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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

    2015-03-06

    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.

  3. Quanta of Geometry: Noncommutative Aspects

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  4. QUANTA: 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…

  5. 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…

  6. Do sympathetic nerves release noradrenaline in "quanta"?

    PubMed

    Stjärne, L

    2000-07-03

    The discovery of excitatory junction potentials (EJPs) in guinea-pig vas deferens by Burnstock and Holman (1960) showed for the first time that a sympathetic transmitter, now known to be ATP, is secreted in "quanta". As it was assumed at the time that EJPS are triggered by noradrenaline, this discovery led to attempts to use the fractional overflow of noradrenaline from sympathetically innervated tissues to assess, indirectly, the number of noradrenaline molecules in the average "quantum". The basic finding was that each pulse released 1/50000 of the tissue content of noradrenaline, when reuptake was blocked and prejunctional alpha(2)-adrenoceptors were intact. This provided the constraints, two extreme alternatives: (i) each pulse releases 0.2-3% of the content of a vesicle from all varicosities, or (ii) each pulse releases the whole content of a vesicle from 0.2 to 3% of the varicosities. New techniques have made it possible to address questions about the release probability in individual sites, or the "quantal" size, more directly. Results by optical (comparison of the labelling of SV2 and synaptotagmin, proteins in the membrane of transmitter vesicles), electrophysiological (excitatory junction currents, EJCs, at single visualized varicosities) and amperometric (the noradrenaline oxidation current at a carbon fibre electrode) methods reveal that transmitter exocytosis in varicosities is intermittent. The EJC and noradrenaline oxidation current responses (in rat arteries) to a train of single pulses were observed to be similar in intermittency and amplitude fluctuation. This suggests that they are caused by exocytosis of single or very few "quanta" of ATP and noradrenaline, respectively, equal to the contents of single vesicles, from a small population of release sites. These findings support, but do not conclusively prove the validity of the "intermittent" model of noradrenaline release. The question if noradrenaline is always secreted in packets of preset size

  7. 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.

  8. Nonlinear nanodevices using magnetic flux quanta.

    PubMed

    Ooi, S; Savel'ev, Sergey; Gaifullin, M B; Mochiku, T; Hirata, K; Nori, Franco

    2007-11-16

    All devices realized so far that control the motion of magnetic flux quanta employ either samples with nanofabricated spatially-asymmetric potentials (which strongly limit controllability), or pristine superconductors rectifying with low-efficiency time-asymmetric oscillations of an external magnetic field. Using layered Bi2Sr2CaCu2O8+delta materials, here we fabricate and simulate two efficient nonlinear superconducting devices with no spatial asymmetry. These devices can rectify with high-efficiency a two-harmonic external current dragging vortices in target directions by changing either the relative phase or the frequency ratio of the two harmonics.

  9. Flip-flopping fractional flux quanta.

    PubMed

    Ortlepp, T; Ariando; Mielke, O; Verwijs, C J M; Foo, K F K; Rogalla, H; Uhlmann, F H; Hilgenkamp, H

    2006-06-09

    The d-wave pairing symmetry in high-critical temperature superconductors makes it possible to realize superconducting rings with built-in pi phase shifts. Such rings have a twofold degenerate ground state that is characterized by the spontaneous generation of fractional magnetic flux quanta with either up or down polarity. We have incorporated pi phase-biased superconducting rings in a logic circuit, a flip-flop, in which the fractional flux polarity is controllably toggled by applying single flux quantum pulses at the input channel. The integration of p rings into conventional rapid single flux quantum logic as natural two-state devices should alleviate the need for bias current lines, improve device symmetry, and enhance the operation margins.

  10. 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.

  11. 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

  12. 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.

  13. The Quanta Image Sensor: Every Photon Counts.

    PubMed

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

    2016-08-10

    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.

  14. 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.

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

    SciTech Connect

    Redhead, M. ); Teller, P. )

    1991-01-01

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

  16. 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.

  17. Bistability and chaos at low levels of quanta.

    PubMed

    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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Metering and routing of liquid quanta in microfluidic devices

    NASA Astrophysics Data System (ADS)

    Cole, Matthew Charles

    Microchemical systems have become increasingly more intricate and complex, and have been used in a wide variety of interesting applications in recent years. However, further advancement of these devices is currently limited by their lack of any significant detection, routing, and scheduling capabilities for the materials moving throughout them. This limited level of control becomes a significant issue when scaling simple, single-channel microfluidic devices to large arrays. The overall goal of this thesis, therefore, is to create and improve several fundamental microfluidic capabilities, including droplet generation, routing, sensing, and scheduling. The integration of these components into larger arrays will also be demonstrated, and will provide a significant step towards more robust and capable heterogeneous microchemical systems. This thesis describes the development of a number of microfluidic handling techniques, including; (i) the detection of individual liquid droplets using electrical position sensors; (ii) the generation and control over the three major microfluidic segmented laminar flow regimes; (iii) the creation of discrete liquid quanta by entirely chip-driven techniques, including on-chip valves and pumps; (iv) the driving around of those resulting liquid quanta; and (v) the combining of multiple microfluidic peristaltic pumps into a multiplexed arrangement, allowing for many pumps to be controlled by a limited number of external pneumatic connections. These techniques were integrated to create an overall microfluidic droplet routing platform, capable of generating and directing individual liquid elements to arbitrary locations within a large microfluidic A I array, using completely chip-driven actuations. As a testbed application, the microfluidic capabilities developed here were utilized in conjunction with an electrohydrodynamic-jet printing process to generate a high resolution heterogeneous printhead.

  3. Effective Mass and g Factor of Four-Flux-Quanta Composite Fermions

    SciTech Connect

    Yeh, A.S.; Tsui, D.C.; Stormer, H.L.; Pfeiffer, L.N.; Baldwin, K.W.; West, K.W.; Stormer, H.L.; Tsui, D.C.

    1999-01-01

    We investigate the properties of composite fermions with four attached flux quanta through tilted-field experiments near Landau level filling factor {nu}=3/4 . The observed collapse of fractional quantum Hall gaps in the vicinity of this quarter-filling state can be comprehensively understood in terms of composite fermions with mass and spin. Remarkably, the effective mass and g factor of these four-flux-quanta composite fermions around {nu}=3/4 are very similar to those of two-flux-quanta composite fermions around {nu}=3/2 . {copyright} {ital 1999} {ital The American Physical Society }

  4. [Changes in the kinetics of quanta secretion-effective mechanism of synaptic transmission modulation].

    PubMed

    Bukharaeva, É A; Nikol'skiĭ, E E

    2010-08-01

    It is widely accepted that the leading presynaptic mechanisms underlying the synaptic plasticity involve changes of the number of neurotransmitter quanta released by one nerve pulse (the quantal content of postsynaptic response) and of the size of a single quantum. In addition, the existence of one more effective though previously ignored mechanism of modulation of synaptic plasticity was suggested related to the change in the time course (kinetics) of secretion of single neurotransmitter quanta forming the multiquantal response. This article reviews current data (including the authors' own results) on the kinetics of evoked neurotransmitter quanta secretion from motor nerve endings in peripheral synapses, mechanisms of their modulation and methods of quantitative analysis.

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  6. 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

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

    PubMed

    Garaud, Julien; Babaev, Egor

    2015-12-03

    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.

  8. How likely are constituent quanta to initiate inflation?

    DOE PAGES

    Berezhiani, Lasha; Trodden, Mark

    2015-08-06

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

  9. Integration of asynchronously released quanta prolongs the postsynaptic spike window.

    PubMed

    Iremonger, Karl J; Bains, Jaideep S

    2007-06-20

    Classically, the release of glutamate in response to a presynaptic action potential causes a brief increase in postsynaptic excitability. Previous reports indicate that at some central synapses, a single action potential can elicit multiple, asynchronous release events. This raises the possibility that the temporal dynamics of neurotransmitter release may determine the duration of altered postsynaptic excitability. In response to physiological challenges, the magnocellular neurosecretory cells (MNCs) in the paraventricular nucleus of the hypothalamus (PVN) exhibit robust and prolonged increases in neuronal activity. Although the postsynaptic conductances that may facilitate this form of activity have been investigated thoroughly, the role of presynaptic release has been largely overlooked. Because the specific patterns of activity generated by MNCs require the activation of excitatory synaptic inputs, we sought to characterize the release dynamics at these synapses and determine whether they contribute to prolonged excitability in these cells. We obtained whole-cell recordings from MNCs in brain slices of postnatal day 21-44 rats. Stimulation of glutamatergic inputs elicited large and prolonged postsynaptic events that resulted from the summation of multiple, asynchronously released quanta. Asynchronous release was selectively inhibited by the slow calcium buffer EGTA-AM and potentiated by brief high-frequency stimulus trains. These trains caused a prolonged increase in postsynaptic spike activity that could also be eliminated by EGTA-AM. Our results demonstrate that glutamatergic terminals in PVN exhibit asynchronous release, which is important in generating large postsynaptic depolarizations and prolonged spiking in response to brief, high-frequency bursts of presynaptic activity.

  10. Integration of sensory quanta in cuneate nucleus neurons in vivo.

    PubMed

    Bengtsson, Fredrik; Brasselet, Romain; Johansson, Roland S; Arleo, Angelo; Jörntell, Henrik

    2013-01-01

    Discriminative touch relies on afferent information carried to the central nervous system by action potentials (spikes) in ensembles of primary afferents bundled in peripheral nerves. These sensory quanta are first processed by the cuneate nucleus before the afferent information is transmitted to brain networks serving specific perceptual and sensorimotor functions. Here we report data on the integration of primary afferent synaptic inputs obtained with in vivo whole cell patch clamp recordings from the neurons of this nucleus. We find that the synaptic integration in individual cuneate neurons is dominated by 4-8 primary afferent inputs with large synaptic weights. In a simulation we show that the arrangement with a low number of primary afferent inputs can maximize transfer over the cuneate nucleus of information encoded in the spatiotemporal patterns of spikes generated when a human fingertip contact objects. Hence, the observed distributions of synaptic weights support high fidelity transfer of signals from ensembles of tactile afferents. Various anatomical estimates suggest that a cuneate neuron may receive hundreds of primary afferents rather than 4-8. Therefore, we discuss the possibility that adaptation of synaptic weight distribution, possibly involving silent synapses, may function to maximize information transfer in somatosensory pathways.

  11. A Flux of Micro Quanta Explains Relativistic Mechanics and the Gravitational Interaction

    NASA Astrophysics Data System (ADS)

    Michelini, Maurizio

    2007-04-01

    In the proposed paradigm the space is filled with a very high flux Phi_0 of very small quanta whose wavelength lambda_0 results equal to the Planck's length. Since their energy E_0=h_0 nu_0 is very small, the relevant quantum constant h_0 is enormously smaller than the usual Planck's constant. Any particle shows a little Compton's cross section sigma_i=A_0 m_i proportional to its mass, so these quanta freely travel in space along large distances (cosmic quanta). Colliding with matter the quanta impose the principles of conservation of energy and momentum, as well as the laws of relativistic mechanics and related inertial forces. The strong equivalence principle, in the version stating that both inertia and gravitation come from a single phenomenon, becomes the relevant test to verify the physical reality of the cosmic quanta i.e. their capacity to explain the gravitational interaction. The quanta colliding with two masses give up a little momentum (E_0-E_1)/c which produces a newtonian force pushing the masses each towards the other. The quantity G=K_0 Phi_0 E_0 A_0^2/4 pi c depends on the quanta characteristics, so the Newton's gravitational mass no longer holds. However the most interesting feature is that the new gravitational force depends also on the quantum energy. For instance a mass facing a very dense star, where the quanta n collisions, receives weakened quanta of energy E_n > (E_0- E_1)/c. This fact increases the newtonian G by the gravity factor (n/a)>= 1 depending on the star mass and density. For instance the gravity factor reaches numbers of 200-300 in the case of neutron stars, incrementing notably their accretion capacity. This property may explain, in particular, the mystery of the obscure galactic supermassive bodies whose gravitational effects have been observed to rise up to 3.7x10^6 times the Sun effects. Current gravitational theories are unable to give a convincing explanation of this

  12. Biologically-inspired Devices for Controlling the Motion of Flux-Quanta

    NASA Astrophysics Data System (ADS)

    Nori, Franco

    2002-03-01

    Motor proteins employ non-equilibrium fluctuations in anisotropic media to transport cargo at the cellular level. Similarly, biologically-inspired devices could transport quanta at the nano-scale. We [1,2,3] have studied non-equilibrium thermal fluctuations in several new type of ratchet systems in superconductors with either (a) channel wall asymmetries, (b) graduated pinning density, (c) anisotropic pinning traps. We study stochastic transport of flux quanta in superconductors by alternating current (AC) rectification. Our simulated systems provide a variety of fluxon pumps, "lenses", or fluxon "rectifiers" because in them the applied electrical AC is transformed into a net DC motion of fluxons. Thermal fluctuations and the asymmetry of the potential (e.g., via channel walls, or inhomegeneous pinning distribution) induce this "diode" effect. The latter can have important applications in devices, like SQUID magnetometers, and for "fluxon optics", including convex and concave "fluxon lenses" that focus/concentrate or disperse flux quanta. Certain features are unique to these novel types of two-dimensional (2D) pumps, and different from the previously studied ratchets (mostly in 1D, with only one particle moving). [1] J. Wambaugh, et. al., Superconducting fluxon pumps and lenses. Phys. Rev. Lett. 83, 5106 (1999). [2] C. Olson, et al., Collective interaction-driven ratchet for transporting flux quanta. Phys. Rev. Lett. 87, 7002 (2001). [3] B.Y. Zhu et al., Biologically-inspired Devices for Controlling the Motion of Flux-Quanta, preprint.

  13. 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

  14. Separation of U-238 and Np-237 nuclei by gamma-quanta intermediate energies

    NASA Astrophysics Data System (ADS)

    Kazakov, A. A.; Kezerashvili, G. Y.; Lazareva, T. Y.; Nedorezov, V. G.; Skrinskiy, A. N.; Sudov, A. S.; Tumaykin, G. M.; Shatunov, Y. M.

    1986-01-01

    A system employing a beam of backscattered Compton quanta based on the e(+)e(-) accumulating complex and an LTI-701 solid state laser is employed to measure the average photoseparation and separability cross sections of U234 and Np237 nuclei at energies ranging from 150 to 170 MeV. The findings contradict the predictions of existing models based on photon-meson nuclear excitation, and suggest that one of the most probable mechanisms underlying the excitation of nuclei by gamma quanta with intermediate energies, in addition to the photogeneration of pions, is the generation of e(+)e(-) pairs in the field of the nucleus: the gamma quanta wavelength energies in this region becomes comparable to the nucleon dimension, so that collective nuclear excitations are generally suppressed.

  15. [Synchronization of secretion of the evoked transmitter quanta as mechanism of the facilitating action of sympathomimetics].

    PubMed

    Bukharaeva, E A; Kim, K Kh; Nikol'skiĭ, E E; Vyskocil, F

    1998-10-01

    Noradrenaline, isoproterenol, dobutamine were found to modulate kinetics of quanta secretion so as to synchronize the transmitter release. This effect could be prevented with blocking agents of beta-adrenoreceptor (atenolol, propranolol). Activators of beta-adrenoreceptors klonidine and phenylephrine did not change the kinetics of quanta secretion, whereas phentolamine did not affect the synchronizing effect of noradrenaline. The change in the time course of the secretion induced by noradrenaline increased the end-plate current amplitude. There seems to exist a specific presynaptic mechanism involving beta-adrenoreceptors for facilitation of effects of sympathomimetics.

  16. Grading the Group: QUANTA 2.0 and the Peer Review

    ERIC Educational Resources Information Center

    Blanton, Casey; Flota, Michael; Gunshanan, Frank

    2013-01-01

    Can students assess their peers on collaboration, a key practice in learning communities? The QUANTA program is a team-taught, two-semester coordinated studies program that is over 25 years old. The central governing ideas for the program are a belief in the social construction of knowledge, and recognition of the value of active, collaborative…

  17. A high resolution magneto-optical system for imaging of individual magnetic flux quanta.

    PubMed

    Golubchik, Daniel; Polturak, Emil; Koren, Gad; Lipson, Stephen G

    2009-08-31

    A high-resolution magneto-optical imaging system is described. In this system magneto-optical Kerr effect is utilized for resolving individual flux quanta in a type II superconductor. Using an ultra thin EuSe indicator a spatial resolution of 0.8 microm is achieved.

  18. Synchrotron radiation treated by the Weizsaecker-Williams method of virtual quanta

    NASA Astrophysics Data System (ADS)

    Lieu, R.; Quenby, J. J.; Axford, W. I.

    1989-01-01

    The method of virtual quanta is employed in a treatment of synchrotron radiation. It is shown that classical radiation is adequately described as Thomson scattering of magnetic field virtual photons by the electron. However, when gamma B = 10 to the 14th Gauss, where gamma is the electron Lorentz factor, Compton scattering becomes important. The result is a reduction in the synchrotron loss rate which agrees closely with quantum electrodynamics. Classical theory fails to produce a cutoff in the emission spectrum at the electron energy, because it ignores the uncertainty principle, and assumes that the electron motion is well-defined at very short times. As a corollary, it is also suggested that the influence of virtual quanta on protons and nuclei sets upper limits on their energy in a given magnetic field.

  19. What Heavy Quanta Bounds Could be Inferred from a Higgs Discovery?

    NASA Astrophysics Data System (ADS)

    Diaz-Cruz, J. Lorenzo

    The Higgs-gauge bosons couplings ghVV (V=g,γ,W,Z) receive non-decoupling corrections due to heavy quanta, and deviations from the SM predictions can be used to test its presence. The possible Higgs signal recently reported at LEP, with mh=115 GeV, severely constrains the presence of heavy quanta, such as a heavy fourth family. At Tevatron, the Higgs production by gluon fusion, followed by the decay h-->WW*, can also be used to probe the existence of heavy colored particles, including additional standard or mirror families, chiral colored sextets and octet quarks. Within the MSSM, we also find that gluon fusion is a sensitive probe for the spectrum of squark masses.

  20. [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.

  1. Role of temperature in quanta mechanisms of facilitation in the frog neuromuscular junction.

    PubMed

    Yeghiazarian, L; Kaiser, M

    1998-07-01

    The results of computer simulations on the Double Barrier Synapse (DBS) model are presented which quantify the relationship between the synapse parameters and the quanta transfer process. The DBS model is applicable to a variety of states of synaptic activity, and by changing the synapse parameters it is possible to simulate various conditions of quanta transmission. The influence of the bathing solution temperature change on the synaptic parameters under different conditions of transmitter release in the frog neuromuscular junction is investigated. Simulations demonstrate that several synaptic parameters, including the parameters of the presynaptic membrane, are not affected by the temperature change. It is shown that a stimulation frequency exists at which the steady-state level of facilitation during a long train of stimuli is the same for a wide range of temperatures.

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

    PubMed

    Meierott, Stefan; Néel, Nicolas; Kröger, Jörg

    2016-07-07

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

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

    SciTech Connect

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

    2010-06-23

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

  4. Enhancements of the Andreev conductance due to emission/absorption of bosonic quanta.

    PubMed

    Barański, J; Domański, T

    2015-08-05

    We predict that the subgap spectrum and transport properties of the quantum dot embedded between superconducting and metallic reservoirs can be substantially enhanced by emission/absorption of external bosonic quanta. Upon tuning the gate voltage the in-gap Andreev states eventually interfere with each other. We explore the measurable signatures of such interference appearing in the differential conductance for both linear and nonlinear regimes.

  5. Estimates for the pool size of releasable quanta at a single central synapse and for the time required to refill the pool.

    PubMed

    Stevens, C F; Tsujimoto, T

    1995-01-31

    Local superfusion of limited dendritic areas with hypertonic or hyperkalemic solutions stimulates the release of quanta from a small population of synapses made on rodent hippocampal neurons maintained in primary culture, and each quantal event can be detected in the postsynaptic neuron. With maintained stimulation, the initial release rate is about 20 quanta per sec per synapse, and this rate declines exponentially to a final low level. These observations can be interpreted as depletion of available quanta and, with this interpretation, a bouton would contain one to two dozen quanta in its readily releasable pool. Tests with a second application of the solution that produces release reveal that the pool of readily releasable quanta is replenished with a time constant of about 10 sec (36 degrees C). The pool of quanta defined in this way may correspond to the population of vesicles docked at the bouton's active zone.

  6. INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Simulation of generation of bremsstrahlung gamma quanta upon irradiation of thin metal films by ultra-intense femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

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

  7. Repetitive nerve stimulation decreases the acetylcholine content of quanta at the frog neuromuscular junction.

    PubMed

    Naves, L A; Van der Kloot, W

    2001-05-01

    We investigated how elevated quantal release produced by motor nerve stimulation affects the size of the quanta. The motor nerve was stimulated at 10 Hz in preparations in which excitation-contraction coupling was disrupted. Two hundred stimuli reduced the size of the time integrals of the miniature endplate currents ([integral]MEPCs), measured at the same junction immediately after stimulation, by 16 %. Three thousand stimuli reduced size by 23 %. When the solution contained 10 microM neostigmine (NEO) 3000 stimuli reduced [integral]MEPCs by 60 %, because with acetylcholinesterase (AChE) inhibited, [integral]MEPC size is more sensitive to changes in acetylcholine (ACh) content. Similar decreases in miniature endplate potential size ([integral]MEPP) followed repetitive stimulation of contracting preparations. The depolarization produced by iontophoretic pulses of ACh was scarcely changed by 3000 nerve stimuli at 10 Hz, suggesting that the decreases in miniature sizes are largely due to less ACh released per quantum. Following 3000 stimuli at 10 Hz the sizes of the [integral]MEPCs increased back to pre-stimulus values with a half-time of 8-10 min. Recovery was blocked by (-)-vesamicol (VES), by hemicholinium-3 (HC3) and by nicotinic cholinergic agonists - all of which inhibit ACh loading into synaptic vesicles. The number of quanta in the total store was estimated by releasing them with carbonyl cyanide m-chlorophenylhydrazone (CCCP). CCCP releases fewer quanta after stimulation than from unstimulated controls. After resting for hours following stimulation, the releasable number increased, even when ACh loading inhibitors were present. We conclude that the inhibitors do not block a significant fraction of the ACh loading into reformed reserve vesicles and propose that ACh can be loaded in a series of steps.

