life. Requirements in terms of quality of energy locate thermal or photochemical activation in the atmosphere as highly likely processes for the formation of activated low-molecular weight organic compounds prone to induce biomolecular self-organization through their ability to deliver quanta of energy matching the needs of early biochemical pathways or the reproduction of self-replicating entities. These lines of reasoning suggest the existence of a direct connection between the free energy content of intermediates of early pathways and the quanta of energy delivered by available sources of energy.

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

    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.

  17. Precision Measurement in Biology

    NASA Astrophysics Data System (ADS)

    Quake, Stephen

    Is biology a quantitative science like physics? I will discuss the role of precision measurement in both physics and biology, and argue that in fact both fields can be tied together by the use and consequences of precision measurement. The elementary quanta of biology are twofold: the macromolecule and the cell. Cells are the fundamental unit of life, and macromolecules are the fundamental elements of the cell. I will describe how precision measurements have been used to explore the basic properties of these quanta, and more generally how the quest for higher precision almost inevitably leads to the development of new technologies, which in turn catalyze further scientific discovery. In the 21st century, there are no remaining experimental barriers to biology becoming a truly quantitative and mathematical science.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Quantum Yields of CAM Plants Measured by Photosynthetic O(2) Exchange.

    PubMed

    Adams, W W; Nishida, K; Osmond, C B

    1986-05-01

    The quantum yield of photosynthetic O(2) exchange was measured in eight species of leaf succulents representative of both malic enzyme type and phosphoenolpyruvate carboxykinase type CAM plants. Measurements were made at 25 degrees C and CO(2) saturation using a leaf disc O(2) electrode system, either during or after deacidification. The mean quantum yield was 0.095 +/- 0.012 (sd) moles O(2) per mole quanta, which compared with 0.094 +/- 0.006 (sd) moles O(2) per mole quanta for spinach leaf discs measured under the same conditions. There were no consistent differences in quantum yield between decarboxylation types or during different phases of CAM metabolism. On the basis of current notions of compartmentation of CAM biochemistry, our observations are interpreted to indicate that CO(2) refixation is energetically independent of gluconeogenesis during deacidification.

  4. 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.

  5. Synchrotron Radiation from a Charge Moving Along Helical Orbit around a Dielectric Cylinder

    NASA Astrophysics Data System (ADS)

    Saharian, A. A.; Kotanjyan, A. S.

    2010-04-01

    The radiation emitted by a charged particle moving along a helical orbit around a dielectric cylinder immersed in a homogeneous medium is investigated. Formulae are derived for the electromagnetic potentials, electric and magnetic fields, and for the spectral-angular distribution of the radiation in the exterior medium. It is shown that under the Cherenkov condition for dielectric permittivity of the cylinder and the velocity of the particle image on the cylinder surface, strong narrow peaks appear in the angular distribution for the number of radiated quanta. At these peaks the radiated energy exceeds the corresponding quantity for a homogeneous medium by some orders of magnitude. The results of numerical calculations for the angular distribution of radiated quanta are presented and they are compared with the corresponding quantities for radiation in a homogeneous medium. It is shown that the presence of the cylinder can increase essentially the radiation intensity.

  6. Visibility Of The Sea With Special Reference To The Secchi Disc

    NASA Astrophysics Data System (ADS)

    Hojerslev, Niels K.

    1986-08-01

    A general visibility theory valid in inhomogeneous hydrosols is presented and experimentally verified for some special cases. The field measurements used in the experimental verification were obtained from both oligotrophic and eutrophic regions in the sea and comprise of a fairly large Danish and French data set consisting of spectral downward and upward irradiances, downward quanta irradiance, spectral light transmission, spectral radiance distributions and finally, spectral Secchi disc measurements.

  7. 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.

  8. 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.

  9. Stimulated second-order processes in the interaction of a spinless quantum particle beam with a self-consistent electromagnetic field

    SciTech Connect

    Kuzelev, M. V.

    2011-02-15

    A nonlinear theory of interaction of two electromagnetic waves with a beam or a gas of spinless charged particles is developed. The effects of stimulated Compton scattering of electromagnetic waves and stimulated particle pair production (annihilation) during a collision of two electromagnetic quanta are investigated. Other stimulated processes that can occur only in a medium and decelerate electromagnetic waves are also considered. The relation between stimulated processes and various types of instabilities considered in classical electrodynamics of plasmas and plasmalike media is demonstrated.

  10. Highlights on Novel Technologies for the Detection of Antibodies to Ro60, Ro52, and SS-B

    PubMed Central

    Infantino, M.; Bentow, C.; Seaman, A.; Benucci, M.; Atzeni, F.; Sarzi-Puttini, P.; Olivito, B.; Meacci, F.; Manfredi, M.; Mahler, M.

    2013-01-01

    Objective. We aimed to compare a chemiluminescent immunoassay (CIA, QUANTA Flash) on BIO-FLASH with a multiplex flow immunoassay (MFI) on BioPlex 2200 for the detection of antibodies to Ro60, Ro52, and SS-B. Methods. The study included 241 samples, from patients suffering from systemic autoimmune diseases (n = 108) as well as disease controls (n = 133). All samples were tested for anti-Ro52, anti-Ro60, and anti-SS-B (La) antibodies on QUANTA Flash (INOVA Diagnostics, San Diego, USA) and BioPlex 2200 (Bio-Rad Laboratories Inc., Hercules, USA). Discrepant samples were tested by two independent methods: BlueDot/ANA and QUANTRIX Microarray (both D-tek, Belgium). Results. The overall qualitative agreements were 95.4% (95% confidence interval, CI 92.0–97.7%) for anti-Ro52, 98.8% (95% CI 96.4–99.7%) for anti-Ro60, and 91.7% (95% CI 87.5–94.9%) for anti-SS-B antibodies. There were 34 discrepant samples among all assays (20 anti-SS-B, 11 anti-Ro52, 3 anti-Ro60). 30/33 of retested samples (by D-tek dot blot) agreed with the QUANTA Flash results. Similar findings were obtained with QUANTRIX Microarray kit. Conclusion. QUANTA Flash and BioPlex 2200 show good qualitative agreement. The clinical performances were similar for anti-Ro52 and anti-Ro60 autoantibodies while differences were observed for anti-SS-B (La) antibodies. PMID:24376466

  11. Simulation of coherent energy transfer in an alpha-helical peptide by Fermi resonance.

    PubMed Central

    Clarke, D L; Collins, M A

    1992-01-01

    A mechanism by which NH stretching quanta are coherently transported along a chain of hydrogen bonded peptide groups is demonstrated by classical simulation of a section of the alpha-helical peptide poly(L-alanine). Vibrational motion takes place on a complex energy surface constructed from earlier ab initio and empirical surfaces. A speculative hypothesis of the biological role of this mechanism is presented, and the critical parameters governing the dynamics are identified and discussed. Images FIGURE 1 PMID:1547322

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. The properties of gamma-radiation and high-energy neutron fluxes in "MIR" station orbit.

    PubMed

    Bogomolov, A V; Bogomolov, V V; Denisov, Yu I; Logachev, Yu I; Svertilov, S I; Kudryavtsev, M I; Lyagushin, V I; Ershova, T V

    2002-10-01

    The study of radiation background components in the near-Earth space is very important for different branches of space research, in particular for space dosimetry and for the planning of gamma-astronomy experiments. Detailed information on the neutral components (gamma-quanta, neutrons) of background radiation was obtained during the Grif-1 experiment onboard Mir orbital station (OS). The measurements of fluxes of 0.05-50 MeV gamma-quanta and >30 MeV neutrons with a large area instrument (approximately 250 cm2 for gamma-quanta, approximately 30 cm2 for neutrons) as well as corresponding charged particle measurements (0.4-1.5 MeV electrons, 1-200 MeV protons) were made during this experiment. The background components induced by the station's own radiation as well as the albedo gamma-rays from the Earth's atmosphere were revealed as the result of data analysis for about 600 h of observation. A mathematical model describing the latitude and energy dependences of atmospheric albedo gamma-rays as well as of those of gamma-quanta produced in the material of the station due to cosmic ray interactions was developed. An analytical approximation of the spectrum of induced gamma-rays from radioactive isotopes stored in the station and instrument's materials is presented. The dynamics of gamma-quantum background fluxes during the geomagnetic disturbances of January 10-11, 1997 are discussed. An analytical representation of the latitude dependence of the integral flux of neutrons with >30 MeV is given.

  17. Novel Role for Phycoerythrin in a Marine Cyanobacterium, Synechococcus Strain DC2.

    PubMed

    Wyman, M; Gregory, R P; Carr, N G

    1985-11-15

    Cyanobacterial picoplankton contribute substantially to oceanic primary productivity. The colored protein phycoerythrin is the major component of their light-harvesting apparatus. It was found that in Synechococcus strain DC2 a variable proportion of the light energy absorbed by phycoerythrin is lost as autofluorescence and therefore is not passed to a photoreaction center. Phycoerythrin may serve two functionally distinct roles in this organism: as a nitrogen reserve and as a collector of quanta for photosynthesis.

  18. Adhesion Forces Between Individual Ligand-Receptor Pairs

    NASA Astrophysics Data System (ADS)

    Florin, Ernst-Ludwig; Moy, Vincent T.; Gaub, Hermann E.

    1994-04-01

    The adhesion force between the tip of an atomic force microscope cantilever derivatized with avidin and agarose beads functionalized with biotin, desthiobiotin, or iminobiotin was measured. Under conditions that allowed only a limited number of molecular pairs to interact, the force required to separate tip and bead was found to be quantized in integer multiples of 160 ± 20 piconewtons for biotin and 85 ± 15 piconewtons for iminobiotin. The measured force quanta are interpreted as the unbinding forces of individual molecular pairs.

  19. 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.

  20. The properties of gamma-radiation and high-energy neutron fluxes in "MIR" station orbit.

    PubMed

    Bogomolov, A V; Bogomolov, V V; Denisov, Yu I; Logachev, Yu I; Svertilov, S I; Kudryavtsev, M I; Lyagushin, V I; Ershova, T V

    2002-10-01

    The study of radiation background components in the near-Earth space is very important for different branches of space research, in particular for space dosimetry and for the planning of gamma-astronomy experiments. Detailed information on the neutral components (gamma-quanta, neutrons) of background radiation was obtained during the Grif-1 experiment onboard Mir orbital station (OS). The measurements of fluxes of 0.05-50 MeV gamma-quanta and >30 MeV neutrons with a large area instrument (approximately 250 cm2 for gamma-quanta, approximately 30 cm2 for neutrons) as well as corresponding charged particle measurements (0.4-1.5 MeV electrons, 1-200 MeV protons) were made during this experiment. The background components induced by the station's own radiation as well as the albedo gamma-rays from the Earth's atmosphere were revealed as the result of data analysis for about 600 h of observation. A mathematical model describing the latitude and energy dependences of atmospheric albedo gamma-rays as well as of those of gamma-quanta produced in the material of the station due to cosmic ray interactions was developed. An analytical approximation of the spectrum of induced gamma-rays from radioactive isotopes stored in the station and instrument's materials is presented. The dynamics of gamma-quantum background fluxes during the geomagnetic disturbances of January 10-11, 1997 are discussed. An analytical representation of the latitude dependence of the integral flux of neutrons with >30 MeV is given. PMID:12442742

  1. On the secretory activity of single varicosities in the sympathetic nerves innervating the rat tail artery.

    PubMed

    Astrand, P; Stjärne, L

    1989-02-01

    1. Nerve terminal impulses (NTIs) and spontaneous or stimulus-evoked excitatory junction currents (SEJCs or EJCs), reflecting secretion of transmitter quanta from release sites in the sympathetic nerves of rat tail artery, were recorded by extracellular electrodes. 2. The release of transmitter quanta from single varicosities was analysed on a pulse-by-pulse basis. 3. Since the SEJCs were tetrodotoxin-resistant, and hence probably caused by single quanta, they were employed to analyse the quantal content of EJCs. 4. In the majority of recordings, EJCs were large compared to SEJCs from the same attachment, and preceded by prominent NTIs. This type of activity appeared to reflect simultaneous activation of several nerve fibres and numerous varicosities. 5. By focal stimulation, it was usually possible to improve the resolution by examining spots in which a large proportion of the suprathreshold stimuli failed to cause EJCs. Here, averaged NTIs preceding large EJCs were indistinguishable from averaged NTIs not followed by EJCs. Thus, failure of invasion by the nerve impulse was not a cause of the frequent secretory failure. 6. In these attachments the amplitude distribution of nerve stimulus-evoked EJCs was similar to that of the SEJCs and many individual EJCs could be matched in amplitude and time course by SEJCs. Thus, transmitter secretion from these sympathetic nerve varicosities seems to be basically monoquantal. 7. Under conditions when all EJCs were smaller than or equal to the largest SEJCs some characteristic EJC profiles appeared only a few times in response to several hundred suprathreshold stimuli at low frequency (0.5-1 Hz). Using tentatively these EJCs as 'fingerprints' of single quanta from particular release sites, the probability for activation of individual release sites ranges from 0.002 to 0.02.

  2. Particles and energy fluxes from a conformal field theory perspective

    NASA Astrophysics Data System (ADS)

    Fabbri, A.; Navarro-Salas, J.; Olmo, G. J.

    2004-09-01

    We analyze the creation of particles in two dimensions under the action of conformal transformations. We focus our attention on Mobius transformations and compare the usual approach, based on the Bogoliubov coefficients, with an alternative but equivalent viewpoint based on correlation functions. In the latter approach the absence of particle production under full Mobius transformations is manifest. Moreover, we give examples, using the moving-mirror analogy, to illustrate the close relation between the production of quanta and energy.

  3. Particles and energy fluxes from a conformal field theory perspective

    SciTech Connect

    Fabbri, A.; Navarro-Salas, J.; Olmo, G.J.

    2004-09-15

    We analyze the creation of particles in two dimensions under the action of conformal transformations. We focus our attention on Mobius transformations and compare the usual approach, based on the Bogoliubov coefficients, with an alternative but equivalent viewpoint based on correlation functions. In the latter approach the absence of particle production under full Mobius transformations is manifest. Moreover, we give examples, using the moving-mirror analogy, to illustrate the close relation between the production of quanta and energy.

  4. Quantized Redshifts of Galaxies: Stimulated Raman Scattering in Cold Intergalactic Rydberg Matter

    NASA Astrophysics Data System (ADS)

    Holmlid, Leif

    2004-05-01

    That the redshifts for galaxies in the local supercluster are quantizedwas recently confirmedby Guthrie and Napier(A&A310 (1996) 353). These redshifts are here proposed to be due to stimulatedStokes Raman processes in intergalactic matter in the form of Rydberg Matter (RM). Rydberg Matteris an electronically excited material, as demonstrated by its use as laser medium in a thermally excitedultra-broadband tunable IR laser (Chem. Phys. Lett. 376 (2003) 812). Its existence in interstellar andintergalactic space is demonstrated by several observational results, notably the unidentified IR bands,that agree well with the emission from Rydberg Matter. A stimulated Raman process will allow theH I 21 cm radiation to proceed without deflection, in agreement with observation. Such redshiftswill be additive during the passage through space. The process in Rydberg Matter here proposed togive rise to the Stokes Raman process is excitation of electronic translational modes in the planarclusters forming the matter. The specific cluster sizes found in laboratory experiments give rise toa few differently sized redshift quanta, which is in good agreement with the observed quanta. Anexcitation level (principal quantum number) of Rydberg Matter in intergalactic space between 175and 200 gives the correct size of the redshift quanta.

  5. 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

  6. The flaw in the firewall argument

    NASA Astrophysics Data System (ADS)

    Mathur, Samir D.; Turton, David

    2014-07-01

    A lot of confusion surrounds the issue of black hole complementarity, because the question has been considered without discussing the mechanism which guarantees unitarity. Considering such a mechanism leads to the following: (1) The Hawking quanta with energy E of order the black hole temperature T carry information, and so only appropriate processes involving E≫T quanta can have any possible complementary description with an information-free horizon; (2) The stretched horizon describes all possible black hole states with a given mass M, and it must expand out to a distance sbubble before it can accept additional infalling bits; (3) The Hawking radiation has a specific low temperature T, and infalling quanta interact significantly with it only within a distance sα of the horizon. One finds sα≪sbubble for E≫T, and this removes the argument against complementarity recently made by Almheiri et al. In particular, the condition E≫T leads to the notion of ‘fuzzball complementarity', where the modes around the horizon are indeed correctly entangled in the complementary picture to give the vacuum.

  7. Feasibility study of activity measurement of positron emitters based on gamma-gamma coincident detection by two NaI(Tl) detectors.

    PubMed

    Volkovitsky, Peter; Unterweger, Michael

    2012-09-01

    Detection of two and more γ-rays in coincidence by two NaI(Tl) detectors with almost 4π geometry allows absolute characterization of radionuclides emitting coincidence gammas. The method is a generalization of the Eldridge-Crowther method developed originally for x-rays and low energy γ-rays. This method is applied to the case of (94)Nb decay with two coincident gamma-rays emitted in one cascade. The application of this method for the case of coincident positron-gamma emission ((22)Na and (26)Al sources) meets some difficulties. In these decays, two 511 keV gamma quanta produced in positron annihilation are strongly correlated. Despite the fact that the third gamma emitted in (22)Na and (26)Al decays is not correlated with two annihilation quanta, the number of independent observables for (22)Na and (26)Al decays is less than the number of unknowns. The small parameter ω(00), the probability that both annihilation quanta escape detection in both NaI(Tl) detectors, cannot be determined. However, if this parameter is defined from experimental data for one source with known activity ((22)Na), the activity of the other source ((26)Al) can be calculated from experimental data for (26)Al decay.

  8. The controversy over the minimum quantum requirement for oxygen evolution.

    PubMed

    Hill, Jane F; Govindjee

    2014-10-01

    During the early- to mid-twentieth century, a bitter controversy raged among researchers on photosynthesis regarding the minimum number of light quanta required for the evolution of one molecule of oxygen. From 1923 until his death in 1970, Otto Warburg insisted that this value was about three or four quanta. Beginning in the late 1930s, Robert Emerson and others on the opposing side consistently obtained a value of 8-12 quanta. Warburg changed the protocols of his experiments, sometimes in unexplained ways, yet he almost always arrived at a value of four or less, except eight in carbonate/bicarbonate buffer, which he dismissed as "unphysiological". This paper is largely an abbreviated form of the detailed story on the minimum quantum requirement of photosynthesis, as told by Nickelsen and Govindjee (The maximum quantum yield controversy: Otto Warburg and the "Midwest-Gang", 2011); we provide here a scientific thread, leaving out the voluminous private correspondence among the principal players that Nickelsen and Govindjee (2011) examined in conjunction with their analysis of the principals' published papers. We explore the development and course of the controversy and the ultimate resolution in favor of Emerson's result as the phenomenon of the two-light-reaction, two-pigment-system scheme of photosynthesis came to be understood. In addition, we include a brief discussion of the discovery by Otto Warburg of the requirement for bicarbonate in the Hill reaction.

  9. The effect of calcium ions and temperature on the binomial parameters that control acetylcholine release by a nerve impulse at amphibian neuromuscular synapses

    PubMed Central

    Bennett, M. R.; Fisher, C.; Florin, T.; Quine, M.; Robinson, J.

    1977-01-01

    1. A study has been made of the effects of changing the external calcium concentration, [Ca]o, and the temperature on both the number of quanta available for release by the nerve impulse (n) as well as the increase in release probability of a quantum p(t) during the release period (from 0 to T) following a nerve impulse at synapses in amphibian striated muscle. 2. When [Ca]o was increased in the low range from 0·25 to 0·4 mM at 18 °C, the average quantal content of the e.p.p. (m̄) increased as the fourth power of [Ca]o and this was primarily due to a third power dependence of n on [Ca]o; the dissociation constants and power dependence of n on calcium determined in the [Ca]o range from 0·25 to 1·0 mM were successfully used to predict the changes in size of the e.p.p. in the very high [Ca]o range from 1 to 10 mM. When the temperature was increased from 7 to 18 °C in a [Ca]o of 0·6 mM or 0·35 mM, n increased with a Q10 of 2·5. 3. When [Ca]o was increased in the range from 0·25 to 1·0 mM at 18 °C, the probability that a quantum initially available for release is released during the release period (p(T)) was very sensitive to [Ca]o, increasing as the third power of [Ca]o and with a dissociation constant of 0·13 mM. When the temperature was increased from 7 to 18 °C in a [Ca]o of 0·6 mM or 0·35 mM, p(T) decreased. 4. The histograms of latencies of individual quanta following a nerve impulse was very temperature dependent: the time to peak of the histograms (i.e. the interval in which most quanta fell) had a Q10 of over 4 as did the time constant of decline of the histograms in the temperature range from 7 to 18 °C. 5. The average number of quanta released up to time t during the release period following a nerve impulse, namely np(t), was well described by a stochastic process in which p(t) was determined by two reactions; one of these reactions released available quanta from the nerve terminal whilst the other made some of the available quanta

  10. 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.

  11. Comparison of two experiments on radiative neutron decay

    NASA Astrophysics Data System (ADS)

    Khafizov, R. U.; Tolokonnikov, S. V.; Solovei, V. A.; Kolhidashvili, M. R.

    2009-12-01

    Over 10 years ago we proposed an experiment on measuring the characteristics of radiative neutron decay in papers [1, 2]. At the same time we had published the theoretical spectrum of radiative gamma quanta, calculated within the framework of the electroweak interactions, on the basis of which we proposed the methodology for the future experiment [3, 4]. However, because we were denied beam time on the intensive cold neutron beam at ILL (Grenoble, France) for a number of years, we could only conduct the experiment in 2005 on the newly opened FRMII reactor of Technical University of Muenchen. The main result of this experiment was the discovery of radiative neutron decay and the measurement of its relative intensity B.R. = (3.2 ± 1.6) × 10-3 with C.L. = 99.7% for radiative gamma quanta with energy over 35 kev [5, 6]. Over a year after our first announcement about the results of the conducted experiment, “Nature” [7] published a letter asserting that its authors have also measured the branching ratio of radiative neutron decay B.R. = (3.13 ± 0.34) × 10-3 with c.l. = 68% and gamma quanta energy from 15 to 340 kev. This article aims to compare these two experiments. It is shown that the use of strong magnetic fields in the NIST (Washington, USA) experiment methodology not only prevents any exact measurement of the branching ratio and identification of radiative neutron decay events, but also makes registration of ordinary neutron decay events impossible.

  12. 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.

  13. 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

  14. Nonlocal thermodynamic equilibrium effects in stratospheric NO and implications for infrared remote sensing

    NASA Technical Reports Server (NTRS)

    Kaye, Jack A.; Kumer, John B.

    1987-01-01

    It is shown that the vibrational state population of stratospheric nitric oxide (NO) could be substantially different from that expected on the basis of LTE. Deviations from LTE may arise because stratospheric NO can be photochemically produced from NO2 with several vibrational quanta. Model calculations suggest that the population of NO(v = 1) could be some 30 percent above that expected from LTE at 30 km, with smaller enhancements above and below. Substantially larger enhancements are predicted for NO(v = 2). This result is shown to have important implications for NO determination by remote sensing of IR emission. Data needed for the quantification of these effects are enumerated.

  15. Description of ion motion in a Paul trap immersed in a cold atomic gas

    NASA Astrophysics Data System (ADS)

    Krych, Michał; Idziaszek, Zbigniew

    2015-02-01

    We investigate the problem of a single ion in a radio-frequency trap immersed in an ultracold Bose gas in either a condensed or a noncondensed phase. We develop a master-equation formalism describing the sympathetic cooling, and we determine the cooling rates of ions. We show that the cold atomic reservoir modifies the stability diagram of the ion in the Paul trap, creating regions where the ion is either cooled or heated due to the energy quanta exchanged with the time-dependent potential.

  16. In search of symmetry lost.

    PubMed

    Wilczek, Frank

    2005-01-20

    Powerful symmetry principles have guided physicists in their quest for nature's fundamental laws. The successful gauge theory of electroweak interactions postulates a more extensive symmetry for its equations than are manifest in the world. The discrepancy is ascribed to a pervasive symmetry-breaking field, which fills all space uniformly, rendering the Universe a sort of exotic superconductor. So far, the evidence for these bold ideas is indirect. But soon the theory will undergo a critical test depending on whether the quanta of this symmetry-breaking field, the so-called Higgs particles, are produced at the Large Hadron Collider (due to begin operation in 2007).

  17. Entropy-enthalpy Compensation of Biomolecular Systems in Aqueous Phase: a Dry Perspective.

    PubMed

    Movileanu, Liviu; Schiff, Eric A

    2013-01-01

    We survey thermodynamic measurements on processes involving biological macromolecules in aqueous solution, which illustrate well the ubiquitous phenomenon of entropy-enthalpy compensation. The processes include protein folding/unfolding and ligand binding/unbinding, with compensation temperatures varying by about 50 K around an average near 293 K. We show that incorporating both near-exact entropy-enthalpy compensation (due to solvent relaxation) and multi-excitation entropy (from vibrational quanta) leads to a compensation temperature in water of about 230 K. We illustrate a general procedure for subtracting solvent and environment-related terms to determine the bare Gibbs free energy changes of chemical processes.

  18. 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)

  19. 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.

  20. Electric discharge in water as a source of UV radiation, ozone and hydrogen peroxide

    NASA Astrophysics Data System (ADS)

    Anpilov, A. M.; Barkhudarov, E. M.; Bark, Yu B.; Zadiraka, Yu V.; Christofi, M.; Kozlov, Yu N.; Kossyi, I. A.; Kop'ev, V. A.; Silakov, V. P.; Taktakishvili, M. I.; Temchin, S. M.