  8. Recycling and refilling of transmitter quanta at the frog neuromuscular junction.

    PubMed

    Van der Kloot, W; Colasante, C; Cameron, R; Molgó, J

    2000-02-15

    1. Fluorescent dyes have been used at the frog neuromuscular junction to label synaptic vesicular membrane. Retrieved membrane is reformed into vesicles, which are released along with pre-existing vesicles. Consequently, if vesicular refilling with acetylcholine (ACh) is depressed by inhibitors, two sizes of quanta should be released: normal and smaller. As recycling continues the fraction of smaller size quanta should increase exponentially. 2. We enhanced the rate of quantal release by elevating the K+ concentration. The principal inhibitors were (-)-vesamicol (VES), hemicholinium-3 (HC3), and NH4+. Quantal size measurements were fitted to one and to two cumulative lognormal probability distribution functions. When two fitted better, the statistical significance assessment took into account the three additional parameters used in calculating the fit. 3. After recycling in the presence of inhibitor, many sets were fitted better by two lognormal functions. As recycling continued, the fraction of the miniature endplate potential voltage-time integrals ( MEPPs) in the larger sub-population decreased exponentially. 4. The size of the releasable pool was estimated by counting the quanta released by carbonyl cyanide m-chlorophenylhydrazone (CCCP). This was compared to pool sizes calculated from the inhibitor experiments. The two estimates of pool size were indistinguishable, with mean values ranging from about 170,000 to 270,000. 5. With all of the treatments tested, the means of the sizes in the smaller sub-population of MEPPs were about 1/3 those of the larger sub-populations. 6. Recycling synaptic vesicles appear to be incorporated into the releasable pool from which they have roughly the same probability of release as the pre-existing vesicles.

  9. A superconducting reversible rectifier that controls the motion of magnetic flux quanta.

    PubMed

    Villegas, J E; Savel'ev, Sergey; Nori, Franco; Gonzalez, E M; Anguita, J V; García, R; Vicent, J L

    2003-11-14

    We fabricated a device that controls the motion of flux quanta in a niobium superconducting film grown on an array of nanoscale triangular pinning potentials. The controllable rectification of the vortex motion is due to the asymmetry of the fabricated magnetic pinning centers. The reversal in the direction of the vortex flow is explained by the interaction between the vortices trapped on the magnetic nanostructures and the interstitial vortices. The applied magnetic field and input current strength can tune both the polarity and magnitude of the rectified vortex flow. Our ratchet system is explained and modeled theoretically, taking the interactions between particles into consideration.

  10. Synchronization of evoked secretion of quanta of mediator as a mechanism facilitating the action of sympathomimetics.

    PubMed

    Bukharaeva, E A; Kim, K K; Nikol'skii, E E; Vyskochil, F

    2000-01-01

    Experiments on frog neuromuscular junction preparations with extracellular recording of nerve terminal action potentials and single-quantum end-plate currents (EPC) were used to assess the time course of evoked quantum secretion of mediator by analyzing histograms of the distribution of true synaptic delays. These studies showed that noradrenaline, isoproterenol, and dobutamine change the kinetics of secretion of quanta, leading to synchronization of the process of mediator release; substances blocking beta-adrenoceptors (atenolol, propranolol) blocked this effect. Clonidine and phenylephrine, which activate alpha-receptors, had no effect on the kinetics of secretion, while the alpha-blocker phentolamine had no effect on the synchronizing action of noradrenaline. Reconstruction of multiquantum EPC from changes in the level of synchronization in the release of individual quanta, showed that EPC amplitude increased in response to noradrenaline by 17%, and that this was due only to alterations in the time course of secretion. These data led to the conclusion that there is a special presynaptic mechanism which facilitates the action of sympathomimetics, acting via beta-adrenoceptors.

  11. Kinetics of acetylcholine quanta release at the neuromuscular junction during high-frequency nerve stimulation.

    PubMed

    Kovyazina, Irina V; Tsentsevitsky, Andrei N; Nikolsky, Evgeny E; Bukharaeva, Ellya A

    2010-11-01

    The effects of high-frequency nerve stimulation (10-100 Hz) on the kinetics of evoked acetylcholine quanta secretion from frog motor nerve endings were studied. The amplitude and temporal parameters of uni- and multiquantal endplate currents were analysed to estimate the possible changes in the degree of synchrony of quantal release. The frog neuromuscular synapse is unusually long and we have placed special emphasis on evaluating the velocity of propagation of excitation along the nonmyelinated nerve ending as this might influence the synchrony of release from the whole terminal and hence affect the time course of postsynaptic currents. The data show that high-frequency firing leads to the desynchronization of acetylcholine release from motor nerve endings governed by at least two independent factors, namely a reduction of nerve pulse propagation velocity in the nonmyelinated parts of the axon and a change of secretion kinetics at single active zones. A computer reconstruction of the multiquantal synaptic response was performed to estimate any contribution of each of the above factors to the total rate of release and amplitude and time characteristics of the endplate currents. The results indicate that modification of the kinetics of neurotransmitter quanta release during high-frequency firing should be taken into account when mechanisms underlying the plasticity of chemical synapses are under investigation.

  12. On the integration of fields and quanta in time dependent backgrounds

    NASA Astrophysics Data System (ADS)

    Castillo, Esteban; Koch, Benjamin; Palma, Gonzalo

    2014-05-01

    Field theories with global continuous symmetries may admit configurations in which time translation invariance is broken by the movement of homogeneous background fields evolving along the flat directions implied by the symmetries. In this context, the field fluctuations along the broken symmetry are well parametrized by a Goldstone boson field that may non-trivially interact with other fields present in the theory. These interactions violate Lorentz invariance as a result of the broken time translation invariance of the background, producing a mixing between the field content and the particle spectrum of the theory. In this article we study the effects of such interactions on the low energy dynamics of the Goldstone boson quanta, paying special attention to the role of the particle spectrum of the theory. By studying the particular case of a canonical two-field model with a mexican-hat potential, we analyze the derivation of the low energy effective field theory for the Goldstone boson, and discuss in detail the distinction between integrating fields v/s integrating quanta, to finally conclude that they are equivalent. In addition, we discuss the implications of our analysis for the study of systems where time translation invariance is broken, such as cosmic inflation and time crystals.

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

    ERIC Educational Resources Information Center

    Avens, Cynthia; Zelley, Richard

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

  14. Clinical comparison of QUANTA Flash dsDNA chemiluminescent immunoassay with four current assays for the detection of anti-dsDNA autoantibodies.

    PubMed

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

    2015-01-01

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

  15. Images from Bits: Non-Iterative Image Reconstruction for Quanta Image Sensors

    PubMed Central

    Chan, Stanley H.; Elgendy, Omar A.; Wang, Xiran

    2016-01-01

    A quanta image sensor (QIS) is a class of single-photon imaging devices that measure light intensity using oversampled binary observations. Because of the stochastic nature of the photon arrivals, data acquired by QIS is a massive stream of random binary bits. The goal of image reconstruction is to recover the underlying image from these bits. In this paper, we present a non-iterative image reconstruction algorithm for QIS. Unlike existing reconstruction methods that formulate the problem from an optimization perspective, the new algorithm directly recovers the images through a pair of nonlinear transformations and an off-the-shelf image denoising algorithm. By skipping the usual optimization procedure, we achieve orders of magnitude improvement in speed and even better image reconstruction quality. We validate the new algorithm on synthetic datasets, as well as real videos collected by one-bit single-photon avalanche diode (SPAD) cameras. PMID:27879687

  16. Lattices of double-quanta vortices and chirality inversion in px+i py superconductors

    NASA Astrophysics Data System (ADS)

    Garaud, Julien; Babaev, Egor; Bojesen, Troels Arnfred; Sudbø, Asle

    2016-09-01

    We investigate the magnetization processes of a standard Ginzburg-Landau model for chiral p -wave superconducting states in an applied magnetic field. We find that the phase diagram is dominated by triangular lattices of doubly quantized vortices. Only in close vicinity to the upper critical field the lattice starts to dissociate into a structure of single-quanta vortices. The degeneracy between states with opposite chirality is broken in a nonzero field. If the magnetization starts with an energetically unfavorable chirality, the process of chirality inversion induced by the external magnetic field results in the formation of a sequence of metastable states with characteristic magnetic signatures that can be probed by standard experimental techniques.

  17. [Effect of lactobacillus and bifidobacteria preparations on the intestinal microflora of mice irradiated with gamma quanta].

    PubMed

    Korshunov, V M; Kissina, E V; Ikonnikova, T B; Mal'tsev, V N; Goncharova, G I

    1980-06-01

    Lactobacilli (strain B12G) and bifidobacteria (strain 75-41), administered orally in a dose of 5 x 10 cells to CBA mice on days 1, 3, 5 and 10 after irradiation with gamma quanta in a dose of 700 rad, restored the "eubiosis" of the intestinal tract, specifically suppressing opportunistic bacteria and facilitating the normalization of the quantitative and qualitative correlation between microbial associations constituting the obligatory intestinal flora. For one thing, the preparations of lactobacilli and bifidobacteria, used for treatment, restored the amount of lactobacilli in the intestinal tract of the irradiated animals to the level, characteristic of the intact animals; for another, these preparations prevented the dissemination of Escherichia, Proteus, Enterococcus in the small intestine and considerably decreased the amount of these microorganisms, as well as Clostridium, in the large intestine.

  18. Biologically inspired devices for easily controlling the motion of magnetic flux quanta

    NASA Astrophysics Data System (ADS)

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

    2003-05-01

    Motor proteins employ non-equilibrium fluctuations in anisotropic media to transport cargo at the cellular level. Here we consider anisotropic pinning to transport magnetic flux quanta inside superconductor. In particular, we consider: (1) composite pins by superimposing two interpenetrating arrays of weak and strong pinning centers; (2) triangular blind antidots; (3) V-shaped pinning sites. Specifically, we study stochastic transport of fluxons by alternating current (AC) rectification. Our simulated systems provide fluxon pumps, or fluxon “rectifiers”, because the applied electrical AC force is transformed into a net DC motion of fluxons. The asymmetry of the ratchet-shaped pinning landscape induce this “diode” effect, which can have important applications in devices, like SQUID magnetometers, and for fluxon optics, including convex and concave fluxon lenses.

  19. 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.

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

    PubMed

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

    2015-12-14

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

  1. Images from Bits: Non-Iterative Image Reconstruction for Quanta Image Sensors.

    PubMed

    Chan, Stanley H; Elgendy, Omar A; Wang, Xiran

    2016-11-22

    A quanta image sensor (QIS) is a class of single-photon imaging devices that measure light intensity using oversampled binary observations. Because of the stochastic nature of the photon arrivals, data acquired by QIS is a massive stream of random binary bits. The goal of image reconstruction is to recover the underlying image from these bits. In this paper, we present a non-iterative image reconstruction algorithm for QIS. Unlike existing reconstruction methods that formulate the problem from an optimization perspective, the new algorithm directly recovers the images through a pair of nonlinear transformations and an off-the-shelf image denoising algorithm. By skipping the usual optimization procedure, we achieve orders of magnitude improvement in speed and even better image reconstruction quality. We validate the new algorithm on synthetic datasets, as well as real videos collected by one-bit single-photon avalanche diode (SPAD) cameras.

  2. [Calcium modulation of the release kinetics of the acetylcholine quanta generating multiquantal postsynaptic response].

    PubMed

    Khuzakhmetova, V F; Fatikhov, N F; Bukharaeva, E A; Nikol'skiĭ, E E

    2011-10-01

    The effects of calcium on the quantal content of nerve-evoked endplate currents (EPC) and on the temporal parameters of quantal release were studied in the frog neuromuscular synapse using the method of "subtractions". It was shown that under physiological conditions quanta generating multiquantal postsynaptic responses were released nonsynchronously because of a considerable variability of latencies of the uniquantal responses forming multiquantal EPC. Different calcium dependences for EPCs quantal content and time course of the quantal release were revealed. The average quantal content grew exponentially with the increase in calcium concentration from 0.4 to 1.8 mmol/L, whereas the release synchronicity reached the maximum at 1 mmol/L calcium. It was suggested that the changes in the synchronicity of the evoked release were one of the mechanisms of the synaptic plasticity.

  3. Effects of trifluoperazine and promethazine on the release of transmitter quanta at the mouse neuromuscular junction.

    PubMed

    Nishimura, M; Komatsu, R; Taquahashi, Y; Shimizu, Y; Satoh, E

    1998-01-01

    The present experiments examined the effects of phenothiazine derivatives, such as trifluoperazine and promethazine, on the release of transmitter quanta in preparations of the mouse diaphragm. The frequency (F, s-1) of miniature end-plate potentials and the quantal content (m) of endplate potentials were measured intracellularly at the same endplate in a bathing solution that contained 0.5-0.8 mM Ca2+ ions and 5 mM Mg2+ ions. Trifluoperazine (4 microM) significantly reduced both F and m. The inhibitory effect on m, but not on F, was subject to competition by Ca2+ ions. Promethazine at 48 microM, but not at 16 microM, reduced the quantal release. It was apparent that the effect of trifluoperazine was competitively antagonized by Ca2+ ions at motor nerve terminals.

  4. 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.

  5. [The time course of the evoked secretion of the mediator quanta in various regions of the frog motor nerve ending].

    PubMed

    Nikol'skiĭ, E E; Bukharaeva, E A; Samigullin, D V; Gaĭnulov, R Kh

    2000-09-01

    Apart from the fact that the gradient of the velocity of the AP propagation along the nerve terminal and the intensity of secretion do exist, the kinetics of a quanta transmitter release may also be revealed in different parts of the terminal. The velocity of the propagation and the minimum sympatric delay tend to diminish along with moving away from the myelinated part of axon, whereas the synchronicity of the quanta release rises. The distinctions in the time course of secretion in different parts of the terminal were amplified when the calcium ion concentration in the medium was enhanced. The observed peculiarities of the secretion kinetics in different regions of nerve ending seem to compensate for diminishing of the amplitude of multiquantal endplate current.

  6. 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.

  7. 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.

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

    PubMed

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

    2015-02-01

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

  9. 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.

  10. Influence of motor activities on the release of transmitter quanta from motor nerve terminals in mice.

    PubMed

    Taquahashi, Y; Yonezawa, K; Nishimura, M

    1999-05-01

    We investigated the effects of motor activities on transmitter release in mouse nerve-muscle preparations of the diaphragm muscle (DPH), extensor digitorum longus muscle (EDL), and soleus muscle (SOL). Mice were divided into a control group, a motor-restricted (RST) group, and a motor-compelled (CMP) group. The quantal content (m) of endplate potentials was measured intracellularly. In DPH the motor activity was unaffected. In the CMP group the m value of the EDL group increased with increases in the cooperativity of Ca2+ in transmitter release. Compared with the CMP group, the SOL of the RST group had a smaller m value with increases in the cooperativity of Ca2+ in transmitter release. These results suggest that motor activities can influence neuromuscular activity specific to different systems, however, the motor compulsion specifically activated the function of EDL and the motor restriction activated the function of SOL, and these effects might lead to altered activity of the release of transmitter quanta in motor nerve terminals of mice.

  11. Experimentally realizable devices for controlling the motion of magnetic flux quanta in anisotropic superconductors.

    PubMed

    Savel'ev, Sergey; Nori, Franco

    2002-11-01

    A new generation of microscopic ratchet systems is currently being developed for controlling the motion of electrons and fluxons, as well as for particle separation and electrophoresis. Virtually all of these use static spatially asymmetric potential energies to control transport properties. Here we propose completely new types of ratchet-like systems that do not require fixed spatially asymmetric potentials in the samples. As specific examples of this novel general class of ratchets, we propose devices that control the motion of flux quanta in superconductors and could address a central problem in many superconducting devices; namely, the removal of trapped magnetic flux that produces noise. In layered superconductors there are two interpenetrating perpendicular vortex lattices consisting of Josephson vortices (JVs) and pancake vortices (PVs). We show that, owing to the JV-PV mutual interaction and asymmetric driving, the a.c. motion of JVs and/or PVs can provide a net d.c. vortex current. This controllable vortex motion can be used for making pumps, diodes and lenses of quantized magnetic flux. These proposed devices sculpt the microscopic magnetic flux profile by simply modifying the time dependence of the a.c. drive, without the need for samples with static pinning--for example, without lithography or irradiation.

  12. 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.

  13. 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.

  14. 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.

  15. [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.

  16. 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.

  17. Calmodulin increases transmitter release by mobilizing quanta at the frog motor nerve terminal.

    PubMed

    Brailoiu, Eugen; Miyamoto, Michael D; Dun, Nae J

    2002-11-01

    The role of calmodulin (CaM) in transmitter release was investigated using liposomes to deliver CaM and monoclonal antibodies against CaM (antiCaM) directly into the frog motor nerve terminal. Miniature endplate potentials (MEPPs) were recorded in a high K+ solution, and effects on transmitter release were monitored using estimates of the quantal release parameters m (number of quanta released), n (number of functional transmitter release sites), p (mean probability of release), and var(s) p (spatial variance in p). Administration of CaM, but not heat-inactivated CaM, encapsulated in liposomes (1000 units ml(-1)) produced an increase in m (25%) that was due to an increase in n. MEPP amplitude was not altered by CaM. Administration of antiCaM, but not heat-inactivated antiCaM, in liposomes (50 microl ml(-1)) produced a progressive decrease in m (40%) that was associated with decreases in n and p. MEPP amplitude was decreased (15%) after a 25 min lag time, suggesting a separation in time between the decreases in quantal release and quantal size. Bath application of the membrane-permeable CaM antagonist W7 (28 microM) produced a gradual decrease in m (25%) that was associated with a decrease in n. W7 also produced a decrease in MEPP amplitude that paralleled the decrease in m. The decreases in MEPP size and m produced by W7 were both reversed by addition of CaM. Our results suggest that CaM increases transmitter release by mobilizing synaptic vesicles at the frog motor nerve terminal.

  18. Depolarization-induced Ca2+ entry preferentially evokes release of large quanta in the developing Xenopus neuromuscular junction.

    PubMed

    Sun, Xiao-Ping; Chen, Bo-Ming; Sand, Olav; Kidokoro, Yoshi; Grinnell, Alan D

    2010-11-01

    The amplitude histogram of spontaneously occurring miniature synaptic currents (mSCs) is skewed positively at developing Xenopus neuromuscular synapses formed in culture. To test whether the quantal size of nerve-evoked quanta (eSCs) distributes similarly, we compared the amplitude histogram of single quantum eSCs in low external Ca(2+) with that of mSCs and found that nerve stimulation preferentially released large quanta. Depolarization of presynaptic terminals by elevating [K(+)] in the external solution or by direct injection of current through a patch pipette increased the mSC frequency and preferentially, but not exclusively, evoked the release of large quanta, resulting in a second broad peak in the amplitude histogram. Formation of the second peak under these conditions was blocked by the N-type Ca(2+) channel blocker, ω-conotoxin GVIA. In contrast, when the mSC frequency was elevated by thapsigargin- or caffeine-induced mobilization of internal Ca(2+), formation of the second peak did not occur. We conclude that the second peak in the amplitude histogram is generated by Ca(2+) influx through N-type Ca(2+) channels, causing a local elevation of internal Ca(2+). The mSC amplitude in the positively skewed portion of the histogram varied over a wide range. A competitive blocker of acetylcholine (ACh) receptors, d-tubocurarine, reduced the amplitude of smaller mSCs in this range relatively more than that of larger mSCs, suggesting that this variation in the mSC amplitude is due to variable amounts of ACh released from synaptic vesicles. We suggest that Ca(2+) influx through N-type Ca(2+) channels preferentially induces release of vesicles with large ACh content.

  19. The effects of noradrenaline on the amplitude-time characteristics of multiquantum endplate currents and the kinetics of induced secretion of transmitter quanta.

    PubMed

    Bukharaeva, E A; Gainulov, R Kh; Nikol'skii, E E

    2002-01-01

    Experiments on frog neuromuscular junctions using a two-electrode membrane potential clamping method were used to study the effects of noradrenaline on the amplitude-time characteristics of multiquantum endplate current (EPC) parameters and the time course of secretion of transmitter quanta during the process of EPC generation. Noradrenaline (10 microM) induced significant increases in EPC amplitude (by 16%), with a decrease in the ratio of the duration of the leading front of the EPC to the duration of the leading front of the miniature endplate current (mEPC). Analysis of the time course of induced secretion, based on sequential subtraction of signals with displacement on the time scale, showed that noradrenaline induced synchronization of the process of secretion of quanta involved in generating multiquantum EPC, resulting in a 25% decrease in parameter P90, which characterizes the extent of synchronization of quantum release. The quantum composition of EPC, measured by dividing the area of induced and spontaneous signals and by analysis of the time course of the secretion of quanta, showed no changes in response to noradrenaline. Thus, in conditions in which responses to single stimuli applied to the motor nerve results in the release of several tens of quanta, noradrenaline can lead to increases in the amplitude of multiquantum EPC by increasing the level of synchronization of secretion of the transmitter quanta forming this signal.

  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. Effect of internal conversion of vibrational quanta in electron tunneling: a scheme for direct experimental observation and current/voltage relationships.

    PubMed

    Kuznetsov, Alexander M

    2006-01-01

    Electron tunneling through bridge molecular groups with a strong coupling to a local quantum vibrational mode is considered. A scheme is suggested for direct experimental observation of the effect of internal conversion of vibrational quanta in inelastic electron tunneling. The effect consists of excitation and re-absorption of vibrational quanta in bridge by tunneling electrons. The tunnel current produced by the absorption of vibrational quanta by the same or another electron can in principle be detected in an experimental setup a scheme of which is suggested. Current/voltage dependences have general spectroscopic features. Possible effects that can take place in the case of additional strong interaction with classical vibrational modes are discussed.

  2. Probabilistic secretion of quanta at somatic motor-nerve terminals: the fusion-pore model, quantal detection and autoinhibition.

    PubMed

    Thomson, P C; Lavidis, N A; Robinson, J; Bennett, M R

    1995-08-29

    The probability of detecting first, second, and later quanta secreted at release sites of a motor-nerve terminal during the early release period following a nerve impulse has been addressed. The possibility that early quantal release autoinhibits later quantal release during this period has also been ascertained. In this investigation, a model for the secretion of a quantum at a release site is developed in which, following the influx and diffusion of calcium ions to a release site protein associated with synaptic vesicles, kappa steps of association of the ions with the protein then occur at rate alpha. The release site protein then undergoes a conformational change which may not go on to completion if calcium ions dissociate from the protein at rate gamma. If this process does reach completion then a fusion-pore between the vesicle and the presynaptic membrane is created; this happens at rate delta. Key assumptions of this fusion-pore model are that the quantal secretions from each site are independent of each other, and that there is a large number of vesicles, each with a small probability of secretion, so that the number of secretions is Poisson in nature. These assumptions allow analytical expressions to be obtained for predicting the times at which first, second and later quanta are secreted during the early release period following an impulse. To test the model, experiments were performed in which the times of first, second and later quantal releases were determined at discrete regions along the length of visualized motor-terminal branches in toad (Bufo marinus) muscles. Estimates of model rate constants and of kappa from the times for first quantal secretions failed to give satisfactory predictions of the observed times of later secretions. Therefore, either the model fails, or the procedure used for detecting later quantal events as a consequence of their being masked by earlier quantal events is inadequate. To solve this detection problem, a two

  3. Nanoscale electrostatic manipulation of magnetic flux quanta in ferroelectric/superconductor BiFeO3/YBa2Cu3O(7-δ) heterostructures.

    PubMed

    Crassous, Arnaud; Bernard, Rozenn; Fusil, Stéphane; Bouzehouane, Karim; Le Bourdais, David; Enouz-Vedrenne, Shaïma; Briatico, Javier; Bibes, Manuel; Barthélémy, Agnès; Villegas, Javier E

    2011-12-09

    Using heterostructures that combine a large-polarization ferroelectric (BiFeO3) and a high-temperature superconductor (YBa2Cu3O(7-δ)), we demonstrate the modulation of the superconducting condensate at the nanoscale via ferroelectric field effects. Through this mechanism, a nanoscale pattern of normal regions that mimics the ferroelectric domain structure can be created in the superconductor. This yields an energy landscape for magnetic flux quanta and, in turn, couples the local ferroelectric polarization to the local magnetic induction. We show that this form of magnetoelectric coupling, together with the possibility to reversibly design the ferroelectric domain structure, allows the electrostatic manipulation of magnetic flux quanta.

  4. Released fraction and total size of a pool of immediately available transmitter quanta at a calyx synapse.

    PubMed

    Schneggenburger, R; Meyer, A C; Neher, E

    1999-06-01

    The size of a pool of readily releasable vesicles at a giant brainstem synapse, the calyx of Held, was probed with three independent approaches. Using simultaneous pre- and postsynaptic whole-cell recordings, two forms of presynaptic Ca2+ stimuli were applied in rapid succession: uncaging of Ca2+ by flash photolysis and the opening of voltage-gated Ca2+ channels. The ensuing transmitter release showed a nearly complete cross-inhibition between the two stimuli, indicating the depletion of a limited pool of about 700 transmitter quanta. The pool size was confirmed in experiments using enhanced extracellular Ca2+ concentrations, as well as short, high-frequency stimulus trains. The results reveal a surprisingly large pool of functionally available vesicles, of which a fraction of about 0.2 is released by a single presynaptic action potential under physiological conditions.

  5. Ratchet without spatial asymmetry for controlling the motion of magnetic flux quanta using time-asymmetric drives.

    PubMed

    Cole, David; Bending, Simon; Savel'ev, Sergey; Grigorenko, Alexander; Tamegai, Tsuyoshi; Nori, Franco

    2006-04-01

    Initially inspired by biological motors, new types of nanodevice have been proposed for controlling the motion of nanoparticles. Structures incorporating spatially asymmetric potential profiles (ratchet substrates) have been realized experimentally to manipulate vortices in superconductors, particles in asymmetric silicon pores, as well as charged particles through artificial pores and arrays of optical tweezers. Using theoretical ideas, we demonstrate experimentally how to guide flux quanta in layered superconductors using a drive that is asymmetric in time instead of being asymmetric in space. By varying the time-asymmetry of the drive, we are able experimentally to increase or decrease the density of magnetic flux at the centre of superconducting samples that have no spatial ratchet substrate. This is the first ratchet without a ratchet potential. The experimental results can be well described by numerical simulations considering the dragging effect of two types of vortices penetrating layered superconductors in tilted magnetic fields.

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

    PubMed

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

    1997-10-01

    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

  7. 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

  8. The role of intracellular cAMP in mediating the synchronizing action of noradrenaline on the evoked release of quanta of mediator in the frog synapse.

    PubMed

    Bukharaeva, E A; Samigullin, D V; Nikol'skii, E E; Vyskochil, F

    2001-01-01

    Experiments on frog neuromuscular junction preparations with extracellular recording of action currents in nerve endings and single-quantum currents from endplates were used to assess the time course of evoked quantum mediator secretion by analyzing histograms showing the distribution of true synaptic delays. Studies using the cyclic AMP analog dibutyryl-cAMP (db-cAMP), the adenylate cyclase activator forskolin, and the nucleotide-dependent phosphodiesterase inhibitor isobutylmethylxanthine, showed that these agents, like noradrenaline, altered the kinetics of secretion of quanta, leading to synchronization of the release of mediator. After preliminary treatment of the neuromuscular preparation with db-cAMP, forskolin, or isobutylmethylxanthine, noradrenaline did not induce the synchronization of mediator release in quanta. It was concluded that the action of noradrenaline on the time course of secretion is mediated by activation of presynaptic beta receptors, increased adenylate cyclase activity, and increases in intracellular cAMP levels.

  9. Characteristics of the time course of evoked secretion of transmitter quanta in different parts of the motor nerve ending in the frog.

    PubMed

    Nikol'kii, E E; Bukharaeva, E A; Samigullin, D V; Gainulo, R Kh

    2002-01-01

    Experiments were performed on neuromuscular preparations from frogs, in which three extracellular microelectrodes were used to record nerve ending currents and single-quantum endplate currents simultaneously from the proximal, central, and distal parts of single synaptic contacts. The rate of propagation of excitation across terminals was measured. along with the minimum synaptic delay, the intensity. and the degree of synchronicity of the secretion of transmitter quanta in different parts of the nerve ending, and the relationships between these factors and the calcium ion concentration in the medium. These studies showed that along with gradients in the rate of conduction of excitation and the intensity of secretion in different parts of the ending. there were also differences in the kinetics of the release of transmitter quanta. As the distance from the end of the myelinated part of the axon increased, the rate of conduction of the nerve impulse and the duration of the synaptic delay decreased, while the synchronicity of the release of quanta increased. Increases in the calcium concentration in the medium produced greater increases in the synchronicity of transmitter quantum release in the distal parts of the synapse than in the proximal parts. Mathematical modeling of multiple-quantum endplate currents showed that the characteristics of the kinetics of the secretion process observed here in different parts of the nerve ending represent a factor which partially compensates for the decrease in the amplitude and extending of the duration of the leading front of the multiple-quantum endplate current which are associated with the low rate of conduction of excitation across the nerve ending. The contribution of this compensation increases as the intensity of secretion of transmitter quanta increases in the distal parts of the synaptic contact.

  10. 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.

  11. Demonstration of thermal dissipation of absorbed quanta during energy-dependent quenching of chlorophyll fluorescence in photosynthetic membranes.

    PubMed

    Yahyaoui, W; Harnois, J; Carpentier, R

    1998-11-27

    When plant leaves or chloroplasts are exposed to illumination that exceeds their photosynthetic capacity, photoprotective mechanisms such as described by the energy-dependent (non-photochemical) quenching of chlorophyll fluorescence are involved. The protective action is attributed to an increased rate constant for thermal dissipation of absorbed quanta. We applied photoacoustic spectroscopy to monitor thermal dissipation in spinach thylakoid membranes together with simultaneous measurement of chlorophyll fluorescence in the presence of inhibitors of opposite action on the formation of delta pH across the thylakoid membrane (tentoxin and nigericin/valinomycin). A linear relationship between the appearance of fluorescence quenching during formation of the delta pH and the reciprocal variation of thermal dissipation was demonstrated. Dicyclohexylcarbodiimide, which is known to prevent protonation of the minor light-harvesting complexes of photosystem II, significantly reduced the formation of fluorescence quenching and the concurrent increase in thermal dissipation. However, the addition of exogenous ascorbate to activate the xanthophyll de-epoxidase increased non-photochemical fluorescence quenching without affecting the measured thermal dissipation. It is concluded that a portion of energy-dependent fluorescence quenching that is independent of de-epoxidase activity can be readily measured by photoacoustic spectroscopy as an increase in thermal deactivation processes.

  12. [Intracellular cAMP involvement in the synchronized activity of noradrenaline in response to evoked release of the transmitter quanta in the frog synapses].

    PubMed

    Bukharaeva, E A; Samigullin, D V; Nikol'skiĭ, E E; Vyskocil, F

    2000-04-01

    An analogue of cyclic AMP (db-cAMP) penetrating into the frog neuromuscular junction's cell, as well as the adenylyl cyclase activator forskolin, and inhibitor of nucleotide-depending phosphodiesterase isobutilmethylxantine alter the kinetics of the quanta secretion resulting in synchronizing of the process of the transmitter release. Following a db-cAMP preliminary action, no such synchronizing of the transmitter release occurred. Action of noradrenaline on the time course of the secretion seems to be realised through activation of presynaptic beta-adrenoreceptors, augmentation of the adenylyl cyclase activity, and the rise of the intracellular cAMP.

  13. 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.

  14. 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.

  15. 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.

  16. Radiation damage effects in Y2SiO5:Ce scintillation crystals under γ-quanta and 24 GeV protons

    NASA Astrophysics Data System (ADS)

    Auffray, E.; Borisevitch, A.; Gektin, A.; Gerasymov, Ia.; Korjik, M.; Kozlov, D.; Kurtsev, D.; Mechinsky, V.; Sidletskiy, O.; Zoueyski, R.

    2015-05-01

    This work focuses on the study of changes in the optical transmission of Y2SiO5:Ce crystals caused by ionizing radiation from γ-quanta and high energy protons. Radioisotope content of proton-irradiated crystals, transmission and induced absorption spectra, and scintillation characteristics are measured after irradiation with protons. In contrast to crystals of heavy complex oxides, Y2SiO5:Ce crystals do not demonstrate significant deterioration of transmission in the luminescence range (400-600 nm) under irradiation. Such crystals can be considered as a material for construction of detecting cells of the calorimetric detectors at LHC with high luminosity. The feasibility of growing large crackless Y2SiO5:Ce crystals with a diameter up to 50 mm and length up to 250 mm is demonstrated.

  17. Results of irradiating aluminum and homogeneous alloy YMn2 by 23 MeV γ-quanta in a molecular deuterium atmosphere at 2 kbar pressure

    NASA Astrophysics Data System (ADS)

    Didyk, A. Yu.; Wisniewski, R.

    2014-03-01

    Specimens of a number of metal were placed successively along the length in a deuterium high-pressure chamber of the "finger type" (DHPC-FT). The specimens were: two aluminum rods, a copper rod, two YMn2 alloy specimens, and stainless steel. The molecular deuterium pressure in the DHPC-FT chamber was 2 kbar. The specimens were irradiated by braking γ-quanta with boundary energy 23 MeV. After irradiation, all specimens were investigated on scanning electron microscopes (SEM) with electron probe X-ray microelement analysis (XMA). Considerable changes in the structure of the surfaces and elemental composition of the measured aluminum, destruction of the homogeneous YMn2 alloy specimen, and the "formation of monocrystalline specimens" of the YMn2 type and structures resembling manganese-based "crystals" were observed. A phenomenological explanation of the observed phenomena and effects based on nuclear reactions is proposed with consideration of certain new approaches, which are examined.

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

    PubMed

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

    2006-09-01

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

  19. Application of the noise power spectrum in modern diagnostic MDCT: part I. Measurement of noise power spectra and noise equivalent quanta.

    PubMed

    Boedeker, K L; Cooper, V N; McNitt-Gray, M F

    2007-07-21

    Dose reduction efforts in diagnostic CT have brought the tradeoff of dose versus image quality to the forefront. The need for meaningful characterization of image noise beyond that offered by pixel standard deviation is becoming increasingly important. This work aims to study the implementation of the noise power spectrum (NPS) and noise equivalent quanta (NEQ) on modern, multislice diagnostic CT scanners. The details of NPS and NEQ measurement are outlined and special attention is paid to issues unique to multislice CT. Aliasing, filter design and effects of acquisition geometry are investigated. While it was found that both metrics can be implemented in modern CT, it was discovered that NEQ cannot be aptly applied with certain non-traditional reconstruction filters or in helical mode. NPS and NEQ under a variety of conditions are examined. Extensions of NPS and NEQ to uses in protocol standardization are also discussed.

  20. Chemical composition and structural phase changes of Pd sample and properties of novel synthesized structure at dense deuterium gas under irradiation by γ-quanta

    NASA Astrophysics Data System (ADS)

    Didyk, A. Yu.; Wiśniewski, R.

    2012-12-01

    Studies have been carried out into the element composition of Pd and brass with associated materials and synthesized novel structure, placed in dense deuterium gas in a deuterium high-pressure chamber (DHPC) under the pressure 3 kbar and irradiated with γ-quanta of energy up to 8.8 MeV. Using the methods of scanning electron microscopy, microelement chemical analysis and X-ray diffraction, it was determined that in the absence in the chamber volume and walls of all HPC-forming materials the synthesized structure is largely composed of alumosilicates and Al and Si oxides with high content of Ti compounds as rutile TiO2. Pd1.5D2. Considerable anomalies in the chemical composition were found both in the surface and at large depth in a Pd specimen. The entire Pd surface turned into a structure comprised of Pd clusters, Cu and Zn compounds, with a notable content of Mg, Al, S, Si, K, Ca, Ti and Fe compounds. Results of evaluative calculations, including computation of the Q-value, are presented for nuclear reactions produced in a saturated with deuterium Pd specimen and dense deuterium gas under the action of γ-quanta, neutrons and protons of energies up to E n + E p ≈ E γ - E D MeV generated by deuteron fission. The obtained results can be explained by "collective effects" as chain reactions caused by deuteron fission induced by protons ( E p > 3.39 MeV) and neutrons ( E n > 2.25 MeV), as well as by thermonuclear synthesis of deuterium atoms elastically scattered by protons of energies up to E P < E γ - E D MeV.

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

    PubMed Central

    Tang, Xiangyang; Yang, Yi; Tang, Shaojie

    2012-01-01

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

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

    SciTech Connect

    Tang Xiangyang; Yang Yi; Tang Shaojie

    2012-07-15

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

  3. Gamma-quanta and charged particles recognition by the counting and triggers signals formation system of GAMMA-400 space gamma-telescope

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    Registered events identification procedures details in three apertures of gamma-telescope GAMMA-400 are discussed in the presented article for gammas, electrons/positrons and protons both in low and high energy bands. Gamma-telescope GAMMA-400 consists of the converter-tracker (C) surrounded by anticoincidence system, time-of-flight system (2 sections S1 and S2) and calorimeter. Anticoincidence system will make of top and lateral sections - ACtop and AClat, time-of-flight system TOF contain 2 segments S1 and S2. Calorimeter consists of position-sensitive calorimeter CC1 makes of 2 strips layers and 2 layers of CsI(Tl) detectors and electromagnetic calorimeter CC2 composed of CsI(Tl) crystals surrounded by plastic lateral detectors LD. Scintillation detectors of the calorimeter S3 and S4 placed correspondingly between CC1 and CC2 and after electromagnetic calorimeter. All segments of detector systems ACtop, AClat, S1-S4, LD composed of two BC-408 based sensitive layers thickness of 1 cm each. Events registration both from upper and lateral directions provides due three apertures: main, additional and lateral. GAMMA-400 parameters are optimized for detection of gamma-quanta with the energy ∼ 100 GeV in the main aperture. Gammas, electrons/positrons and protons recognition in main aperture provides due energy deposition analysis in individual detectors of ACtop, AClat, S1-S3 and CC1 individual scintillator detectors discriminators. Particles identification in the additional aperture supplied by study of energy deposition in the individual detectors S2, S3 and position-sensitive calorimeter individual scintillator detectors discriminators. In the lateral aperture low energy (0.2 - 100 MeV) photons classified by using simple anticoincidence signals from the individual detectors of LD and CC2. Higher energies γ-quanta (E>100 MeV) recognized using energy deposition analysis in the individual detectors of S3, S4, LD and CC2.

  4. New results on P -odd asymmetry of γ -quanta emission in 10B(n, α)7Li* rightarrow γ + 7Li(g.s.) nuclear reaction

    NASA Astrophysics Data System (ADS)

    Vesna, V. A.; Gledenov, Yu. M.; Nesvizhevsky, V. V.; Sedyshev, P. V.; Shulgina, E. V.

    2011-03-01

    A series of ultra-sensitive experiments has been carried out in 2001-2009 at the ILL measuring P -odd asymmetry in γ -quanta emission in the nuclear reaction 10B ( n, α) 7Li* rightarrow γ + 7Li(g.s.) with polarized cold neutrons. The resulting value of the asymmetry coefficient is ensuremath α_{P-odd}= +(0.0 ± 2.6_{stat} ± 1.1_{syst}) × 10^{-8} . These experiments profited from high-intensity PF1B neutron facility and a new version of the integral measuring method: for decreasing experimental uncertainties, the frequency of neutron spin-flip was higher than a typical reactor power noise frequency. Using the new value, we constrain the weak neutral current constant in the cluster model framework to ensuremath f_{π}^{^{10}B} ≤ 0.6 × 10^{-7} (at 90% c.l.). This constraint agrees with that following from the nuclear reaction 6Li ( n, α) 3H : ensuremath f_{π}^{6Li} ≤ 1.1 × 10^{-7} (at 90% c.l.). However, they both contradict the "best" value in the quark model by Desplanques, Donoughe, and Holstein ensuremath f_{π}^{DDH}=4.6\\cdot 10^{-7} . We invite experts in the field to contribute to the theoretical analysis of the problem.

  5. 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.

  6. Action potential-independent and nicotinic receptor-mediated concerted release of multiple quanta at hippocampal CA3-mossy fiber synapses.

    PubMed

    Sharma, Geeta; Grybko, Michael; Vijayaraghavan, Sukumar

    2008-03-05

    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 alpha7-subtype of nicotinic acetylcholine receptors (alpha7-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 alpha7-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 alpha7-nAChR activation are mediated by biologically relevant doses of nicotine. Our results demonstrate a novel form of synaptic plasticity mediated by presynaptic alpha7-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.

  7. Synthesis of microparticles in 1-kbar hydrogen induced by 10-MeV bremsstrahlung γ quanta in a reaction chamber (Part 2)

    NASA Astrophysics Data System (ADS)

    Didyk, A. Yu.; Wiśniewski, R.

    2015-01-01

    A chamber filled with molecular hydrogen at 1.0-kbar pressure was irradiated by bremsstrahlung γ quanta with a threshold energy of 10 MeV at a 20- to 21-μA electron beam intensity for 14 h. Investigations of changes in the structure and elemental composition of the entrance window, manganin foil, and reaction product collector are presented in Part 1 of the article [1]. In this work the results of studying synthesized particles and different formations on inner surfaces of the cut-in-half irradiation chamber (brass sleeve) are discussed. Investigations into the two largest synthesized structures, detected after the irradiation, made it possible to establish the presence of light elements from carbon to calcium in them. Like in the first part of the paper, multiple small lead particles were found and studied. The detected synthesized particles have a complex shape and composition. On both sides of inner surfaces of the cut brass sleeve, thin-walled microtubes are also found, like in Part 1 [1]. The formation of new elements and structures is discussed on the basis of the upstream (fusion) and downstream (fission) models of nuclear reactions [1].