    2001-03-01

    Results are presented from investigations of multispark electric discharge in water excited along multielectrode metal-dielectric systems with gas supply into the interelectrode gaps. The intensity distribution of discharge radiation in the region covering the biologically active soft UV (190≤λ≤430 nm) has been determined and the absolute number of quanta in this wavelength interval has been measured. The potentiality of the slipping surface discharge in water for its disinfection is analysed. The energy expenditure for water cleansing is estimated to be as low as ~10-4 kWh l-1.

  1. Gravity from a modified commutator

    SciTech Connect

    Jackson, Mark G.; /Fermilab

    2005-05-01

    We show that a suitably chosen position-momentum commutator can elegantly describe many features of gravity, including the IR/UV correspondence and dimensional reduction (''holography''). Using the most simplistic example based on dimensional analysis of black holes, we construct a commutator which qualitatively exhibits these novel properties of gravity. Dimensional reduction occurs because the quanta size grow quickly with momenta, and thus cannot be ''packed together'' as densely as naively expected. We conjecture that a more precise form of this commutator should be able to quantitatively reproduce all of these features.

  2. Entropy-enthalpy Compensation of Biomolecular Systems in Aqueous Phase: a Dry Perspective

    PubMed Central

    Movileanu, Liviu; Schiff, Eric A.

    2013-01-01

    We survey thermodynamic measurements on processes involving biological macromolecules in aqueous solution, which illustrate well the ubiquitous phenomenon of entropy-enthalpy compensation. The processes include protein folding/unfolding and ligand binding/unbinding, with compensation temperatures varying by about 50 K around an average near 293 K. We show that incorporating both near-exact entropy-enthalpy compensation (due to solvent relaxation) and multi-excitation entropy (from vibrational quanta) leads to a compensation temperature in water of about 230 K. We illustrate a general procedure for subtracting solvent and environment-related terms to determine the bare Gibbs free energy changes of chemical processes. PMID:23976794

  3. 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.

  4. 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.

  5. 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

  6. Formation of metallacyclic C[sub 60] derivatives via gas-phase ion-molecule reactions

    SciTech Connect

    Kan, S.Z.; Byun, Y.G.; Freiser, B.S. )

    1995-01-25

    In this paper we report the gas-phase reactions of C[sub 60] with Fe(benzyne)[sup +] in which metallacyclic C[sub 80] derivatives are formed. All experiments were performed on an Extrel FTMS-2000 dual cell Fourier transform ion cyclotron resonance mass spectrometer equipped with a 3 T superconducting magnet. The ion-trapping potential was set at 2 V. A Bayard-Alpert ion gauge was used to monitor pressure. Fe[sup +] was generated by laser desorption of the pure iron metal target using a Quanta-Ray Nd:YAG laser operated at its fundamental output (1064 nm). 43 refs., 1 fig.

  7. 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

  8. [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

  9. 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.

  10. 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.

  11. 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.

  12. Surface plasmon amplification by stimulated emission of radiation: quantum generation of coherent surface plasmons in nanosystems.

    PubMed

    Bergman, David J; Stockman, Mark I

    2003-01-17

    We make a step towards quantum nanoplasmonics: surface plasmon fields of a nanosystem are quantized and their stimulated emission is considered. We introduce a quantum generator for surface plasmon quanta and consider the phenomenon of surface plasmon amplification by stimulated emission of radiation (spaser). Spaser generates temporally coherent high-intensity fields of selected surface plasmon modes that can be strongly localized on the nanoscale, including dark modes that do not couple to far-zone electromagnetic fields. Applications and related phenomena are discussed. PMID:12570577

  13. 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.

  14. 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

  15. IS THE GALACTIC COSMIC-RAY SPECTRUM CONSTANT IN TIME?

    SciTech Connect

    Eichler, David; Kumar, Rahul; Pohl, Martin E-mail: rahuliitk@gmail.com

    2013-06-01

    The hypothesis is considered that the present, local Galactic cosmic-ray spectrum is, due to source intermittency, softer than average over time and over the Galaxy. Measurements of muogenic nuclides underground could provide an independent measurement of the time-averaged spectrum. Source intermittency could also account for the surprising low anisotropy reported by the IceCube Collaboration. Predictions for Galactic emission of ultrahigh-energy (UHE) quanta, such as UHE gamma rays and neutrinos, might be higher or lower than previously estimated.

  16. 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.

  17. Vibration wavenumbers of 3-aminobenzotrifluoride in the ground and S1 electronic states from its infrared, Raman, and supersonic jet S1- S0 fluorescence spectra

    NASA Astrophysics Data System (ADS)

    Ribeiro-Claro, Paulo J. A.; Teixeira-Dias, JoséJ. C.; Gordon, Robert D.; Hollas, J. Michael

    1991-11-01

    Raman and infrared spectra of 3-aminobenzotrifluoride, in the liquid phase, and single vibronic level fluorescence spectra, in a supersonic jet, have been obtained and interpreted to give a fairly complete set of vibrational assignments in S0. These include the observation of the I 20 band in fluorescence, where ν1 is the NH 2-inversion vibration, in agreement with a previous interpretation of the gas phase far infrared spectrum. A strong Fermi resonance between one quantum of the a'CCF 3 bending vibration and two quanta of the a″CCF 3 bending vibration has been identified in S1.

  18. Optical properties of monodispersed silver nanoparticles produced via reverse micelle microemulsion

    NASA Astrophysics Data System (ADS)

    Zhang, Danhui; Liu, Xiaoheng; Wang, Xin; Yang, Xujie; Lu, Lude

    2011-04-01

    Silver nanoparticles produced by the sodium borohydride reduction of silver nitrate were stabilized by means of 1-dodecanethiol providing sulfur atom. (n-Dodecyl) trimethylammonium bromide (DTAB), which was used as a phase transfer agent in two-phase system involving water and toluene, played a significant role in the formation of monolayer-protected silver nanoparticles. These nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible absorption spectroscopy (UV-vis), FT-IR spectra and fluorescence. The results indicate that the system is monodispersed and leads to the self-assembly of silver nanoparticles into 0-D quanta-dot arrays.

  19. 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.

  20. 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.

  1. 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

  2. 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. .

  3. Vortex imaging of magnetic superconductor HoNi 2B 2C by scanning SQUID microscopy

    NASA Astrophysics Data System (ADS)

    Hata, Y.; Suzuki, J.; Kakeya, I.; Kadowaki, K.; Nakayama, S.; Nagata, A.; Odawara, A.; Chinone, K.

    2002-10-01

    We have observed vortex trapped images in the ab-plane of a HoNi 2B 2C single crystal in a magnetic field of 1.2 μT at 4 K using a scanning SQUID microscope. The vortex observed has a fine structure consisting of two regions with opposite signs of the magnetic field which is quantized with multiple flux quanta as a whole. The spatial size of the magnetic field distribution extends over 10 μm. Such giant vortices are also observed at TN< T< TC and disappear above TC where TN is the magnetic transition temperature and TC is the superconducting transition temperature.

  4. Waiting for the W - and the Higgs

    NASA Astrophysics Data System (ADS)

    Tannenbaum, M. J.

    2016-10-01

    The search for the left-handed W ± bosons, the proposed quanta of the weak interaction, and the Higgs boson, which spontaneously breaks the symmetry of unification of electromagnetic and weak interactions, has driven elementary-particle physics research from the time that I entered college to the present and has led to many unexpected and exciting discoveries which revolutionized our view of subnuclear physics over that period. In this article I describe how these searches and discoveries have intertwined with my own career.

  5. 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 .

  6. 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.

  7. 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.

  8. 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.

  9. Optimal feedback in efficient single-cavity optical parametric oscillators

    SciTech Connect

    Petnikova, V M; Shuvalov, Vladimir V

    2010-09-10

    An approach based on the description of competition of quadratic processes of merging and decomposition of quanta resulting in the formation of cnoidal waves on an effective cascade cubic Kerr-type nonlinearity is used to optimise the scheme of a single-cavity optical parametric oscillator. It is shown that the use of a feedback circuit (cavity) decreases the period of cnoidal waves produced in a nonlinear crystal, while the optimisation procedure of the transfer constant of this circuit (reflectivity of the output mirror of the cavity) is reduced to matching this period with the nonlinear crystal length. (optical parametric oscillators)

  10. Oil from plants

    NASA Astrophysics Data System (ADS)

    Calvin, M.

    1983-01-01

    As a result of the exhaustion of our supplies of ancient photosynthesis (oil and gas) it is necessary to develop renewable fuels for the future. The most immediate source of renewable fuel is, of course, the annually growing green plants, some of which produce hydrocarbon(s) directly. New plant sources can be selected for this purpose, plants which have high potential for production of chemicals and liquid fuels. Suggestions are made for modification of both the product character and the productivity of the plants. Ultimately, a totally synthetic device will be developed for the conversion of solar quanta into useful chemical form completely independent of the need for arable land.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. [Quantitative and qualitative characteristics of representatives of the enterobacteriaceae family in postradiation intestinal dysbacteriosis].

    PubMed

    Pinegin, B V; Korshunov, V M; Ikonnikova, T B; Kissina, E V

    1980-08-01

    The irradiation of CBA mice with gamma quanta in a dose of 700 C/kg resulted in the development of postradiation intestinal dysbacteriosis in the animals. The dysbacteriosis was characterized by a considerable increase in the number of Escherichia and Proteus mirabilis in the large intestine and by the insemination of the small intestine with these microbial associations. Pr. vulgaris, Pr. morganii, Ent. aerogenes, Ent. cloacae, Citrobacter appeared in great numbers in the intestinal tract of the irradiated mice, while none of these organisms were found in the intact mice.

  16. 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.

  17. Quantised transistor response to ion channels revealed by nonstationary noise analysis

    NASA Astrophysics Data System (ADS)

    Becker-Freyseng, C.; Fromherz, P.

    2011-11-01

    We report on the quantised response of a field-effect transistor to molecular ion channels in a biomembrane. HEK293-type cells overexpressing the Shaker B potassium channel were cultured on a silicon chip. An enhanced noise of the transistor is observed when the ion channels are activated. The analysis of the fluctuations in terms of binomial statistics identifies voltage quanta of about 1 μV on the gate. They are attributed to the channel currents that affect the gate voltage according to the Green's function of the cell-chip junction.

  18. Electric spaser in the extreme quantum limit.

    PubMed

    Li, Dabing; Stockman, Mark I

    2013-03-01

    We consider theoretically the spaser that is excited electrically via a nanowire with ballistic quantum conductance. We show that, in the extreme quantum regime, i.e., for a single conductance-quantum nanowire, the spaser with a core made of common plasmonic metals, such as silver and gold, is fundamentally possible. For ballistic nanowires with multiple-quanta or nonquantized conductance, the performance of the spaser is enhanced in comparison with the extreme quantum limit. The electrically pumped spaser is promising as an optical source, nanoamplifier, and digital logic device for optoelectronic information processing with a speed of ~100 GHz to ~100 THz. PMID:23521278

  19. 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.

  20. 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

  1. Development of defects in the structure of PIN dosimetry diodes exposed to gamma radiation

    NASA Astrophysics Data System (ADS)

    Sopko, V.; Sopko, B.; Chren, D.; Dammer, J.

    2013-12-01

    Studies of radiation induced defects continue to be relevant as they find an ever greater application due to the increasing radiation doses to which semiconductor detectors are exposed. Efforts of figuring out the changes due to high radiation doses provide the fundamental motivation for this type of experiments. The PIN diode is described, and a developmental disorder caused thereto by 60Co source gamma quanta ranging from 100 kGy to 1 MGy. The calibration curve shows the effect of disturbances on the volt-ampere characteristics as a function of the dose of gamma radiation. The results are compared with earlier published data.

  2. 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.

  3. 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.

  4. 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.

  5. Performance of an X-ray imaging detector based on a structured scintillator

    NASA Astrophysics Data System (ADS)

    Svenonius, Olof; Sahlholm, Anna; Wiklund, Per; Linnros, Jan

    2009-08-01

    Structured scintillator plates have been fabricated by filling thallium-doped caesium iodide (CsI) into a silicon pore array. Their X-ray imaging properties have been characterized using a standard dental X-ray source and a charge coupled device (CCD) detector. Results indicate that finer structured pore arrays provide superior imaging resolution while their light output is lower. Direct absorption of X-ray quanta in the CCD is a significant contributor of detector noise. This can be avoided by using a thick fibre optic plate or, in certain cases, by using a hot-pixel software algorithm.

  6. 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.

  7. 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.

  8. Black holes and beyond

    NASA Astrophysics Data System (ADS)

    Mathur, Samir D.

    2012-11-01

    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.

  9. 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

  10. 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 }.

  11. Co-regulation of dark and light reactions in three biochemical subtypes of C(4) species.

    PubMed

    Kiirats, Olavi; Kramer, David M; Edwards, Gerald E

    2010-08-01

    Regulation of light harvesting in response to changes in light intensity, CO(2) and O(2) concentration was studied in C(4) species representing three different metabolic subtypes: Sorghum bicolor (NADP-malic enzyme), Amaranthus edulis (NAD-malic enzyme), and Panicum texanum (PEP-carboxykinase). Several photosynthetic parameters were measured on the intact leaf level including CO(2) assimilation rates, O(2) evolution, photosystem II activities, thylakoid proton circuit and dissipation of excitation energy. Gross rates of O(2) evolution (J(O)₂'), measured by analysis of chlorophyll fluorescence), net rates of O(2) evolution and CO(2) assimilation responded in parallel to changes in light and CO(2) levels. The C(4) subtypes had similar energy requirements for photosynthesis since there were no significant differences in maximal quantum efficiencies for gross rates of O(2) evolution (average value = 0.072 O(2)/quanta absorbed, approximately 14 quanta per O(2) evolved). At saturating actinic light intensities, when photosynthesis was suppressed by decreasing CO(2), ATP synthase proton conductivity (g (H) (+)) responded strongly to changes in electron flow, decreasing linearly with J(O)₂', which was previously observed in C(3) plants. It is proposed that g (H) (+) is controlled at the substrate level by inorganic phosphate availability. The results suggest development of nonphotochemical quenching in C(4) plants is controlled by a decrease in g (H) (+), which causes an increase in proton motive force by restricting proton efflux from the lumen, rather than by cyclic or pseudocyclic electron flow.

  12. Correction of emission spectra in microspectrofluorimetry using a reference lamp: computations.

    PubMed

    Galassi, L

    1992-01-01

    Accurate correction of emission spectra in microspectrofluorimetry, using a reference lamp, may require that a factor for the emissivity of tungsten be introduced. This is only possible provided that the true temperature of the lamp filament is known. A method is given for obtaining the true temperature from the knowledge of the colour temperature. Also, the values of the spectral concentration of the radiance of the black body, either computed according to Planck's equation or taken from available published tables, have to be converted from energetic units to units of quanta since the photomultiplier is linear not to absorbed power but to units of quanta. When the fluorescence spectra to be corrected extend into the far red it is preferable to use a lower temperature (by lowering the supply voltage) than that for which the lamp is certified. It is possible to determine the new temperature (and then the corresponding spectral distribution) by taking a few pairs of measurements at different wavelengths both at the lower voltage and at the voltage for which the lamp is certified and then introducing these values in a non-linear regression soluble on a PC with a curve fitting program. The microscope tungsten halogen lamp can conveniently be used as a reference, thanks to its small size and its steady spectral characteristics. When high accuracy is required, however, the halogen lamp should be calibrated against a certified ribbon filament lamp.

  13. Generation of hydrogen peroxide in chloroplasts of Arabidopsis overexpressing glycolate oxidase as an inducible system to study oxidative stress.

    PubMed

    Fahnenstich, Holger; Scarpeci, Telma E; Valle, Estela M; Flügge, Ulf-Ingo; Maurino, Verónica G

    2008-10-01

    Arabidopsis (Arabidopsis thaliana) overexpressing glycolate oxidase (GO) in chloroplasts accumulates both hydrogen peroxide (H(2)O(2)) and glyoxylate. GO-overexpressing lines (GO plants) grown at 75 micromol quanta m(-2) s(-1) show retarded development, yellowish rosettes, and impaired photosynthetic performance, while at 30 micromol quanta m(-2) s(-1), this phenotype virtually disappears. The GO plants develop oxidative stress lesions under photorespiratory conditions but grow like wild-type plants under nonphotorespiratory conditions. GO plants coexpressing enzymes that further metabolize glyoxylate but still accumulate H(2)O(2) show all features of the GO phenotype, indicating that H(2)O(2) is responsible for the GO phenotype. The GO plants can complete their life cycle, showing that they are able to adapt to the stress conditions imposed by the accumulation of H(2)O(2) during the light period. Moreover, the data demonstrate that a response to oxidative stress is installed, with increased expression and/or activity of known oxidative stress-responsive components. Hence, the GO plants are an ideal noninvasive model system in which to study the effects of H(2)O(2) directly in the chloroplasts, because H(2)O(2) accumulation is inducible and sustained perturbations can reproducibly be provoked by exposing the plants to different ambient conditions.

  14. Quantum Charged Fields in (1+1) Rindler Space

    NASA Astrophysics Data System (ADS)

    Gabriel, Cl.; Spindel, Ph.

    2000-09-01

    We study, using Rindler coordinates, the quantization of a charged scalar field interacting with a constant (Poincaré invariant), external, electric field in (1+1) dimensionnal flatspace: our main motivation is pedagogy. We illustrate in this framework the equivalence between various approaches to field quantization commonly used in the framework of curved backgrounds. First we establish the expression of the Schwinger vacuum decay rate, using the operator formalism. Then we rederive it in the framework of the Feynman path integral method. Our analysis reinforces the conjecture which identifies the zero winding sector of the Minkowski propagator with the Rindler propagator. Moreover, we compute the expression of the Unruh's modes that allow us to make a connection between the Minkowskian and Rindlerian quantization schemes by purely algebraic relations. We use these modes to study the physics of a charged two level detector moving in an electric field whose transitions are due to the exchange of charged quanta. In the limit where the Schwinger pair production mechanism of the exchanged quanta becomes negligible we recover the Boltzman equilibrium ratio for the population of the levels of the detector. Finally we explicitly show how the detector can be taken as the large mass and charge limit of an interacting fields system.

  15. Half-quantum vortices

    NASA Astrophysics Data System (ADS)

    Mineev, V. P.

    2013-10-01

    Unlike to superfluid 4He the superfluid 3He-A support the existence of vortices with half-quantum of circulation as well as single quantum vortices. The singular single quanta vortices as well as nonsingular vortices with 2 quanta of circulation have been revealed in rotating 3He-A. However, the half-quantum vortices in open geometry always possess an extra energy due to spin-orbit coupling leading to formation of domain wall at distances larger than dipole length ˜10-3 cm from the vortex axis. Fortunately the same magnetic dipole-dipole interaction does not prevent the existence of half-quantum vortices in the polar phase of superfluid 3He recently discovered in peculiar porous media "nematically ordered" aerogel. Here we discuss this exotic possibility. The discoveries of half-quantum vortices in triplet pairing superconductor Sr2RuO4 as well in the exciton-polariton condensates are the other parts of the story about half-quantum vortices also described in the paper.

  16. Information capacity of electronic vision systems

    NASA Astrophysics Data System (ADS)

    Taubkin, Igor I.; Trishenkov, Mikhail A.

    1996-10-01

    The comparison of various electronic-optical vision systems has been conducted based on the criterion ultimate information capacity, C, limited by fluctuations of the flux of quanta. The information capacity of daylight, night, and thermal vision systems is determined first of all by the number of picture elements, M, in the optical system. Each element, under a sufficient level of irradiation, can transfer about one byte of information for the standard frame time and so C ≈ M bytes per frame. The value of the proportionality factor, one byte per picture element, is referred to systems of daylight and thermal vision, in which a photocharge in a unit cell of the imager is limited by storage capacity, and in general it varies within a small interval of 0.5 byte per frame for night vision systems to 2 bytes per frame for ideal thermal imagers. The ultimate specific information capacity, C ∗, of electronic vision systems under low irradiation levels rises with increasing density of optical channels until the number of the irradiance gradations that can be distinguished becomes less than two in each channel. In this case, the maximum value of C ∗ turns out to be proportional to the flux of quanta coming from an object under observation. Under a high level of irradiation, C ∗ is limited by difraction effects and amounts oto 1/ λ2 bytes/cm 2 frame.

  17. 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.

  18. 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).

  19. 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.

  20. Light-dependent magnetoreception in birds: the behaviour of European robins, Erithacus rubecula, under monochromatic light of various wavelengths and intensities.

    PubMed

    Wiltschko, W; Wiltschko, R

    2001-10-01

    To investigate how magnetoreception is affected by the wavelength and intensity of light, we tested European robins, Erithacus rubecula, under monochromatic lights of various wavelengths at two intensities using oriented behaviour as an indicator of whether the birds could derive directional information from the geomagnetic field. At a quantal flux of 7 x 10(15) quanta s(-1) m(-2), the birds were well oriented in their migratory direction east of North under 424 nm blue, 510 nm turquoise and 565 nm green light, whereas they were disoriented under 590 nm yellow light. Increasing the intensity of light at the same wavelengths more than sixfold to 43 x 10(15) quanta s(-1) m(-2) resulted in a change in behaviour: under bright blue and green light, the birds now showed a preference for the East-West axis, with the majority of headings at the western end; under bright turquoise light, they oriented unimodally towards a direction slightly west of North. Under bright yellow light, the birds continued to be disoriented. These findings suggest a rather complex relationship between the receptors involved in magnetoreception. Magnetoreception appears to follow rules that are different from those of vision, suggesting that light-dependent magnetoreception may involve receptors and neuronal pathways of its own.

  1. Two different types of light-dependent responses to magnetic fields in birds.

    PubMed

    Wiltschko, Roswitha; Ritz, Thorsten; Stapput, Katrin; Thalau, Peter; Wiltschko, Wolfgang

    2005-08-23

    A model of magnetoreception proposes that the avian magnetic compass is based on a radical pair mechanism, with photon absorption leading to the formation of radical pairs. Analyzing the predicted light dependency by testing migratory birds under monochromatic lights, we found that the responses of birds change with increasing intensity. The analysis of the orientation of European robins under 502 nm turquoise light revealed two types of responses depending on light intensity: under a quantal flux of 8.10(15) quanta m(-2) s(-1), the birds showed normal migratory orientation in spring as well as in autumn, relying on their inclination compass. Under brighter light of 54.10(15) quanta m(-2) s(-1), however, they showed a "fixed" tendency toward north that did not undergo the seasonal change and proved to be based on magnetic polarity, not involving the inclination compass. When birds were exposed to a weak oscillating field, which specifically interferes with radical pair processes, the inclination compass response was disrupted, whereas the response to magnetic polarity remained unaffected. These findings indicate that the normal inclination compass used for migratory orientation is based on a radical-pair mechanism, whereas the fixed direction represents a novel type of light-dependent orientation based on a mechanism of a different nature.

  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. 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

    2015-06-24

    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.

  4. 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.

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

    PubMed Central

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

    2003-01-01

    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

  6. 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.

  7. 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.

  8. Emergence of a low spin phase in group field theory condensates

    NASA Astrophysics Data System (ADS)

    Gielen, Steffen

    2016-11-01

    Recent results have shown how quantum cosmology models can be derived from the effective dynamics of condensate states in group field theory (GFT), where ‘cosmology is the hydrodynamics of quantum gravity’: the classical Friedmann dynamics for homogeneous, isotropic universes, as well as loop quantum cosmology (LQC) corrections to general relativity have been shown to emerge from fundamental quantum gravity. We take one further step towards strengthening the link with LQC and show, in a class of GFT models for gravity coupled to a free massless scalar field and for generic initial conditions, that GFT condensates dynamically reach a low spin phase of many quanta of geometry, in which all but an exponentially small number of quanta are characterised by a single spin j 0 (i.e. by a constant volume per quantum). As the low spin regime is reached, GFT condensates expand to exponentially large volumes, and the dynamics of the total volume follows precisely the classical Friedmann equations. This behaviour follows from a single requirement on the couplings in the GFT model under study. We present one particular simple case in which the dominant spin is the lowest one: {j}0=0 or, if this is excluded, {j}0=1/2. The type of quantum state usually assumed in the derivation of LQC is hence derived from the quantum dynamics of GFT. These results confirm and extend recent results by Oriti, Sindoni and Wilson-Ewing in the same setting.

  9. Gas Exchange Analysis of the Relative Importance of Stomatal and Biochemical Factors in Photosynthetic Induction in Alocasia macrorrhiza1

    PubMed Central

    Kirschbaum, Miko U. F.; Pearcy, Robert W.

    1988-01-01

    When leaves of Alocasia macrorrhiza adapted to 10 micromole quanta per square meter per second were transferred to 500 micromole quanta per square meter per second, the rate of photosynthetic CO2 assimilation increased for over 45 minutes. For the first 10 to 15 minutes, increases in both stomatal conductance and the leaf's photosynthetic capacity were responsible for the increase in assimilation rate. Thereafter, continuing increases in stomatal conductance were almost entirely responsible for further increases in assimilation rate. When conductances were initially high, assimilation rates 1 minute after the increase in photon flux density could be more than six times as high as for similar leaves with initially low conductance. Further increases in assimilation rate in these leaves with high conductance were predominantly due to increases in the induction state at the biochemical level and followed an exponential time course. When stomatal conductances were initially low, then increases in conductance were predominantly responsible for the increases in assimilation rate, with both following a sigmoidal time course. In these leaves, it was important to also consider the effect of cuticular water loss on the calculation of the intracellular partial pressure of CO2, and an assessment of the relative importance of stomatal conductance differed considerably from one that did not include cuticular water loss. PMID:16665988

  10. 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.