  8. 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.

  9. Triode for Magnetic Flux Quanta

    SciTech Connect

    Vlasko-Vlasov, V. K.; Colauto, F.; Benseman, T.; Rosenmann, D.; Kwok, W. -K.

    2016-11-15

    In an electronic triode, the electron current emanating from the cathode is regulated by the electric potential on a grid between the cathode and the anode. Here we demonstrate a triode for single quantum magnetic field carriers, where the flow of individual magnetic vortices in a superconducting film is regulated by the magnetic potential of striae of soft magnetic strips deposited on the film surface. By rotating an applied in-plane field, the magnetic strip potential can be varied due to changes in the magnetic charges at the strip edges, allowing accelerated or retarded motion of magnetic vortices inside the superconductor. Scaling down our design and reducing the gap width between the magnetic stripes will enable controlled manipulation of individual vortices and creation of single flux quantum circuitry for novel high-speed low-power superconducting electronics.

  10. Triode for Magnetic Flux Quanta

    DOE PAGES

    Vlasko-Vlasov, V. K.; Colauto, F.; Benseman, T.; ...

    2016-11-15

    In an electronic triode, the electron current emanating from the cathode is regulated by the electric potential on a grid between the cathode and the anode. Here we demonstrate a triode for single quantum magnetic field carriers, where the flow of individual magnetic vortices in a superconducting film is regulated by the magnetic potential of striae of soft magnetic strips deposited on the film surface. By rotating an applied in-plane field, the magnetic strip potential can be varied due to changes in the magnetic charges at the strip edges, allowing accelerated or retarded motion of magnetic vortices inside the superconductor.more » Scaling down our design and reducing the gap width between the magnetic stripes will enable controlled manipulation of individual vortices and creation of single flux quantum circuitry for novel high-speed low-power superconducting electronics.« less

  11. Quanta of geometry and unification

    NASA Astrophysics Data System (ADS)

    Chamseddine, Ali H.

    2016-11-01

    This is a tribute to Abdus Salam’s memory whose insight and creative thinking set for me a role model to follow. In this contribution I show that the simple requirement of volume quantization in spacetime (with Euclidean signature) uniquely determines the geometry to be that of a noncommutative space whose finite part is based on an algebra that leads to Pati-Salam grand unified models. The Standard Model corresponds to a special case where a mathematical constraint (order one condition) is satisfied. This provides evidence that Salam was a visionary who was generations ahead of his time.

  12. Quanta of Geometry and Unification

    NASA Astrophysics Data System (ADS)

    Chamseddine, Ali H.

    This is a tribute to Abdus Salam's memory whose insight and creative thinking set for me a role model to follow. In this contribution I show that the simple requirement of volume quantization in space-time (with Euclidean signature) uniquely determines the geometry to be that of a noncommutative space whose finite part is based on an algebra that leads to Pati-Salam grand unified models. The Standard Model corresponds to a special case where a mathematical constraint (order one condition) is satisfied. This provides evidence that Salam was a visionary who was generations ahead of his time.

  13. Triode for Magnetic Flux Quanta

    NASA Astrophysics Data System (ADS)

    Vlasko-Vlasov, V. K.; Colauto, F.; Benseman, T.; Rosenmann, D.; Kwok, W.-K.

    2016-11-01

    In an electronic triode, the electron current emanating from the cathode is regulated by the electric potential on a grid between the cathode and the anode. Here we demonstrate a triode for single quantum magnetic field carriers, where the flow of individual magnetic vortices in a superconducting film is regulated by the magnetic potential of striae of soft magnetic strips deposited on the film surface. By rotating an applied in-plane field, the magnetic strip potential can be varied due to changes in the magnetic charges at the strip edges, allowing accelerated or retarded motion of magnetic vortices inside the superconductor. Scaling down our design and reducing the gap width between the magnetic stripes will enable controlled manipulation of individual vortices and creation of single flux quantum circuitry for novel high-speed low-power superconducting electronics.

  14. Triode for Magnetic Flux Quanta.

    PubMed

    Vlasko-Vlasov, V K; Colauto, F; Benseman, T; Rosenmann, D; Kwok, W-K

    2016-11-15

    In an electronic triode, the electron current emanating from the cathode is regulated by the electric potential on a grid between the cathode and the anode. Here we demonstrate a triode for single quantum magnetic field carriers, where the flow of individual magnetic vortices in a superconducting film is regulated by the magnetic potential of striae of soft magnetic strips deposited on the film surface. By rotating an applied in-plane field, the magnetic strip potential can be varied due to changes in the magnetic charges at the strip edges, allowing accelerated or retarded motion of magnetic vortices inside the superconductor. Scaling down our design and reducing the gap width between the magnetic stripes will enable controlled manipulation of individual vortices and creation of single flux quantum circuitry for novel high-speed low-power superconducting electronics.

  15. Triode for Magnetic Flux Quanta

    PubMed Central

    Vlasko-Vlasov, V. K.; Colauto, F.; Benseman, T.; Rosenmann, D.; Kwok, W.-K.

    2016-01-01

    In an electronic triode, the electron current emanating from the cathode is regulated by the electric potential on a grid between the cathode and the anode. Here we demonstrate a triode for single quantum magnetic field carriers, where the flow of individual magnetic vortices in a superconducting film is regulated by the magnetic potential of striae of soft magnetic strips deposited on the film surface. By rotating an applied in-plane field, the magnetic strip potential can be varied due to changes in the magnetic charges at the strip edges, allowing accelerated or retarded motion of magnetic vortices inside the superconductor. Scaling down our design and reducing the gap width between the magnetic stripes will enable controlled manipulation of individual vortices and creation of single flux quantum circuitry for novel high-speed low-power superconducting electronics. PMID:27845375

  16. Dissecting weak discernibility of quanta

    NASA Astrophysics Data System (ADS)

    Bigaj, Tomasz

    2015-05-01

    In this paper I critically examine latest attempts to formalize quantum-mechanical relations that are supposed to weakly discern elementary particles. I argue that all of them make illegitimate and unavoidable reference to numerical identity, and therefore cannot be used as a means to ground (or derive) quantitative facts of identity/distinctness in the qualitative characteristics of quantum systems. I compare my criticism of weak discernibility with the general circularity objection known from the literature, and I show that my argument is more specific, as it is based on a particular criterion which differentiates between legitimate and illegitimate uses of identity. In the end I suggest that we should reevaluate the role of permutation invariance in expressing the facts of qualitative differences between particles. Taking into account the inevitable symmetrization requirement applied to operators in tensor product spaces, it may be claimed that particles of the same type can be absolutely discerned in some accessible states.

  17. Nuclear reactions in deuterium-saturated palladium under irradiation by 10 MeV γ-quanta, in dense molecular deuterium at 1.2 kbar pressure

    NASA Astrophysics Data System (ADS)

    Didyk, A. Yu.; Wisniewski, R. S.

    2013-08-01

    A high-pressure chamber with a Pd-rod inside was filled up with 1.2 kbar molecular deuterium (DHPC). Then the saturated by deuterium palladium rod was irradiated during 18 hours by 11 MeV braking γ-quanta at 11-13 μA electron beam using the MT-25 electron accelerator. The element compositions of all the DHPC surfaces which had been in contact with dense deuterium gas were studied using scanning electronic microscopes with Roentgen microprobe analysis. It was determined that all the surfaces, including surfaces of the high-purity Pd-rod (99.995%), were covered either by a partially homogeneous layer or large microparticles of lead. Also, light elements as C, O, Na, Mg, Al, Si, Ti, Mn, Fe, Cu, Zn and heavy metals as Ag, Ta, W, Pt, Au and Pb were observed on the chambers inner surfaces.

  18. Results from the irradiation of stainless steel and copper by 23 MeV γ-quanta in the atmosphere of molecular deuterium at a pressure of 2 kbar

    NASA Astrophysics Data System (ADS)

    Didyk, A. Yu.; Wisniewski, R.

    2014-05-01

    Metal samples were arranged inside a "finger-type" high-pressure chamber (DHPC-FT) filled by deuterium. They were two aluminum rods, a copper rod, two specimens of homogeneous YMn2 alloy, and a stainless steel wire. The pressure of molecular deuterium in DHPC-FT was about 2 kbar. The samples were irradiated by braking γ-quanta at a threshold energy of 23 MeV. All the samples were studied using scanning electron microscopy (SEM) and X-ray (roentgen) microelement probe analysis (RMPA). Considerable changes in the surface structure and elemental composition were found for the samples of copper, aluminum, YMn2 alloy, and stainless steel. Unusual results were analyzed in detail and compared with the earlier data.

  19. 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.

  20. Synthesis of microobjects in 1-kbar hydrogen induced by 10-MeV bremsstrahlung γ quanta on inner surfaces of components of a high-pressure chamber (Part 1)

    NASA Astrophysics Data System (ADS)

    Didyk, A. Yu.; Wiśniewski, R.

    2015-01-01

    A high-pressure chamber filled with molecular hydrogen at 1-kbar pressure was exposed to 10-MeV bremsstrahlung γ quanta produced by an electron beam of 20-21 μA intensity for 14 h. Postirradiation investigations of the structure and elemental composition of the irregularities at the surface, as well as of two largest synthesized particles among those detected after irradiation, made it possible to reveal the presence of light elements from carbon to calcium in them. Multiple lead particles of small size were found and studied. The detected synthesized particles have a complex shape and composition. On both sides of inner surfaces of the cut brass sleeve, thin-walled microtubes and other objects of complex shape are found. The observed anomalies are discussed on the basis of a model of the fusion reactions of hydrogen nuclei and heavier nuclei ("upstream" reactions) and of the fission ("downstream") and fusion ("upstream") reactions in nuclei of the chamber walls.

  1. Changes of surface structure and elemental composition of Pd rod and collector of nuclear reaction products irradiated with 10-MeV γ-quanta in dense deuterium gas

    NASA Astrophysics Data System (ADS)

    Didyk, A. Yu.; Wiśniewski, R.; Wilczynska-Kitowska, T.

    2013-12-01

    A high-pressure chamber is filled with 1.2 kbar molecular deuterium (DHPC). The palladium rod saturated with deuterium is loaded inside the DHPC and irradiated with 10-MeV bremsstrahlung γ-quanta for 18 h with a 11-13 μA electron beam using the MT-25 electron accelerator. The elemental compositions of all surfaces of the DHPC element inside the dense deuterium gas were studied using scanning electronic microscopes with X-ray microelement microprobe analysis. It is found that all surfaces, including the surface of a high-purity palladium rod (99.995%), are covered with a partly homogeneous layer or large microparticles of lead. Also, light elements such as 6C, 8O, 11Na, 12Mg, 13Al, 14Si, 22Ti, 25Mn, 26Fe, 29Cu, and 30Zn and heavy metals such as 47Ag, 73Ta, 74W, 78Pt, 79Au, and 82Pb are observed. Possible processes that can cause the anomalies observed in the newly formed chemical elements are briefly discussed.

  2. Changes of surface structure and elemental composition of components of deuterium high-pressure chamber with Pd rod inside irradiated with 10-MeV γ-quanta in dense deuterium gas

    NASA Astrophysics Data System (ADS)

    Didyk, A. Yu.; Wiśniewski, R.; Wilczynska-Kitowska, T.

    2013-12-01

    This work is a continuation and addition to Ref. [1], which presents results on studies of the surface and elemental compositions of a Pd rod and brass screw for the collection of nuclear and chemical reaction products in a deuterium high-pressure chamber (DHPC) under irradiation with γ-quanta with an energy of 10 MeV for 18 h at the MT-25 electron accelerator at a beam current of 11-13 μA. The DHPC is filled with 1.2-kbar molecular deuterium in which a Pd rod saturated with deuterium is loaded. After irradiation, the elemental compositions of other surfaces of all DHPC elements, which are inside the DHPC in dense deuterium, are studied using an electron scanning microscope and X-ray microprobe analysis. It is established that all surfaces, including the surface of a high-purity palladium rod (99.995%), are covered with a partly homogeneous layer of large microparticles of lead. Also, light elements such as 6C, 8O, 11Na, 12Mg, 13Al, 14Si, 22Ti, 25Mn, 26Fe, 29Cu, and 30Zn and heavy metals such as 47Ag, 73Ta, 74W, 78Pt, 79Au, and 82Pb are observed. Possible processes that can cause the anomalies observed in the new synthesized elements are briefly discussed.

  3. IP3-induced Ca2+ release in A7r5 vascular smooth-muscle cells represents a partial emptying of the stores and not an all-or-none Ca2+ release of separate quanta.

    PubMed

    Missiaen, L; Sipma, H; Parys, J B; De Smet, P; Callewaert, G; Hill, E; McCarthy, T V; De Smedt, H

    1999-04-01

    There is still no agreement on the mechanism of the intracellular action of low concentrations of inositol 1,4,5-trisphosphate (IP3). Intracellular Ca2+ stores may transiently release some Ca2+ before they become insensitive to IP3. Alternatively, stores with a low IP3 threshold may lose all their Ca2+ and the others none. We now report that the IP3 threshold was not correlated with the extent of Ca2+ release in permeabilized A7r5 smooth-muscle cells. In contrast, the maximum rate of release, which was changed either by varying the level of IP3 receptor (IP3R) activation, or by changing the concentration of IP3R at a constant level of IP3R activation, was directly related to the extent of Ca2+ release. We conclude that IP3-induced Ca2+ release reflects partial emptying of the stores and not all-or-none Ca2+ release of separate quanta.

  4. Investigation of the performance of digital mammographic X-ray equipment: determination of noise equivalent quanta (NEQQC) and detective quantum efficiency (DQEQC) compared with the automated analysis of CDMAM test images with CDCOM and CDIC programs.

    PubMed

    Loos, C; Buhr, H; Blendl, C

    2013-07-01

    The purpose of this study was to determine the values for noise equivalent quanta, detective quantum efficiency, modulation transfer function, noise power spectrum, and the values for the parameters for automated CDMAM test phantom analyses required to achieve satisfactory quality of digital mammograms. During the course of tests according to PAS 1054 (8 CR and 12 DR systems), test images were made with a test phantom insertion plate containing two lead edges in nearly horizontal and vertical directions. Only original data were processed with a program that was developed at the Cologne University of Applied Sciences (FH-Köln). All equipment systems complied with the requirements regarding visual recognition of gold-plated mammo detail test objects. CDMAM test images were also evaluated using the CDIC (CUAS) and CDCOM (EUREF) programs. CDMAM test images show comparable values for the parameters, precision, sensitivity and specificity. DR systems require about half the dose used for CR systems for similar results. The NEQ values achieved with the dose used for the CDMAM test images show larger scatter ranges. The MTF of the different equipment system types differ significantly from each other. Visual evaluation of CDMAM test images can be replaced by automated evaluation. Limiting values were determined for each parameter. Automated evaluation of CDMAM test phantom images should be used to determine the physical parameter NEQQC. This method is much more sensitive to noise and sharpness influences and has a higher validity than diagnostic methods. Automated evaluation objectivizes testing. © Georg Thieme Verlag KG Stuttgart · New York.

  5. 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.

  6. 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

  7. Controlling the motion of magnetic flux quanta.

    PubMed

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

    2004-05-07

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

  8. Optical manipulation of single flux quanta.

    PubMed

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

    2016-09-28

    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.

  9. Optical manipulation of single flux quanta

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    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.

  10. 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.

  11. Does mean mean MEAN!? Digits For A Very Long Time Giving Us The Finger!: 1881 Statistics Log-Law was: Quanta=Digits!: BEC; Zipf 1/f-Law; Information-Thy; Random-#s = Euler V Bernoulli; Q-Computing = Arithmetic; P=/=NP SANS Complexity: Euclid 3-Mille

    NASA Astrophysics Data System (ADS)

    Siegel, Edward

    2008-03-01

    Classic statistics digits Newcomb[Am.J.Math.4,39,1881]-Weyl[Goett.Nachr.1912]-Benford[Proc.Am.Phil.Soc.78,4,51,1938]("NeWBe")probability ON-AVERAGE/MEAN log-law: =log[1+1/d]=log[(d+1)/d][google:``Benford's-Law'';"FUZZYICS": Siegel[AMS Nat.-Mtg.:2002&2008)]; Raimi[Sci.Am.221,109,1969]; Hill[Proc.AMS,123,3,887,1996]=log-base=units=SCALE-INVARIANCE!. Algebraic-inverse d=1/[ê(w)-1]: BOSONS(1924)=DIGITS(<1881): Energy-levels:ground=(d=0),first-(d=1)-excited ,... No fractions; only digit-integer-differences=quanta! Quo vadis digit =oo vs. <<,... simple-arithmetic!

  12. Wave mechanics: The interplay between stochastics and quanta

    NASA Astrophysics Data System (ADS)

    Cetto, A. M.; de La Peña, L.

    The authors make an attempt to understand the wave aspects of quantum mechanics within the framework of stochastic electrodynamics. The electron, considered originally as a point particle, is seen to perform a fine vibration of wave-number k c = mc/ħ sustained by the zeropoint radiation field; its interaction with the field waves of frequencies close to ω c = ck c gives rise to a modulation wave with de Broglie's wavelength. A heuristic analysis leads to the construction of the wave equation for the modulation amplitude. A few simple examples are given to illustrate the appearance of interference phenomena and quantization as the result of demanding that a standing modulation characterizes any stationary dynamical situation.

  13. Atempts to link Quanta & Atoms before the Bohr Atom model

    NASA Astrophysics Data System (ADS)

    Venkatesan, A.; Lieber, M.

    2005-03-01

    Attempts to quantize atomic phenomena before Bohr are hardly ever mentioned in elementary textbooks.This presentation will elucidate the contributions of A.Haas around 1910. Haas tried to quantize the Thomson atom model as an optical resonator made of positive and negative charges. The inherent ambiguity of charge distribution in the model made him choose a positive spherical distribution around which the electrons were distributed.He obtained expressions for the Rydberg constant and what is known today as the Bohr radius by balancing centrifugal energy with Coulomb energy and quantizing it with Planck's relation E=hν. We point out that Haas would have arrived at better estimates of these constants had he used the virial theorem apart from the fact that the fundamental constants were not well known. The crux of Haas's physical picture was to derive Planck's constant h from charge quantum e , mass of electron m and atomic radius. Haas faced severe criticism for applying thermodynamic concepts like Planck distribution to microscopic phenomena. We will try to give a flavor for how quantum phenomena were viewed at that time. It is of interest to note that the driving force behind Haas's work was to present a paper that would secure him a position as a Privatdozent in History of Physics. We end with comments by Bohr and Sommerfeld on Haas's work and with some brief biographical remarks.

  14. A delayed random choice quantum mechanics experiment using light quanta

    NASA Astrophysics Data System (ADS)

    Jakubowicz, O. G.

    1984-01-01

    Wheeler has often articulated during the past seven years several delayed choice Gendanken experiments which are intended to focus attention on the meaning of the elementary quantum phenomenon. Attempts to realize a delayed choice Gendanken xperiment in the spirit John Wheeler's thinking were undertaken. Short laser pulses attenuated to the single photon detection level are introduced into a Mach-Zehnder interferometer one at a time. There is a very fast completely random choice (yes/no) optical switch in one of the arms. Any photons in that arm would be reflected out and into a photomultiplier (PMT) if the optical switch decided to be closed. And any photon in the other arm would have equal probability of going into either of the PMTs that normally monitor interference. If the optical switch chooses to leave the pathway in its arm clear (open) then the photon must split at the beamsplitter and no photons will be detected in the PMT waiting for reflections out of that arm. Additionally, the phase of the interferometer may be set beforehand so that one PMT monitoring interference will register the photon and the other PMT monitoring interference will have zero probability of photon registration. The results are consistent with conventional quantum mechanics even if the decision to block or unblock one arm of the interferometer occurs after the single photon light pulse has passed the entrance beamsplitter of the interferometer.

  15. 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.

  16. 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)

  17. Electron vortex beams with high quanta of orbital angular momentum.

    PubMed

    McMorran, Benjamin J; Agrawal, Amit; Anderson, Ian M; Herzing, Andrew A; Lezec, Henri J; McClelland, Jabez J; Unguris, John

    2011-01-14

    Electron beams with helical wavefronts carrying orbital angular momentum are expected to provide new capabilities for electron microscopy and other applications. We used nanofabricated diffraction holograms in an electron microscope to produce multiple electron vortex beams with well-defined topological charge. Beams carrying quantized amounts of orbital angular momentum (up to 100ħ) per electron were observed. We describe how the electrons can exhibit such orbital motion in free space in the absence of any confining potential or external field, and discuss how these beams can be applied to improved electron microscopy of magnetic and biological specimens.

  18. Collective interaction-driven ratchet for transporting flux quanta.

    PubMed

    Olson, C J; Reichhardt, C; Jankó, B; Nori, F

    2001-10-22

    We propose and study a novel way to produce a dc transport of vortices when applying an ac electrical current to a sample. Specifically, we study superconductors with a graduated random pinning density, which transports interacting vortices as a ratchet system. We show that a ratchet effect appears as a consequence of the long range interactions between the vortices. The pinned vortices create an asymmetric periodic flux density profile, which results in an asymmetric effective potential for the unpinned interstitial vortices. The latter exhibit a net longitudinal rectification under an applied transverse ac electric current.

  19. Integration of quanta in cerebellar granule cells during sensory processing.

    PubMed

    Chadderton, Paul; Margrie, Troy W; Häusser, Michael

    2004-04-22

    To understand the computations performed by the input layers of cortical structures, it is essential to determine the relationship between sensory-evoked synaptic input and the resulting pattern of output spikes. In the cerebellum, granule cells constitute the input layer, translating mossy fibre signals into parallel fibre input to Purkinje cells. Until now, their small size and dense packing have precluded recordings from individual granule cells in vivo. Here we use whole-cell patch-clamp recordings to show the relationship between mossy fibre synaptic currents evoked by somatosensory stimulation and the resulting granule cell output patterns. Granule cells exhibited a low ongoing firing rate, due in part to dampening of excitability by a tonic inhibitory conductance mediated by GABA(A) (gamma-aminobutyric acid type A) receptors. Sensory stimulation produced bursts of mossy fibre excitatory postsynaptic currents (EPSCs) that summate to trigger bursts of spikes. Notably, these spike bursts were evoked by only a few quantal EPSCs, and yet spontaneous mossy fibre inputs triggered spikes only when inhibition was reduced. Our results reveal that the input layer of the cerebellum balances exquisite sensitivity with a high signal-to-noise ratio. Granule cell bursts are optimally suited to trigger glutamate receptor activation and plasticity at parallel fibre synapses, providing a link between input representation and memory storage in the cerebellum.

  20. [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.

  1. 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.

  2. 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)

  3. 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.

  4. Inelastic intermolecular exchange of vibrational quanta and relaxation of vibrationally excited states in binary solid systems

    NASA Astrophysics Data System (ADS)

    Aliev, A. R.; Akhmedov, I. R.; Kakagasanov, M. G.; Aliev, Z. A.; Gafurov, M. M.; Rabadanov, K. Sh.; Amirov, A. M.

    2017-04-01

    The processes of molecular relaxation in the binary nitrate-perchlorate solid systems LiNO3-LiClO4, NaNO3-NaClO4, and KNO3-KClO4 have been investigated using Raman spectroscopy. It has been found that the relaxation time of the ν1( A) vibration of the NO3 - anion in the binary solid system is shorter than that in the pure metal nitrates. It has been shown that an increase in the relaxation rate is caused by the existence of an additional mechanism of relaxation of vibrationally excited states of the nitrate ion in the system. This mechanism is associated with the excitation of a vibration of another anion (ClO4 -), as well as with the "creation" of a lattice phonon. It has been established that the condition for the realization of the relaxation mechanism is that the difference between the frequencies of the aforementioned vibrations should correspond to the range of sufficiently high densities of states of the phonon spectrum.

  5. 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…

  6. ON THE QUANTA OF LIGHT PRODUCED AND THE MOLECULES OF OXYGEN UTILIZED DURING CYPRIDINA LUMINESCENCE

    PubMed Central

    Harvey, E. Newton

    1927-01-01

    A study of the oxygen consumed per lumen of luminescence during oxidation of Cypridina luciferin in presence of luciferase, gives 11.4 x 10–5 gm. oxygen per lumen or 88 molecules per quantum of λ = 0.48µ, the maximum in the Cypridina luminescence spectrum. For reasons given in the text, the actual value is probably somewhat less than this, perhaps of the order of 6.48 x 10–5 gm. per lumen or 50 molecules of oxygen and 100 molecules of luciferin per quantum. It is quite certain that more than 1 molecule per quantum must react. On the basis of a reaction of the type: luciferin + 1/2 O2 = oxyluciferin + H2O + 54 Cal., it is calculated that the total efficiency of the luminescent process, energy in luminescence/heat of reaction, is about 1 per cent; and that a luciferin solution containing 4 per cent of dried Cypridina material should rise in temperature about 0.001°C. during luminescence, and contain luciferin in approximately 0.00002 molecular concentration. PMID:19872367

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

    NASA Astrophysics Data System (ADS)

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

    2008-09-01

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

  8. Magnetic-flux quanta in superconducting thin films observed by electron holography and digital phase analysis

    SciTech Connect

    Hasegawa, S.; Matsuda, T.; Endo, J.; Osakabe, N.; Igarashi, M.; Kobayashi, T.; Naito, M.; Tonomura, A. ); Aoki, R. )

    1991-04-01

    Singly quantized magnetic fluxes in superconducting lead films have been directly observed in the form of magnetic-flux-line distributions by using an electron-holography technique. Combining this with the digital-phase-analysis method, we were able to determine the flux quantum {ital h}/2{ital e} for individual fluxes with a precision of {similar to}{ital h}/100{ital e}, and analyze the distributions of field-vector components around the fluxon centers. The internal-field distributions obtained were compared with those calculated from the Ginzburg-Landau equations with use of some models, and an overall agreement was found between them. We also observed the changes of the magnetic-flux structures of lead thin films as a function of their thickness. Fluxon pairs were observed in 0.2-{mu}m-thick films, which may correspond to those suggested by Kosterlitz-Thouless theory.

  9. 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…

  10. [Effect of antibiotics and bifiodobacterium preparations on the intestinal microflora of mice irradiated with gamma quanta].

    PubMed

    Korshunov, V M; Pinegin, B V; Mal'tsev, V N; Kissina, E V; Ikonnikova, T B

    1980-07-01

    The treatment of CBA mice, irradiated in a dose of 700 Gy with antibiotics (penicillin V, oxytetracycline, streptomycin) in combination with bacterial therapy (B. bifidum, strain 75-41) or with antibiotics alone led to the increased percentage of survivors among them in comparison with the control animals. At the same time the medical prognosis was better in cases of the combined treatment with antibiotics and bifidobacteria. This circumstance was due to the fact that the combined treatment with antibiotics and bifidobacteria, considerably facilitated the normalization of the microbial picture of the intestine; in this case the "eubiosis" of the intestinal tract was almost completely restored by the 22nd day after the irradiation, whereas in the treatment with antibiotics alone the inhibitory effect on the development of the opportunistic flora at a later period of the development of dysbacteriosis was less pronounced, while the number of lactic acid bacteria remained at the same low level as in the untreated mice.

  11. 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.

  12. Accessing electronic and vibronic quanta and their coherent interactions in atomically precise nanostructures

    NASA Astrophysics Data System (ADS)

    Zeltzer, Gabriel

    In condensed matter systems the spatial limit is given by the fundamental atomic and molecular interactions. Controlling matter at these length scales hold promise in both fundamental scientific research as well as applications in nanotechnology and related fields such as electronics, biochemistry and medicine. Atomic and molecular manipulation on surfaces has opened a new realm of possibilities where materials can be engineered at the spatial limit and artificial structures can be constructed with a bottom-up approach, one building block at a time. This thesis describes nanostructures assembled from CO molecules on Cu(111) using a custom-built low-temperature ultra-high vacuum (UHV) scanning tunneling microscope (STM). The design and performance of the atom-manipulation apparatus that has enabled these experiments is presented. The control of electronic and vibronic states is demonstrated in several coherent quantum geometries and interactions between these two degrees of freedom are investigated. This work has revealed a virtual vibron process where non-local vibrons are synthesized and focused using a two-dimensional electron gas as a propagation medium and molecular oscillators as a source. Analysis of higher order harmonic modes of quartz tuning fork sensors is presented in the context of high frequency optical homodyne interferometric detection of subnanometer oscillatory motion. Further developments which could expand upon the work presented herein, in which STM may be combined with quantum force sensing through the use of quartz tuning forks, are suggested.

  13. Formation and annihilation of laser light pulse quanta in a thermodynamic-like pathway.

    PubMed

    Vodonos, Boris; Weill, Rafi; Gordon, Ariel; Bekker, Alexander; Smulakovsky, Vladimir; Gat, Omri; Fischer, Baruch

    2004-10-08

    We present a theoretical and experimental study of multiple pulse formation in passively mode-locked lasers. Following a statistical-mechanics approach, the study yields a thermodynamic-like "phase diagram" with boundaries representing cascaded first order phase transitions. They correspond to abrupt creation or annihilation of pulses and a quantized rf power behavior, as system parameters (noise and/or pumping levels) are varied, in excellent accordance with the experiments. Remarkably, individual pulses carry an almost constant quantum of energy.

  14. 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.

  15. 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)

  16. [An attempt at the objective evaluation of systems quanta in the drinking behavior of rats].

    PubMed

    Tolpygo, S M; Pevtsova, E I; Kotov, A V; Sudakov, K V

    1997-01-01

    The system architectonics of "systemoquanta" of rat drinking behavior was objectively evaluated in the dynamic process of its formation by means of studying intermediate and final results. The developed experimental equipment made it possible to determine characteristic features of formation and realization of drinking "systemoquanta" and the dynamics of their internal structure. Various "strategies" of system organization of identical behavior were revealed in rats of different groups. The revealed peculiarities of the internal structure of "systemoquanta" in rats of different groups are probably determined by the innate individual differences in the processes of prediction and estimation of intermediate and final results in the framework of strategic "systemoquantum" of drinking behavior.

  17. Recovering hidden quanta of Cu(2+)-doped ZnS quantum dots in reductive environment.

    PubMed

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

    2014-01-21

    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 Cu(2+)-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 Cu(2+) 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.

  18. Intact connecting filaments change length in 2.3-nm quanta.

    PubMed

    Blyakhman, F; Tourovskaya, A; Pollack, G H

    2000-01-01

    In isolated titin molecules, length changes may occur in discrete steps (Tskhovrebova et al., 1997; Rief et al., 1997). The extent to which such steps are preserved in the intact muscle-filament lattice has remained unclear. We carried out experiments on single isolated insect-flight-muscle myofibrils in which thin filaments had been functionally removed either by stretch beyond overlap or by a "rigor-stretch" protocol, leaving the connecting (titin) filaments as the sole length-absorbing agent. The myofibril was released or stretched by a motor in ramp-like fashion. The time course of length change in the single sarcomere was stepwise. The same was true for half-sarcomere lengths. The presence of steps at the sarcomere level implies that parallel filaments step synchronously, with high cooperativity. Step sizes showed a consistent distribution: The smallest size was approximately 2.3 nm, and others were integer multiples of that value. Similar results were found for stretch and release. To our knowledge, the approximately 2.3-nm step quantum is the smallest consistent biomechanical event ever demonstrated. This quantum is an order of magnitude smaller than anticipated from the folding/unfolding of a complete Ig- or fibronectin-like domain, and may imply that folding occurs in sub-domain increments. The 2.3-nm incremental length change corresponds to a single turn of the domains' beta sheet.

  19. Nanoscale friction: kinetic friction of magnetic flux quanta and charge density waves.

    PubMed

    Maeda, A; Inoue, Y; Kitano, H; Savel'ev, Sergey; Okayasu, S; Tsukada, I; Nori, Franco

    2005-02-25

    In analogy with the standard macroscopic friction, here we present a comparative study of the friction force felt by moving vortices in superconductors and charge density waves. Using experiments and a model for this data, our observations (1) provide a link between friction at the micro- and macroscopic scales, (2) explain the roundness of the static-kinetic friction transition in terms of thermal fluctuations, particle interactions, and system size (critical-phenomena view), and (3) explain the crossing of the kinetic friction F(k) versus velocity V for our pristine (high density of very weak defects) and our irradiated samples (with lower density of deeper pinning defects).

  20. Efficacy of thalamocortical and intracortical synaptic connections: quanta, innervation, and reliability.

    PubMed

    Gil, Z; Connors, B W; Amitai, Y

    1999-06-01

    Thalamocortical (TC) synapses carry information into the neocortex, but they are far outnumbered by excitatory intracortical (IC) synapses. We measured the synaptic properties that determine the efficacy of TC and IC axons converging onto spiny neurons of layer 4 in the mouse somatosensory cortex. Quantal events from TC and IC synapses were indistinguishable. However, TC axons had, on average, about 3 times more release sites than IC axons, and the mean release probability at TC synapses was about 1.5 times higher than that at IC synapses. Differences of innervation ratio and release probability make the average TC connection several times more effective than the average IC connection, and may allow small numbers of TC axons to dominate the activity of cortical layer 4 cells during sensory inflow.

  1. Loose-patch recordings of single quanta at individual hippocampal synapses.

    PubMed

    Forti, L; Bossi, M; Bergamaschi, A; Villa, A; Malgaroli, A

    1997-08-28

    Synapses in the central nervous system are typically studied by recording electrical responses from the cell body of the postsynaptic cell. Because neurons are normally connected by multiple synaptic contacts, these postsynaptic responses reflect the combined activity of many thousands synapses, and it remains unclear to what extent the properties of individual synapses can be deduced from the population response. We have therefore developed a method for recording the activity of individual hippocampal synapses. By capturing an isolated presynaptic bouton inside a loose-patch pipette and recording from the associated patch of postsynaptic membrane, we were able to detect miniature excitatory postsynaptic currents ('minis') arising from spontaneous vesicle exocytosis at a single synaptic site, and to compare these with minis recorded simultaneously from the cell body. The average peak conductance at a single synapse was about 900 pS, corresponding roughly to the opening of 90 AMPA-type glutamate-receptor channels. The variability in this conductance was about 30%, matching the value reported for the neuromuscular junction. Given that our synapses displayed single postsynaptic densities (PSDs), this variability is larger than would be predicted from the random opening of receptor channels, suggesting that they are not saturated by the content of a single vesicle. Therefore the response to a quantum of neurotransmitter at these synapses is not limited by the number of available postsynaptic receptors.

  2. 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.

  3. 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

  4. Scalar quanta in Fermi liquids: Zero sounds, instabilities, Bose condensation, and a metastable state in dilute nuclear matter

    NASA Astrophysics Data System (ADS)

    Kolomeitsev, E. E.; Voskresensky, D. N.

    2016-12-01

    The spectrum of bosonic scalar-mode excitations in a normal Fermi liquid with local scalar interaction is investigated for various values and momentum dependence of the scalar Landau parameter f0 in the particle-hole channel. For f0 > 0 the conditions are found when the phase velocity on the spectrum of zero sound acquires a minimum at non-zero momentum. For -1 < f0 < 0 there are only damped excitations, and for f0 < -1 the spectrum becomes unstable against the growth of scalar-mode excitations. An effective Lagrangian for the scalar excitation modes is derived after performing a bosonization procedure. We demonstrate that the instability may be tamed by the formation of a static Bose condensate of the scalar modes. The condensation may occur in a homogeneous or inhomogeneous state relying on the momentum dependence of the scalar Landau parameter. We show that in the isospin-symmetric nuclear matter there may appear a metastable state at subsaturation nuclear density owing to the condensate. Then we consider a possibility of the condensation of the zero-sound-like excitations in a state with a non-zero momentum in Fermi liquids moving with overcritical velocities, provided an appropriate momentum dependence of the Landau parameter f0(k) > 0. We also argue that in peripheral heavy-ion collisions the Pomeranchuk instability may occur already for f0 > -1.

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

    NASA Astrophysics Data System (ADS)

    Egorov, Vladimir V.

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

  6. Direct stimulation of the retina by the method of virtual-quanta for heavy cosmic-ray nuclei

    NASA Technical Reports Server (NTRS)

    Mcnulty, P. J.; Madey, R.

    1972-01-01

    The contribution to the frequency of visual sensations induced in the dark-adapted eye by the virtual photon field was calculated, this field is associated with the heavy nuclei that exist in space beyond the geomagnetic field. In order to determine the probability that the virtual photon field induces a light flash, only the portion of the virtual photon spectrum that corresponds to the known frequency dependence of the sensitivity of human rods to visible light was utilized. The results can be expressed as a curve of the mean frequency of light flashes induced by the absorption of at least R virtual photons versus the threshold number R. The contribution to the light flash frequency from the virtual photon field of heavy cosmic ray nuclei is smaller than that from Cerenkov photons. The flux and energy spectra of galactic cosmic ray nuclei helium to iron were used.

  7. Quanta, a Learning Community at Daytona Beach Community College and the Use of the Myers-Briggs Type Inventory.

    ERIC Educational Resources Information Center

    Bushnell, Jay R.

    In fall 1984, a program was implemented at Daytona Beach Community College (Florida) with the dual purpose of integrating subject material between courses and establishing a close community of learners to cooperate in the mastery of subject matter. In the fall semester, participating students enroll in a block of three courses; English I,…

  8. Anderson localized state as a predissipative state: irreversible emission of thermalized quanta from a dynamically delocalized state.

    PubMed

    Yamada, Hiroaki; Ikeda, Kensuke S

    2002-04-01

    It was shown that localization in one-dimensional disordered (quantum) electronic system is destroyed against coherent harmonic perturbations and the delocalized electron exhibits an unlimited diffusive motion [Yamada and Ikeda, Phys. Rev. E 59, 5214 (1999)]. The appearance of diffusion implies that the system has potential for irreversibility and dissipation. In the present paper, we investigate dissipative property of the dynamically delocalized state, and we show that an irreversible quasistationary energy flow indeed appears in the form of a "heat" flow when we couple the system with another dynamical degree of freedom. In the concrete we numerically investigate dissipative properties of a one-dimensional tight-binding electronic system perturbed by time-dependent harmonic forces, by coupling it with a quantum harmonic oscillator or a quantum anharmonic oscillator. It is demonstrated that if the on-site potential is spatially irregular an irreversible energy transfer from the scattered electron to the test oscillator occurs. Moreover, the test oscillator promptly approaches a thermalized state characterized by a well-defined time-dependent temperature. On the contrary, such a relaxation process cannot be observed at all for periodic potential systems. Our system is one of the minimal quantum systems in which a distinct nonequilibrium statistical behavior is self-induced.

  9. Temperature dependence of probability of absorption of. gamma. -quanta by Sn(II)-containing complexes of transition metals

    SciTech Connect

    Yurchenko, E.N.; Kuznetsov, v.I.; Burgina, E.B.

    1985-09-01

    A study has been made of the relationship f'(T) (T = 77-300/sup 0/K) for platinum-group metal complexes containing Sn(II)-X (X= F, Cl, Br); these data have been used to determine the mean-square amplitudes of vibrations of the Sn atom in the anions and together with the anion, and their temperature dependences have been found. The observed relationships at f'(T) depend to a considerable degree on the vibrations of the first type, i.e., on the rigidity of the bonds between the Sn and the immediate environment. The different Sn-X ligands have their own characteristic relationships f'(T), so that they can be used for identification of types of Sn(II)-containing complexes. The normal vibrations of the different complexes have been calculated, and it has been established that the observed changes in their f'(T) in the series of halides can be explained by the increase in the number of low-frequency vibrations in the series Br > Cl > F and by their effective inclusion in the absorption of the recoil energy given up by the Sn atom. Within the framework of the analysis, an explanation has been found for the increase in f' of the complexes when they are supported on the surface of substances containing acidic OH groups.

  10. Spacetime quanta?: the discrete spectrum of a quantum spacetime four-volume operator in unimodular loop quantum cosmology

    NASA Astrophysics Data System (ADS)

    Bunao, J.

    2017-02-01

    This study considers the operator \\hat{T} corresponding to the classical spacetime four-volume \\tilde{T} (on-shell) of a finite patch of spacetime in the context of unimodular loop quantum cosmology for the homogeneous and isotropic model with flat spatial sections and without matter sources. Since the spacetime four-volume is canonically conjugate to the cosmological ‘constant’, the operator \\hat{T} is constructed by solving its canonical commutation relation with {\\hat Λ } —the operator corresponding to the classical cosmological constant on-shell {\\tilde Λ } . This conjugacy, along with the action of \\hat{T} on definite volume states reducing to \\tilde{T} , allows us to interpret that \\hat{T} is indeed a quantum spacetime four-volume operator. The discrete spectrum of \\hat{T} is calculated by considering the set of all τ’s where the eigenvalue equation has a solution {{ Φ }τ} in the domain of \\hat{T} . It turns out that, upon assigning the maximal domain D≤ft(\\hat{T}\\right) to \\hat{T} , we have {{ Φ }τ}\\in D≤ft(\\hat{T}\\right) for all τ \\in {C} so that the spectrum of \\hat{T} is purely discrete and is the entire complex plane. A family of operators {{\\hat{T}}≤ft({{b0},{φ0}\\right)}} was also considered as possible self-adjoint versions of \\hat{T} . They represent the restrictions of \\hat{T} on their respective domains D≤ft({{\\hat{T}}≤ft({{b0},{φ0}\\right)}}\\right) which are just the maximal domain with additional quasi-periodic conditions. Their possible self-adjointness is motivated by their discrete spectra only containing real and discrete numbers {τm} for m=0,+/- 1,+/- 2,... .

  11. Measurements of the scintillation time constants of inorganic crystals for the development of a triple-Phoswich detector for high-energy X-ray quanta

    NASA Astrophysics Data System (ADS)

    Michelis, Thilo

    1987-04-01

    A setup for the measurement of the rise time distribution of pulses measured by a triple-Phoswich detector that is planned as component of an imaging system of a rotation-modulation telescope (RMT) was built. The principles and characteristics of scintillation crystals, scintillation detectors, and RMT's are outlined. Measurements on CsT(Tl) test crystals show a strong dependence of rise time distribution on Tl-concentration, and a clear dependence on temperature. A system for optimum light collection was developed for a Phoswich detector. The scintillation crystals NaJ(Tl) and CsJ(Na) are very suitable for a strip Phoswich. Proposals for a triple-Phoswich as detector for an RMT are given.

  12. On the replication of Kristofferson's (1980) quantal timing for duration discrimination: some learning but no quanta and not much of a Weber constant.