  11. 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.

  12. Gamma-radiation with E gamma 5 MeV detected from Seyfert galaxy 3C120 and region with 1" = 190 deg and b" = 20 deg

    NASA Technical Reports Server (NTRS)

    Damle, S. V.; Fradkin, M. I.; Iyudin, A. F.; Kirillov-Ugryumov, V. G.; Kotov, Y. D.; Kurnosova, L. V.; Smirnov, Y. V.; Yurov, V. N.

    1985-01-01

    The observation of the Galaxy anticenter region in gamma-rays with E gamma = 5 / 100 MeV was made by gamma-telescope Natalya-1 in a balloon flight. The flight was performed at the ceiling 5.1 + or - 0.1 g/sq cm, magnetic cutoff being 17 GV. The description of the instrument and the analysis of the experiment conditions are given. The tracks of electron-positron pairs generated by gamma-quanta in the convertors were detected by wire spark chambers. The recorded events were classified manually by an operator using a graphic display into three classes: pairs, single and bad events. The arrival angle of gamma-quanta and their energy for selected gamma-ray events (pairs and singles) were determined through multiple scattering of pair components in the convertors. On the basis of the data obtained the celestial maps were made in gamma-rays for E sub gamma 5 MeV and E gamma 20 MeV energy ranges.

  13. 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.

  14. 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

  15. 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°.

  16. ACTIVE MEDIA: Pump and amplification dynamics of gamma rays in a nuclear medium with the hidden population inversion

    NASA Astrophysics Data System (ADS)

    Rivlin, Lev A.

    2009-12-01

    The features of the pump dynamics of isomeric nuclei excited by X-rays of a repetitively pulsed relativistic electron beam followed by the production of a medium with the negative absorption of gamma quanta are analysed. In the extended nuclear medium, the pump excites a travelling hidden-population-inversion wave with the anisotropic gamma amplification, which becomes positive in the case of the excess over the critical pump parameter equal to the product of the peak spectral power density of the X-ray source and the relative duration of an ultrashort relativistic electron bunch. In the alternative scheme with orthogonal directions of pumping X-rays and a flux of amplified gamma quanta, the absence of the amplification anisotropy opens up the possibility for constructing a standard two-mirror resonator with Bragg single-crystal reflectors. The critical peak value of the spectral pump power density is compared with the known characteristics of relativistic-electron X-ray sources by examples of some nuclides.

  17. 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.

  18. Preillumination of lettuce seedlings with red light enhances the resistance of photosynthetic apparatus to UV-A.

    PubMed

    Kreslavski, Vladimir D; Lyubimov, Valery Yu; Shirshikova, Galina N; Shmarev, Alexander N; Kosobryukhov, Anatoly A; Schmitt, Franz-Josef; Friedrich, Thomas; Allakhverdiev, Suleyman I

    2013-05-01

    Seedlings of 10-day-old lettuce (Lactuca sativa L., cultivar Berlin) were preilluminated by low intensity red light (λmax=660 nm, 10 min, 5 μmol quanta m(-2) s(-1)) and far-red light (λmax=730 nm, 10 min, 5 μmol quanta m(-2) s(-1)) to study the effect of pre-treatment on photosynthesis, photochemical activity of photosystem II (PSII), the contents of photosynthetic and UV-A-absorbing pigments (UAPs) and H2O2, as well as total and ascorbate peroxidase activities in cotyledonary leaves of seedlings exposed to UV-A. UV radiation reduced the photosynthetic rate (Pn), the activity of PSII, and the contents of Chl a and b, carotenoids and UAPs in the leaves, but increased the content of H2O2 and the total peroxidase activity. Preillumination with red light removed these effects of UV. In turn, the illumination with red light, then far-red light removed the effect of the red light. Illumination with red light alone increased the content of UAPs, as well as peroxidase activity. It is suggested that higher resistance of the lettuce photosynthetic apparatus to UV-A radiation is associated with involvement of the active form of phytochrome B, thereby increasing peroxidase activities as well as UAPs and saving preservation of photosynthetic pigment contents due to pre-illumination with red light.

  19. 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.

  20. 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.

  1. 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

  2. Transient analysis of a chemical synaptic transmission.

    PubMed

    Melkonian, D S

    1993-01-01

    The statistical dynamics of an impulse induced quanta turnover is studied by means of a nonstationary stochastic model--double barrier synapse--resulting from a previously developed mathematical theory of chemical synaptic transmission. An essential aspect of nonstationarities of the model is that the interpool quanta transfers follow binomial distribution at impulse arrival time, while in the absence of stimulation they obey Yule-Furry statistics. Under a variety of conditions, corresponding to those in actual experiments, the transient behaviour of the model is simulated and analysed in detail. As a result, the quantitative description of immediate and delayed components of synaptic action is introduced. If simulations of quantal fluctuations are performed numerically, then for the treatment of dynamic regularities, besides numerical procedures, an analytical method of envelopes is developed. It is supported by the theorems which reduce behaviour of the double-barrier synapse to the super-position of simpler solutions for single-barrier systems. With short-term facilitation quantitative analysis and simulations, the synaptic resonance phenomenon is theoretically predicted: different resonant frequencies are found at different levels of facilitation. The importance of this phenomenon treated as a clue to the information processing capabilities of a chemical synapse is discussed. PMID:8097407

  3. 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.

  4. High resolution pulsed field ionization-photoelectron study of CO{sub 2}{sup +}(X {sup 2}{pi}{sub g}) in the energy range of 13.6-14.7 eV

    SciTech Connect

    Liu, Jianbo; Chen, Wenwu; Hsu, C.-W.; Hochlaf, M.; Evans, M.; Stimson, S. [Ames Laboratory, USDOE; Ng, C. Y. [Ames Laboratory, USDOE

    2000-06-22

    The vacuum ultraviolet pulsed field ionization-photoelectron (PFI-PE) spectra for CO{sub 2} have been measured in the energy range of 13.6-14.7 eV, revealing complex vibronic structures for the ground CO{sub 2}{sup +}(X {sup 2}{pi}{sub g}) state. Many vibronic bands for CO{sub 2}{sup +}(X {sup 2}{pi}{sub g}), which were not resolved in previous photoelectron studies, are identified in the present measurement based on comparison with available optical data and theoretical predictions. As observed in the HeI photoelectron spectrum of CO{sub 2}, the PFI-PE spectrum is dominated by the symmetry allowed {nu}{sub 1}{sup +} (symmetric stretch) vibrational progression for CO{sub 2}{sup +}(X {sup 2}{pi}{sub g}). However, PFI-PE vibronic bands due to excitation of the symmetry disallowed {nu}{sub 2}{sup +} (bending) and {nu}{sub 3}{sup +} (asymmetric stretch) modes with both odd quanta, together with the symmetry allowed even quanta excitations, are clearly discernible. The simulation of rotational contours resolved in PFI-PE vibronic bands associated with excitation to the ({nu}{sub 1}{sup +}=0-1, {nu}{sub 2}{sup +}=0-2, {nu}{sub 3}{sup +}=0) vibrational levels has yielded accurate ionization energies for the formation of these vibronic states from CO{sub 2}(X {sup 1}{sigma}{sub g}{sup +}). (c) 2000 American Institute of Physics.

  5. 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

  6. 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°.

  7. Young's double-slit experiment: noise-resolution duality.

    PubMed

    Nesterets, Yakov I; Gureyev, Timur E

    2015-02-01

    Statistical aspects of Young's double-slit diffraction experiment are analysed quantitatively. It is shown that the signal-to-noise ratio and the spatial resolution in the detected diffraction pattern satisfy a duality relationship which implies that both of them cannot be improved simultaneously beyond a certain limit if the total number of particles forming the image is fixed. As a consequence of this duality, it is possible to estimate the minimal number of particles that have to be detected in order for two slits separated by a given distance to be resolved with a confidence level corresponding to a pre-defined signal-to-noise ratio, e.g. according to the Rose criterion. These results are related to the recently introduced imaging system quality characteristic which combines the spatial resolution and the noise sensitivity, and allows one to estimate the efficiency with which imaging quanta are utilised in a system to deliver maximal amount of information about the imaged object. The presented results can be useful for applications where the imaging quanta are at a premium or where minimization of the radiation dose is important.

  8. Synaptic vesicle exocytosis captured by quick freezing and correlated with quantal transmitter release

    PubMed Central

    1979-01-01

    We describe the design and operation of a machine that freezes biological tissues by contact with a cold metal block, which incorporates a timing circuit that stimulates frog neuromuscular junctions in the last few milliseconds before thay are frozen. We show freeze-fracture replicas of nerve terminals frozen during transmitter discharge, which display synpatic vesicles caught in the act of exocytosis. We use 4-aminopyridine (4-AP) to increase the number of transmitter quanta discharged with each nerve impulse, and show that the number of exocytotic vesicles caught by quick-freezing increases commensurately, indicating that one vesicle undergoes exocytosis for each quantum that is discharged. We perform statistical analyses on the spatial distribution of synaptic vesicle discharge sites along the "active zones" that mark the secretory regions of these nerves, and show that individual vesicles fuse with the plasma membrane independent of one another, as expected from physiological demonstrations that quanta are discharged independently. Thus, the utility of quick- freezing as a technique to capture biological processes as evanescent as synaptic transmission has been established. An appendix describes a new capacitance method to measure freezing rates, which shows that the "temporal resolution" of our quick-freezing technique is 2 ms or better. PMID:38256

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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

  16. 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

  17. Assessment of wavelength-dependent parameters of photosynthetic electron transport with a new type of multi-color PAM chlorophyll fluorometer.

    PubMed

    Schreiber, Ulrich; Klughammer, Christof; Kolbowski, Jörg

    2012-09-01

    Technical features of a novel multi-color pulse amplitude modulation (PAM) chlorophyll fluorometer as well as the applied methodology and some typical examples of its practical application with suspensions of Chlorella vulgaris and Synechocystis PCC 6803 are presented. The multi-color PAM provides six colors of pulse-modulated measuring light (peak-wavelengths at 400, 440, 480, 540, 590, and 625 nm) and six colors of actinic light (AL), peaking at 440, 480, 540, 590, 625 and 420-640 nm (white). The AL can be used for continuous illumination, maximal intensity single-turnover pulses, high intensity multiple-turnover pulses, and saturation pulses. In addition, far-red light (peaking at 725 nm) is provided for preferential excitation of PS I. Analysis of the fast fluorescence rise kinetics in saturating light allows determination of the wavelength- and sample-specific functional absorption cross section of PS II, Sigma(II)(λ), with which the PS II turnover rate at a given incident photosynthetically active radiation (PAR) can be calculated. Sigma(II)(λ) is defined for a quasi-dark reference state, thus differing from σ(PSII) used in limnology and oceanography. Vastly different light response curves for Chlorella are obtained with light of different colors, when the usual PAR-scale is used. Based on Sigma(II)(λ) the PAR, in units of μmol quanta/(m(2) s), can be converted into PAR(II) (in units of PS II effective quanta/s) and a fluorescence-based electron transport rate ETR(II) = PAR(II) · Y(II)/Y(II)(max) can be defined. ETR(II) in contrast to rel.ETR qualifies for quantifying the absolute rate of electron transport in optically thin suspensions of unicellular algae and cyanobacteria. Plots of ETR(II) versus PAR(II) for Chlorella are almost identical using either 440 or 625 nm light. Photoinhibition data are presented suggesting that a lower value of ETR(II)(max) with 440 nm possibly reflects photodamage via absorption by the Mn-cluster of the oxygen

  18. TeV AGN Observation by SHALON: Far Quasars 1739+522 (z=1.375) and 3C454.3 (z=0.859) in Comparision with MKN421 and MKN 501

    NASA Astrophysics Data System (ADS)

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

    2006-01-01

    The cosmological processes connecting matter structure physics with its superdense quasistable state in the active galactic nuclei will be observed only by the energy spectra of their electromagnetic radiation and may be in future by the high-energy neutrino flux. So the possibilities of the experimental studying of the concrete stellar object properties and processes are expanding. The greater place in modern physics and astrophysics is acquired by researches of galactic and metagalactic objects, where the proton and nucleus acceleration processes, accompanying with generation of not dissipated by magnetic fields of Universe gamma-quanta and neutrinos, will be realized. These researches are carried out by SHALON mirror telescope on the Tien-Shan high mountainous station. Created in Lebedev Physical Institute and installed 1991-1992 years in Alatoo mountains at 3338m high, the SHALON mirror telescope with matrix of 144 PMT and full angle of > 8°during 1992-2004 years was used for observation of metagalactic sources: Mkn421, Mkn501, NGC1275, 3c454.3, 1739+522 and galactic sources: Crab Nebula, Cygnus X-3, Tycho's SNR, Geminga, 2129+47XR. The new metagalactic sources of gamma-quanta with energy more than 0.8TeV are detected. It is the Seyfert galaxy NGC1275 with flux of (0.78 ± 0.13) • 10-12cm-2s-1, as well active galactic nuclei 3c454.3 and 1739+522 (z=0.859 and z=1.375) with flux of (0.43 ± 0.13) • 10-12cm-2s-1 and (0.53 ± 0.10) • 10-12cm-2s-1 accordingly. The most far metagalactic source 1739+522 with red shift of z=1.375, is also most powerful. But the spectral distribution of emitting gamma-quanta differs from average on other known metagalactic sources F(>E)˜E: Mkn 421 (z=0.031) k=-1.53±0.41; Mkn 501 (z=0.034) k=-1.89±0.11 and for far sources - 3c454.3 (z=0.859) k=-1.20±0.17; 1739+522 (z=1.375) k=-1.10±0.06. Thus, the energy spectrum of Mkn421, Mkn501 quasars at range 1012 1013 eV differs from spectra of 1739+522 and 3c454.3 far quasars that don

  19. 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.

  20. 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

  1. Survival strategies of plants during water stress

    SciTech Connect

    Scheuermann, R.; Stuhlfauth, T.; Sueltemeyer, D.; Fock, H.

    1989-04-01

    Fluorescence and gas exchange of bean, maize, sunflower and wooly foxglove were simultaneously measured at 250 {mu}mol quanta/m{sup 2}/s. Under severe water stresses conditions about 40% of the photochemical energy was converted to heat at PS II. This is interpreted as a protective mechanism against photoinhibitory damage when net CO{sub 2} uptake is reduced by about 70%. After {sup 14}CO{sub 2} gas exchange, only in bean was a homogeneous distribution of radioactivity over the leaf observed. In all other plants we found a patchy distribution of regions with either an intensive or a reduced gas exchange. We conclude that CO{sub 2}-recycling (photorespiration and reassimilation) behind closed stomata also contributed to energy dissipation under severe stress conditions.

  2. Fine structure constant and quantized optical transparency of plasmonic nanoarrays.

    PubMed

    Kravets, V G; Schedin, F; Grigorenko, A N

    2012-01-01

    Optics is renowned for displaying quantum phenomena. Indeed, studies of emission and absorption lines, the photoelectric effect and blackbody radiation helped to build the foundations of quantum mechanics. Nevertheless, it came as a surprise that the visible transparency of suspended graphene is determined solely by the fine structure constant, as this kind of universality had been previously reserved only for quantized resistance and flux quanta in superconductors. Here we describe a plasmonic system in which relative optical transparency is determined solely by the fine structure constant. The system consists of a regular array of gold nanoparticles fabricated on a thin metallic sublayer. We show that its relative transparency can be quantized in the near-infrared, which we attribute to the quantized contact resistance between the nanoparticles and the metallic sublayer. Our results open new possibilities in the exploration of universal dynamic conductance in plasmonic nanooptics.

  3. Transfer of optical orbital angular momentum to a bound electron

    PubMed Central

    Schmiegelow, Christian T.; Schulz, Jonas; Kaufmann, Henning; Ruster, Thomas; Poschinger, Ulrich G.; Schmidt-Kaler, Ferdinand

    2016-01-01

    Photons can carry angular momentum, not only due to their spin, but also due to their spatial structure. This extra twist has been used, for example, to drive circular motion of microscopic particles in optical tweezers as well as to create vortices in quantum gases. Here we excite an atomic transition with a vortex laser beam and demonstrate the transfer of optical orbital angular momentum to the valence electron of a single trapped ion. We observe strongly modified selection rules showing that an atom can absorb two quanta of angular momentum from a single photon: one from the spin and another from the spatial structure of the beam. Furthermore, we show that parasitic ac-Stark shifts from off-resonant transitions are suppressed in the dark centre of vortex beams. These results show how light's spatial structure can determine the characteristics of light–matter interaction and pave the way for its application and observation in other systems. PMID:27694805

  4. 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

  5. Large non-gaussianity in axion inflation.

    PubMed

    Barnaby, Neil; Peloso, Marco

    2011-05-01

    The inflationary paradigm has enjoyed phenomenological success; however, a compelling particle physics realization is still lacking. Axions are among the best-motivated inflaton candidates, since the flatness of their potential is naturally protected by a shift symmetry. We reconsider the cosmological perturbations in axion inflation, consistently accounting for the coupling to gauge fields cΦFF, which is generically present in these models. This coupling leads to production of gauge quanta, which provide a new source of inflaton fluctuations, δΦ. For c≥10(2)M(p)(-1), these dominate over the vacuum fluctuations, and non-Gaussianity exceeds the current observational bound. This regime is typical for concrete realizations that admit a UV completion; hence, large non-Gaussianity is easily obtained in minimal and natural realizations of inflation.

  6. Features of multiphoton-stimulated bremsstrahlung in a quantized field

    NASA Astrophysics Data System (ADS)

    Burenkov, Ivan A.; Tikhonova, Olga V.

    2010-12-01

    The process of absorption and emission of external field quanta by a free electron during the scattering on a potential centre is investigated in the case of interaction with a quantized electromagnetic field. The analytical expression for differential cross-sections and probabilities of different multiphoton channels are obtained. We demonstrate that in the case of a non-classical 'squeezed vacuum' initial field state the probability for the electron to absorb a large number of photons appears to be larger by several orders of magnitude in comparison to the classical field and leads to the formation of the high-energy plateau in the electron energy spectrum. The generalization of the Marcuse effect to the case of the quantized field is worked out. The total probability of energy absorption by electron from the non-classical light is analysed.

  7. Planetary nebulae. V

    NASA Astrophysics Data System (ADS)

    Gieseking, F.

    1984-01-01

    The characterization of the central stars of planetary nebulae (CSPN) using observations of their shells (SPN), is discussed. The observability, from earth and space, of the emission spectrum of a typical CSPN (represented by a 50,000-K blackbody) at a distance of several kpc is illustrated graphically. It is shown that the most important and intense portion of this spectrum, the Lyman quanta below 912 A, is absorbed by the interstellar medium, and specifically by the SPN itself. The method developed by Zanstra in 1927 to estimate the Lyman emission of the CSPN from the Balmer emission (or the optical He-recombination spectrum) of the SPN is explained. Recent satellite observations in the 100-300-nm range have confirmed the accuracy of the H and/or He Zanstra temperature as an estimate of CSPN effective temperature.

  8. Nature's Swiss Army Knife: The Diverse Protective Roles of Anthocyanins in Leaves.

    PubMed

    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.

  9. 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.

  10. Possibilities of Verifying Dynamical Casimir Effect with Nonlinear Materials in Microwave Cavities

    NASA Astrophysics Data System (ADS)

    Dodonov, Viktor

    2015-03-01

    I evaluate the number of ``Casimir quanta'' that could be created in high-quality electromagnetic cavities containing materials with big third-order nonlinear optical coefficients, due to the parametric amplification of the microwave vacuum field, if the effective refractive index of the material is modulated by periodic high-intensity short laser pulses. The main result is that the expected total number of created microwave photons depends neither on the laser beam shape, nor on the duration or power of individual pulses, but it is determined by the total energy of all pulses, provided the duration of each pulse is much shorter than the period of field oscillations in the selected resonant mode. The experiment can be feasible in small cavities with high resonance frequencies. Possible spurious effects will be discussed, too.

  11. Readily releasable pool of synaptic vesicles measured at single synaptic contacts.

    PubMed

    Trigo, Federico F; Sakaba, Takeshi; Ogden, David; Marty, Alain

    2012-10-30

    To distinguish between different models of vesicular release in brain synapses, it is necessary to know the number of vesicles of transmitter that can be released immediately at individual synapses by a high-calcium stimulus, the readily releasable pool (RRP). We used direct stimulation by calcium uncaging at identified, single-site inhibitory synapses to investigate the statistics of vesicular release and the size of the RRP. Vesicular release, detected as quantal responses in the postsynaptic neuron, showed an unexpected stochastic variation in the number of quanta from stimulus to stimulus at high intracellular calcium, with a mean of 1.9 per stimulus and a maximum of three or four. The results provide direct measurement of the RRP at single synaptic sites. They are consistent with models in which release proceeds from a small number of vesicle docking sites with an average occupancy around 0.7.

  12. Should processed or raw image data be used in mammographic image quality analyses? A comparative study of three full-field digital mammography systems.

    PubMed

    Borg, Mark; Badr, Ishmail; Royle, Gary

    2015-01-01

    The purpose of this study is to compare a number of measured image quality parameters using processed and unprocessed or raw images in two full-field direct digital units and one computed radiography mammography system. This study shows that the difference between raw and processed image data is system specific. The results have shown that there are no significant differences between raw and processed data in the mean threshold contrast values using the contrast-detail mammography phantom in all the systems investigated; however, these results cannot be generalised to all available systems. Notable differences were noted in contrast-to-noise ratios and in other tests including: response function, modulation transfer function , noise equivalent quanta, normalised noise power spectra and detective quantum efficiency as specified in IEC 62220-1-2. Consequently, the authors strongly recommend the use of raw data for all image quality analyses in digital mammography.

  13. 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.

  14. [Radiobiological effects of total mice irradiation with Bragg's peak protons].

    PubMed

    Ivanov, A A; Molokanov, A G; Ushakov, I B; Bulynina, T M; Vorozhtsova, S V; Abrosimova, A N; Kryuchkova, D M; Gaevsky, V N

    2013-01-01

    Outbred CD-1 female mice were irradiated in a proton beam (171 MeV, 5 Gy) on the phasotron at the Joint Institute of Nuclear Research (Dubna, Russia). Radiation was delivered in two points of the depth dose distribution: at the beam entry and on Bragg's peak. Technical requirements for studying the effects of Bragg's peak protons on organism of experimental animals were specified. It was recognized that protons with high linear energy transfer (mean LET = 1.6 keV/microm) cause a more severe damaging effect to the hemopoietic system and cytogenetic apparatus in bone marrow cells as compared with entry protons and 60Co gamma-quanta. It was shown that recovery of the main hemopoietic organs and immunity as well as elimination of chromosomal aberrations take more time following irradiation with Bragg's peak protons but not protons with the energy of 171 MeV.

  15. Quantum entanglement of high angular momenta.

    PubMed

    Fickler, Robert; Lapkiewicz, Radek; Plick, William N; Krenn, Mario; Schaeff, Christoph; Ramelow, Sven; Zeilinger, Anton

    2012-11-01

    Single photons with helical phase structures may carry a quantized amount of orbital angular momentum (OAM), and their entanglement is important for quantum information science and fundamental tests of quantum theory. Because there is no theoretical upper limit on how many quanta of OAM a single photon can carry, it is possible to create entanglement between two particles with an arbitrarily high difference in quantum number. By transferring polarization entanglement to OAM with an interferometric scheme, we generate and verify entanglement between two photons differing by 600 in quantum number. The only restrictive factors toward higher numbers are current technical limitations. We also experimentally demonstrate that the entanglement of very high OAM can improve the sensitivity of angular resolution in remote sensing.

  16. 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.

  17. 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.

  18. Cluster physics and the importance of forbiddenness

    NASA Astrophysics Data System (ADS)

    Hess, P. O.; Yépez-Martínez, H.

    2016-07-01

    We review the concept of forbiddenness as introduced by Smirnov and Yu M. Tchuvil'sky [1], which states that most of the properties of nuclear reactions and cluster structure is based on structural effects (Pauli exclusion principle). This becomes also clear when one tries to obtain the ground state of the united nucleus by two heavy clusters, which is not possible when all excitations are put into the relative motion. Smirnov et al. introduced the concept of forbiddenness, which is defined as the minimal number of relative oscillation quanta which have to be shifted to internal excitations of the clusters, such that the ground state can be reached. We show that Smirnov et al. committed and error in the derivation, leading us to reevaluate the derivation of the forbiddenness. We deduce the correct expression for the forbiddenness, leading to a simple interpretation and implementation in a cluster model and some applications are presented.

  19. 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.

  20. Basics of quantum plasmonics

    NASA Astrophysics Data System (ADS)

    Hieu Nguyen, Van; Nguyen, Bich Ha

    2015-01-01

    The present work is a topical review of the theoretical research on the quantum theory of plasmons and plasmon-photon interaction. The plasmons are defined as the quanta of the quantized plasmonic field. The corresponding classical plasmonic field was constructed on the basis of the study of collective oscillations of the electron gas in the solid. The electron-electron Coulomb interaction is taken into account. The explicit forms of the plasmon-photon interaction Lagrangian in canonical quantum mechanics and the plasmon-photon interaction action functional in the functional integral approach are derived. They all show that the interaction processes are nonlocal ones. The physical origin of the nonlocality is the complex structure of plasmons as composite quasiparticles: they cannot be considered as point particles, as was assumed in all phenomenological theories.

  1. 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.

  2. Relativistic Non-Thermal Bremsstrahlung Radiation

    NASA Astrophysics Data System (ADS)

    Zeković, Vladimir; Arbutina, Bojan; Dobardžić, Aleksandra; Pavlović, Marko Z.