    PubMed

    Matthews, William J; Grondin, Simon

    2012-07-01

    This study revisited Kristofferson's (Perception & Psychophysics 27:300-306, 1980) report showing that, with sufficient practice at interval discrimination, the relationship between timing variability and physical time is a step function-in other words, that psychological time is quantized. Two participants completed 260 sessions of a temporal discrimination task, 20 consecutive sessions for each of 13 base durations ranging from 100 to 1,480 ms. The data do not replicate Kristofferson's (Perception & Psychophysics 27:300-306, 1980) quantal finding, and it is argued that the effect Kristofferson reported may have been due to specific methodological decisions. Importantly, the data show (1) some limitation of Weber's law for time, even for the narrow range of the present investigation, and (2) that extensive training provides some modest benefit to temporal discrimination, mainly for longer intervals, and that this benefit primarily occurs in the first few sessions.

  13. Measurement of photochemical quenching of absorbed quanta in photosystem I of intact leaves using simultaneous measurements of absorbance changes at 830 nm and thermal dissipation.

    PubMed

    Bukhov, Nikolai G; Carpentier, Robert

    2003-02-01

    The relationship between the redox state of the photosystem (PS) I primary donor, P700, and thermal energy dissipation in PSI were examined in intact leaves using simultaneous measurements of absorbance changes at 830 nm and variations of thermal emission monitored by photoacoustic (PA) spectroscopy, respectively. A strict proportionality (close to a 1:1 ratio) was found between the magnitudes of P700 oxidation and a positive variable PA signal induced by far-red light of various irradiances under conditions favoring effective electron donation from PSII to PSI. The proportionality was observed also between the ratio of reduced P700 to the total P700 content and the ratio of the variable component to the total PA signal measured with modulated light of 695 nm. Those findings clearly revealed that in intact leaves, variable thermal dissipation in PSI is determined by the fraction of P700 in the reduced state. Diuron-treated leaves exposed to 45 degrees C in which PSI received electrons not from PSII, but from soluble reductants localized in the chloroplast stroma were also used. In such leaves, the linear relationship between the ratio of reduced P700 to the total P700 content and the ratio of the variable component to the total PA signal measured with modulated light of 700 nm has been found as well, but its slope was twice smaller than in untreated leaves. This is probably related to an increased contribution of thermal emission from inactive PSII to the steady-state level of the PA signal in diuron-treated leaves exposed to high temperatures. The results demonstrated that the yield of variable thermal dissipation is strictly dependent on the redox pressure applied to the photosystem. The above illustrates the strong photochemical energy quenching occurring when the reaction centers are in open state (reduced P700).

  14. 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...

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. La mécanique du point matériel en théorie de relativité et en théorie des quanta [56

    NASA Astrophysics Data System (ADS)

    ne légère modification de la mécanique d'EmsTEiN (remplacant l'extrémum de int {m d s = } int {m sqrt { - dot q_μ dot q^μ } } dλ par celui de tfrac{1} {2} int {dot q_μ dot q^μ } dλ ) permet d'établir une nouvelle mécanique relativiste. Ses résultata ne diffèrent pas des résultate obtenus par la forme habituelle, si l'on ne fait intervenir que des champs gravifiques et électromàgnétiques. Mais, tout en gardant la covariance de la théorie, on peut introdurre des champs nouveaux qui ont pour consequence la création de partientes dans la théorie classique.

  20. Optimizing the Efficiency of Computer-Aided Instruction. Final Report. Report No. 2992.

    ERIC Educational Resources Information Center

    Feurzeig, Wallace; And Others

    To minimize training time, an adaptive training model for optimizing path sequencing in computer aided instruction was developed. The model reduced a course to logical components or quanta, then plotted the material for possible sequences and evaluated each component quanta as to importance to subject assimilation. For implementation and testing,…

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

    NASA Astrophysics Data System (ADS)

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

    1988-07-01

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

  2. Multiquanta breather model for PtCl

    SciTech Connect

    Voulgarakis, N. K.; Kalosakas, G.; Bishop, A. R.; Tsironis, G. P.

    2001-07-01

    We study the many-quanta problem of an intramolecular vibrational excitation interacting with optical phonons, that may represent the nonlinearity from intrinsic electron-lattice interactions. In the adiabatic limit we calculate numerically the ground-state energy and the corresponding wave functions for N vibrational quanta. In the one-dimensional case we find strong redshifts in the overtone spectra and an increasing spatial localization as the number of quanta increases. Through model parameter fitting we achieve very good quantitative agreement with experimental resonant Raman scattering measurements in the quasi-one-dimensional charge transfer solid PtCl. Accurate analytical expressions for the redshifts are also obtained.

  3. 76 FR 48130 - Southern Illinois University, et al.; Notice of Decision on Applications for Duty-Free Entry of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-08

    ...--Mailcode 4402, Carbondale, IL 62901. Instrument: Quanta 450 scanning electron microscope. Manufacturer: FEI...: Field-emission transmission electron microscope. Manufacturer: FEI Company, the Netherlands. Intended...: Scanning transmission electron microscope. Manufacturer: FEI Company, the Netherlands. Intended Use:...

  4. 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.''

  5. 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.

  6. Limits of scintillation materials for future experiments at high luminosity LHC and FCC

    NASA Astrophysics Data System (ADS)

    Korjik, M.

    2017-08-01

    This paper gives a summary of the systematic study of the radiation damage phenomena in scintillation materials which are caused by γ -quanta and energetic hadrons, the main contributors to the irradiation environment in further hadron collider experiments.

  7. 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".

  8. Photon polarization version of the GHz-Mermin Gedanken

    NASA Technical Reports Server (NTRS)

    Kiess, Thomas E.

    1992-01-01

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

  9. Staging quantum cryptography with chocolate ballsa)

    NASA Astrophysics Data System (ADS)

    Svozil, Karl

    2006-09-01

    Moderated by a director, laypeople and students assume the role of quanta and enact a quantum cryptographic protocol. The performance is based on a generalized urn model capable of reproducing complementarity even for classical chocolate balls.

  10. Optomechanics: Listening to quantum grains of sound

    NASA Astrophysics Data System (ADS)

    Favero, Ivan

    2015-04-01

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

  11. 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.

  12. USSR Report, Life Sciences Biomedical and Behavioral Sciences.

    DTIC Science & Technology

    1987-05-28

    No 3, May-Jun 85) 64 Cytogenetic Effects of Gamma Quanta and of Secondary Emission Generated by 70 GeV Protons on Chinese Hamster Fibroblasts...Irradiation With Gamma Quanta and Secondary Emission Generated by 70 GeV Protons (A.Kh. Akhmadiyeva, S.I. Zaichkina, et al.; RADIOBIOLOGIYA, No 3, May-Jun...ase, the enzyme assuring an active transfer of univalent cations through the membrane. Natural metabolites (I) and (II) exhibited the highest

  13. Alpha clustering near nuclear surface and harmonic-oscillator excitations

    NASA Astrophysics Data System (ADS)

    Horiuchi, W.; Suzuki, Y.

    2017-06-01

    We quantify how it is difficult to describe an alpha(α)-cluster state with single-particle harmonic-oscillator (HO) bases in the low-lying16O states by counting the number of HO quanta of12 C+n+n+p+p five-body wave functions. We also discuss how many HO quanta are needed for describing a localized α cluster near the nuclear surface towards understanding of the shell and cluster coexistence in heavier nuclei.

  14. Justification of the new approach to the testing of the candidate ITER materials in fission reactor

    NASA Astrophysics Data System (ADS)

    Nikolaenko, V. A.; Karpukhin, V. I.; Krasikov, E. A.; Kuznetsov, V. N.

    Routine approaches to the candidate ITER materials reactor testing have to be modified by taking into account the large, difference between fusion and fission reactor gamma-quanta fluxes. Recent analyses have shown clear evidence of the relationship between the steel ductile to brittle transition temperature (DBTT) shift and the gamma-quanta flux during the reactor irradiation. For example, if during the reactor irradiation of the 25Cr3NiMo type steel gamma-quanta the flux increases from 5 × 10 11 to 5 × 10 12 sm -2 s -1 to obtain the DBTT=160°C, it is necessary to increase the neutron fluence by one order of magnitude. Simultaneous neutron and gamma irradiation is characterized by an Irradiation Composition Factor (ICF) - neutron flux/gamma-quanta flux. For example, for a fast neutron fluence ( E > 0.5 MeV) of 2.4 × 10 19 cm -2 and 1.6 × 10 19 cm -2 and corresponding values of ICF of 0.4 and 2.1, the DBTT shift is greater for the smaller neutron fluence. Hence, the smaller is the ICF the greater is the gamma-quanta of the nescient defects restoring (annealing) action. For the ITER first wall the ICF is 4, whereas for a nuclear reactor it is only 0.1-0.3. Therefore the new approach to the experimental procedure of the experimental procedure of the canditate ITER materials testing in a fission reactor is justified.

  15. Effect of finite detector-element width on the spatial-frequency-dependent detective quantum efficiency

    NASA Astrophysics Data System (ADS)

    Cunningham, Ian A.; Westmore, Michael S.; Fenster, Aaron

    1995-05-01

    Image blur in digital imaging systems results from both the spatial spreading of quanta representing the image in the detector system and from the integration of quanta over the finite detector element width. Linear-systems theory has often been used to describe these blurring mechanisms as a convolution, implying the existence of a corresponding modulation transfer function (MTF) in the spatial-frequency domain. This also implies that the resulting noise- power spectrum (NPS) is modified by the square of the blurring MTF. This deterministic approach correctly describes the effect of each blurring mechanism on the overall system MTF, but does not correctly describe image noise characteristics. This is because the convolution is a deterministic calculation, and neglects the statistical properties of the image quanta. Rabbani et al. developed an expression for the NPS following a stochastic spreading mechanism that correctly accounts for these statistical properties. Use of their results requires a modification in how we should interpret the convolution theorem. We suggest the use of a `stochastic' convolution operator, that uses the Rabbani equation for the NPS rather than the deterministic result. This approach unifies the description of both image blur and image noise into a single linear-systems framework. This method is then used to develop expressions for the signal, NPS, DQE, and pixel SNR for a hypothetical digital detector design that includes the effects of conversion to secondary quanta, stochastic spreading of the secondary quanta, and a finite detector-element width.

  16. Experiments with Individual Photons

    NASA Astrophysics Data System (ADS)

    Beck, Mark

    2004-05-01

    I describe several different experiments we have performed with individual photons. For example, 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. To prove the existence of light quanta one must perform an experiment whose results cannot be explained using classical waves. We have performed such an experiment--it demonstrates the localization of light quanta by showing that a single photon only goes one way when it leaves a beamsplitter [1]. In a second experiment we demonstrate that this single photon will interfere with itself when it transits an interferometer. The experiments have been performed by undergraduates, and the goal of this project is to develop a series of experiments exploring fundamental aspects of quantum mechanics for an undergraduate teaching lab. [1] P. Grangier, G. Roger and A. Aspect, Europhys. Lett. 1, 173 (1986).

  17. The Possibilist Transactional Interpretation and Relativity

    NASA Astrophysics Data System (ADS)

    Kastner, Ruth E.

    2012-08-01

    A recent ontological variant of Cramer's Transactional Interpretation, called "Possibilist Transactional Interpretation" or PTI, is extended to the relativistic domain. The present interpretation clarifies the concept of `absorption,' which plays a crucial role in TI (and in PTI). In particular, in the relativistic domain, coupling amplitudes between fields are interpreted as amplitudes for the generation of confirmation waves (CW) by a potential absorber in response to offer waves (OW), whereas in the nonrelativistic context CW are taken as generated with certainty. It is pointed out that solving the measurement problem requires venturing into the relativistic domain in which emissions and absorptions take place; nonrelativistic quantum mechanics only applies to quanta considered as `already in existence' (i.e., `free quanta'), and therefore cannot fully account for the phenomenon of measurement, in which quanta are tied to sources and sinks.

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  19. Finite quantum kinematics of the harmonic oscillatora)

    NASA Astrophysics Data System (ADS)

    Shiri-Garakani, Mohsen; Finkelstein, David Ritz

    2006-03-01

    Arbitrarily small changes in the commutation relations suffice to transform the usual singular quantum theories into regular quantum theories. This process is an extension of canonical quantization that we call general quantization. Here we apply general quantization to the time-independent linear harmonic oscillator. The unstable Heisenberg group becomes the stable group SO(3). This freezes out the zero-point energy of very soft or very hard oscillators, like those responsible for the infrared or ultraviolet divergencies of usual field theories, without much changing the medium oscillators. It produces pronounced violations of equipartition and of the usual uncertainty relations for soft or hard oscillators, and interactions between the previously uncoupled excitation quanta of the oscillator, weakly attractive for medium quanta, strongly repulsive for soft or hard quanta.

  20. Image x-ray emission converters and microstrip porous dielectric x-ray detector

    SciTech Connect

    Lorikyan, M. P.

    2008-11-01

    The effective, fast, and accurate registration of x ray depends on the quality conversion of the X-quanta to photoelectrons. In this respect, of high interest are porous x-ray emission converters (PXECs). They are analogs of porous secondary electron emitters (PSEEs); the only difference is that active porous material should have high absorption properties for the X-quanta energies to be detected. Microstrip porous dielectric detector (MSPDD) is highly effective for x-ray registration without preliminary conversion of the X-quanta. Earlier it was shown that PSEE similar to PXEC has a high emission factor for 1-2 MeV {beta}-particles and 5 MeV {alpha}-particles. It was shown that MSPDDs and PSEEs are very stable.

  1. Finite quantum kinematics of the harmonic oscillator

    SciTech Connect

    Shiri-Garakani, Mohsen; Finkelstein, David Ritz

    2006-03-15

    Arbitrarily small changes in the commutation relations suffice to transform the usual singular quantum theories into regular quantum theories. This process is an extension of canonical quantization that we call general quantization. Here we apply general quantization to the time-independent linear harmonic oscillator. The unstable Heisenberg group becomes the stable group SO(3). This freezes out the zero-point energy of very soft or very hard oscillators, like those responsible for the infrared or ultraviolet divergencies of usual field theories, without much changing the medium oscillators. It produces pronounced violations of equipartition and of the usual uncertainty relations for soft or hard oscillators, and interactions between the previously uncoupled excitation quanta of the oscillator, weakly attractive for medium quanta, strongly repulsive for soft or hard quanta.

  2. 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.

  3. Maxwell-Boltzmann type Hawking radiation

    NASA Astrophysics Data System (ADS)

    Yoon, Youngsub

    2017-04-01

    Twenty years ago, Rovelli proposed that the degeneracy of black hole (i.e. the exponential of the Bekenstein-Hawking entropy) is given by the number of ways the black hole horizon area can be expressed as a sum of unit areas. However, when counting the sum, one should treat the area quanta on the black hole horizon as distinguishable. This distinguishability of area quanta is noted in Rovelli’s paper. Building on this idea, we derive that the Hawking radiation spectrum is not given by Planck radiation spectrum (i.e. Bose-Einstein distribution) but given by Maxwell-Boltzmann distribution.

  4. 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.

  5. Dressed Hard States and Black Hole Soft Hair

    NASA Astrophysics Data System (ADS)

    Mirbabayi, Mehrdad; Porrati, Massimo

    2016-11-01

    A recent, intriguing Letter by Hawking, Perry, and Strominger suggests that soft photons and gravitons can be regarded as black hole hair and may be relevant to the black hole information paradox. In this Letter we make use of factorization theorems for infrared divergences of the S matrix to argue that by appropriately dressing in and out hard states, the soft-quanta-dependent part of the S matrix becomes essentially trivial. The information paradox can be fully formulated in terms of dressed hard states, which do not depend on soft quanta.

  6. 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.

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

    SciTech Connect

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

    2011-07-15

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

  8. Potential scattering of electrons in a quantized radiation field

    NASA Astrophysics Data System (ADS)

    Bergou, J.; Ehlotzky, F.

    1986-05-01

    Potential scattering of electrons in a strong laser field is reconsidered. The laser beam is described by a quantized single-mode plane-wave field with a finite number of quanta in the mode. The scattering amplitude is expanded in powers of the potential, and the first two Born terms are considered. It is shown that in the limit of an infinite number of field quanta, the Kroll-Watson approximation is recovered. Additional insight is gained into the validity of this low-frequency theorem. The approach rests on the introduction of electron-dressed quantized-field states. Relations to earlier work are indicated.

  9. Dressed Hard States and Black Hole Soft Hair.

    PubMed

    Mirbabayi, Mehrdad; Porrati, Massimo

    2016-11-18

    A recent, intriguing Letter by Hawking, Perry, and Strominger suggests that soft photons and gravitons can be regarded as black hole hair and may be relevant to the black hole information paradox. In this Letter we make use of factorization theorems for infrared divergences of the S matrix to argue that by appropriately dressing in and out hard states, the soft-quanta-dependent part of the S matrix becomes essentially trivial. The information paradox can be fully formulated in terms of dressed hard states, which do not depend on soft quanta.

  10. GASEOUS SCINTILLATION COUNTER

    DOEpatents

    Eggler, C.; Huddleston, C.M.

    1959-04-28

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

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

    NASA Astrophysics Data System (ADS)

    Borisov, A. Yu.

    2011-11-01

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

  12. 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.

  13. Quantal basis of photoreceptor spectral sensitivity of Drosophila melanogaster

    PubMed Central

    1975-01-01

    Small potential fluctuations ("bumps"), boyh spontaneous and light induced, can be recorded intracellularly from the photoreceptors of Drosophila melanogaster. Statistical analyses of these bumps in the spectral range, 400-600 nm, lead to the following interpretations; (a) For weak stimuli at least, these bumps are the quantal units of the receptor potential. (b) Quanta of various wavelengths, when effectively absorbed, will elicit bumps of the same average size. (c) The spectral sensitivity of the receptor potential appears to have its origin in the relative efficiency of quantum bump production at different wavelengths, and not in the intrinsic difference in the properties of bumps produced by quanta of differenct wavelengths. PMID:809537

  14. Comment on ``Improvement of the Davydov theory of bioenergy transport in protein molecular systems''

    NASA Astrophysics Data System (ADS)

    Cruzeiro-Hansson, Leonor

    2002-08-01

    It is shown that a certain wave function represents a two quanta state of the Davydov-Scott model, contrary to the claims of Pang. Furthermore, Pang's choice of wave function and derivation of equation of motions are criticized. Directions for future work in this area are indicated.

  15. Efficient Injection of Electron Beams into Magnetic Guide Fields

    DTIC Science & Technology

    1999-06-01

    S. Maharam, E. Domanov , "Bremsstrahlung Converter with Increased Emission of Quanta with Energies < 100 ke V", Pribory i Tekhnika Experimenta, vol...Papers of the 11th IEEE International Pulsed Power Conference, IEEE Cat.# 97CH36127, 821, July, 1997. 5. V. Chomy, V. Morhun, 0. Maharam, E. Domanov

  16. Involvement of dihydropyridine-sensitive calcium channels in high asynchrony of transmitter release in neuromuscular synapses of newborn rats.

    PubMed

    Khuzakhmetova, V F; Nurullin, L F; Bukharaeva, E A; Nikolsky, E E

    2016-09-01

    Experiments on neuromuscular synapses of rats at different stages of ontogenesis have been performed. It has been found that one of the reasons of higher asynchrony of the release of single quanta of acetylcholine in the synapses of newborn animals is the activity of the presynaptic dihydropyridine-sensitive calcium channels of the L-type.

  17. 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…

  18. Effect of irradiation and thermal annealing on quartz materials luminescence

    NASA Astrophysics Data System (ADS)

    Korovkin, M. V.; Ananyeva, L. G.

    2017-01-01

    X-ray and gamma-quanta irradiation of radiation-resistant quartz materials including natural and synthetic quartz crystals and high-purity quartzite causes the luminescence in the ultraviolet range (365 nm), thermally stimulated luminescence and radiofrequency electromagnetic emission. Preliminary radiation and thermal annealing improves luminescence properties of quartz materials.

  19. 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)

  20. AN ELECTROPHYSIOLOGICAL INVESTIGATION OF NEUROMUSCULAR TRANSMISSION IN MYASTHENIA GRAVIS,

    DTIC Science & Technology

    with myasthenia gravis . With repetitive nerve stimulation at frequencies above 2/sec, only the first few stimuli elicited muscle contractions in most...It is tentatively concluded that in myasthenia gravis there is a deficiency in the amount of ACh in the quanta of transmitter released from the motor nerve terminals. (Author)

  1. 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.

  2. 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…

  3. 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.

  4. 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…

  5. 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.

  6. Light-dependent magnetoreception in birds: analysis of the behaviour under red light after pre-exposure to red light.

    PubMed

    Wiltschko, Wolfgang; Möller, Andrea; Gesson, Marcus; Noll, Catrin; Wiltschko, Roswitha

    2004-03-01

    In previous experiments, migratory birds had been disoriented under 635 nm red light, apparently unable to use their magnetic compass. The present study with European robins, Erithacus rubecula, confirms these findings for red light at the levels of 6 x 10(15) quanta s(-1) m(-2) and 43 x 10(15) quanta s(-1) m(-2), suggesting that the disorientation under red light was not caused by the test light being below the threshold for magnetoreception. However, pre-exposure to red light for 1 h immediately before the critical tests under red light of 6-7 x 10(15) quanta s(-1) m(-2) enabled robins to orient in their seasonally appropriate migratory direction in spring as well as in autumn. Pre-exposure to darkness, by contrast, failed to induce orientation under red light. Under green light of 7 x 10(15) quanta s(-1) m(-2), the birds were oriented in their migratory orientation after both types of pre-exposure. These findings suggest that the newly gained ability to orient under red light might be based on learning to interpret a novel pattern of activation of the magnetoreceptors and hence may represent a parallel to the previously described enlargement of the functional window to new magnetic intensities. Mechanisms involving two types of spectral mechanisms with different absorbance maxima and their possible interactions are discussed.