    2013-11-01

    By applying a method of virtual quanta we derive formulae for relativistic non-thermal bremsstrahlung radiation from relativistic electrons as well as from protons and heavier particles with power-law momentum distribution N(p)dp = k p-qdp. We show that emission which originates from an electron scattering on an ion, represents the most significant component of relativistic non-thermal bremsstrahlung. Radiation from an ion scattering on electron, known as inverse bremsstrahlung, is shown to be negligible in overall non-thermal bremsstrahlung emission. These results arise from theory refinement, where we introduce the dependence of relativistic kinetic energy of an incident particle, upon the energy of scattered photon. In part, it is also a consequence of a different mass of particles and relativistic effects.

  3. 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.

  4. Weber Blockade Theory of Magnetoresistance Oscillations in Superconducting Strips

    NASA Astrophysics Data System (ADS)

    Pekker, David; Refael, Gil; Goldbart, Paul M.

    2011-07-01

    Recent experiments on the conductance of thin, narrow superconducting strips have found periodic fluctuations, as a function of the perpendicular magnetic field, with a period corresponding to approximately two flux quanta per strip area [A. Johansson , Phys. Rev. Lett. 95, 116805 (2005)PRLTAO0031-900710.1103/PhysRevLett.95.116805]. We argue that the low-energy degrees of freedom responsible for dissipation correspond to vortex motion. Using vortex-charge duality, we show that the superconducting strip behaves as the dual of a quantum dot, with the vortices, magnetic field, and bias current respectively playing the roles of the electrons, gate voltage, and source-drain voltage. In the bias-current versus magnetic-field plane, the strip conductance displays regions of small vortex conductance (i.e., small electrical resistance) that we term “Weber blockade” diamonds, which are dual to Coulomb blockade diamonds in quantum dots.

  5. 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

  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. 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.

  8. 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.

  9. Highly tunable propagating surface plasmons on supported silver nanowires

    PubMed Central

    Wei, Hong; Zhang, Shunping; Tian, Xiaorui; Xu, Hongxing

    2013-01-01

    Surface plasmons, the quanta of the collective oscillations of free electrons at metal surface, can be easily tuned by changing the surrounding dielectric materials, which is well known for metal nanoparticles and metal surfaces, but less is known for one-dimensional metal nanowires. Here, we find an extremely large tunability of surface plasmons on Ag nanowires with a beat period of the near-field distribution pattern increasing by 90 nm per nanometer of Al2O3 coating, or by 16 µm per refractive index unit change in the surrounding medium. Such high sensitivity is crucial to directly control the optical signal distribution for various routing and demultiplexing functions in plasmonic circuits and may pave the way to the development of on-chip ultrasensitive biosensing. PMID:23487763

  10. The generation of gravitational waves. IV - Bremsstrahlung

    NASA Technical Reports Server (NTRS)

    Kovacs, S. J., Jr.; Thorne, K. S.

    1978-01-01

    Previously derived waveforms for gravitational bremsstrahlung are discussed along with their spectra and their limiting structure at high and low relative velocities. Waveforms and spectra are presented for a low-velocity bremsstrahlung encounter, and waveforms are given for encounters of arbitrary relative velocity. Limiting forms for the gravitational-wave amplitudes in the 'forward', 'intermediate', and 'backward' regions are derived in the high-velocity limit. The energy spectra seen by observers in the three regions are computed for arbitrary and high velocities. Simpler methods for analyzing special cases of the bremsstrahlung problem are examined, and the results of those methods are compared with the present results. Those methods include the quadrupole-moment and post-Newtonian formalisms, linear perturbations of the Schwarzschild metric, the method of colliding plane waves, the method of virtual quanta, and the zero-frequency limit. Classical gravitational bremsstrahlung is then compared with classical electromagnetic bremsstrahlung.

  11. [Mechanisms of charge separation in photosynthetic reaction centers].

    PubMed

    Vorotyntsev, M A; Itskovich, E M

    1980-01-01

    Light quanta absorbed by means of light -- absorbing matrix of pigment molecules are transferred with several special molecules forming the photoreaction centre (PhRC). The following conditions should be met for an effective storage of electron excitation energy in PhRC resulting from charge division: 1) electron transfer from donor to acceptor should proceed in the time less than life time of the initial excited state; 2) this transfer ought to be irreversible to a sufficient degree; 3) the less possible portion of the excitation energy should be lost in this process. Simultaneous fulfilment of these conditions is concerned with certain difficulties. Two means for overcoming these difficulties (multistage process and contribution of conformation degree of freedom) are proposed. Their realization at various stages of charge division involves probable mechanism of PhPC functioning.

  12. Interactions and stabilities of the UV RESISTANCE LOCUS8 (UVR8) protein dimer and its key mutants.

    PubMed

    Wu, Min; Strid, Ake; Eriksson, Leif A

    2013-07-22

    The dimeric UVR8 protein is an ultraviolet-B radiation (280-315 nm) photoreceptor responsible for the first step in UV-B regulation of gene expression in plants. Its action comprises the actual absorption of the UV quanta by a tryptophan array at the protein-protein interface, followed by monomerization and subsequent aggregation with downstream signaling components. A crystal structure of the Arabidopsis thaliana tryptophan-rich wild type UVR8 protein dimer was recently published, showing the presence of several salt bridges involving arginines R146, R286, R338, and R354. In this work, molecular dynamics simulations in conjunction with umbrella sampling were used to calculate the binding free energy for the wild type UVR8 dimer and three of its mutants (R286A, R338A, and R286A/R338A), in order to verify whether the key mutants are able to disrupt the dimeric structure as indicated experimentally.

  13. 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.

  14. 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.

  15. '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.

  16. Influence of [ital H][sub [ital c]1] on the irreversibility line in YBa[sub 2]Cu[sub 3]O[sub 7] thin films

    SciTech Connect

    Civale, L.; Worthington, T.K.; Gupta, A. )

    1993-09-01

    The irreversibility line of a type-II superconductor separates the [ital H]-[ital T] plane into a region above the line where the critical current is zero and the magnetic properties are reversible, and a region below where a critical current is observed and the magnetic properties are irreversible. Although there is great controversy over the various models proposed to explain these observations, they all depend on the existence of magnetic-flux quanta in the sample. This implies that the irreversibility line cannot cross [ital H][sub [ital c]1]([ital T]). In bulk samples, assuming that the observed functional forms are maintained, this would be expected to occur much too close to [ital T][sub [ital c

  17. Manifestation of topological surface electron states in the photoelectromagnetic effect induced by terahertz laser radiation

    NASA Astrophysics Data System (ADS)

    Galeeva, A. V.; Egorova, S. G.; Chernichkin, V. I.; Tamm, M. E.; Yashina, L. V.; Rumyantsev, V. V.; Morozov, S. V.; Plank, H.; Danilov, S. N.; Ryabova, L. I.; Khokhlov, D. R.

    2016-09-01

    We demonstrate that measurements of the photoelectromagnetic effect using terahertz laser radiation may provide a unique opportunity to discriminate between the topological surface states and other highly conductive surface electron states. We performed a case study of mixed (Bi{}1-xIn x )2Se3 crystals undergoing a topological phase transformation due to the transition from the inverse to the direct electron energy spectrum in the crystal bulk at variation of the composition x. We show that for the topological insulator phase, the photoelectromagnetic effect amplitude is defined by the number of incident radiation quanta, whereas for the trivial insulator phase, it depends on the power in a laser pulse irrespective of its wavelength. We assume that such behavior is attributed to a strong damping of the electron-electron interaction in the topological insulator phase compared to the trivial insulator.

  18. 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

  19. Total Reaction Cross Section Excitation Function Studies for 6He Interaction with 181Ta, 59Co, natSi, 9Be Nuclei

    NASA Astrophysics Data System (ADS)

    Sobolev, Yu. G.; Penionzhkevich, Yu. E.; Borcea, C.; Demekhina, N. A.; Eshanov, A. G.; Ivanov, M. P.; Kabdrakhimova, G. D.; Kabyshev, A. M.; Kugler, A.; Kuterbekov, K. A.; Lukyanov, K. V.; Maj, A.; Maslov, V. A.; Negret, A.; Skobelev, N. K.; Testov, D.; Trzaska, W. H.; Voskobojnik, E. I.; Zemlyanaya, E. V.

    2015-06-01

    Total reaction cross section excitation functions σR(E) were measured for 6He secondary beam particles on 181Ta, 59Co, natSi and 9Be targets in a wide energy range by direct and model-independent method. This experimental method was based on prompt n-γ 4π-technique applied in event-by event mode. A high efficiency CsI(Tl) γ-spectrometer was used for the detection of reaction products (prompt γ-quanta and neutrons) accompanying each reaction event. Using the ACCULINNA fragment-separator 6He fragments (produced by 11B primary beam with 9Be target) are separated and transported to n-γ shielded experimental cave at FLNR JINR. The measured total reaction cross section data σR(E) for the above mentioned reactions are compared with a theoretical calculation based on the optical potential with the real part having the double-folding form.

  20. Application of information theory to the assessment of computed tomography.

    PubMed

    Wagner, R F; Brown, D G; Pastel, M S

    1979-01-01

    The imaging process has two fundamental stages: detection and display. The detection stage can be quantified rigourously using Shannon's information theory. This requires the contrast scale (CS), modulation transfer function (MTF), and noise power spectrum [N(f)] to be combined into a signal-to-noise ratio (SNR). This results in two fundamental summary figures of merit: the density of noise equivalent quanta (NEQ) in the image and the information bandwidth integral (IBWI). These algorithm-independent measures are used to quantify the recording stage. The display stage is less well understood since it couples to an external observer. Several types of decision makers are treated. Examples are drawn from first and second generation CT, demonstrating that thye are nearly quantum limited for large signals, indicating how their algorithms are matched or mismatched to the geometry, and calculating the contrast-detail diagrams for those decision makers.

  1. 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.

  2. Revisiting a pre-inflationary radiation era and its effect on the CMB power spectrum

    SciTech Connect

    Das, Suratna; Goswami, Gaurav; Rangarajan, Raghavan; Prasad, Jayanti E-mail: gaugo@prl.res.in E-mail: raghavan@prl.res.in

    2015-06-01

    We revisit the scenario where inflation is preceded by a radiation era by considering that the inflaton too could have been in thermal equilibrium early in the radiation era. Hence we take into account not only the effect of a pre-inflationary era on the inflaton mode functions but also that of a frozen thermal distribution of inflaton quanta. We initially discuss in detail the issues relevant to our scenario of a pre-inflationary radiation dominated era and then obtain the scalar power spectrum for this scenario. We find that the power spectrum is free from infrared divergences. We then use the WMAP and Planck data to determine the constraints on the inflaton comoving 'temperature' and on the duration of inflation. We find that the best fit value of the duration of inflation is less than 1 e-folding more than what is required to solve cosmological problems, while only an upper bound on the inflaton temperature can be obtained.

  3. 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.

  4. A high repetition rate plasma focus for neutron interrogation applications

    NASA Astrophysics Data System (ADS)

    Bures, Brian; Krishnan, Mahadevan; James, Colt; Madden, Robert; Hennig, Wolfgang; Breus, Dimitry; Asztalos, Stephen; Sabourov, Konstantin; Lane, Stephen

    2011-10-01

    A fast pulsed neutron source enables identification and ranging of contraband nuclear material using time-of-flight separation of the probe neutron pulse from the fission induced emission quanta. Alameda Applied Sciences Corporation has demonstrated a 1 Hz plasma focus neutron source that uses an impedance matching transformer to better couple the power from the driver to the dynamic pinch load. For a 24 kV primary charge, the system produces a 61 kA peak current with a neutron yield up to 5 ×105 neutrons/pulse at 1 Hz. Experiments are described in which induced 845 keV gamma emission from iron targets (by 2.45 MeV DD neutrons) was separated (by time of flight) from the 20-30 ns probe neutron pulses. Monte Carlo simulations are used to optimize the concept for a fieldable system. Work supported by US Department of Homeland Security (DNDO) and by the US Air Force (KAFB).

  5. 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).

  6. Black hole as a point radiator and recoil effect on the brane world.

    PubMed

    Frolov, Valeri; Stojković, Dejan

    2002-10-01

    A small black hole attached to a brane in a higher-dimensional space emitting quanta into the bulk may leave the brane as a result of a recoil. We construct a field theory model in which such a black hole is described as a massive scalar particle with internal degrees of freedom. In this model, the probability of transition between the different internal levels is identical to the probability of thermal emission calculated for the Schwarzschild black hole. The discussed recoil effect implies that the thermal emission of the black holes, which might be created by interaction of high energy particles in colliders, could be terminated and the energy nonconservation can be observed in the brane experiments.

  7. Regular vibrational state progressions at the dissociation limit of SCCl2.

    PubMed

    Chowdary, Praveen D; Gruebele, Martin

    2009-01-14

    We observe sharp features in the vibrational spectrum of SCCl(2) at and above its two lowest-lying dissociation limits. Highly regular vibrational progressions persist at dissociation, as in some smaller molecules studied previously by others. Nearly all of the SCCl(2) transitions studied by stimulated emission pumping can be assigned and fitted by a simple effective Hamiltonian without resonance terms, up to a total vibrational excitation of 36 quanta. The character of the highly excited vibrational wave functions is not normal mode-like, but it nonetheless arises gradually from the normal modes as the energy increases. The number of sharp vibrational features observed matches a scaling model that predicts localization of nearly all vibrational states near dissociation as the size of a polyatomic molecule increases.

  8. 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.

  9. Remarks on the black hole information problem

    SciTech Connect

    Lowe, David A.; Thorlacius, Larus

    2006-05-15

    String theory provides numerous examples of duality between gravitational theories and unitary gauge theories. To resolve the black hole information paradox in this setting, it is necessary to better understand how unitarity is implemented on the gravity side. We argue that unitarity is restored by nonlocal effects whose initial magnitude is suppressed by the exponential of the Bekenstein-Hawking entropy. Time-slicings for which effective field theory is valid are obtained by demanding the mutual back-reaction of quanta be small. The resulting bounds imply that nonlocal effects do not lead to observable violations of causality or conflict with the equivalence principle for infalling observers, yet implement information retrieval for observers who stay outside the black hole.

  10. 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

  11. 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.

  12. 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)

  13. Schrödinger's cat and the firewall

    NASA Astrophysics Data System (ADS)

    Hollowood, Timothy J.

    2014-05-01

    It has been argued that when black holes are treated as quantum systems there are implications at the horizon and not just the singularity. Infalling observers will meet a firewall of high energy quanta. We argue that the question of whether an observer falling into a black hole experiences a smooth horizon or a firewall is identical to the question of whether Schrödinger's cat is either in a definite state, alive or dead, or in a superposition of the two. Since experience with real macro-systems indicate the former, the black hole state vector is seen to describe a set of decoherent alternatives each with a smooth horizon and the entanglement puzzle is thereby side stepped.

  14. [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.

  15. Effect of the tilted magnetic field on the magnetosubbands and conductance in the bilayer quantum wire

    NASA Astrophysics Data System (ADS)

    Chwiej, T.

    2016-10-01

    We theoretically study the single electron magnetotransport in GaAs and InGaAs vertically stacked bilayer nanowires. In considered geometry, the tilted magnetic field is always perpendicular to the main (transport) axis of the quantum wire and, therefore its transverse and vertical components allow separately for changing the magnitude of intralayer and interlayer subbands mixing. We study the changes introduced to energy dispersion relation E(k) by tilted magnetic field of strength up to several tesla and analyze their origins for symmetric as well as asymmetric confining potentials in the growth direction. Calculated energy dispersion relations are thereafter used to show that the value of a conductance of the bilayer nanowire may abruptly rise as well as fall by few conductance quanta when the Fermi energy in nanosystem is changed. It is also shown that such conductance oscillations, in conjunction with spin Zeeman effect, may give a moderately spin polarized current in the bilayer nanowire.

  16. 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.

  17. Path entanglement of surface plasmons

    NASA Astrophysics Data System (ADS)

    Fakonas, James S.; Mitskovets, Anna; Atwater, Harry A.

    2015-02-01

    Metals can sustain traveling electromagnetic waves at their surfaces supported by the collective oscillations of their free electrons in unison. Remarkably, classical electromagnetism captures the essential physics of these ‘surface plasma’ waves using simple models with only macroscopic features, accounting for microscopic electron-electron and electron-phonon interactions with a single, semi-empirical damping parameter. Nevertheless, in quantum theory these microscopic interactions could be important, as any substantial environmental interactions could decohere quantum superpositions of surface plasmons, the quanta of these waves. Here we report a measurement of path entanglement between surface plasmons with 95% contrast, confirming that a path-entangled state can indeed survive without measurable decoherence. Our measurement suggests that elastic scattering mechanisms of the type that might cause pure dephasing in plasmonic systems must be weak enough not to significantly perturb the state of the metal under the experimental conditions we investigated.

  18. 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

  19. 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.}

  20. 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.

  1. Quantum analysis of atom-ion sympathetic cooling in the presence of micromotion

    NASA Astrophysics Data System (ADS)

    Krych, Michal; Idziaszek, Zbigniew

    2014-05-01

    We investigate the problem of a single ion in a radio-frequency trap and immersed in an ultracold Bose gas either in condensed or non-condensed phase. We develop master equation formalism describing the sympathetic cooling and we determine the cooling rates and final energies of ions. We show that cold atomic reservoir modifies the stability diagram of the ion in the Paul trap creating the regions where the ion is either cooled or heated due to the energy quanta exchanged with the time-dependent potential. Our calculation indicates that micromotion constitutes an important source of heating limiting the final temperature of ions to values higher than 100 μK for parameters of present experiments.

  2. Transfer of optical orbital angular momentum to a bound electron

    NASA Astrophysics Data System (ADS)

    Schmiegelow, Christian T.; Schulz, Jonas; Kaufmann, Henning; Ruster, Thomas; Poschinger, Ulrich G.; Schmidt-Kaler, Ferdinand

    2016-10-01

    Photons can carry angular momentum, not only due to their spin, but also due to their spatial structure. This extra twist has been used, for example, to drive circular motion of microscopic particles in optical tweezers as well as to create vortices in quantum gases. Here we excite an atomic transition with a vortex laser beam and demonstrate the transfer of optical orbital angular momentum to the valence electron of a single trapped ion. We observe strongly modified selection rules showing that an atom can absorb two quanta of angular momentum from a single photon: one from the spin and another from the spatial structure of the beam. Furthermore, we show that parasitic ac-Stark shifts from off-resonant transitions are suppressed in the dark centre of vortex beams. These results show how light's spatial structure can determine the characteristics of light-matter interaction and pave the way for its application and observation in other systems.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    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. 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.

  4. From photons to phonons and back: a THz optical memory in diamond.

    PubMed

    England, D G; Bustard, P J; Nunn, J; Lausten, R; Sussman, B J

    2013-12-13

    Optical quantum memories are vital for the scalability of future quantum technologies, enabling long-distance secure communication and local synchronization of quantum components. We demonstrate a THz-bandwidth memory for light using the optical phonon modes of a room temperature diamond. This large bandwidth makes the memory compatible with down-conversion-type photon sources. We demonstrate that four-wave mixing noise in this system is suppressed by material dispersion. The resulting noise floor is just 7×10(-3) photons per pulse, which establishes that the memory is capable of storing single quanta. We investigate the principle sources of noise in this system and demonstrate that high material dispersion can be used to suppress four-wave mixing noise in Λ-type systems. PMID:24483658

  5. 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

  6. 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.

  7. From photons to phonons and back: a THz optical memory in diamond.

    PubMed

    England, D G; Bustard, P J; Nunn, J; Lausten, R; Sussman, B J

    2013-12-13

    Optical quantum memories are vital for the scalability of future quantum technologies, enabling long-distance secure communication and local synchronization of quantum components. We demonstrate a THz-bandwidth memory for light using the optical phonon modes of a room temperature diamond. This large bandwidth makes the memory compatible with down-conversion-type photon sources. We demonstrate that four-wave mixing noise in this system is suppressed by material dispersion. The resulting noise floor is just 7×10(-3) photons per pulse, which establishes that the memory is capable of storing single quanta. We investigate the principle sources of noise in this system and demonstrate that high material dispersion can be used to suppress four-wave mixing noise in Λ-type systems.

  8. Manifestation of topological surface electron states in the photoelectromagnetic effect induced by terahertz laser radiation

    NASA Astrophysics Data System (ADS)

    Galeeva, A. V.; Egorova, S. G.; Chernichkin, V. I.; Tamm, M. E.; Yashina, L. V.; Rumyantsev, V. V.; Morozov, S. V.; Plank, H.; Danilov, S. N.; Ryabova, L. I.; Khokhlov, D. R.

    2016-09-01

    We demonstrate that measurements of the photoelectromagnetic effect using terahertz laser radiation may provide a unique opportunity to discriminate between the topological surface states and other highly conductive surface electron states. We performed a case study of mixed (Bi{}1-xIn x )2Se3 crystals undergoing a topological phase transformation due to the transition from the inverse to the direct electron energy spectrum in the crystal bulk at variation of the composition x. We show that for the topological insulator phase, the photoelectromagnetic effect amplitude is defined by the number of incident radiation quanta, whereas for the trivial insulator phase, it depends on the power in a laser pulse irrespective of its wavelength. We assume that such behavior is attributed to a strong damping of the electron–electron interaction in the topological insulator phase compared to the trivial insulator.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. Shell Effects in Fusion-Fission of Heavy and Superheavy Nuclei

    NASA Astrophysics Data System (ADS)

    Itkis, M. G.; Bogatchev, A. A.; Itkis, I. M.; Jandel, M.; Kliman, J.; Kniajeva, G. N.; Kondratiev, N. A.; Korzyukov, I. V.; Kozulin, E. M.; Krupa, L.; Oganessian, Yu. Ts.; Pokrovsky, I. V.; Prokhorova, E. V.; Voskresenski, V. M.; Zagrebaev, V. I.; Rusanov, A. Ya.; Corradi, L.; Gadea, A.; Latina, L.; Stefanini, A. M.; Szilner, S.; Trotta, M.; Vinodkumar, A. M.; Beghini, S.; Montagnoli, G.; Scarlassara, F.; Äystö, J.; Khlebnikov, S. V.; Rubchenya, V. A.; Trzaska, W. H.; Vakhtin, D. N.; Goverdovski, A. A.; Hanappe, F.; Materna, T.; Dorvaux, O.; Rowley, N.; Stuttge, L.; Giardina, G.

    2003-07-01

    The process of fusion-fission of heavy and superheavy nuclei with Z=82-122 formed in the reactions with 48Ca, 58Fe and 64Ni ions at energies near and below the Coulomb barrier has been studied. The experiments were carried out at the U-400 accelerator of the Flerov Laboratory of Nuclear Reactions (JINR, Russia), the XTU Tandem accelerator of the National Laboratory of Legnaro (LNL, Italy ) and the Accelerator of the Laboratory of University of Jyväskylä (JYFL, Finland) using the time-of-flight spectrometer of fission fragments CORSET[1] and the neutron multi-detector DEMON[2,3]. As a result of the experiments, mass and energy distributions (MED) of fission fragments, cross-sections of fission, quasi-fission and evaporation residues, multiplicities of neutrons and γ-quanta and their dependence on the mechanism of formation and decay of compound systems have been studied.

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

    PubMed Central

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

    2015-01-01

    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. 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. PMID:25728197

  16. Readily releasable pool of synaptic vesicles measured at single synaptic contacts

    PubMed Central

    Trigo, Federico F.; Sakaba, Takeshi; Ogden, David; Marty, Alain

    2012-01-01

    To distinguish between different models of vesicular release in brain synapses, it is necessary to know the number of vesicles of transmitter that can be released immediately at individual synapses by a high-calcium stimulus, the readily releasable pool (RRP). We used direct stimulation by calcium uncaging at identified, single-site inhibitory synapses to investigate the statistics of vesicular release and the size of the RRP. Vesicular release, detected as quantal responses in the postsynaptic neuron, showed an unexpected stochastic variation in the number of quanta from stimulus to stimulus at high intracellular calcium, with a mean of 1.9 per stimulus and a maximum of three or four. The results provide direct measurement of the RRP at single synaptic sites. They are consistent with models in which release proceeds from a small number of vesicle docking sites with an average occupancy around 0.7. PMID:23074252

  17. Robust Concurrent Remote Entanglement Between Two Superconducting Qubits

    NASA Astrophysics Data System (ADS)

    Narla, A.; Shankar, S.; Hatridge, M.; Leghtas, Z.; Sliwa, K. M.; Zalys-Geller, E.; Mundhada, S. O.; Pfaff, W.; Frunzio, L.; Schoelkopf, R. J.; Devoret, M. H.

    2016-07-01

    Entangling two remote quantum systems that never interact directly is an essential primitive in quantum information science and forms the basis for the modular architecture of quantum computing. When protocols to generate these remote entangled pairs rely on using traveling single-photon states as carriers of quantum information, they can be made robust to photon losses, unlike schemes that rely on continuous variable states. However, efficiently detecting single photons is challenging in the domain of superconducting quantum circuits because of the low energy of microwave quanta. Here, we report the realization of a robust form of concurrent remote entanglement based on a novel microwave photon detector implemented in the superconducting circuit quantum electrodynamics platform of quantum information. Remote entangled pairs with a fidelity of 0.57 ±0.01 are generated at 200 Hz. Our experiment opens the way for the implementation of the modular architecture of quantum computation with superconducting qubits.