  7. 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.

  8. Ultraviolet Resonance Raman Enhancements in the Detection of Explosives

    DTIC Science & Technology

    2009-06-01

    SUBJECT TERMS Raman Spectroscopy, Standoff Detection, High Explosives, Explosive Detection, Inelastic Scattering, Resonance Raman 16. PRICE CODE...absolute Raman cross sections of TATP, PETN, RDX and TNT explosives from 620 to 248 nm at a constant flux of 2.5 1024 quanta s1 cm2 using KNO3

  9. Thom, Alexander (1894-1945)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    British engineer and archaeo-astronomer, born in Scotland, became professor of engineering science at Oxford University. Accurately surveyed the megalithic sites in Britain and the megalithic lunar observatories, identifying their shapes and astronomical alignments. He claimed to have discovered in the dimensions of the circles, as apparently used by the megalithic constructors, quanta of length ...

  10. Teaching Quantum Physics without Paradoxes

    ERIC Educational Resources Information Center

    Hobson, Art

    2007-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  13. A Comparison of the Accuracy of Discrete Event and Discrete Time

    DTIC Science & Technology

    2010-12-01

    over these places and may not be able to capture the rate at which the changes are occurring. In these circumstances the time step is too big . Finally...different sized quanta D. All solutions converged quickly to the neighborhood of the steady-state value of 1.0. Those for which the steady-state value was

  14. 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.

  15. 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)

  16. 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…

  17. Comparison of flux motion in type-II superconductors including pinning centers with the shapes of nano-rods and nano-particles by using 3D-TDGL simulation

    NASA Astrophysics Data System (ADS)

    Ito, Shintaro; Ichino, Yusuke; Yoshida, Yutaka

    2015-11-01

    Time-dependent Ginzburg-Landau (TDGL) equations are very useful method for simulation of the motion of flux quanta in type-II superconductors. We constructed the 3D-TDGL simulator and succeeded to simulate the motion of flux quanta in 3-dimension. We carried out the 3D-TDGL simulation to compare two superconductors which included only pinning centers with the shape of nano-rods and only nano-particle-like pinning centers in the viewpoint of the flux motion. As a result, a motion of "single-kink" caused the whole motion of a flux quantum in the superconductor including only the nano-rods. On the other hand, in the superconductor including the nano-particles, the flux quanta were pinned by the nano-particles in the various magnetic field applied angles. As the result, no "single-kink" occurred in the superconductor including the nano-particles. Therefore, the nano-particle-like pinning centers are effective shape to trap flux quanta for various magnetic field applied angles.

  18. Terahertz Generation & Vortex Motion Control in Superconductors

    NASA Astrophysics Data System (ADS)

    Nori, Franco

    2005-03-01

    A grand challenge is to controllably generate electromagnetic waves in layered superconducting compounds because of its Terahertz frequency range. We propose [1] four experimentally realizable devices for generating continuous and pulsed THz radiation in a controllable frequency range. We also describe [2-4] several novel devices for controlling the motion of vortices in superconductors, including a reversible rectifier made of a magnetic-superconducting hybrid structure [4]. Finally, we summarize a study [5] of the friction force felt by moving vortices. 1) S. Savel'ev, V. Yampol'skii, A. Rakhmanov, F. Nori, Tunable Terahertz radiation from Josephson vortices, preprint 2) S. Savel'ev and F. Nori, Experimentally realizable devices for controlling the motion of magnetic flux quanta, Nature Mat. 1, 179 (2002) 3) S. Savel'ev, F. Marchesoni, F. Nori, Manipulating small particles, PRL 92, 160602 (2004); B. Zhu, F. Marchesoni, F. Nori, Controlling the motion of magnetic flux quanta, PRL 92, 180602 (2004) 4) J.E. Villegas, et al., Reversible Rectifier that Controls the Motion of Magnetic Flux Quanta, Science 302, 1188 (2003) 5) A. Maeda, et al., Nano-scale friction: kinetic friction of magnetic flux quanta and charge density waves, preprint

  19. 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

    ..., Elec & Eltek, Kowloon, HONG KONG-CHINA; Guangdong Shengyi Sci. Tech Co., Guangdong, PEOPLE'S REPUBLIC OF CHINA; Ibiden, Toshiba-cho, JAPAN; Pacific Insulating Material Co., Ltd., Shenzhen, PEOPLE'S REPUBLIC OF CHINA; Lenovo, Quarry Bay, HONG KONG- CHINA; and Quanta Computer Inc., Tao Yuan Shien, TAIWAN...

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

    PubMed

    Norbury, J W; Townsend, L W

    1986-01-01

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

  1. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  3. A quantum accounting and detective quantum efficiency analysis for video-based portal imaging.

    PubMed

    Bissonnette, J P; Cunningham, I A; Jaffray, D A; Fenster, A; Munro, P

    1997-06-01

    The quality of images generated with radiographic imaging systems can be degraded if an inadequate number of secondary quanta are used at any stage before production of the final image. A theoretical technique known as a "quantum accounting diagram" (QAD) analysis has been developed recently to predict the detective quantum efficiency (DQE) of an imaging system as a function of spatial frequency based on an analysis of the propagation of quanta. It is used to determine the "quantum sink" stage(s) (stages which degrade the DQE of an imaging system due to quantum noise caused by a finite number of quanta), and to suggest design improvements to maximize image quality. We have used this QAD analysis to evaluate a video-based portal imaging system to determine where changes in design will have the most benefit. The system consists of a thick phosphor layer bonded to a 1 mm thick copper plate which is viewed by a T.V. camera. The imaging system has been modeled as ten cascaded stages, including: (i) conversion of x-ray quanta to light quanta; (ii) collection of light by a lens; (iii) detection of light quanta by a T.V. camera; (iv) the various blurring processes involved with each component of the imaging system; and, (v) addition of noise from the T.V. camera. The theoretical DQE obtained with the QAD analysis is in excellent agreement with the experimental DQE determined from previously published data. It is shown that the DQE is degraded at low spatial frequencies (< 0.25 cycles/mm) by quantum sinks both in the number of detected x rays and the number of detected optical quanta. At higher spatial frequencies, the optical quantum sink becomes the limiting factor in image quality. The secondary quantum sinks can be prevented, up to a spatial frequency of 0.5 cycles/mm, by increasing the overall system gain by a factor of 9 or more, or by improving the modulation transfer function (MTF) of components in the optical chain.

  4. Phenomenology of Particle Production during Ination

    NASA Astrophysics Data System (ADS)

    Namba, Ryo

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

  5. 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

  6. International multi-center evaluation of a novel chemiluminescence assay for the detection of anti-dsDNA antibodies.

    PubMed

    Bentow, C; Lakos, G; Martis, P; Wahl, E; Garcia, M; Viñas, O; Espinosa, G; Cervera, R; Sjöwall, C; Carmona-Fernandes, D; Santos, M J; Hanly, J G; Mahler, M

    2016-07-01

    Anti-double stranded desoxyribonucleic acid (anti-dsDNA) antibodies are considered fairly specific for systemic lupus erythematosus (SLE) and their quantification is useful for the clinical management of SLE patients. We assessed the diagnostic performance of the QUANTA Flash dsDNA chemiluminescent immunoassay (CIA) in comparison to an ELISA, using patients from five participating countries. The main focus was to evaluate the correlation between anti-dsDNA antibody results from the CIA and global SLE disease activity, as measured by the SLE Disease Activity Index 2000 (SLEDAI-2K). A total of 1431 samples (SLE, n = 843; disease controls, n = 588) from five countries (Canada, USA, Portugal, Sweden and Spain) were tested with QUANTA Flash dsDNA (Inova Diagnostics, San Diego, CA, USA). Data obtained with the QUANTA Lite dsDNA SC ELISA (Inova Diagnostics) were available for samples from three sites (Canada, USA and Sweden, n = 566). The SLEDAI-2K scores were available for 805 SLE patients and a cut-off of > 4 was used to define active disease. QUANTA Flash dsDNA had a sensitivity of 54.3% for the diagnosis of SLE, combined with 89.8% specificity. Anti-dsDNA antibody levels were significantly higher (p < 0.0001) in active SLE (SLEDAI-2K > 4; n = 232; median value 83.0 IU/mL) versus the inactive patients (n = 573; median value 22.3 IU/mL), and the SLEDAI-2K scoring correlated with their dsDNA antibody levels (Spearman's rho = 0.44, p < 0.0001). Similar but less pronounced findings were also found for the ELISA, in relation to disease activity. The QUANTA Flash dsDNA assay showed good clinical performance in a large international multi-center study. Additionally, the strong correlation between anti-dsDNA antibody results and SLEDAI-2K scores supported the potential utility of QUANTA Flash dsDNA for monitoring disease activity. © The Author(s) 2016.

  7. Quantum Theory of Fermion Production after Inflation

    NASA Astrophysics Data System (ADS)

    Berges, Jürgen; Gelfand, Daniil; Pruschke, Jens

    2011-08-01

    We show that quantum effects dramatically enhance the production of fermions following preheating after inflation in the early Universe in the presence of high excitations of bosonic quanta. As a consequence, fermions rapidly approach a quasistationary distribution with a thermal occupancy in the infrared, while the inflaton enters a turbulent scaling regime. The failure of standard semiclassical descriptions based on the Dirac equation with a homogeneous background field is caused by nonperturbatively high boson occupation numbers. During preheating the inflaton occupation number increases, thus leading to a dynamical mechanism for the enhanced production of fermions from the rescattering of the inflaton quanta. We comment on related phenomena in heavy-ion collisions for the production of quark matter fields from highly occupied gauge bosons.

  8. 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.

  9. 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.

  10. Micro-fabricated stylus ion trap.

    PubMed

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

    2013-08-01

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

  11. 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.

  12. Quantum Concepts in Physics

    NASA Astrophysics Data System (ADS)

    Longair, Malcolm

    2013-01-01

    Part I. The Discovery of Quanta: 1. Physics and theoretical physics in 1895; 2. Planck and black-body radiation; 3. Einstein and quanta, 1900-1911; Part II. The Old Quantum Theory: 4. The Bohr model of the hydrogen atom; 5. Sommerfield and Ehrenfest - generalising the Bohr model; 6. Einstein coefficients, Bohr's correspondence principle and the first selection rules; 7. Understanding atomic spectra - additional quantum numbers; 8. Bohr's model of the periodic table and the origin of spin; 9. The wave-particle duality; Part III. The Discovery of Quantum Mechanics; 10. The collapse of the old quantum theory and the seeds of its regeneration; 11. The Heisenberg breakthrough; 12. Matrix mechanics; 13. Dirac's quantum mechanics; 14. Schrödinger and wave mechanics; 15. Reconciling matrix and wave mechanics; 16. Spin and quantum statistics; 17. The interpretation of quantum mechanics; 18. The aftermath; 19. Epilogue; Indices.

  13. Vibrationally quantum-state-specific reaction dynamics of H atom abstraction by CN radical in solution.

    PubMed

    Greaves, Stuart J; Rose, Rebecca A; Oliver, Thomas A A; Glowacki, David R; Ashfold, Michael N R; Harvey, Jeremy N; Clark, Ian P; Greetham, Gregory M; Parker, Anthony W; Towrie, Michael; Orr-Ewing, Andrew J

    2011-03-18

    Solvent collisions can often mask initial disposition of energy to the products of solution-phase chemical reactions. Here, we show with transient infrared absorption spectra obtained with picosecond time resolution that the nascent HCN products of reaction of CN radicals with cyclohexane in chlorinated organic solvents exhibit preferential excitation of one quantum of the C-H stretching mode and up to two quanta of the bending mode. On time scales of approximately 100 to 300 picoseconds, the HCN products undergo relaxation to the vibrational ground state by coupling to the solvent bath. Comparison with reactions of CN radicals with alkanes in the gas phase, known to produce HCN with greater C-H stretch and bending mode excitation (up to two and approximately six quanta, respectively), indicates partial damping of the nascent product vibrational motion by the solvent. The transient infrared spectra therefore probe solvent-induced modifications to the reaction free energy surface and chemical dynamics.

  14. 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.

  15. Programmable flux DACs in a Quantum Annealing Processor

    NASA Astrophysics Data System (ADS)

    Hoskinson, Emile M.; Altomare, Fabio; Berkeley, Andrew J.; Bunyk, Paul; Harris, Richard; Johnson, Mark W.; Lanting, Trevor M.; Tolkacheva, Elena; Perminov, Ilya; Uchaikin, Sergey; Whittaker, Jed D.

    2014-03-01

    Programming the D-Wave Two processor to solve a given problem involves adjustment of thousands of independent flux biases. This is accomplished with an array of 4480 on-chip digital-to-analog converters (DACs), addressed using 56 external lines. Each DAC comprises a superconducting loop and control circuitry that allows injection of a deterministic number of flux quanta, up to a maximum value determined by the device parameters and the addressing scheme. In-depth characterization is performed to determine DAC transfer-functions and the addressing levels needed for fast and reliable programming. In contrast with traditional single-flux-quanta (SFQ) circuitry, zero static power during programming is dissipated on-chip, allowing efficient operation at mK temperatures.

  16. Constructive and Destructive Interference in Nonadiabatic Tunneling via Conical Intersections

    DOE PAGES

    Xie, Changjian; Kendrick, Brian K.; Yarkony, David R.; ...

    2017-03-31

    As a manifestation of the molecular Aharonov–Bohm effect, tunneling-facilitated dissociation under a conical intersection (CI) requires the inclusion of the geometric phase (GP) to ensure a single-valued adiabatic wave function encircling the CI. Here, we demonstrate using a simple two-dimensional model that the GP induces destructive interference for vibrational states with even quanta in the coupling mode, but it leads to constructive interference for those with odd quanta. The interference patterns are manifested in tunneling wave functions and clearly affect the tunneling lifetime. Furthermore, we show that the inclusion of the diagonal Born–Oppenheimer correction is necessary for agreement with exactmore » results.« less

  17. Optomechanical sideband cooling of a micromechanical oscillator close to the quantum ground state

    SciTech Connect

    Riviere, R.; Deleglise, S.; Weis, S.; Schliesser, A.; Kippenberg, T. J.; Gavartin, E.; Arcizet, O.

    2011-06-15

    Cooling a mesoscopic mechanical oscillator to its quantum ground state is elementary for the preparation and control of quantum states of mechanical objects. Here, we pre-cool a 70-MHz micromechanical silica oscillator to an occupancy below 200 quanta by thermalizing it with a 600-mK cold {sup 3}He gas. Two-level-system induced damping via structural defect states is shown to be strongly reduced and simultaneously serves as a thermometry method to independently quantify excess heating due to the cooling laser. We demonstrate that dynamical back action optical sideband cooling can reduce the average occupancy to 9{+-}1 quanta, implying that the mechanical oscillator can be found (10{+-}1)% of the time in its quantum ground state.

  18. 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.

  19. The simple perfection of quantum correlation in human vision.

    PubMed

    Bouman, Maarten A

    2006-01-01

    A theory is presented that specifies the amount of light that is needed for the perception of any stimulus that is defined in space, time and color. For detection and discrimination mechanistic neural elements with deterministic procedures exist. Twin pairs of red and green cones are ordered in three sets along clockwise and counter clockwise revolving spirals and along circles around the center of the fovea. In the rod-free fovea the red pairs are ordered along the spirals and the green along the circles. Each cone is accompanied by--dependent on retinal eccentricity--up to 100 satellite rods. For the retinal signal processing such a receptor group constitutes a space-quantum in analogy with time-quanta of about 0.04 s. In the peripheral retina the red and green twin pairs of space-quanta are roughly ordered along and at random distributed over the spirals and circles. Over each time-quantum, the cone and rods of a space-quantum sum their responses in a common nerve circuit of the luminosity channel. The summation's results from twin pairs of the same set of space-quanta are correlated by two-fold spatio-temporal coincidence mechanisms in the retina. Their outcome signals the perception of light, movement and edge. In the fused binocular visual field the movement and edge signals of the three sets from both eyes perfectly join vectorially together, provided the responding pairs of space-quanta are binocularly in perfect register as they normally are. The receptor's Weber gain control makes the receptor an all-or-none-system. The space-quantum's De Vries gain control makes its sensitivity equal to the average of the poisson fluctuations in quantum absorption per time-quantum. The controls are based on, respectively, arithmetically feed forward and backward inhibitive nerve mechanisms. The thermal noise of the photo-pigment resets the controls. The response to the second quantum absorption in a time-quantum in the individual rod, red or green cone has accession to

  20. 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.

  1. Flyby Anomaly via Least Action

    NASA Astrophysics Data System (ADS)

    Annila, A.

    2017-04-01

    The observed but unexpected changes in velocity during spacecraft flybys of Earth are examined using the principle of least action in its original dissipative form. In general, the spacecraft's momentum will change when it travels through an energy density gradient of space that is enfolding a gravitating, orbiting and rotating body. When space is understood as a physical substance that embodies quanta of actions, rather than being modeled by a mere metric, it becomes apparent that the changes in momentum couple with flux of quanta from the local system of bodies to the universal surroundings or vice versa. In this way the original least-action principle accounts also for the 'anomalous' change in velocity by an equation of motion which complies with the empirical relation that has been deduced from Earth-flybys.

  2. Secure space-to-space interferometric communications and its nexus to the physics of quantum entanglement

    NASA Astrophysics Data System (ADS)

    Duarte, F. J.

    2016-12-01

    The history of the probability amplitude equation |ψ>=(|x ,y >-|y ,x >) applicable to quanta pairs, propagating in different directions with entangled polarizations, is reviewed and traced back to the 1947-1949 period. The interferometric Dirac foundations common to |ψ>=(|x ,y >-|y ,x >) and the generalized N-slit interferometric equation, for indistinguishable quanta, are also described. The results from a series of experiments on N-slit laser interferometers, with intra interferometric propagation paths up to 527 m, are reviewed. Particular attention is given to explain the generation of interferometric characters, for secure space-to-space communications, which immediately collapse on attempts of interception. The design of a low divergence N-slit laser interferometer for low Earth orbit-low Earth orbit (LEO-LEO), and LEO-geostationary Earth orbit (LEO-GEO), secure interferometric communications is described and a weight assessment is provided.

  3. 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.

  4. Hadronic Spectrum of a Holographic Dual of QCD

    SciTech Connect

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

    2005-05-27

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

  5. Registration of the Atmospheric Gamma Radiation on Board the Russian Segment of the International Space Station

    NASA Astrophysics Data System (ADS)

    Andreevsky, S. E.; Kuznetsov, V. D.; Sinelnikov, V. M.

    2016-11-01

    The paper describes the complex of scientific instruments and the algorithm of the "Molniya-Gamma" experiment on measuring gamma-ray fluxes in the energy range of 32-750 keV carried out in 2011 on board the Russian Segment (RS) of the International Space Station (ISS). About 500 thousand energy spectra with a time resolution of 1 min were obtained in 512 energy channels during 232 days. One-second variations in the number of gamma quanta in four energy channels and the triggered fluxes of gamma quanta lasting less than 100 ms were recorded simultaneously. The data obtained allow us to study temporal and spatial variation of gamma-ray radiation to detect terrestrial gamma flashes (TGFs). Data on very large number of gamma-ray spikes were acquired through a trigger data mode with a low threshold.

  6. The Hadronic Spectrum of a Holographic Dual of QCD

    SciTech Connect

    de T'eramond, G.

    2005-01-04

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

  7. Phenomenology of a pseudo-scalar inflaton: naturally large nongaussianity

    SciTech Connect

    Barnaby, Neil; Namba, Ryo; Peloso, Marco E-mail: namba@physics.umn.edu

    2011-04-01

    Many controlled realizations of chaotic inflation employ pseudo-scalar axions. Pseudo-scalars φ are naturally coupled to gauge fields through cφF F-tilde . In the presence of this coupling, gauge field quanta are copiously produced by the rolling inflaton. The produced gauge quanta, in turn, source inflaton fluctuations via inverse decay. These new cosmological perturbations add incoherently with the ''vacuum'' perturbations, and are highly nongaussian. This provides a natural mechanism to generate large nongaussianity in single or multi field slow-roll inflation. The resulting phenomenological signatures are highly distinctive: large nongaussianity of (nearly) equilateral shape, in addition to detectably large values of both the scalar spectral tilt and tensor-to-scalar ratio (both being typical of large field inflation). The WMAP bound on nongaussianity implies that the coupling c of the pseudo-scalar inflaton to any gauge field must be smaller than about 10{sup 2} M{sub p}{sup −1}.

  8. 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.

  9. 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.

  10. Gravity by corpuscular radiation pressure.

    NASA Astrophysics Data System (ADS)

    Reimers, C.