  18. Quantum-to-classical transition in cavity quantum electrodynamics.

    PubMed

    Fink, J M; Steffen, L; Studer, P; Bishop, Lev S; Baur, M; Bianchetti, R; Bozyigit, D; Lang, C; Filipp, S; Leek, P J; Wallraff, A

    2010-10-15

    The quantum properties of electromagnetic, mechanical or other harmonic oscillators can be revealed by investigating their strong coherent coupling to a single quantum two level system in an approach known as cavity quantum electrodynamics (QED). At temperatures much lower than the characteristic energy level spacing the observation of vacuum Rabi oscillations or mode splittings with one or a few quanta asserts the quantum nature of the oscillator. Here, we study how the classical response of a cavity QED system emerges from the quantum one when its thermal occupation-or effective temperature-is raised gradually over 5 orders of magnitude. In this way we explore in detail the continuous quantum-to-classical crossover and demonstrate how to extract effective cavity field temperatures from both spectroscopic and time-resolved vacuum Rabi measurements.

  19. THE INTERPLAY OF LIGHT AND HEAT IN BLEACHING RHODOPSIN

    PubMed Central

    St. George, Robert C. C.

    1952-01-01

    Rhodopsin, the pigment of the retinal rods, can be bleached either by light or by high temperature. Earlier work had shown that when white light is used the bleaching rate does not depend on temperature, and so must be independent of the internal energy of the molecule. On the other hand thermal bleaching in the dark has a high temperature dependence from which one can calculate that the reaction has an apparent activation energy of 44 kg. cal. per mole. It has now been shown that the bleaching rate of rhodopsin becomes temperature-dependent in red light, indicating that light and heat cooperate in activating the molecule. Apparently thermal energy is needed for bleaching at long wave lengths where the quanta are not sufficiently energy-rich to bring about bleaching by themselves. The temperature dependence appears at 590 mµ. This is the longest wave length at which bleaching by light proceeds without thermal activation, and corresponds to a quantum energy of 48.5 kg. cal. per mole. This value of the minimum energy to bleach rhodopsin by light alone is in agreement with the activation energy of thermal bleaching in the dark. At wave lengths between 590 and 750 mµ, the longest wave length at which the bleaching rate was fast enough to study, the sum of the quantum energy and of the activation energy calculated from the temperature coefficients remains between 44 and 48.5 kg. cal. This result shows that in red light the energy deficit of the quanta can be made up by a contribution of thermal energy from the internal degrees of freedom of the rhodopsin molecule. The absorption spectrum of rhodopsin, which is not markedly temperature-dependent at shorter wave lengths, also becomes temperature-dependent in red light of wave lengths longer than about 570 to 590 mµ. The temperature dependence of the bleaching rate is at least partly accounted for by the temperature coefficient of absorption. There is some evidence that the temperature coefficient of bleaching is

  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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. Search for electron liquids with non-Abelian quasiparticles

    NASA Astrophysics Data System (ADS)

    Wójs, Arkadiusz

    2010-03-01

    We use exact numerical diagonalization in the search of fractional quantum Hall states with non-Abelian quasiparticle statistics. For the (most promising) states in a partially filled second Landau level, the search is narrowed to the range of filling factors 7/3 < ve < 8/3. In this range, the analysis of energy spectra and correlation functions, calculated including finite width and Landau level mixing, supports the prominent non-Abelian candidates at ve = 5/2 (paired Moore-Read "pfafian" state) and 12/5 (clustered Read-Rezayi "parafermion" state). Outside of this range, the noninteracting composite fermion model with four attached flux quanta is validated, yielding the family of quantum liquids with fractional, but Abelian statistics. The borderline ve = 7/3 state is shown to be adiabatically connected to the Laughlin liquid, but its short-range correlations are significantly different.

  8. 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)

  9. {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.

  10. 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.

  11. Manifestations of advanced civilizations

    NASA Astrophysics Data System (ADS)

    Bracewell, R. N.

    A list of possible modes of detecting advanced civilizations elsewhere in the universe is provided, including EM Alfven, and gravity waves, matter transfer, and exotica such as tachyons, black hole tunneling, and telepathy. Further study is indicated for low frequency radio wave propagation, which may travel along magnetic fields to reach the earth while laser beams are not favored because of the power needed for transmitting quanta instead of waves. IR, X ray, and UV astronomy are noted to be suitable for detecting signals in those ranges, while Alfven wave communication will be best observed by probes outside the orbit of Jupiter, where local anomalies have less effect. Particle propagation communication is viewed as unlikely, except as a trace of an extinct civilization, but panspermia, which involves interstellar spreading of seeds and/or spores, receives serious attention, as does laser probe or pellet propulsion.

  12. 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

  13. 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.

  14. 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.

  15. Analytic continuation of the rotating black hole state counting

    NASA Astrophysics Data System (ADS)

    Achour, Jibril Ben; Noui, Karim; Perez, Alejandro

    2016-08-01

    In loop quantum gravity, a spherical black hole can be described in terms of a Chern-Simons theory on a punctured 2-sphere. The sphere represents the horizon. The punctures are the edges of spin-networks in the bulk which cross the horizon and carry quanta of area. One can generalize this construction and model a rotating black hole by adding an extra puncture colored with the angular momentum J in the 2-sphere. We compute the entropy of rotating black holes in this model and study its semi-classical limit. After performing an analytic continuation which sends the Barbero-Immirzi parameter to γ = ± i,weshowthattheleadingorderterminthesemi-classicalexpansionoftheentropy reproduces the Bekenstein-Hawking law independently of the value of J.

  16. 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).

  17. 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.

  18. Theory of scattering of electromagnetic waves of the microwave range in a turbid medium

    NASA Astrophysics Data System (ADS)

    Konstantinov, O. V.; Matveentsev, A. V.

    2013-02-01

    The coefficient of extinction of electromagnetic waves of the microwave range due to their scattering from clusters suspended in an amorphous medium and responsible for turbidity is calculated. Turbidity resembles the case when butter clusters transform water into milk. In the case under investigation, the clusters are conductors (metallic or semiconducting). The extinction coefficient is connected in a familiar way with the cross section of light scattering from an individual cluster. A new formula is derived for the light scattering cross section in the case when damping of oscillations of an electron is due only to spontaneous emission of light quanta. In this case, the resonant scattering cross section for light can be very large. It is shown that this can be observed only in a whisker nanocluster. In addition, the phonon energy on a whisker segment must be higher than the photon energy, which is close to the spacing between the electron energy levels in the cluster.

  19. 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.

  20. 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.

  1. Cosmological implications of interacting group field theory models: Cyclic universe and accelerated expansion

    NASA Astrophysics Data System (ADS)

    de Cesare, Marco; Pithis, Andreas G. A.; Sakellariadou, Mairi

    2016-09-01

    We study the cosmological implications of interactions between spacetime quanta in the group field theory (GFT) approach to quantum gravity from a phenomenological perspective. Our work represents a first step towards understanding early Universe cosmology by studying the dynamics of the emergent continuum spacetime, as obtained from a fundamentally discrete microscopic theory. In particular, we show how GFT interactions lead to a recollapse of the Universe while preserving the bounce replacing the initial singularity, which has already been shown to occur in the free case. It is remarkable that cyclic cosmologies are thus obtained in this framework without any a priori assumption on the geometry of spatial sections of the emergent spacetime. Furthermore, we show how interactions make it possible to have an early epoch of accelerated expansion, which can be made to last for an arbitrarily large number of e -folds, without the need to introduce an ad hoc potential for the scalar field.

  2. 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.

  3. Five-body calculation with Pauli constraint for shell- and cluster-structure in 16O

    NASA Astrophysics Data System (ADS)

    Horiuchi, Wataru; Suzuki, Yasuyuki

    2016-07-01

    A 12C+four-nucleon (4N) five-body model is applied for the ground and first excited states of 16O. The 4N configurations are selected in a wide Hilbert space under the fulfillment of the Pauli principle excluding the occupied orbits in 12C. The energies of both the states are obtained in excellent agreement with experiment. Analysis of the wave functions indicates a spatially localized alpha-particle-like cluster structure for the excited state and a shell-model-like delocalized structure for the ground state. The difficulty of describing the cluster structure by a standard shell model approach is discussed by calculating components of the harmonic-oscillator quanta in the wave functions.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Space γ-observatory GAMMA-400 Current Status and Perspectives

    NASA Astrophysics Data System (ADS)

    Galper, A. M.; Bonvicini, V.; Topchiev, N. P.; Adriani, O.; Aptekar, R. L.; Arkhangelskaja, I. V.; Arkhangelskiy, A. I.; Bergstrom, L.; Berti, E.; Bigongiari, G.; Bobkov, S. G.; Boezio, M.; Bogomolov, E. A.; Bonechi, S.; Bongi, M.; Bottai, S.; Castellini, G.; Cattaneo, P. W.; Cumani, P.; Dedenko, G. L.; De Donato, C.; Dogiel, V. A.; Gorbunov, M. S.; Gusakov, Yu. V.; Hnatyk, B. I.; Kadilin, V. V.; Kaplin, V. A.; Kaplun, A. A.; Kheymits, M. D.; Korepanov, V. E.; Larsson, J.; Leonov, A. A.; Loginov, V. A.; Longo, F.; Maestro, P.; Marrocchesi, P. S.; Mikhailov, V. V.; Mocchiutti, E.; Moiseev, A. A.; Mori, N.; Moskalenko, I. V.; Naumov, P. Yu.; Papini, P.; Pearce, M.; Picozza, P.; Rappoldi, A.; Ricciarini, S.; Runtso, M. F.; Ryde, F.; Serdin, O. V.; Sparvoli, R.; Spillantini, P.; Suchkov, S. I.; Tavani, M.; Taraskin, A. A.; Tiberio, A.; Tyurin, E. M.; Ulanov, M. V.; Vacchi, A.; Vannuccini, E.; Vasilyev, G. I.; Yurkin, Yu. T.; Zampa, N.; Zirakashvili, V. N.; Zverev, V. G.

    GAMMA-400 γ-ray telescope is designed to measure fluxes of γ-rays and the electron-positron cosmic ray component possibly generated in annihilation or decay of dark matter particles; to search for and study in detail discrete γ-ray sources, to examine the energy spectra of Galactic and extragalactic diffuse γ-rays, to study γ-ray bursts and γ-rays from the active Sun. GAMMA-400 consists of plastic scintillation anticoincidence top and lateral detectors, converter-tracker, plastic scintillation detectors for the time-of-flight system (TOF), two-part calorimeter (CC1 and CC2), plastic scintillation lateral detectors of calorimeter, plastic scintillation detectors of calorimeter, and neutron detector. The converter-tracker consists of 13 layers of double (x, y) silicon strip coordinate detectors (pitch of 0.08 mm). The first three and final one layers are without tungsten while the middle nine layers are interleaved with nine tungsten conversion foils. The thickness of CC1 and CC2 is 2 X0 (0.1λ0) and 23 X0 (1.1λ0) respectively (where X0 is radiation length and λ0 is nuclear interaction one). The total calorimeter thickness is 25 X0 or 1.2λ0 for vertical incident particles registration and 54 X0 or 2.5λ0 for laterally incident ones. The energy range for γ-rays and electrons (positrons) registration in the main aperture is from ∼0.1 GeV to ∼3.0 TeV. The γ-ray telescope main aperture angular and energy resolutions are respectively ∼0.01 and ∼1% for 102 GeV γ-quanta, the proton rejection factor is ∼5×105. The first three strip layers without tungsten provide the registration of γ-rays down to ∼20 MeV in the main aperture. Also this aperture allows investigating high energy light nuclei fluxes characteristics. Electrons, positrons, light nuclei and gamma-quanta will also register from the lateral directions due to special aperture configuration. Lateral aperture energy resolution is the same as for main aperture for electrons, positrons, light

  9. The light-cone Fock state expansion and hadron physics phenomenology

    SciTech Connect

    Brodsky, S.J.

    1997-06-01

    The light-cone Fock expansion is defined in the following way: one first constructs the light-cone time evolution operator and the invariant mass operator in light-cone gauge from the QCD Lagrangian. The total longitudinal momentum and transverse momenta are conserved, i.e. are independent of the interactions. The matrix elements of the invariant mass operator on the complete orthonormal basis of the free theory can then be constructed. The matrix elements connect Fock states differing by 0, 1, or 2 quark or gluon quanta, and they include the instantaneous quark and gluon contributions imposed by eliminating dependent degrees of freedom in light-cone gauge. Applications of light-cone methods to QCD phenomenology are briefly described.

  10. 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

  11. Distribution patterns of zoochlorellae and zooxanthellae hosted by two Pacific Northeast anemones, Anthopleura elegantissima and A. xanthogrammica.

    PubMed

    Bates, Amanda E; McLean, Lily; Laing, Patrick; Raeburn, Lisa A; Hare, Crystal

    2010-06-01

    This study investigated patterns in the relative abundance of two photosynthetic algal symbionts, zoochlorellae (ZC) and zooxanthellae (ZX), hosted by two temperate anemones, Anthopleura elegantissima and A. xanthogrammica. Previous studies have documented varying proportions of each symbiont along environmental gradients, presumably determined by their respective physiological capabilities. To test for differences in the algal type between the two host species, we sampled anemone tissues (tentacle or tentacle and body column) of similarly sized polyps that were located close together in multiple habitats: tidepools, crevices, underneath rock ledges, and along natural light gradients in caves. The ZC-A. elegantissima symbiosis was rare on the west coast of Vancouver Island, British Columbia, Canada. Even in low-irradiance habitats, ZC were the dominant algae hosted by A. xanthogrammica, while nearby A. elegantissima hosted ZX or was algae-free. As a first step in determining whether symbiont growth rates differed between the two host species, we quantified mitotic index (MI), the percentage of cells with division furrows, under artificial light and in the field by simultaneously sampling tentacles from both species. MI was more stable in A. elegantissima: the MI of ZX isolated from the tentacles of A. xanthogrammica was slightly higher at a light level of 80 micromol quanta m(-2) s(-1) than it was for ZX from A. elegantissima (respectively, 7.3 vs. 6.2) and relatively lower at 40 micromol quanta m(-2) s(-1) (3.9 vs. 5.6). Our data indicate host-specific differences in symbiont distributions and MI when extrinsic physical parameters were similar. PMID:20570847

  12. Efficiency of the Human Observer Compared to an Ideal Observer Based on a Generalized NEQ Which Incorporates Scatter and Geometric Unsharpness: Evaluation with a 2AFC Experiment

    PubMed Central

    Kyprianou, Iacovos S.; Ganguly, Arundhuti; Rudin, Stephen; Bednarek, Daniel R.; Gallas, Brandon D.; Myers, Kyle J.

    2011-01-01

    Under certain assumptions the detectability of the ideal observer can be defined as the integral of the system Noise Equivalent Quanta multiplied by the squared object spatial frequency distribution. Using the detector Noise-Equivalent-Quanta (NEQD) for the calculation of detectability inadequately describes the performance of an x-ray imaging system because it does not take into account the effects of patient scatter and geometric unsharpness. As a result, the ideal detectability index is overestimated, and hence the efficiency of the human observer in detecting objects is underestimated. We define a Generalized-NEQ (GNEQ) for an x-ray system referenced at the object plane that incorporates the scatter fraction, the spatial distributions of scatter and focal spot, the detector MTFD, and the detector Normalized-Noise-Power-Spectrum (NNPSD). This GNEQ was used in the definition of the ideal detectability for the evaluation of the human observer efficiency during a two Alternative Forced Choice (2-AFC) experiment, and was compared with the case where only the NEQD was used in the detectability calculations. The 2-AFC experiment involved the detection of images of polyethylene tubes (diameters between 100–300 μm) filled with iodine contrast (concentrations between 0–120 mg/cm3) placed onto a uniform head equivalent phantom placed near the surface of a microangiographic detector (43 μm pixel size). The resulting efficiency of the human observer without regarding the effects of scatter and geometric unsharpness was 30%. When these effects were considered the efficiency was increased to 70%. The ideal observer with the GNEQ can be a simple optimization method of a complete imaging system. PMID:21311735

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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

  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. 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.

  1. The photon-plasmon transitions and diagnostics of the space plasma turbulence

    NASA Astrophysics Data System (ADS)

    Glushkov, A.; Malinovskaya, S.; Ambrosov, S.

    We present a new approach to treating the space plasma turbulence based on using to make diagnostic data regarding the photon-plasmon transitions The theoretical definition of characteristics for these transitions is caried out within consistent theoretical approach based on the Gell-Mann and Low formalism energy approach in QED theory We apply it to calculation of such transitions Ps with emission of photon and Langmuir quanta It is well known that the positronium Ps is an exotic hydrogen isotope with the atomic mass M 2m e sim 1 milli-amu and ground state binding energy of E 6 8 eV The hfs states of Ps differ in spin S life time t and mode of annihilation para-Ps S 0 t 1 25 cdot 10 -10 n 3 s 2 gamma annihilation and ortho-Ps S 1 t 1 4 cdot 10 -7 n 3 s 3 gamma annihilation As a rule probabilities of the cascade radiation transitions are more than the annihilation probability The ortho-Ps atom has a metastable state 2 3 s 1 and probability of two-photon radiation transition from this state into 1 3 s 1 state 1 8 cdot 10 -3 s -1 is significantly less than probability of the three-photon annihilation directly from 2 3 s 1 level 8 9 cdot 10 5 s -1 i e it is usually supposed that the ortho-Ps annihilates from 2 3 s 1 state Another situation may take place in plasma where it is arisen the competition process of destruction of the metastable level -- the photon-plasmon transition 2 3 s 1 -1 3 s 1 with emission of photon and Langmuir quanta

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. From the sparse to the statistical limit of intramolecular vibrational redistribution in vibrational predissociation: ArCl2 as an example

    NASA Astrophysics Data System (ADS)

    Roncero, Octavio; Caloto, David; Janda, Kenneth C.; Halberstadt, Nadine

    1997-08-01

    The dynamics of intramolecular vibrational relaxation (IVR) for ArCl2 are examined for a wide range of vibrational and rotational excitation. In order to describe the IVR more efficiently, and characterize it more quantitatively, we propose a refinement of the traditional Bixon-Jortner description in which the active states are prediagonalized to simplify the coupling scheme that must be considered. This allows for an explicit determination of the average density of states and average coupling strength for each initial excitation. We find that the IVR dynamics proceed from the sparse regime for v=11, for which the first open dissociation channel corresponds to the loss of two Cl2 quanta, to the intermediate-dense regime for v=25 which dissociates by the loss of 4 quanta. We find that over this range the increase in the density of states is less important than the increase in the coupling strength. For v = 18 we examine the effect of rotation in considerable detail. Initial states that couple via a manifold of 6000 channels can be considered since the calculation is performed on a parallel computer. The effect of increasing J, the total angular momentum excitation, is found to be less than that of increasing K, the degree of rotation about the van der Waals bond. This means that the main effect is not simply an increase of the available density of states due to Coriolis coupling. Understanding the details of IVR in a relatively simple system like ArCl2 should help us understand the dynamics of more complicated molecules. In particular, the case of ArI2 is discussed.

  7. Improved Serological Differentiation between Systemic Lupus Erythematosus and Mixed Connective Tissue Disease by Use of an SmD3 Peptide-Based Immunoassay

    PubMed Central

    Mahler, M.; Stinton, L. M.; Fritzler, M. J.

    2005-01-01

    Autoantibodies to the Sm antigens are specifically found in 5 to 30% of patients with systemic lupus erythematosus (SLE) depending on the detection system and the patient group. Several immunoassays designed for research and diagnostic laboratory use have been developed. The autoantigens employed in these tests include purified native proteins, recombinant polypeptides, and synthetic peptides. In the present study, we compared the clinical accuracy of anti-Sm autoantibody assays from commercial suppliers including different conventional enzyme-linked immunosorbent assay (ELISA) systems based on purified Sm antigens, an addressable laser bead assay and a newly developed anti-Sm peptide assay. Although the clinical sensitivity of all assays under investigation was comparable, relatively poor correlations and significant differences in specificity were found with a patient cohort of 150 patients. The sensitivity and specificity were 10 and 94%, respectively, for the anti-Sm ELISA from Euroimmun, 10 and 90%, respectively, for the QuantaLite Sm (INOVA), 12 and 88%, respectively, for the Sm assay in the Varelisa ReCombi ANA profile (Pharmacia Diagnostics), 10 and 94%, respectively, for the QuantaPlex Sm (INOVA), and 12 and 100%, respectively, for the new SmD3 peptide-based ELISA (Varelisa Sm Antibodies). The majority of positive test results within the control groups were found in patients with mixed connective tissue disease. Based on the results, we conclude that the detection of anti-Sm antibodies strongly depends both on the nature of the antigen and on the detection system. Finally, we conclude that the recently identified SmD peptide containing a symmetrical dimethylarginine at position 112 of D3 represents a promising tool for the detection of a highly specific subpopulation of anti-Sm antibodies. PMID:15642993

  8. Efficient method for calculations of ro-vibrational states in triatomic molecules near dissociation threshold: Application to ozone

    NASA Astrophysics Data System (ADS)

    Teplukhin, Alexander; Babikov, Dmitri

    2016-09-01

    A method for calculations of rotational-vibrational states of triatomic molecules up to dissociation threshold (and scattering resonances above it) is devised, that combines hyper-spherical coordinates, sequential diagonalization-truncation procedure, optimized grid DVR, and complex absorbing potential. Efficiency and accuracy of the method and new code are tested by computing the spectrum of ozone up to dissociation threshold, using two different potential energy surfaces. In both cases good agreement with results of previous studies is obtained for the lower energy states localized in the deep (˜10 000 cm-1) covalent well. Upper part of the bound state spectrum, within 600 cm-1 below dissociation threshold, is also computed and is analyzed in detail. It is found that long progressions of symmetric-stretching and bending states (up to 8 and 11 quanta, respectively) survive up to dissociation threshold and even above it, whereas excitations of the asymmetric-stretching overtones couple to the local vibration modes, making assignments difficult. Within 140 cm-1 below dissociation threshold, large-amplitude vibrational states of a floppy complex O⋯O2 are formed over the shallow van der Waals plateau. These are assigned using two local modes: the rocking-motion and the dissociative-motion progressions, up to 6 quanta in each, both with frequency ˜20 cm-1. Many of these plateau states are mixed with states of the covalent well. Interestingly, excitation of the rocking-motion helps keeping these states localized within the plateau region, by raising the effective barrier.

  9. 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

  10. Mechanisms underlying the influence of saliency on value-based decisions

    PubMed Central

    Chen, Xiaomo; Mihalas, Stefan; Niebur, Ernst; Stuphorn, Veit

    2013-01-01

    Objects in the environment differ in their low-level perceptual properties (e.g., how easily a fruit can be recognized) as well as in their subjective value (how tasty it is). We studied the influence of visual salience on value-based decisions using a two alternative forced choice task, in which human subjects rapidly chose items from a visual display. All targets were equally easy to detect. Nevertheless, both value and salience strongly affected choices made and reaction times. We analyzed the neuronal mechanisms underlying these behavioral effects using stochastic accumulator models, allowing us to characterize not only the averages of reaction times but their full distributions. Independent models without interaction between the possible choices failed to reproduce the observed choice behavior, while models with mutual inhibition between alternative choices produced much better results. Mutual inhibition thus is an important feature of the decision mechanism. Value influenced the amount of accumulation in all models. In contrast, increased salience could either lead to an earlier start (onset model) or to a higher rate (speed model) of accumulation. Both models explained the data from the choice trials equally well. However, salience also affected reaction times in no-choice trials in which only one item was present, as well as error trials. Only the onset model could explain the observed reaction time distributions of error trials and no-choice trials. In contrast, the speed model could not, irrespective of whether the rate increase resulted from more frequent accumulated quanta or from larger quanta. Visual salience thus likely provides an advantage in the onset, not in the processing speed, of value-based decision making. PMID:24167161

  11. Photoacclimation of Prochlorococcus sp. (Prochlorophyta) Strains Isolated from the North Atlantic and the Mediterranean Sea.

    PubMed Central

    Partensky, F.; Hoepffner, N.; Li, WKW.; Ulloa, O.; Vaulot, D.

    1993-01-01

    Two Atlantic (SARG and NATL1) strains and one Mediterranean (MED) strain of Prochlorococcus sp., a recently discovered marine, free-living prochlorophyte, were grown over a range of "white" irradiances (lg) and under low blue light to examine their photoacclimation capacity. All three strains contained divinyl (DV) chlorophylls (Chl) a and b, both distinguishable from "normal" Chls by their red-shifted blue absorption maximum, a Chl c-like pigment at low concentration, zeaxanthin, and [alpha]-carotene. The presence of two phaeophytin b peaks in acidified extracts from both Atlantic strains grown at high lg suggests that these strains also had a normal Chl b-like pigment. In these strains, the total Chl b to DV-Chl a molar ratio decreased from about 1 at 7.5 [mu]mol quanta m-2 s-1 to 0.4 to 0.5 at 133 [mu]mol quanta m-2 s-1. In contrast, the MED strain always had a low DV-Chl b to DV-Chl a molar ratio, ranging between 0.13 at low lg and 0.08 at high lg. The discrepancies between the Atlantic and MED strains could result from differences either in the number of light-harvesting complexes (LHC) II per photosystem II or in the Chl b-binding capacity of the apoproteins constituting LHC II. Photosynthesis was saturated at approximately 5 fg C(fg Chl)-1 h-1 or 6 fg C cell-1 h-1, and growth was saturated at approximately 0.45 d-1 for both MED and SARG strains at 18[deg]C, but saturating irradiances differed between strains. Atlantic strains exhibited increased light-saturated rates and quantum yield for carbon fixation under blue light. PMID:12231684

  12. Light dependence of [3H]leucine incorporation in the oligotrophic North Pacific ocean.

    PubMed

    Church, Matthew J; Ducklow, Hugh W; Karl, David M

    2004-07-01

    The influence of irradiance on bacterial incorporation of [(3)H]leucine was evaluated at Station ALOHA in the oligotrophic North Pacific subtropical gyre. Six experiments were conducted on three cruises to Station ALOHA to examine how [(3)H]leucine incorporation varied as a function of irradiance. Two experiments were also conducted to assess the photoautotrophic response to irradiance (based on photosynthetic uptake of [(14)C]bicarbonate) in both the upper and lower photic zones. Rates of [(3)H]leucine incorporation responded to irradiance in a photosynthesis-like manner, increasing sharply at low light and then saturating and sometimes declining with increasing light intensity. The influence of irradiance on bacterial growth was evaluated in both the well-lit (5 to 25 m) and dimly lit regions of the upper ocean (75 to 100 m) to determine whether the bacterial response to irradiance differed along the depth-dependent light gradient of the photic zone. [(3)H]leucine incorporation rates were analyzed with a photosynthesis-irradiance model for a quantitative description of the relationships between [(3)H]leucine incorporation and irradiance. Maximum rates of [(3)H]leucine incorporation in the upper photic zone increased 48 to 92% relative to those of dark-incubated samples, with [(3)H]leucine incorporation saturating at light intensities between 58 and 363 micromol of quanta m(-2) s(-1). Rates of [(3)H]leucine incorporation in the deep photic zone were photostimulated 53 to 114% and were susceptible to photoinhibition, with rates declining at light intensities of >100 micromol of quanta m(-2) s(-1). The results of these experiments revealed that sunlight directly influences bacterial growth in this open-ocean ecosystem.

  13. GEMS (Gravity Electro-Magnetism Strong) SU(5) Theory and The Prediction of Exchange Boson Masses

    NASA Astrophysics Data System (ADS)

    Brandenburg, John

    2012-10-01

    The GEMS SU(5) [1] theory includes short range Nuclear Forces in the GEM unification theory [2], where the importance of the square root of the proton-electron mass ratio: σ = 42.8503 was found. The creation of mass by a Higgs field coupling must, by the Equivalence Principle, be viewed in the context of General Relativity. This is done here using Kaluza-Klein theory in a Feynman-Hawkings path integral formalism. GEM theory, quantum concepts of virtual particles, and ZPF (Zero Point Fluctuation) allow understanding of the Strong Force and Weak forces as the extension of electrodynamics in the quantum limit. The Strong and Weak forces are found to be associated with EM models of the electron and proton as finite sized structures respectively. Higher order Mie resonances off the EM ``mass at a distance'' structures associated with the electron, proton and fifth dimension generate the quanta with masses of the pion mπ = 2 me /α 140.0 MeV and Z boson: mZ = 2σ mp = 80.4 GeV. The ηc meson mη = 2980 GeV is identified with the 5^th dimension compactification force mediated by the Radion field. Another particle associated with this mass inducing field is the ``Radion'' or Higgs scattering quanta off the fifth dimension with a mass σmη 128.6 GeV which is the Higgs Boson. A GEMS SU(5) Georgi-Glashow model, is proposed, where the unification energy is now the Planck energy.[0pt] [1] Brandenburg, J.E. (2012)., STAIF II Conference Albuquerque NM[0pt] [2] Brandenburg, J.E. (2007). IEEE Transactions On Plasma Science, Vol. 35, No. 4., p845.

  14. 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.

  15. 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.

  16. 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!!!

  17. 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

  18. 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

  19. THE QUANTIC AND STATISTICAL BASES OF VISUAL EXCITATION

    PubMed Central

    Baumgardt, Ernest L. M.

    1948-01-01

    1. The photochemical theories of vision cannot provide a valid interpretation of the facts over the whole range of brightness. The fact that liminal excitation is increased by the absorption of a very small number of quanta, each absorbing rod receiving a single quantum, excludes the intervention of the mass action law which is the basis of all photochemical theories. 2. Owing to the quantic structure of light and to the random distribution of quanta in a faint light pencil, there must exist numerical relations between the threshold energy on the one hand and the size of the retinal area stimulated and the stimulation time on the other, whatever may be the inner mechanism of liminal excitation. When taking as a basis Van der Velden's experimental results, viz. that two quanta absorbed during a certain interval of time are sufficient to raise threshold excitation, the probability calculus enables us to compute the course of threshold energy in relation to the stimulation time and to the stimulated retinal area. No arbitrary parameter is needed to do so; the only constant to be used is found by experiment. 3. The quantic and statistical theory of visual excitation that we put forward in the present paper enables us to predict the validity of Ricco's law within what we call a "quasi-independent unit" and the validity of Piper's law within a test area made up of a certain number of such units. This theory does not correspond exactly with Piéron's law for foveal threshold in relation to the size of the stimulated area, but the deviation is probably due to an artefact; viz., the action of the micronystagmus. 4. Experiment proves that in region IV of the retina, 15° temporally from the fovea of the right eye of two observers, Ricco's law applies strictly in rod vision from 2'12'' to 31'36'' and, perhaps, further on. 5. In the same region, from 12'30'' to 31'36'', Piper's law applies strictly in cone vision of extremely red light. 6. In peripheral vision with extremely

  20. 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

  1. Propagation of longitudinal thermoplastic waves in layered structures

    NASA Astrophysics Data System (ADS)

    Li, Chen; Cetinkaya, Cetin

    2000-05-01

    The recent advances in photonics and laser instrumentation have been creating a favorable environment for thermal-based elastic wave generation techniques and their applications in various fields, such as nondestructive testing and smart structures. The main advantages of laser-based NDE include noncontact evaluation, freedom for complex surface geometry, high spatial and temporal resolution, easy access to cavities, and fast scanning. Two disadvantages are that the laser-based method requires a good physical understanding of thermoelastic wave propagation in solids, which is considerably more complicated than elastic wave propagation, and more complicated instrumentation needed for data collection. In an idealized solid, thermal energy is transported by two different mechanisms: by quantized electronic excitations, which are called free electrons, and the quanta of lattice vibrations, which are called phonons. These quanta undergo collisions of a dissipative nature, giving rise to thermal resistance in the medium. A relaxation time is associated with the average communication time between these collisions for the commencement of resistive flow. There are a number of optical methods available for elastic wave generation and detection. The most commonly utilized techniques include interferometric and noninterferometric techniques, optical heterodyning, differential interferometry, and time-delay interferometry. In the current work, a transfer matrix formulation including the second sound effect is developed for a thermoelastic layer. The second sound effect is included to eliminate the thermal wave travelling with infinite velocity as predicted by the diffusion heat transfer model, and, consequently, the immediate arrival of waves. Utilizing this formulation and the periodic systems framework, the attenuation and propagation properties of one-dimensional thermoelastic wave in both continuum and layered structures are studied. A perturbation analysis is carried out

  2. 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

  3. 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

  4. Regulation of Ribulose-1,5-Bisphosphate Carboxylase Activity in Alocasia macrorrhiza in Response to Step Changes in Irradiance 1

    PubMed Central

    Seemann, Jeffrey R.; Kirschbaum, Miko U. F.; Sharkey, Thomas D.; Pearcy, Robert W.

    1988-01-01

    The regulation of ribulose-1,5-bisphosphate (RuBP) carboxylase (Rubisco) activity and pool sizes of RuBP and P-glycerate were examined in the tropical understory species Alocasia macrorrhiza following step changes in photon flux density (PFD). Previous gas exchange analysis of this species following a step increase in PFD from 10 to 500 micromoles quanta per square meter per second suggested that the increase in photosynthetic rate was limited by the rate of increase of Rubisco activity for the first 5 to 10 minutes. We demonstrate here that the increase in photosynthetic rate was correlated with an increase in both the activation state of Rubisco and the total kcat (fully activated specific activity) of the enzyme. Evidence presented here suggests that a change in the pool size of the naturally occurring tight binding inhibitor of Rubisco activity, 2-carboxyarabinitol 1-phosphate, was responsible for the PFD-dependent change in the total kcat of the enzyme. RuBP pool size transiently increased after the increase in PFD, indicating that photosynthesis was limited by the capacity for carboxylation. After 5 to 10 minutes, RuBP pool size was again similar to the pool size at low PFD, presumably because of the increased activity of Rubisco. Following a step decrease in PFD from 500 to 10 micromoles quanta per square meter per second, Rubisco activity declined but at a much slower rate than it had increased in response to a step increase in PFD. This slower rate of activity decline than increase was apparently due to the slower rate of 2-carboxyarabinitol 1-phosphate synthesis than degradation and, to a lesser degree, to slower deactivation than activation. RuBP pool size initially declined following the decrease in PFD, indicating that RuBP regeneration was limiting photosynthesis. As Rubisco activity decreased, RuBP slowly increased to its original level at high PFD. The slow rate of activity loss by Rubisco in this species suggests a biochemical basis for the

  5. 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.

  6. Temperature Dependence of the Linkage of Quantum Yield of Photosystem II to CO2 Fixation in C4 and C3 Plants.

    PubMed

    Oberhuber, W.; Edwards, G. E.

    1993-02-01

    The temperature dependence of quantum yields of electron transport from photosystem II (PSII) ([phi]II, determined from chlorophyll a fluorescence) and CO2 assimilation ([phi]CO2, apparent quantum yield for CO2 assimilation) were determined simultaneously in vivo. With C4 species representing NADP-malic enzyme, NAD-malic enzyme, and phosphoenolpyruvate carboxykinase subgroups, the ratio of [phi]II/[phi]CO2 was constant over the temperature range from 15 to 40[deg]C at high light intensity (1100 [mu]mol quanta m-2 s-1). A similar response was obtained at low light intensity (300 [mu]mol quanta m-2 s-1), except the ratio of [phi]II/[phi]CO2 increased at high temperature. When the true quantum yield for CO2 fixation ([phi]CO2*) was calculated by correcting for respiration in the light (estimated from temperature dependence of dark respiration), the ratio of [phi]II/[phi]C02* remained constant with varying temperature and under both light intensities in all C4 species examined. Because the [phi]II/[phi]CO2* ratio was the same in C4 monocots representing the three subgroups, the ratio was not affected by differences in the bio-chemical mechanism of concentrating CO2 in the bundle sheath cells. The results suggest that PSII activity is closely linked to the true rate of CO2 fixation in C4 plants. The close relationship between [phi]II and [phi]CO2* in C4 species under varying temperature and light intensity conditions is apparently due to a common low level of photorespiration and a primary requirement for reductive power in the C3 pathway. In contrast, in a C3 plant the [phi] II/[phi]CO2* ratio is higher under normal atmospheric conditions than under nonphotorespiratory conditions and it increases with rising temperature. This decrease in efficiency in utilizing energy derived from PSII for CO2 fixation is due to an increase in photorespiration. In both the C3 and C4 species, photochemistry is limited under low temperature, and thus excess energy must be dissipated by

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. Physiology and Phylogeny of Green Sulfur Bacteria Forming a Monospecific Phototrophic Assemblage at a Depth of 100 Meters in the Black Sea†

    PubMed Central

    Manske, Ann K.; Glaeser, Jens; Kuypers, Marcel M. M.; Overmann, Jörg

    2005-01-01

    The biomass, phylogenetic composition, and photoautotrophic metabolism of green sulfur bacteria in the Black Sea was assessed in situ and in laboratory enrichments. In the center of the western basin, bacteriochlorophyll e (BChl e) was detected between depths of 90 and 120 m and reached maxima of 54 and 68 ng liter−1. High-pressure liquid chromatography analysis revealed a dominance of farnesyl esters and the presence of four unusual geranyl ester homologs of BChl e. Only traces of BChl e (8 ng liter−1) were found at the northwestern slope of the Black Sea basin, where the chemocline was positioned at a significantly greater depth of 140 m. Stable carbon isotope fractionation values of farnesol indicated an autotrophic growth mode of the green sulfur bacteria. For the first time, light intensities in the Black Sea chemocline were determined employing an integrating quantum meter, which yielded maximum values between 0.0022 and 0.00075 μmol quanta m−2 s−1 at the top of the green sulfur bacterial layer around solar noon in December. These values represent by far the lowest values reported for any habitat of photosynthetic organisms. Only one 16S rRNA gene sequence type was detected in the chemocline using PCR primers specific for green sulfur bacteria. This previously unknown phylotype groups with the marine cluster of the Chlorobiaceae and was successfully enriched in a mineral medium containing sulfide, dithionite, and freshly prepared yeast extract. Under precisely controlled laboratory conditions, the enriched green sulfur bacterium proved to be capable of exploiting light intensities as low as 0.015 μmol quanta m−2 s−1 for photosynthetic 14CO2 fixation. Calculated in situ doubling times of the green sulfur bacterium range between 3.1 and 26 years depending on the season, and anoxygenic photosynthesis contributes only 0.002 to 0.01% to total sulfide oxidation in the chemocline. The stable population of green sulfur bacteria in the Black Sea

  14. Photosynthetic Characteristics of Segregates from Hybrids between Flaveria brownii (C4 Like) and Flaveria linearis (C3-C4).

    PubMed

    Brown, R. H.; Byrd, G. T.; Bouton, J. H.; Bassett, C. L.

    1993-03-01

    Characteristics related to C4 photosynthesis were studied in reciprocal F1 hybrids and F2 plants from Flaveria brownii (C4 like) and Flaveria linearis (C3-C4). The reciprocal F1 plants differed in 13C/12C ratios of leaves and the percentage of 14C initially incorporated into C4 acids, being more like the pollen parents in these traits. They did not differ in apparent photosynthesis or in O2 inhibition of apparent photosynthesis and differed only slightly in CO2 compensation concentration at 175 [mu]mol quanta m-2 s-1 and 400 mL L-1 O2. The 13C/12C ratios of 78 F2 progeny from the two F1 plants exhibited a normal distribution centered between those of the parents, with a few values slightly higher and lower than the parents. Apparent photosynthesis at 130 [mu]L L-1 CO2 and inhibition of photosynthesis by O2 was nearly normally distributed in the F2 population, but no values for F2 plants approached those for F. brownii (15.4 [mu]mol m-2 s-1 and 7.8%, respectively). Distribution of the CO2 compensation concentration measured at 1000 [mu]mol quanta m-2 s-1 and 400 mL L-1 of O2 in the F2 population was skewed toward F. brownii with 72% of the progeny having values <9 [mu]L of CO2 L-1 compared to 1.5 and 27.2 [mu]L L-1 for F. brownii and F. linearis, respectively. Correlations among traits of F2 plants were low (coefficients of 0.30 to -0.49), indicating that the C4- related traits are not closely linked in segregating populations. Plants in the F2 population selected for high or low apparent photosynthesis at 130 [mu]L of CO2 L-1 (six each) did not rank consistently high or low for 13C/12C ratios, O2 inhibition of apparent photosynthesis, CO2 compensation concentration, or activities of phosphoenolpyruvate carboxylase or NADP-malic enzyme. This study confirms results of earlier work that indicates independent segregation of C4 traits and also shows that the C4-like parental type can be recovered, at least for some characteristics (13C/12C ratio), in segregating

  15. 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

  16. [THE CHARACTERISTICS OF MORPHOLOGY OF BIOFILM OF PERIODONTIUM UNDER INFLAMMATORY DISEASES OF GUMS (CHRONIC CATARRHAL GINGIVITIS, CHRONIC PERIODONTITIS, CANDIDA-ASSOCIATED PERIODONTITIS) ACCORDING RESULTS OF ELECTRONIC MICROSCOPY].

    PubMed

    Ippolitov, E V; Didenko, L V; Tzarev, V N

    2015-12-01

    The study was carried out to analyze morphology of biofilm of periodontium and to develop electronic microscopic criteria of differentiated diagnostic of inflammatory diseases of gums. The scanning electronic microscopy was applied to analyze samples of bioflm of periodont from 70 patients. Including ten patients with every nosologic form of groups with chronic catarrhal periodontitis. of light, mean and severe degree, chronic catarrhal gingivitis, Candida-associated paroperiodontitis and 20 healthy persons with intact periodontium. The analysis was implemented using dual-beam scanning electronic microscope Quanta 200 3D (FEI company, USA) and walk-through electronic micJEM 100B (JEOL, Japan). To detect marker DNA of periodont pathogenic bacteria in analyzed samples the kit of reagentsfor polymerase chain reaction "MultiDent-5" ("GenLab", Russia). The scanning electronic microscopy in combination with transmission electronic microscopy and polymerase chain reaction permits analyzing structure, composition and degree of development of biofilm of periodontium and to apply differentiated diagnostic of different nosologic forms of inflammatory diseases of periodontium, including light form of chronic periodontitis and gingivitis. The electronic microscopical indications of diseases ofperiodontium of inflammatory character are established: catarrhal gingivitis, (coccal morphological alternate), chronic periodontitis (bacillary morphological alternate), Candida-associated periodontitis (Candida morphological alternate of biofilm ofperiodontium).

  17. Interactions between the visual and the magnetoreception system: different effects of bichromatic light regimes on the directional behavior of migratory birds.

    PubMed

    Wiltschko, Roswitha; Dehe, Lars; Gehring, Dennis; Thalau, Peter; Wiltschko, Wolfgang

    2013-01-01

    When magnetic compass orientation of migratory robins was tested, the birds proved well oriented under low intensity monochromatic light of shorter wavelengths up to 565 nm green; from 583 nm yellow onward, they were disoriented. In the present study, we tested robins under bichromatic lights composed (1) of 424 nm blue and 565 nm green and (2) of 565 nm green and 583 nm yellow at two intensities. Under dim blue-green light with a total quantal flux of ca. 8 × 10(15)quanta/sm(2), the birds were well oriented in their migratory direction by their inclination compass; under blue-green light of twice this intensity, their orientation became axial. In both cases, the magnetic directional information was mediated by the radical pair processes in the eye. When green and yellow light were combined, however, the nature of the behavior changed. Under green-yellow light of the higher intensity, the birds showed a 'fixed direction' response that was polar, no longer controlled by the normal inclination compass; under dim green-yellow light, the response became axial. Under these two light conditions, the respective directional information was mediated by the magnetite-based receptors in the skin of the upper beak. Apparently, yellow light leads to a change from one magnetoreception system to the other. How this change is effected is still unknown; it appears to reflect complex interactions between the visual and the two magnetoreception systems.

  18. Rayleigh instability of confined vortex droplets in critical superconductors

    NASA Astrophysics Data System (ADS)

    Lukyanchuk, I.; Vinokur, V. M.; Rydh, A.; Xie, R.; Milošević, M. V.; Welp, U.; Zach, M.; Xiao, Z. L.; Crabtree, G. W.; Bending, S. J.; Peeters, F. M.; Kwok, W. K.

    2015-01-01

    Depending on the Ginzburg-Landau parameter κ, superconductors can either be fully diamagnetic if (type I superconductors) or allow magnetic flux to penetrate through Abrikosov vortices if (type II superconductors; refs , ). At the Bogomolny critical point, , a state that is infinitely degenerate with respect to vortex spatial configurations arises. Despite in-depth investigations of conventional type I and type II superconductors, a thorough understanding of the magnetic behaviour in the near-Bogomolny critical regime at κ ~ κc remains lacking. Here we report that in confined systems the critical regime expands over a finite interval of κ forming a critical superconducting state. We show that in this state, in a sample with dimensions comparable to the vortex core size, vortices merge into a multi-quanta droplet, which undergoes Rayleigh instability on increasing κ and decays by emitting single vortices. Superconducting vortices realize Nielsen-Olesen singular solutions of the Abelian Higgs model, which is pervasive in phenomena ranging from quantum electrodynamics to cosmology. Our study of the transient dynamics of Abrikosov-Nielsen-Olesen vortices in systems with boundaries promises access to non-trivial effects in quantum field theory by means of bench-top laboratory experiments.

  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. Mesoscopic surface roughness of ice crystals pervasive across a wide range of ice crystal conditions

    NASA Astrophysics Data System (ADS)

    Magee, N. B.; Miller, A.; Amaral, M.; Cumiskey, A.

    2014-11-01

    Here we show high-magnification images of hexagonal ice crystals acquired by environmental scanning electron microscopy (ESEM). Most ice crystals were grown and sublimated in the water vapor environment of an FEI-Quanta-200 ESEM, but crystals grown in a laboratory diffusion chamber were also transferred intact and imaged via ESEM. All of these images display prominent mesoscopic topography including linear striations, ridges, islands, steps, peaks, pits, and crevasses; the roughness is not observed to be confined to prism facets. The observations represent the most highly magnified images of ice surfaces yet reported and expand the range of conditions in which rough surface features are known to be conspicuous. Microscale surface topography is seen to be ubiquitously present at temperatures ranging from -10 °C to -40 °C, in supersaturated and subsaturated conditions, on all crystal facets, and irrespective of substrate. Despite the constant presence of surface roughness, the patterns of roughness are observed to be dramatically different between growing and sublimating crystals, and transferred crystals also display qualitatively different patterns of roughness. Crystals are also demonstrated to sometimes exhibit inhibited growth in moderately supersaturated conditions following exposure to near-equilibrium conditions, a phenomenon interpreted as evidence of 2-D nucleation. New knowledge about the characteristics of these features could affect the fundamental understanding of ice surfaces and their physical parameterization in the context of satellite retrievals and cloud modeling. Links to supplemental videos of ice growth and sublimation are provided.

  1. Mesoscopic surface roughness of ice crystals pervasive across a wide range of ice crystal conditions

    NASA Astrophysics Data System (ADS)

    Magee, N. B.; Miller, A.; Amaral, M.; Cumiskey, A.

    2014-03-01

    Here we show high-magnification images of hexagonal ice crystals acquired by Environmental Scanning Electron Microscopy (ESEM). Most ice crystals were grown and sublimated in the water vapor environment of an FEI-Quanta-200 ESEM, but crystals grown in a laboratory diffusion chamber were also transferred intact and imaged via ESEM. All of these images display prominent mesoscopic topography including linear striations, ridges, islands, steps, peaks, pits, and crevasses; the roughness is not observed to be confined to prism facets. The observations represent the most highly magnified images of ice surfaces yet reported and expand the range of conditions where the rough surface features are known to be conspicuous. Microscale surface topography is seen to be ubiquitously present at temperatures ranging from -10 °C to -40 °C, at super-saturated and sub-saturated conditions, on all crystal facets, and irrespective of substrate. Despite the constant presence of surface roughness, the patterns of roughness are observed to be dramatically different between growing and sublimating crystals, and transferred crystals also display qualitatively different patterns of roughness. Crystals are also demonstrated to sometimes exhibit inhibited growth in moderately supersaturated conditions following exposure to near-equilibrium conditions, a phenomena interpreted as evidence of 2-D nucleation. New knowledge of the characteristics of these features could affect the fundamental understanding of ice surfaces and their physical parameterization in the context of satellite retrievals and cloud modeling. Links to Supplement videos of ice growth and sublimation are provided.

  2. Physical Realization of von Neumann Lattices in Rotating Bose Gases with Dipole Interatomic Interactions

    NASA Astrophysics Data System (ADS)

    Cheng, Szu-Cheng; Jheng, Shih-Da

    2016-08-01

    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.

  3. Translationally invariant calculations of form factors, nucleon densities and momentum distributions for finite nuclei with short-range correlations included

    NASA Astrophysics Data System (ADS)

    Shebeko, A. V.; Grigorov, P. A.; Iurasov, V. S.

    2012-11-01

    Relying upon our previous treatment of the density matrices for nuclei (in general, nonrelativistic self-bound finite systems) we are studying a combined effect of center-of-mass motion and short-range nucleon-nucleon correlations on the nucleon density and momentum distributions in light nuclei (4He and 16O). Their intrinsic ground-state wave functions are constructed in the so-called fixed center-of-mass approximation, starting with mean-field Slater determinants modified by some correlator ( e.g., after Jastrow or Villars). We develop the formalism based upon the Cartesian or boson representation, in which the coordinate and momentum operators are linear combinations of the creation and annihilation operators for oscillatory quanta in the three different space directions, and get the own "Tassie-Barker" factors for each distribution and point out other model-independent results. After this separation of the center-of-mass motion effects we propose additional analytic means in order to simplify the subsequent calculations ( e.g., within the Jastrow approach or the unitary correlation operator method). The charge form factors, densities and momentum distributions of 4He and 16O evaluated by using the well-known cluster expansions are compared with data, our exact (numerical) results and microscopic calculations.

  4. Magnetic field-induced helical mode and topological transitions in a topological insulator nanoribbon

    NASA Astrophysics Data System (ADS)

    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.

  5. Logical operations with single x-ray photons via dynamically-controlled nuclear resonances.

    PubMed

    Gunst, Jonas; Keitel, Christoph H; Pálffy, Adriana

    2016-04-27

    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.

  6. Effect of high-intensity ultrasonic treatment on microstructure, hardness and wear behaviour of the hypereutectic Mg-5Si alloy

    NASA Astrophysics Data System (ADS)

    Moussa, M. E.; Waly, M. A.; El-Sheikh, A. M.

    2016-07-01

    The effect of high-intensity ultrasonic treatment (HIUST) on microstructure, hardness and wear behavior in Mg-5wt.%Si hypereutectic alloy has been investigated. The results showed clearly that without HIUST, most of primary Mg2Si appeared as coarse dendritic morphology with average size of about 200 µm. With HIUST, the average size of primary Mg2Si decreased significantly to about 33 µm and their morphologies changed to polyhedral shape. The modification mechanism is mainly attributed conjugation of two mechanisms: cavitation-enhanced heterogeneous nucleation and cavitation-induced dendrite fragmentation. The alloy treated with HIUST has higher hardness and wear resistance than that untreated with HIUST. The wear mechanism of investigated alloys at low applied load (10 N) and low sliding speed (0.3 m/s) is a mild abrasive oxidative wear with little adhesion. However, the wear mechanism due to the applied high loads (30, 50 N) at low sliding speed (0.3 m/s) and/or to the applied high sliding speeds (0.6, 0.9 m/s) under low load (10 N), could be described as delamination mechanism. The microstructures of the specimens were analyzed by optical microscope (OM) (model OPTIKA M-790, Italy). Energy dispersion spectrum (EDS) affiliated to field emission scanning electron microscopy (FESEM) (model Quanta FEG, The Netherlands) were performed to reveal the concentration of alloying elements in selected areas of the microstructure.

  7. 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.

  8. Efficience quantique et efficience quantique de détection des photomultiplicateurs et des matériaux photographiques.

    PubMed

    Thiry, H

    1972-12-01

    The cathode quantum efficiency of several photomultipliers is evaluated at He-Ne laser wavelength from manufacturer's data. The quantum efficiency of the photographic process is defined as the ratio of developed grains (fog grains deduced) in an area A over the number of incident quanta. Five photographic materials were tested, and the quantum efficiency lies between 4 x 10(-4) and 1.1 x 10(-2); the quantum efficiency of photographic materials may be comparable to that of the cathode of photomultipliers. The detective quantum efficiency (EQD) of any detector is defined as the mean square of the SNR over the square of the same ratio obtained with a noiseless detector. The EQD of the photomultiplier 1P21 is equal to 1.4 x 10(-4). Following Shaw, the EQD of five photographic materials is evaluated at zero spatial frequency. The range of the EQD values is 3 x 10(-6) to 1.6 x 10(-4). The EQD values of photomul ipliers and photographic materials may thus be comparable.

  9. Quadraplex qRT-PCR assay for the simultaneous detection of Eastern equine encephalitis virus and West Nile virus.

    PubMed

    Zink, Steven D; Jones, Susan A; Maffei, Joseph G; Kramer, Laura D

    2013-10-01

    In order to increase testing throughput and reduce cost, we developed a multiplex real-time assay that identifies both Eastern equine encephalitis virus and West Nile virus. The assay allows for the screening for the presence of both the nonstructural and envelope genes of both viruses simultaneously allowing for confirmatory testing to be done in a single assay. We utilized newly designed primers and probes, each labeled with a unique fluorescent label allowing for differentiation using an ABI 7500 real-time PCR machine. The use of Quanta Biosciences qScript XLT One-Step RT-qPCR® Toughmix allowed for a quadraplex assay without loss of sensitivity when compared to the previously run singleplex reaction as seen with viral RNA PFU control dilution series. There was no cross reactivity between the viruses within the reaction, and upon utilization of the assay during surveillance, there was no cross reactivity with other historically encountered arthropod-borne viruses. The results from the quantitative Reverse Transcriptase - Polymerase Chain Reaction were comparable to those achieved by cell culture which was performed on a subset of the field mosquito pools screened during the 2012 surveillance season. The multiplex assay resulted in savings in both time and resources for the lab and faster turn-around of results.

  10. Microwave amplification with nanomechanical resonators.

    PubMed

    Massel, F; Heikkilä, T T; Pirkkalainen, J-M; Cho, S U; Saloniemi, H; Hakonen, P J; Sillanpää, M A

    2011-12-15

    The sensitive measurement of electrical signals is at the heart of modern technology. According to the principles of quantum mechanics, any detector or amplifier necessarily adds a certain amount of noise to the signal, equal to at least the noise added by quantum fluctuations. This quantum limit of added noise has nearly been reached in superconducting devices that take advantage of nonlinearities in Josephson junctions. Here we introduce the concept of the amplification of microwave signals using mechanical oscillation, which seems likely to enable quantum-limited operation. We drive a nanomechanical resonator with a radiation pressure force, and provide an experimental demonstration and an analytical description of how a signal input to a microwave cavity induces coherent stimulated emission and, consequently, signal amplification. This generic scheme, which is based on two linear oscillators, has the advantage of being conceptually and practically simpler than the Josephson junction devices. In our device, we achieve signal amplification of 25 decibels with the addition of 20 quanta of noise, which is consistent with the expected amount of added noise. The generality of the model allows for realization in other physical systems as well, and we anticipate that near-quantum-limited mechanical microwave amplification will soon be feasible in various applications involving integrated electrical circuits.

  11. Evidence of Diel Vertical Migration in Mnemiopsis leidyi

    PubMed Central

    Haraldsson, Matilda; Båmstedt, Ulf; Tiselius, Peter; Titelman, Josefin; Aksnes, Dag L.

    2014-01-01

    The vertical distribution and migration of plankton organisms may have a large impact on their horizontal dispersal and distribution, and consequently on trophic interactions. In this study we used video-net profiling to describe the fine scale vertical distribution of Mnemiopsis leidyi in the Kattegat and Baltic Proper. Potential diel vertical migration was also investigated by frequent filming during a 24-hour cycle at two contrasting locations with respect to salinity stratification. The video profiles revealed a pronounced diel vertical migration at one of the locations. However, only the small and medium size classes migrated, on average 0.85 m h−1, corresponding to a total migration distance of 10 m during 12 h. Larger individuals (with well developed lobes, approx. >27 mm) stay on average in the same depth interval at all times. Biophysical data suggest that migrating individuals likely responded to light, and avoided irradiance levels higher than approx. 10 µmol quanta m−2 s−1. We suggest that strong stratification caused by low surface salinity seemed to prohibit vertical migration. PMID:24466162

  12. Rapid Production of Bose-Einstein Condensates at a 1 Hz Rate

    NASA Astrophysics Data System (ADS)

    Farkas, Daniel; Ramirez-Serrano, Jaime; Salim, Evan

    2013-05-01

    The speed at which Bose-Einstein condensates (BECs) can be produced is a key metric for the performance of ultracold-atom inertial sensors, gravimeters, and magnetometers, where production cycle time of ultracold atoms determines sensor bandwidth. Here, we demonstrate production of 87Rb BECs at rates exceeding 1 Hz. Not only can we create a BEC from a hot vapor in less than one second, but we can continuously repeat the process for several cycles. Such speeds are possible because of the short evaporation times that result when atoms are confined in tight traps. In our case, we magnetically trap atoms with an atom chip that seals the top of one of ColdQuanta's RuBECi®vacuum cells. With RF evaporative cooling sequences as short as 450 ms, we attain nearly pure condensates of 2 × 104 atoms. In the future, the apparatus described here will be integrated into a portable system that houses all of the components needed to produce BECs (e.g. lasers, vacuum, electronics, imaging, etc.) in a volume less than 0.3 m3. This work was supported by the Office of Naval Research (SBIR contract N00014-10-C-0282).

  13. Marker and pen graffiti cleaning on diverse calcareous stones by different laser techniques

    NASA Astrophysics Data System (ADS)

    Andriani, S. E.; Catalano, I. M.; Daurelio, G.; Albanese, A.

    2007-05-01

    Industries nowadays continuously produce new types of inks for markers and pens, so new different graffiti appear . In this paper laser cleaning tests on 41 new marker and pen types ( fluorescent, permanent, water-based, acrylic tempera, metallic paint, waterproof inks ), applied into laboratory on different litho- type samples (Chianca, Travertino di Roma, Tufo Carparo fine grain, Sabbie), typical stones employed in much more monuments in Puglia and Italian architectures were carried out. The same ones, were exposed for twelve months to outdoor ageing, subject to sunshine, rain, wind, IR and UV solar radiations. Ablation experiments and tests by using different cleaning techniques, each one in Dry and Wet condition (classic technique, Daurelio technique 1 and Daurelio technique 2 and others new techniques) and two different Nd:YAG laser systems (Palladio by QUANTA SYSTEM and SMART CLEAN II by EL.EN.), were adopted. The experimental modes, N-Mode (1064nm - 150, 300 and 500 μs pulse duration), Q-Switch (1064nm - 8 ns pulse duration) and SFR (Short Free Running - 1064 nm - 40 to 110μs pulse duration) were tested on each marked stones. It was found that according to the different ink types and stone substrate, Q-Switch laser cleaning ablation with optimized laser technique are the best solution to marker an pen graffiti removal. The work is still in progress.

  14. X-ray-generated heralded macroscopical quantum entanglement of two nuclear ensembles.

    PubMed

    Liao, Wen-Te; Keitel, Christoph H; Pálffy, Adriana

    2016-09-19

    Heralded entanglement between macroscopical samples is an important resource for present quantum technology protocols, allowing quantum communication over large distances. In such protocols, optical photons are typically used as information and entanglement carriers between macroscopic quantum memories placed in remote locations. Here we investigate theoretically a new implementation which employs more robust x-ray quanta to generate heralded entanglement between two crystal-hosted macroscopical nuclear ensembles. Mössbauer nuclei in the two crystals interact collectively with an x-ray spontaneous parametric down conversion photon that generates heralded macroscopical entanglement with coherence times of approximately 100 ns at room temperature. The quantum phase between the entangled crystals can be conveniently manipulated by magnetic field rotations at the samples. The inherent long nuclear coherence times allow also for mechanical manipulations of the samples, for instance to check the stability of entanglement in the x-ray setup. Our results pave the way for first quantum communication protocols that use x-ray qubits.

  15. 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.

  16. Walther Bothe and Bruno Rossi: The birth and development of coincidence methods in cosmic-ray physics

    NASA Astrophysics Data System (ADS)

    Bonolis, Luisa

    2011-11-01

    In 1924, Walther Bothe and Hans Geiger applied a coincidence method to the study of Compton scattering with Geiger needle counters. Their experiment confirmed the existence of radiation quanta and established the validity of conservation principles in elementary processes. At the end of the 1920s, Bothe and Werner Kolhörster coupled the coincidence technique with the new Geiger-Müller counter to study cosmic rays, marking the start of cosmic-ray research as a branch of physics. The coincidence method was further refined by Bruno Rossi, who developed a vacuum-tube device capable of registering the simultaneous occurrence of electrical pulses from any number of counters with a tenfold improvement in time resolution. The electronic coincidence circuit bearing Rossi's name was instrumental in his research on the corpuscular nature and the properties of cosmic radiation during the early 1930s, a period characterized by a lively debate between Millikan and followers of the corpuscular interpretation. The Rossi coincidence circuit was also at the core of the counter-controlled cloud chamber developed by Patrick Blackett and Giuseppe Occhialini, and became one of the important ingredients of particle and nuclear physics. During the late 1930s and 1940s, coincidences, anti-coincidences and delayed coincidences played a crucial role in a series of experiments on the decay of the muon, which inaugurated the current era of particle physics.

  17. Arctic Tundra Vegetation Functional Types Based on Photosynthetic Physiology and Optical Properties

    NASA Technical Reports Server (NTRS)

    Huemmrich, Karl F.; Gamon, John; Tweedie, Craig; Campbell, Petya K.; Landis, David R.; Middleton, Elizabeth M.

    2013-01-01

    Non-vascular plants (lichens and mosses) are significant components of tundra landscapes and may respond to climate change differently from vascular plants affecting ecosystem carbon balance. Remote sensing provides critical tools for monitoring plant cover types, as optical signals provide a way to scale from plot measurements to regional estimates of biophysical properties, for which spatial-temporal patterns may be analyzed. Gas exchange measurements were collected for pure patches of key vegetation functional types (lichens, mosses, and vascular plants) in sedge tundra at Barrow AK. These functional types were found to have three significantly different values of light use efficiency (LUE) with values of 0.013+/-0.001, 0.0018+/-0.0002, and 0.0012+/-0.0001 mol C/mol absorbed quanta for vascular plants, mosses and lichens, respectively. Discriminant analysis of the spectra reflectance of these patches identified five spectral bands that separated each of these vegetation functional types as well as nongreen material (bare soil, standing water, and dead leaves). These results were tested along a 100 m transect where midsummer spectral reflectance and vegetation coverage were measured at one meter intervals.

  18. 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.

  19. Light-induced isomerization of the LHCII-bound xanthophyll neoxanthin: possible implications for photoprotection in plants.

    PubMed

    Zubik, Monika; Luchowski, Rafał; Grudzinski, Wojciech; Gospodarek, Małgorzata; Gryczynski, Ignacy; Gryczynski, Zygmunt; Dobrucki, Jerzy W; Gruszecki, Wiesław I

    2011-09-01

    Light-harvesting pigment-protein complex of Photosystem II (LHCII) is the largest photosynthetic antenna complex of plants and the most abundant membrane protein in the biosphere. Plant fitness and productivity depend directly on a balance between excitations in the photosynthetic apparatus, generated by captured light quanta, and the rate of photochemical processes. Excess excitation energy leads to oxidative damage of the photosynthetic apparatus and entire organism and therefore the balance between the excitation density and photosynthesis requires precise and efficient regulation, operating also at the level of antenna complexes. We show that illumination of the isolated LHCII leads to isomerization of the protein-bound neoxanthin from conformation 9'-cis to 9',13- and 9',13'-dicis forms. At the same time light-driven excitation quenching is observed, manifested by a decrease in chlorophyll a fluorescence intensity and shortened fluorescence lifetimes. Both processes, the neoxanthin isomerization and the chlorophyll excitation quenching, are reversible in dim light. The results of the 77K florescence measurements of LHCII show that illumination is associated with appearance of the low-energy states, which can serve as energy traps in the pigment-protein complex subjected to excess excitation. Possible sequence of the molecular events is proposed, leading to a protective excess excitation energy quenching: neoxanthin photo-isomerization→formation of LHCII supramolecular structures which potentiate creation of energy traps→excitation quenching.

  20. Molecular basis of photoprotection and control of photosynthetic light-harvesting.

    PubMed

    Pascal, Andrew A; Liu, Zhenfeng; Broess, Koen; van Oort, Bart; van Amerongen, Herbert; Wang, Chao; Horton, Peter; Robert, Bruno; Chang, Wenrui; Ruban, Alexander

    2005-07-01

    In order to maximize their use of light energy in photosynthesis, plants have molecules that act as light-harvesting antennae, which collect light quanta and deliver them to the reaction centres, where energy conversion into a chemical form takes place. The functioning of the antenna responds to the extreme changes in the intensity of sunlight encountered in nature. In shade, light is efficiently harvested in photosynthesis. However, in full sunlight, much of the energy absorbed is not needed and there are vitally important switches to specific antenna states, which safely dissipate the excess energy as heat. This is essential for plant survival, because it provides protection against the potential photo-damage of the photosynthetic membrane. But whereas the features that establish high photosynthetic efficiency have been highlighted, almost nothing is known about the molecular nature of the dissipative states. Recently, the atomic structure of the major plant light-harvesting antenna protein, LHCII, has been determined by X-ray crystallography. Here we demonstrate that this is the structure of a dissipative state of LHCII. We present a spectroscopic analysis of this crystal form, and identify the specific changes in configuration of its pigment population that give LHCII the intrinsic capability to regulate energy flow. This provides a molecular basis for understanding the control of photosynthetic light-harvesting.

  1. Electronic torsional sound in linear atomic chains: Chemical energy transport at 1000 km/s.

    PubMed

    Kurnosov, Arkady A; Rubtsov, Igor V; Maksymov, Andrii O; Burin, Alexander L

    2016-07-21

    We investigate entirely electronic torsional vibrational modes in linear cumulene chains. The carbon nuclei of a cumulene are positioned along the primary axis so that they can participate only in the transverse and longitudinal motions. However, the interatomic electronic clouds behave as a torsion spring with remarkable torsional stiffness. The collective dynamics of these clouds can be described in terms of electronic vibrational quanta, which we name torsitons. It is shown that the group velocity of the wavepacket of torsitons is much higher than the typical speed of sound, because of the small mass of participating electrons compared to the atomic mass. For the same reason, the maximum energy of the torsitons in cumulenes is as high as a few electronvolts, while the minimum possible energy is evaluated as a few hundred wavenumbers and this minimum is associated with asymmetry of zero point atomic vibrations. Theory predictions are consistent with the time-dependent density functional theory calculations. Molecular systems for experimental evaluation of the predictions are proposed. PMID:27448902

  2. 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.

  3. Site-selective red-edge spectroscopy of disordered materials and microheterogeneous systems: polymers, phospholipid membranes and proteins

    NASA Astrophysics Data System (ADS)

    Demchenko, Alexander P.; Ercelen, Sebnem; Klymchenko, Andriy S.

    2002-12-01

    For aromatic fluorophores embedded into different rigid and highly viscous media with low structural order the spectroscopic properties do not conform to classical rules. The fluorescence spectra can depend on excitation wavelength, and the excited-state energy transfer, if present, fails at the 'red' excitation edge. These Red-Edge effects are observed due to the existence of excited-state distribution of fluorophores on their interaction energy with the environment and the slow rate of dielectric relaxations. In these conditions the site-selection can be provided by variation of energy of illuminating light quanta, and the behavior of selected species can be followed as a function of time and other variables. These observations foudn extensive application in different areas of research: colloid and polymer science, photophysics and molecular biophysics. Site-selection effects were discovered for electron-transfer and proton-transfer reactions if they depend on the dynamics of the environment. In this report we concentrate on fluroescence of 3-hydroxyflavone derivatives as the probes that exhibit the excited-state proton transfer reaction. The studies in polymer films, phospholipid membranes and in complexes with proteins allow characterizing the static and dynamic disorder in these systems.

  4. Beyond Archimedean Space-Time Structure

    NASA Astrophysics Data System (ADS)

    Rosinger, Elemér E.; Khrennikov, Andrei

    2011-03-01

    It took two millennia after Euclid and until in the early 1880s, when we went beyond the ancient axiom of parallels, and inaugurated geometries of curved spaces. In less than one more century, General Relativity followed. At present, physical thinking is still beheld by the yet deeper and equally ancient Archimedean assumption. In view of that, it is argued with some rather easily accessible mathematical support that Theoretical Physics may at last venture into the non-Archimedean realms. In this introductory paper we stress two fundamental consequences of the non-Archimedean approach to Theoretical Physics: one of them for quantum theory and another for relativity theory. From the non-Archimedean viewpoint, the assumption of the existence of minimal quanta of light (of the fixed frequency) is an artifact of the present Archimedean mathematical basis of quantum mechanics. In the same way the assumption of the existence of the maximal velocity, the velocity of light, is a feature of the real space-time structure which is fundamentally Archimedean. Both these assumptions are not justified in corresponding non-Archimedean models.

  5. 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.

  6. 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

  7. 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

  8. Semiclassical S-matrix for black holes

    SciTech Connect

    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. 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.

  9. X-ray-generated heralded macroscopical quantum entanglement of two nuclear ensembles

    PubMed Central

    Liao, Wen-Te; Keitel, Christoph H.; Pálffy, Adriana

    2016-01-01

    Heralded entanglement between macroscopical samples is an important resource for present quantum technology protocols, allowing quantum communication over large distances. In such protocols, optical photons are typically used as information and entanglement carriers between macroscopic quantum memories placed in remote locations. Here we investigate theoretically a new implementation which employs more robust x-ray quanta to generate heralded entanglement between two crystal-hosted macroscopical nuclear ensembles. Mössbauer nuclei in the two crystals interact collectively with an x-ray spontaneous parametric down conversion photon that generates heralded macroscopical entanglement with coherence times of approximately 100 ns at room temperature. The quantum phase between the entangled crystals can be conveniently manipulated by magnetic field rotations at the samples. The inherent long nuclear coherence times allow also for mechanical manipulations of the samples, for instance to check the stability of entanglement in the x-ray setup. Our results pave the way for first quantum communication protocols that use x-ray qubits. PMID:27640348

  10. Interfacial radiolysis effects in tank waste speciation. 1998 annual progress report

    SciTech Connect

    Orlando, T.M.; Camaioni, D.; Meisel, D.

    1998-06-01

    'The purpose of this program is to deliver pertinent, fundamental information that can be used to make technically defensible decisions on safety issues and processing strategies associated with storage and clean up of DOE mixed chemical and radioactive wastes. The radioactive and chemical wastes present in DOE underground storage tanks contain complex mixtures of sludges, salts, and supernatant liquids. These mixtures, which contain a wide variety of oxide materials, aqueous solvents, and organic components, are constantly bombarded with gamma quanta, beta and alpha particles produced via the decay of radioactive isotopes. Currently, there is a vital need to understand radiolysis of organic and inorganic species present in mixed waste tanks because these processes: (a) produce mixtures of toxic, flammable, and potentially explosive gases (i.e., H{sub 2}, N{sub 2}O and volatile organics) (b) degrade organics, possibly to gas-generating organic fragments, even as the degradation reduces the hazards associated with nitrate-organic mixtures, (c) alter the surface chemistry of insoluble colloids in tank sludge, influencing sedimentation and the gas/solid interactions that may lead to gas entrapment phenomena. This report summarizes the technical achievements of a 3-year project that is now in its 2nd year. Progress in three areas is reported: (1) radiation effects at NaNO 3 crystal interfaces, (2) reactions of organic complexants with NO{sub 2} in water, and (3) radiation effects in oxide particles.'

  11. Vibrational relaxation dynamics of SD molecules in As{sub 2}S{sub 3}: Observation of an anomalous isotope effect

    SciTech Connect

    Engholm, J.R.; Happek, U.; Rella, C.W.

    1995-12-31

    It is generally assumed that the vibrational relaxation of molecular impurities in crystals and glasses mainly depends on the order of the decay process, with lower order processes leading to more rapid relaxation (a behavior that is known under the term {open_quotes}gap-law{close_quotes}). Here we present measurements that contradict this assumption. Using high intensity psec pulses of the Stanford FEL we measured the relaxation rate of the SD vibrational stretch mode (at a frequency of 1800 cm) by applying a pump-probe technique. We find relaxation rates on the order of 2x10{sup 9} sec{sup -1}, which are a factor of 2 lower than those found for the isotope molecule SH (at a frequency of about 2500 cm{sup - 1}) in the same host{sup 1}. We recall that the relaxation of the SD vibrational stretch mode is controlled by a lower order process as compared to the SH molecule, which is due to the smaller number of host vibrational quanta to match the energy of the stretch mode; a fact we have confirmed experimentally by temperature dependent relaxation measurements. Thus our remits are in marked contrast to the so-called {open_quotes}Gap-Law{close_quotes} and emphasize the importance of the molecule - host coupling in the relaxation dynamics.

  12. Heterostructures as a quantum optical klistron

    SciTech Connect

    Malov, Yu.A.

    1995-12-31

    THE beam of {open_quotes}hot{close_quotes} ballistic electrons which were first obtained experimentally in (1) is considered when passing through the heterostructures consisting of two potential barriers in barriers in the presence of FEL tuning in infra-red region. In the presence of the first barrier the electron beam in the FEL electromagnetic field can either absorb or emit the field quanta. The initial electron beam may split into states n=1 (absorption of one quantum), n=0 (the beam energy unchanged), and n=-1 (emission of one quantum). The interference of the states with n=0, n=1 and n=0, n=1 results in the initiation of two traveling modulation waves at electromagnetic frequency w. Beats between these waves in the region of the of their overlapping lead to a periodic dependence of the modulation from w. It has been found that the spontaneous coherent radiation (SCR) intensity oscillates with the period depending on FEL frequency w. It is possible to increase or to decrease the spectral intensity of SCR varying w. The suggested idea of modulation on the first barrier of heterostructures and the radiation of modulated electron beam on the second barrier is a scheme of an quantum optical klistron in infra-red region.

  13. 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.

  14. The influence of time-dependent electric and magnetic fields on the dynamic localization of lattice electrons

    NASA Astrophysics Data System (ADS)

    Papp, E.; Micu, C.; Aur, L.

    2008-12-01

    In this paper we deal with the derivation of dynamic localization conditions for electrons on the one-dimensional (1D) lattice under the influence of ac electric and magnetic fields of the same frequency. We resort, for convenience, to a tight-binding single-band Hamiltonian. Our emphasis is on a more fundamental theoretical understanding by investigating interplays between such fields and the nearest-neighbor hopping interactions characterizing the Hamiltonian. In general, such conditions get expressed in terms of infinite sums of binary products of Bessel functions of the first kind. These sums are hardly tractable, but we found that selecting in a suitable manner the phases of time-dependent modulations leads to controllable frequency-mixing effects providing appreciable simplifications. Such mixings concern competitions between the number of flux quanta and the quotients of field amplitudes and field frequencies. More exactly, tuning one of the mixed frequencies to zero opens the way to establishing the simplified dynamic localization conditions. By resorting again to the zeros of the Bessel function of zeroth order. This results in quickly tractable relationships between the amplitudes of electric and magnetic fields, the field frequency, and the zeros referred to just above. Pure field limits and superpositions between uniform electric and time-dependent magnetic fields are also discussed. Comments concerning the role of disorder and of the Coulomb interaction are also made.

  15. Causal patch complementarity: The inside story for old black holes

    NASA Astrophysics Data System (ADS)

    Ilgin, Irfan; Yang, I.-Sheng

    2014-02-01

    We carefully analyze the causal patches which belong to observers falling into an old black hole. We show that without a distillation-like process, the Almheiri-Marolf-Polchinski-Sully (AMPS) paradox cannot challenge complementarity. That is because the two ingredients for the paradox, the interior region and the early Hawking radiation, cannot be spacelike separated and both low energy within any single causal patch. Either the early quanta have Planckian wavelengths, or the interior region is exponentially smaller than the Schwarzschild size. This means that their appearances in the low-energy theory are strictly timelike separated, which nullifies the problem of double entanglement/purity or quantum cloning. This verifies that the AMPS paradox is either only a paradox in the global description like the original information paradox, or a direct consequence of the assumption that a distillation process is feasible without hidden consequences. We discuss possible relations to cosmological causal patches and the possibility of transferring energy without transferring quantum information.

  16. How quantum entanglement in DNA synchronizes double-strand breakage by type II restriction endonucleases.

    PubMed

    Kurian, P; Dunston, G; Lindesay, J

    2016-02-21

    Macroscopic quantum effects in living systems have been studied widely in pursuit of fundamental explanations for biological energy transport and sensing. While it is known that type II endonucleases, the largest class of restriction enzymes, induce DNA double-strand breaks by attacking phosphodiester bonds, the mechanism by which simultaneous cutting is coordinated between the catalytic centers remains unclear. We propose a quantum mechanical model for collective electronic behavior in the DNA helix, where dipole-dipole oscillations are quantized through boundary conditions imposed by the enzyme. Zero-point modes of coherent oscillations would provide the energy required for double-strand breakage. Such quanta may be preserved in the presence of thermal noise by the enzyme's displacement of water surrounding the DNA recognition sequence. The enzyme thus serves as a decoherence shield. Palindromic mirror symmetry of the enzyme-DNA complex should conserve parity, because symmetric bond-breaking ceases when the symmetry of the complex is violated or when physiological parameters are perturbed from optima. Persistent correlations in DNA across longer spatial separations-a possible signature of quantum entanglement-may be explained by such a mechanism.

  17. Direct Measurement of Photon Recoil from a Levitated Nanoparticle

    NASA Astrophysics Data System (ADS)

    Jain, Vijay; Gieseler, Jan; Moritz, Clemens; Dellago, Christoph; Quidant, Romain; Novotny, Lukas

    2016-06-01

    The momentum transfer between a photon and an object defines a fundamental limit for the precision with which the object can be measured. If the object oscillates at a frequency Ω0 , this measurement backaction adds quanta ℏΩ0 to the oscillator's energy at a rate Γrecoil, a process called photon recoil heating, and sets bounds to coherence times in cavity optomechanical systems. Here, we use an optically levitated nanoparticle in ultrahigh vacuum to directly measure Γrecoil. By means of a phase-sensitive feedback scheme, we cool the harmonic motion of the nanoparticle from ambient to microkelvin temperatures and measure its reheating rate under the influence of the radiation field. The recoil heating rate is measured for different particle sizes and for different excitation powers, without the need for cavity optics or cryogenic environments. The measurements are in quantitative agreement with theoretical predictions and provide valuable guidance for the realization of quantum ground-state cooling protocols and the measurement of ultrasmall forces.

  18. I.I. Rabi Prize Talk: Artificial gauge fields in multi-level atoms

    NASA Astrophysics Data System (ADS)

    Spielman, Ian

    2015-05-01

    We used Raman lasers to induce artificial gauge fields or spin-orbit coupling in the three-level system formed by the f=1 electronic ground state manifold of rubidium-87. In this colloquium I will report on two effects of this laser-coupling. I will explore the itinerant magnetic phases present in a spin-1 spin-orbit coupled atomic Bose-Einstein condensate (BEC); in this system, itinerant ferromagnetic order is stabilized by the spin-orbit coupling, vanishing in its absence. We first located a second-order phase transition that continuously stiffens until, at a tricritical point, it transforms into a first-order transition. These measurements are all in agreement with theory. We engineered a two-dimensional magnetic lattice in an elongated strip geometry, with effective per-plaquette flux about 4/3 times the flux quanta. We imaged the localized edge and bulk states of atomic Bose-Einstein condensates in this strip, with single lattice-site resolution along the narrow direction. Further, we observed both the skipping orbits of excited atoms traveling down our system's edges, analogues to edge magnetoplasmons in 2-D electron systems. Our lattice's long direction consisted of the sites of an optical lattice and its narrow direction consisted of the internal atomic spin states: a synthetic dimension.

  19. Logical operations with single x-ray photons via dynamically-controlled nuclear resonances

    NASA Astrophysics Data System (ADS)

    Gunst, Jonas; Keitel, Christoph H.; Pálffy, Adriana

    2016-04-01

    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.

  20. Development of a high-Q superconducting microwave resonator for coupling to trapped laser-cooled atoms

    NASA Astrophysics Data System (ADS)

    Hertzberg, Jared; Voigt, Kristen; Kim, Zaeill; Hoffman, Jonathan; Grover, Jeff; Lee, Jongmin; Solano, Pablo; Budoyo, Rangga; Ballard, Cody; Anderson, James; Lobb, Chris; Orozco, Luis; Rolston, Steven; Wellstood, Frederick

    2014-03-01

    We present progress towards a hybrid quantum system in which microwave quanta may be exchanged between a superconducting qubit and laser-trapped atoms via a magnetic dipole interaction. In initial experiments, we seek to couple a thin-film superconducting LC resonator cooled to 20 mK to the 6.835 GHz hyperfine splitting in an ensemble of optically trapped 87Rb atoms. The atoms will be trapped in the evanescent optical field on the waist of a tapered 500-nm-diameter optical fiber which is moved to within a few microns of the inductor in the LC resonator. Rayleigh scattered light from defects in the optical fiber will impinge on the superconducting device. We describe the resulting effects of absorbed photons and how to minimize optical effects as well as results on positioning the resonator relative to the optical fiber within a dilution refrigerator. Work supported by NSF through the Physics Frontier Center at the Joint Quantum Institute, Dept. of Physics, Univ. of Maryland.

  1. Twenty Years of Laser Cooling of Solids

    NASA Astrophysics Data System (ADS)

    Nemova, Galina; Kashyap, Raman

    2015-06-01

    Laser induced cooling of solids or optical refrigeration is an area of optical science investigating interaction of light with condensed matter. This addresses a very important practical issue: design and construction all optical solid-state cryocoolers, which are compact devices, free from mechanical vibrations, moving parts, or fluids. They are based on reliable diode pump technology and in the most part free from electromagnetic interference in the cooled area. The optical cryocooler has a broad range of applications such as in the development of biomedical sensing, magnetometers for geophysical sensors and other sensors, satellite instrumentations where compactness and the lack of vibration are key parameters. The operation of these devices is based on anti-Stokes fluorescence also known as luminescence upconversion, in which light quanta in the red tail of the absorption spectrum are absorbed in a material from a pump laser and by adding thermal energy, blue-shifted photons are spontaneously emitted. Laser cooling of solids can be realized in rare-earth doped low phonon energy glasses and crystals as well as in direct band gap semiconductors. Both of these areas are very interesting and important and are discussed in this article.

  2. 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

  3. A new type of half-quantum circulation in a macroscopic polariton spinor ring condensate

    PubMed Central

    Liu, Gangqiang; Snoke, David W.; Daley, Andrew; Pfeiffer, Loren N.; West, Ken

    2015-01-01

    We report the observation of coherent circulation in a macroscopic Bose–Einstein condensate of polaritons in a ring geometry. Because they are spinor condensates, half-quanta are allowed in where there is a phase rotation of π in connection with a polarization vector rotation of π around a closed path. This half-quantum behavior is clearly seen in the experimental observations of the polarization rotation around the ring. In our ring geometry, the half-quantum state that we see is one in which the handedness of the spin flips from one side of the ring to the other side in addition to the rotation of the linear polarization component; such a state is allowed in a ring geometry but will not occur in a simply connected geometry. This state is lower in energy than a half-quantum state with no change of the spin direction and corresponds to a superposition of two different elementary half-quantum states. The direction of circulation of the flow around the ring fluctuates randomly between clockwise and counterclockwise from one shot to the next; this fluctuation corresponds to spontaneous breaking of time-reversal symmetry in the system. This type of macroscopic polariton ring condensate allows for the possibility of direct control of the circulation to excite higher quantized states and the creation of Josephson junction tunneling barriers. PMID:25730875

  4. Separability and Non-Individuality: Is It Possible to Conciliate (At Least A Form Of) Einstein's Realism with Quantum Mechanics?

    NASA Astrophysics Data System (ADS)

    Krause, Décio; Arenhart, Jonas R. B.

    2014-12-01

    In this paper we argue that physical theories, including quantum mechanics, refer to some kind of `objects', even if only implicitly. We raise questions about the logico-mathematical apparatuses commonly employed in such theories, bringing to light some metaphysical presuppositions underlying such apparatuses. We point out to some incongruities in the discourse holding that quantum objects would be entities of some `new kind' while still adhering to the logico-mathematical framework we use to deal with classical objects. The use of such apparatus would hinder us from being in complete agreement with the ontological novelties the theories of quanta seem to advance. Thus, we join those who try to investigate a `logic of quantum mechanics', but from a different point of view: looking for a formal foundation for a supposed new ontology. As a consequence of this move, we can revisit Einstein's ideas on physical reality and propose that, by considering a new kind of object traditionally termed `non-individuals', it is possible to sustain that they still obey some of Einstein's conditions for `physical realities', so that it will be possible to talk of a `principle of separability' in a sense which is not in complete disagreement with quantum mechanics. So, Einstein's departure from quantum mechanics might be softened at least concerning a form of his realism, which sees separated physical objects as distinct `physical realities'.

  5. Parity Protection in Flux-Pairing Qubits

    NASA Astrophysics Data System (ADS)

    Zhang, Wenyuan; Bell, Matthew; Jin, Xiaoyue; Ioffe, Lev; Gershenson, Michael

    2015-03-01

    We have studied a novel qubit whose logical states are decoupled from the environment due to parity protection. The flux-pairing qubit (FPQ) is a superconducting loop consisting of a 4 π periodic Josephson element (a Cooper pair box with the e charge on the central island) and a superinductor. This device is dual to the charge-pairing qubit. The FPQ design suppresses tunneling of single flux lines through the junctions in the Cooper pair box and enforces simultaneous tunneling of pairs of flux lines. The lowest-energy quantum states of the FPQ are encoded in the parity of the magnetic flux quanta inside the loop. Parity protection prohibits the mixing of these states, and reduces both the decay and dephasing rates. We will discuss the experimental aspects of the FPQ optimization and the possibility of fault-tolerant operations with these qubits. The work was supported in part by grants from the Templeton Foundation (40381) and the NSF (DMR-1006265).

  6. [Physiological response of Vallisneria natans to nitrogen and phosphorus contents in eutrophic waterbody].

    PubMed

    Song, Yu-Zhi; Yang, Mei-Jiu; Qin, Bo-Qiang

    2011-09-01

    The response of Vallisneria natans to the increase contents of nitrogen and phosphorus were studied under laboratory conditions by measuring chlorophyll fluorescence parameters of V. natans using a pulse-amplitude modulated fluorometer (Diving-PAM), combined with measuring some other physiological indexes of V. natans. The results showed that V. natans responded quickly to water nitrogen and phosphorus concentration changes, the maximum quantum yield decreased significantly after 2 h and 6 h, the maximum quanta yield returned to normal levels 12 h after the treatment. There was no significant difference between treatment groups for the maximum quantum yield. Inhibitory effect of light intensity on photosynthesis of V. natans was more obvious under higher (treatment D) or lower (treatment A) concentrations of nitrogen and phosphorus. The average quantum yields of four measurements in the treatment B or C was significantly higher than that of A or D (p < 0.05). Within a certain range, chlorophyll content increased significantly with the nitrogen and phosphorus concentrations. When nitrogen and phosphorus concentrations further increased and reached the level of D treatment, chlorophyll content of V. natans decreased. Malondialdehyde (MDA) content of V. natans changed in the different treatment groups, MDA content of treatment B was the lowest while treatment D was the highest. It shows that V. natans is more suitable for growing in eutrophic waterbodies, but excessive nitrogen and phosphorus could inhibit the physiological activities of V. natans. PMID:22165222

  7. Einstein's Revolutionary Light--Quantum Hypothesis

    NASA Astrophysics Data System (ADS)

    Stuewer, R. H.

    2006-03-01

    Albert Einstein's light-quantum paper was the only one of his great papers of 1905 that he himself called ``very revolutionary''. I sketch his arguments for light quanta, his analysis of the photoelectric effect, and his introduction of the wave-particle duality into physics in 1909. I show that Robert Andrews Millikan, in common with almost all physicists at the time, rejected Einstein's light-quantum hypothesis as an interpretation of his photoelectric-effect experiments of 1915. I then trace the complex experimental and theoretical route that Arthur Holly Compton followed between 1916 and 1922 that led to his discovery of the Compton effect, a discovery that Peter Debye also made virtually simultaneously and independently. Compton's discovery, however, was challenged on experimental grounds by William Duane and on theoretical grounds by Niels Bohr in the Bohr--Kramers--Slater theory of 1924, and only after that theory was disproved experimentally the following year by Walther Bothe and Hans Geiger in Berlin and by Compton and Alfred W. Simon in Chicago was Einstein's light-quantum hypothesis generally accepted by physicists.

  8. An evaluation of psychophysical models of auditory change perception.

    PubMed

    Micheyl, Christophe; Kaernbach, Christian; Demany, Laurent

    2008-10-01

    In many psychophysical experiments, the participant's task is to detect small changes along a given stimulus dimension or to identify the direction (e.g., upward vs. downward) of such changes. The results of these experiments are traditionally analyzed with a constant-variance Gaussian (CVG) model or a high-threshold (HT) model. Here, the authors demonstrate that for changes along three basic sound dimensions (frequency, intensity, and amplitude-modulation rate), such models cannot account for the observed relationship between detection thresholds and direction-identification thresholds. It is shown that two alternative models can account for this relationship. One of them is based on the idea of sensory quanta; the other assumes that small changes are detected on the basis of Poisson processes with low means. The predictions of these two models are then compared against receiver operating characteristics (ROCs) for the detection of changes in sound intensity. It is concluded that human listeners' perception of small and unidimensional acoustic changes is better described by a discrete-state Poisson model than by the more commonly used CVG model or by the less favored HT and quantum models.

  9. Polarisation-based coincidence event discrimination: an in silico study towards a feasible scheme for Compton-PET.

    PubMed

    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 [Formula: see text] 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. PMID:27405797

  10. System Responses to Equal Doses of Photosynthetically Usable Radiation of Blue, Green, and Red Light in the Marine Diatom Phaeodactylum tricornutum

    PubMed Central

    Valle, Kristin Collier; Nymark, Marianne; Aamot, Inga; Hancke, Kasper; Winge, Per; Andresen, Kjersti; Johnsen, Geir; Brembu, Tore; Bones, Atle M.

    2014-01-01

    Due to the selective attenuation of solar light and the absorption properties of seawater and seawater constituents, free-floating photosynthetic organisms have to cope with rapid and unpredictable changes in both intensity and spectral quality. We have studied the transcriptional, metabolic and photo-physiological responses to light of different spectral quality in the marine diatom Phaeodactylum tricornutum through time-series studies of cultures exposed to equal doses of photosynthetically usable radiation of blue, green and red light. The experiments showed that short-term differences in gene expression and profiles are mainly light quality-dependent. Transcription of photosynthesis-associated nuclear genes was activated mainly through a light quality-independent mechanism likely to rely on chloroplast-to-nucleus signaling. In contrast, genes encoding proteins important for photoprotection and PSII repair were highly dependent on a blue light receptor-mediated signal. Changes in energy transfer efficiency by light-harvesting pigments were spectrally dependent; furthermore, a declining trend in photosynthetic efficiency was observed in red light. The combined results suggest that diatoms possess a light quality-dependent ability to activate photoprotection and efficient repair of photodamaged PSII. In spite of approximately equal numbers of PSII-absorbed quanta in blue, green and red light, the spectral quality of light is important for diatom responses to ambient light conditions. PMID:25470731

  11. EGS4. Electron-Gamma Shower Monte Carlo Code

    SciTech Connect

    Nelson, W.R.

    1989-06-01

    EGS4 (Electron-Gamma Shower) is a general purpose Monte Carlo simulation of the coupled transport of electrons and photons in an arbitrary geometry for particles with energies above a few keV up to several TeV. The radiation transport of electrons or photons can be simulated in any element, compound, or mixture. The following physics processes can be taken into account: bremsstrahlung production (excluding the Elwert correction at low energies), positron annihilation in flight and at rest (the annihilation quanta are followed to completion), Moliere multiple scattering (i.e., Coulomb scattering from nuclei), Moller and Bhabha scattering, continuous energy loss applied to charged particle tracks between discrete interactions, pair production, Compton scattering, coherent (Rayleigh) scattering, and photoelectric effect. EGS4 allows for the implementation of importance sampling and other variance reduction techniques (e.g., leading particle biasing, splitting, path length biasing, Russian roulette, etc.). PEGS4 is a preprocessor for EGS4. It constructs piecewise-linear fits over a large number of energy intervals of the cross section and branching ratio data and contains options to plot any of the physical quantities used by EGS4, as well as to compare sampled distributions produced by user code with theoretical spectra.

  12. Experimental and theoretical studies of the vibrational spectra of CHD2Br

    NASA Astrophysics Data System (ADS)

    Baldacci, A.; Stoppa, P.; Baldan, A.; Visinoni, R.; Gambi, A.

    2012-09-01

    The dideuterated form of methyl bromide, CHD2Br, has been synthesized and the gas-phase infrared spectra investigated in the range 400-10,000 cm-1 using a medium-resolution FTIR spectrometer. The nine fundamental bands have been characterized in detail. Six of them, i.e. ν 1, ν 4, ν 5, ν 7, ν 8 and ν 9, have been rotationally analysed through the assignment of the partially resolved structure of the PQK and RQK cluster of lines and the spectroscopic parameters have been derived in the symmetric top limit approximation. Among the fundamental levels, anharmonic resonance occurs between ν 7/ν 4 + ν 8 and ν 8/ν 6 + ν 9. An isotopic 79/81Br shift was found for ν 6 and in the more complex region of the ν 8 fundamental. High-quality ab initio calculations - carried out at coupled cluster level [CCSD(T)] employing the correlation-consistent basis set of Dunning (cc-pVTZ) - were performed to determine quadratic, cubic and quartic (semidiagonal) force constants. Using these constants and applying second-order vibrational perturbation theory (VPT2), with allowance for resonances (when necessary), permitted us to identify and assign, in addition to the fundamentals, about 70 overtones and combination bands up to three quanta.

  13. 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.

  14. New observation of 2β2ν decay of 100Mo to the 01+ level of 100Ru in the ARMONIA experiment

    NASA Astrophysics Data System (ADS)

    Belli, P.; Bernabei, R.; Boiko, R. S.; Cappella, F.; Cerulli, R.; Danevich, F. A.; d'Angelo, S.; Incicchitti, A.; Kobychev, V. V.; Kropivyansky, B. N.; Laubenstein, M.; Nagornyi, P. G.; Nagorny, S. S.; Nisi, S.; Nozzoli, F.; Poda, D. V.; Prosperi, D.; Polischuk, O. G.; Tretyak, V. I.; Vyshnevskyi, I. M.; Yurchenko, S. S.

    2010-11-01

    A sample of 100MoO 3 powder with molybdenum enriched in 100Mo to 99.5% and mass of 1199 g was measured for 18120 h in a low-background set-up with 4 HP Ge detectors ( ≃225 cm volume each one) deep underground (3600 m w.e.) at the Laboratori Nazionali del Gran Sasso of the INFN (Italy). The two γ quanta of 540 keV and of 591 keV emitted in the deexcitation process after a 2β2ν decay of 100Mo to the 01+ excited level of 100Ru ( E=1131 keV) are observed in the accumulated data both in coincidence and in the 1-dimensional sum spectrum. The measured half life is: T=6.9-0.8+1.0(stat.)±0.7(syst.)×10 yr, well in agreement with positive results obtained in previous experiments. Moreover, the limit on charge non-conserving β decay of 100Mo is also set: τ>4.5×10 yr at 90% C.L.; it corresponds to the limit on CNC admixture in weak currents: ɛν2<2.9×10.

  15. Power Hardware-in-the-Loop-Based Anti-Islanding Evaluation and Demonstration

    SciTech Connect

    Schoder, Karl; Langston, James; Hauer, John; Bogdan, Ferenc; Steurer, Michael; Mather, Barry

    2015-10-01

    The National Renewable Energy Laboratory (NREL) teamed with Southern California Edison (SCE), Clean Power Research (CPR), Quanta Technology (QT), and Electrical Distribution Design (EDD) to conduct a U.S. Department of Energy (DOE) and California Public Utility Commission (CPUC) California Solar Initiative (CSI)-funded research project investigating the impacts of integrating high-penetration levels of photovoltaics (PV) onto the California distribution grid. One topic researched in the context of high-penetration PV integration onto the distribution system is the ability of PV inverters to (1) detect islanding conditions (i.e., when the distribution system to which the PV inverter is connected becomes disconnected from the utility power connection) and (2) disconnect from the islanded system within the time specified in the performance specifications outlined in IEEE Standard 1547. This condition may cause damage to other connected equipment due to insufficient power quality (e.g., over-and under-voltages) and may also be a safety hazard to personnel that may be working on feeder sections to restore service. NREL teamed with the Florida State University (FSU) Center for Advanced Power Systems (CAPS) to investigate a new way of testing PV inverters for IEEE Standard 1547 unintentional islanding performance specifications using power hardware-in-loop (PHIL) laboratory testing techniques.

  16. Two-vortex structure of electron, nonlocality and Dirac equation

    NASA Astrophysics Data System (ADS)

    Tiwari, S. C.

    2012-02-01

    The dimensionless electromagnetic coupling constant α=e2/planckc may have three interpretations: as the well-known ratio between the electron charge radius e2/mc2 and the Compton wavelength of an electron λc=planck/mc, as the ratio of two angular momenta since the Planck constant has the dimension of angular momentum and as the ratio of two flux quanta e and hc/e . The anomalous part of the electron magnetic moment together with the unified picture of the three interpretations of α is suggested to have deep physical significance. The electric charge is proposed to be a new quantum of flux that leads to a new model of the electron envisaging a two-vortex structure. In analogy with quantum conditions, we postulate sub-quantum conditions applicable in a region of the order of λc replacing planck by a universal constant f=e2/2πc and we apply it to the Dirac equation in internal space that gives rise to the anomalous magnetic moment of an electron. The Dirac spinor and two-spinor representations for the vortex structure of an electron in the single-particle Dirac framework are discussed. The role of sub-quantum rules and internal variables in developing the present ideas is also discussed. A critical discussion of past attempts at giving fundamental importance to magnetism and flux quantum is presented in order to delineate the new ideas in the present work.

  17. Unparticle, a special case of unmatter

    NASA Astrophysics Data System (ADS)

    Smarandache, Florentin

    2011-10-01

    The idea of unparticle was first considered by F. Smarandache in 2004, 2005 and 2006, when he uploaded a paper on CERN web site and he published three papers about what he called ``unmatter,'' which is a new form of matter formed by matter and antimatter that bind together. Unmatter was introduced in the context of ``neutrosophy'' (Smarandache, 1995) and ``paradoxism'' (Smarandache, 1980), which are based on combinations of opposite entities ``A'' and ``antiA'' together with their neutralities ``neutA'' that are in between. In 2006 E. Goldfain introduced the concept of ``fractional number of field quanta'' and he conjectured that these exotic phases of matter may emerge in the near or deep ultraviolet sector of quantum field theory, as a result of non-equilibrium dynamics and the onset of complex behavior. In the TeV sector the hypothetical high energy states consist of arbitrary mixtures of particles and antiparticles, which are similar to unparticles, and thus unparticles are particular cases of unmatter. H. Georgi proposed the theory of unparticle physics in 2007 that conjectures matter that cannot be explained in terms of particles using the Standard Model of particle physics, because its components are scale invariant. Unparticles are massless fields of nonintegral scaling dimensions.

  18. Determining Ca2+-sensor binding time and its variability in evoked neurotransmitter release

    PubMed Central

    Yoon, Ava Chomee; Kathpalia, Vinnie; D/Silva, Sahana; Cimenser, Aylin; Hua, Shao-Ying

    2008-01-01

    The speed and reliability of neuronal reactions are important factors for proper functioning of the nervous system. To understand how organisms use protein molecules to carry out very fast biological actions, we quantified single-molecule reaction time and its variability in synaptic transmission. From the synaptic delay of crayfish neuromuscular synapses the time for a few Ca2+ ions to bind with their sensors in evoked neurotransmitter release was estimated. In standard crayfish saline at room temperature, the average Ca2+ binding time was 0.12 ms for the first evoked quanta. At elevated extracellular Ca2+ concentrations this binding time reached a limit due to saturation of Ca2+ influx. Analysis of the synaptic delay variance at various Ca2+ concentrations revealed that the variability of the Ca2+-sensor binding time is the major source of the temporal variability of synaptic transmission, and that the Ca2+-independent molecular reactions after Ca2+ influx were less stochastic. The results provide insights into how organisms maximize reaction speed and reliability. PMID:18063666

  19. Evaluation of a new ultraviolet-emitting rare-earth film-screen combination.

    PubMed

    Farajollahi, A R; Sutton, D

    1997-06-01

    The performance of a 400 speed class DuPont Ultra Vision Rapid (UVR) film-screen combination has been evaluated and compared with that of DuPont Quanta Fast Detail screens with Cronex 10L film (QFD-200 speed class). The speed was calculated from the constructed characteristic curves (H&D) at different energies. Image quality was derived objectively using the Leeds test object TOR (CDR). An anthropomorphic phantom was then employed to determine image quality subjectively by means of radiologist appraisal. Lumbar spine and chest radiography of patients were performed to evaluate the potential for dose reduction in clinical conditions by measuring skin entrance doses with thermoluminescent dosimeters (TLDs). UVR provided better resolution (9 lp mm-1 as opposed to 8 lp mm-1) and contrast response than QFD. UVR has accommodated a wider exposure latitude than might be expected with conventional 400 speed class film-screen combinations. Use of UVR resulted in better image quality than use of QFD over a wide range of exposure factors. The use of UVR can result in a dose reduction of 50% with no loss in image quality. PMID:9227257

  20. 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.