    1995-09-01

    It is shown how four orders of magnitude of energy quanta provide all mass/energy in the universe, how their random motion transfers momentum to accelerate intercepting bodies of mass and how shielding causes gravity. Counting of impacts per second measures and defines force: F = (ML/T)/T. Basic field equations are developed. Crucial tests are proposed. It is shown how these quanta add mass/energy to intercepting systems and how a breakdown into the smallest order causes a virtual vacuum in the core of stars and galaxies which allows alternative explanations for their radiation and rotation patterns. Whirlpools are observed in optical, infrared, radio, X- and γ-radiation which show the evolution from gas to stars and galaxies. Oersted effects, accretion, plasma jets and extended lobes stabilize the system to form pairs of large vortex-rings, and the hemispheres of spiral galaxies.

  11. 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.

  12. Energy Sources, Self-organization, and the Origin of Life

    NASA Astrophysics Data System (ADS)

    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.

  13. Registration of the Atmospheric Gamma Radiation on Board the Russian Segment of the International Space Station

    NASA Astrophysics Data System (ADS)

    Andreevsky, S. E.; Kuznetsov, V. D.; Sinelnikov, V. M.

    2017-03-01

    The paper describes the complex of scientific instruments and the algorithm of the "Molniya-Gamma" experiment on measuring gamma-ray fluxes in the energy range of 32-750 keV carried out in 2011 on board the Russian Segment (RS) of the International Space Station (ISS). About 500 thousand energy spectra with a time resolution of 1 min were obtained in 512 energy channels during 232 days. One-second variations in the number of gamma quanta in four energy channels and the triggered fluxes of gamma quanta lasting less than 100 ms were recorded simultaneously. The data obtained allow us to study temporal and spatial variation of gamma-ray radiation to detect terrestrial gamma flashes (TGFs). Data on very large number of gamma-ray spikes were acquired through a trigger data mode with a low threshold.

  14. Collisional metastability of high rotational states of CN(X 2Σ +, ? = 0)

    NASA Astrophysics Data System (ADS)

    Hay, S.; Shokoohi, F.; Callister, S.; Wittig, C.

    1985-07-01

    CN(X 2Σ +, v'' = 0) high rotational states relax slowly via 300 K collisions with Ar and Kr. Relaxation decreases with increasing rotation, and the partially relaxed distributions are bimodal, with low N'' thermalized (300 K), and N'' = 80 unrelaxed after 1000 collisions. Relaxation by N 2, CO, and Xe is similar to Ar and Kr, but more efficient. He and NO remove many quanta in a single collision.

  15. Space and Time in a Quantized World

    NASA Astrophysics Data System (ADS)

    Svozil, Karl

    2015-12-01

    Rather than consider space-time as an a priori arena in which events take place, it is a construction of our mind making possible a particular kind of ordering of events. As quantum entanglement is a property of states independent of classical distances, the notion of space and time has to be revised to represent the holistic interconnectedness of quanta. We also speculate about various forms of reprogramming, or reconfiguring, the propagation of information for multipartite statistics and in quantum field theory.

  16. The band systems of alkali vapors

    NASA Technical Reports Server (NTRS)

    Weizel, W.; Kulp, M.

    1988-01-01

    A number of band edges of the molecules, Na2, K2, NaK, NaCs, LiK, LiRb, LiCs, and NaRb are arranged in edge schemes. The vibrational quanta of the base terms and the upper terms can be approximately determined. Viewpoints are produced for interpreting electron terms. The terms Na2 are interpreted as terms of a photo-electron.

  17. A simplified derivation of stimulated emission by black holes

    NASA Technical Reports Server (NTRS)

    Sorkin, Rafael D.

    1987-01-01

    A black hole, when acting as a scatterer for quanta in a single mode of a massless scalar field, is known to convert any ingoing Gibbs state of that mode into an outgoing Gibbs state (with some other mean particle number). The paper presents a simple derivation for this property which may help to clarify what relation, if any, it bears to the microscopic structure of the black hole horizon.

  18. 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.

  19. Theory of cross phase modulation for the vibrational modes of trapped ions

    NASA Astrophysics Data System (ADS)

    Nie, X. Rebecca; Roos, Christian F.; James, Daniel F. V.

    2009-01-01

    We analyze nonlinear coupling between individual vibrational quanta for trapped ions. The nonlinear Coulomb interaction causes a Kerr-type Hamiltonian, for which we derive an analytical expression for the coupling constant χ. In contrast to a previously published formula [C.F. Roos, T. Monz, K. Kim, M. Riebe, H. Häffner, D.F.V. James, R. Blatt, Phys. Rev. A 77 (2008) 040302(R)], our result is in close agreement with experimental data.

  20. The influence of DNA inhibitor synthesis on the induction and repair of double-strand DNA breaks in human lymphocytes under action of radiation with a different linear energy transfer

    NASA Astrophysics Data System (ADS)

    Boreyko, A. V.; Chausov, V. N.; Krasavin, E. A.; Ravnachka, I.; Stukova, S. I.

    2011-07-01

    The influence that inhibitors of repair and replicative DNA synthesis, 1-β-D-arabinofuranosyl-cytosine and hydroxyurea, have on the formation and repair kinetics of double-strand breaks (DSBs) in peripheral human blood lymphocytes under the influence of radiation with a different linear energy transfer (LET) (gamma quanta and accelerated heavy ions) is studied. It is demonstrated that lithium and boron ions with LETs of 20 and 40 keV/μm, respectively, possess higher biological effectiveness with respect to the DNA DSB induction criterion. The value of the relative biological effectiveness of accelerated lithium and boron ions is 1.5 ± 0.1 and 1.6 ± 0.1, respectively. It is found that, upon cell irradiation by gamma quanta in the absence of inhibitors, efficient DNA DSB repair is observed during incubation. Under the conditions of cell incubation and in the presence of inhibitors, some growth in the number of DNA DSBs, rather than a reduction, is observed after 5-h incubation. In the case of the action of accelerated boron ions (as well as gamma quanta), under normal conditions, the efficient repair of induced DNA lesions takes place. Unlike the action of gamma quanta, in the case of cell incubation in the presence of radiomodifiers, the number of induced DNA DSBs falls. These results may testify to the fact that the repair of double-strand DNS breaks takes place under the action of ionizing radiation with a different LET on mammalian cells in the presence of DNA synthesis inhibitors Ara-C and HU. It is concluded that, for cells subject to gamma irradiation, no DNA DSB repair is observed due to the large contribution of single-strand incision DNA breaks formed in the postradiation period in the course of excision nucleotide repair.

  1. Comprehensive Materials and Morphologies Study of Ion Traps (COMMIT) for Scalable Quantum Computation

    DTIC Science & Technology

    2012-04-21

    Graduate Students DisciplinePERCENT_SUPPORTEDNAME Shannon Wang 0.50 Yufei Ge 0.75 Jaroslaw Labaziewicz 0.50 Paul Antohi 0.25 David Leibrandt 0.50 Tony...1Total Number: Names of personnel receiving PHDs NAME Robert Clark Jaroslaw Labaziewicz David Leibrandt Paul Antohi 4Total Number: Names of other...Above the mirror surface, the best heating rate observed was 110 quanta/sec (at 150 µm height). Publications: [PhD Thesis] David Leibrandt (2009

  2. Investigation of polycapillary structures transmission

    NASA Astrophysics Data System (ADS)

    Chertov, Yuri P.

    2002-07-01

    For technological proces of polycapillary produciotn and for their further use it is necessary to know x-ray radiation transmission by polycapillary structures and its dependence on quanta energy. For this purpose special installation was assembled, technique was worked out and measurements were carried out. This paper incldues a description of the set-up, details the process of measurement and covers the outcome results.

  3. 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.

  4. Study of Xanthorhodopsin, the Retinal-Protein Proton Pump of Salinibacter ruber with Light-Harvesting Carotenoid Antenna

    DTIC Science & Technology

    2009-03-19

    because at this wavelength the carotenoids usually exhibit strong Sz-Sn transition [28]. Simultaneously, one can monitor the appearance of the product ...other documentation. 14. ABSTRACT The project produced initial characterization ofxanthorhodopsin, a novel carotenoid /retinal protein complex from the...not found in any other retinal-based pumps. Fluorescence studies showed that 45% oflight quanta absorbed by the carotenoid salinixanthin is transferred

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

    PubMed Central

    Astrand, P; Stjärne, L

    1989-01-01

    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. PMID:2573723

  6. Duration of classicality in highly degenerate interacting Bosonic system

    NASA Astrophysics Data System (ADS)

    Todarello, Elisa; Sikivie, Pierre

    2017-01-01

    We study sets of oscillators that have high quantum occupancy and that interact by exchanging quanta. It is shown by analytical arguments and numerical simulations that such systems obey classical equations of motion only on timescales of order their relaxation time τ and not longer than that. The results are relevant to the cosmology of axions and axion-like particles. U. S. Department of Energy.

  7. Laser Cooling of Solids

    DTIC Science & Technology

    2009-01-01

    journal.org) Schematic of an optical refrigeration system. Pump light is efficiently generated by a semicon- ductor diode laser. The laser light en- ters...efficiency of light emitting diodes (LEDs). Various methods have been devised to remedy this prob- lem for LEDs but not all are applicable to laser...cooling: light quanta in the red tail of the absorption spectrum are absorbed from a monochro- matic source followed by spontaneous emission of more

  8. 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.

  9. 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.

  10. Recording of relativistic particles in thin scintillators

    SciTech Connect

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

    2014-11-01

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

  11. 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.

  12. 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.

  13. The band systems of alkali vapors

    NASA Technical Reports Server (NTRS)

    Weizel, W.; Kulp, M.

    1988-01-01

    A number of band edges of the molecules, Na2, K2, NaK, NaCs, LiK, LiRb, LiCs, and NaRb are arranged in edge schemes. The vibrational quanta of the base terms and the upper terms can be approximately determined. Viewpoints are produced for interpreting electron terms. The terms Na2 are interpreted as terms of a photo-electron.

  14. On-demand superradiant conversion of atomic spin gratings into single photons with high efficiency.

    PubMed

    Black, Adam T; Thompson, James K; Vuletić, Vladan

    2005-09-23

    We create quantized spin gratings by single-photon detection and convert them on demand into photons with retrieval efficiencies exceeding 40% (80%) for single (a few) quanta. We show that the collective conversion process, proceeding via superradiant emission into a moderate-finesse optical resonator, requires phase matching. The storage time of 3 micros in the cold-atom sample, as well as the peak retrieval efficiency, are likely limited by Doppler decoherence of the entangled state.

  15. Extraction of information from a single quantum

    SciTech Connect

    Paraoanu, G. S.

    2011-04-15

    We investigate the possibility of performing quantum tomography on a single qubit with generalized partial measurements and the technique of measurement reversal. Using concepts from statistical decision theory, we prove that, somewhat surprisingly, no information can be obtained using this scheme. It is shown that, irrespective of the measurement technique used, extraction of information from single quanta is at odds with other general principles of quantum physics.

  16. Broadband waveguide QED system on a chip

    SciTech Connect

    Quan Qimin; Bulu, Irfan; Loncar, Marko

    2009-07-15

    We demonstrate that a slot waveguide provides a broadband loss-free platform suitable for applications in quantum optics. We find that strong coupling between light quanta and a single quantum emitter placed in the waveguide slot can be achieved with efficiency higher than 96% and Purcell factor (spontaneous emission factor) larger than 200. The proposed system is a promising platform for quantum information processing and can be used to realize an efficient single photon source and optically addressable photon register.

  17. High-Field Fractional Quantum Hall Effect in Optical Lattices

    SciTech Connect

    Palmer, R.N.; Jaksch, D.

    2006-05-12

    We consider interacting bosonic atoms in an optical lattice subject to a large simulated magnetic field. We develop a model similar to a bilayer fractional quantum Hall system valid near simple rational numbers of magnetic flux quanta per lattice cell. Then we calculate its ground state, magnetic lengths, fractional fillings, and find unexpected sign changes in the Hall current. Finally we study methods for detecting these novel features via shot noise and Hall current measurements.

  18. 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.

  19. Generation of Cross-Polarized Photon Pairs in a Microstructure Fiber With Frequency-Conjugate Laser Pump Pulses

    DTIC Science & Technology

    2005-07-25

    54, 2011 (1985). 6. S. Friberg and L. Mandel, "Production of squeezed states by combination of parametric down-conversion and harmonic generation," Opt...Rosen-Bohm experiment using pairs of light quanta produced by type-II parametric down-conversion," Phys. Rev. lett. 71, 3893 (1993). 25. L. J. Wang...or a MF, correlated Stokes (ws) and anti-Stokes (was) photon pairs at conjugate frequencies are generated via degenerate four-wave mixing process ( FWM

  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.

  1. The Gamma-Ray Spectrometer Experiment on the Solar Maximum Mission Satellite

    NASA Technical Reports Server (NTRS)

    Chupp, E. L. (Principal Investigator)

    1986-01-01

    Observations by the Gamma-Ray Spectrometer (GRS) on the Solar Maximum Mission (SMM) are examined. This detector system is sensitive to high-energy X-rays, gamma-rays, and energetic neutrons. These neutral quanta provide a probe of the highest energy processes in a flare. The GRS has recorded over 150 flares since launch. In addition to the solar discoveries, the SMM GRS has made important discoveries about cosmic gamma-ray sources. These discoveries are summarized.

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

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

    PubMed Central

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

    2015-01-01

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

  5. Particle production in a gravitational wave background

    NASA Astrophysics Data System (ADS)

    Jones, Preston; McDougall, Patrick; Singleton, Douglas

    2017-03-01

    We study the possibility that massless particles, such as photons, are produced by a gravitational wave. That such a process should occur is implied by tree-level Feynman diagrams such as two gravitons turning into two photons, i.e., g +g →γ +γ . Here we calculate the rate at which a gravitational wave creates a massless scalar field. This is done by placing the scalar field in the background of a plane gravitational wave and calculating the 4-current of the scalar field. Even in the vacuum limit of the scalar field it has a nonzero vacuum expectation value (similar to what occurs in the Higgs mechanism) and a nonzero current. We associate this with the production of scalar field quanta by the gravitational field. This effect has potential consequences for the attenuation of gravitational waves since the massless field is being produced at the expense of the gravitational field. This is related to the time-dependent Schwinger effect, but with the electric field replaced by the gravitational wave background and the electron/positron field quanta replaced by massless scalar "photons." Since the produced scalar quanta are massless there is no exponential suppression, as occurs in the Schwinger effect due to the electron mass.

  6. The GRIF-2 solar-geophysical experiment on board ALPHA

    NASA Astrophysics Data System (ADS)

    Logachev, Yu. I.; Denisov, Yu. I.; Svertilov, S. I.; Bogomolov, A. V.; Bogomolov, V. V.; Kudryavtsev, M. I.; Pankov, V. M.

    1996-11-01

    The main purpose of the GRIF-2 solar-geophysical experiment on board the ALPHA space vehicle is the comprehensive study of the temporal and spectral characteristics of the high-energy neutral radiations (gamma-quanta, neutrons, etc.) generated in solar flares. Another important part of the experiment is the study of the dynamics of energetic charged particles (electrons, protons, etc.) in the circumterrestrial space and its correlation with solar phenomena. The complex of instruments includes a high-sensitivity oriented spectrometer of gamma-quanta and neutrons, an oriented spectrometer of X-rays and electrons with a large geometrical factor, and a spectrometer of electrons and protons with a small geometrical factor. The spectrometer of gamma-quanta and neutrons measures particle fluxes and spectra in the gamma-quantum energy range 0.1 10 MeV and the spectrometer of neutrons is used for energies over 10 MeV. The spectrometer of X-rays and electrons is intended for both the continuous control of magnetospheric electron precipitations and monitoring the X-ray solar activity in the range 10 100 keV. The spectrometer of charged particles with a small geometrical factor is intended for measurement of high-intensity charged particle fluxes in the trapped radiation zones in the Earth magnetosphere.

  7. 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.

  8. Method of measuring NEQ as a quality control metric for digital mammography.

    PubMed

    Bloomquist, Aili K; Mainprize, James G; Mawdsley, Gordon E; Yaffe, Martin J

    2014-03-01

    Current quality control protocols for digital mammography rely on subjective assessments of image quality or simple measures that are not comparable between vendor platforms. The noise-equivalent quanta (NEQ) can be expressed in units of image quanta (fluence) for the spatial frequency range of interest, enabling comparisons between systems and x-ray spectra. The purpose of this work is to explore use of a simple phantom to measure the components of the noise-equivalent quanta of digital mammography systems for use in routine quality control. A simple phantom is imaged on six mammography systems from different vendors. The phantom contains uniform regions for measurement of noise power spectrum (NPS), slanted edges for measurement of modulation transfer function (MTF), and objects of various thicknesses for measurement of contrast. Images were acquired at a range of dose levels on each system to examine how measurements scale with dose, and multiple images were taken at a single dose point to examine measurement reproducibility. The phantom and measurement methods show good reproducibility, with average coefficient of variation values of less than or equal to 15% on all systems evaluated. Measured MTF and NPS values are comparable to other published results when the increase in scattered radiation generated by placing the phantom on the breast support is accounted for. Measurement of the parameters required to calculate NEQ from a single image of a simple phantom is practical, and shows promise as a method of evaluating image quality for routine quality control of digital mammography systems.

  9. Pulse-shape discrimination with Cs2HfCl6 crystal scintillator

    NASA Astrophysics Data System (ADS)

    Cardenas, C.; Burger, A.; Goodwin, B.; Groza, M.; Laubenstein, M.; Nagorny, S.; Rowe, E.

    2017-10-01

    The results of investigation into cesium hafnium chloride (Cs2HfCl6) scintillating crystals as a promising detector to search for rare nuclear processes occurring in Hf isotopes is reported. The light output, quenching factor, and pulse-shape characteristics have been investigated at room temperature. The scintillation response of the crystal induced by α-particles and γ-quanta were studied to determine possibility of particle discrimination. Using the optimal filter method we obtained clear separation between signals with a factor of merit (FOM) = 9.3. This indicates that we are able to fully separate signals originating from α-particles and γ-quanta. Similar fruitful discrimination power was obtained by applying the mean time method (FOM = 7) and charge integration method (FOM = 7.5). The quenching factor for collimated 4 MeV α-particles is found to be 0.36, showing that α-particles generate more than a third of the light compared to γ-quanta at the same energy.

  10. Microfabrication of Surface Electrode Ion Traps for Quantum Information Experiments

    NASA Astrophysics Data System (ADS)

    Ge, Yufei; Labaziewicz, Jaroslaw; Antohi, Paul; Chuang, Isaac

    2008-03-01

    Surface electrode ion traps, while promising for large-scale quantum computation, have long been challenged by ion heating rates which increase rapidly as trap length scales are reduced. Through a series of measurements on over fifteen traps, we show that ion heating rates are surprisingly sensitive to electrode material and morphology, and in particular, to details of the fabrication procedure. For example, one 75 μm size trap, made of chemically etched silver on a single crystal quartz substrate, showed a minimum heating rate of ˜40 quanta/second, when prepared by annealing at 760^oC in vacuum for one hour. This annealing smooths sharp edges, and significantly reduces breakdown voltage. However, if the annealing temperature is lowered to 720^oC, leaving the breakdown voltage still robustly high, the heating rate jumps to ˜1000 quanta/second. With electroplated gold, on a silver seed layer, a record low heating rate of ˜2 quanta/second is obtained. We present details of the fabrication procedures, evaluate alternative electrode materials such as niobium nitride, and explain how these measurements were obtained with an ion trap operated at 6 Kelvin, containing a single strontium ion, sideband cooled to its quantum ground state of motion.

  11. Mesoscopic superconductor as a ballistic quantum switch.

    SciTech Connect

    Melnikov, A. S.; Vinokur, V. M.; Materials Science Division; Russian Academy of Sciences

    2002-01-03

    Several key experiments have revealed a rich variety of vortex structures in mesoscopic superconductors in which only a few quanta of magnetic flux are trapped: these structures are polygon-like vortex 'molecules' and multi-quanta giant vortices. Ginzburg-Landau calculations confirmed second-order phase transitions between the giant vortex states and stable molecule-like configurations. Here we study theoretically the electronic structure and the related phase-coherent transport properties of such mesoscopic superconductor systems. The quasiparticle excitations in the vortices form coherent quantum-mechanical states that offer the possibility of controlling the phase-coherent transport through the sample by changing the number of trapped flux quanta and their configuration. The sample conductance measured in the direction of the applied magnetic field is determined by the transparency of multi-vortex configurations, which form a set of quantum channels. The transmission coefficient for each channel is controlled by multiple Andreev reflections within the vortex cores and at the sample edge. These interference phenomena result in a stepwise behaviour of the conductance as a function of the applied magnetic field, and we propose to exploit this effect to realize a vortex-based quantum switch where the magnetic field plays the role of the gate voltage.

  12. 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.

  13. The functional organization of motor nerve terminals.

    PubMed

    Slater, Clarke R

    2015-11-01

    Neuromuscular junctions (NMJs) have long been studied as particularly accessible examples of chemical synapses. Nonetheless, some important features of neuromuscular transmission are still poorly understood. One of these is the low statistical variability of the number of transmitter quanta released from motor nerve terminals by successive nerve impulses. This variability is well-described by a binomial distribution, suggesting that the quanta released are drawn, at high probability, from a small subset of those in the terminals. However, the nature of that subset remains unclear. In an effort to clarify what is understood, and what is not, about quantal release at NMJs, this review addresses the relationship between NMJ structure and function. After setting the biological context in which NMJs operate, key aspects of the variability of release and the structure of the motor nerve terminals are described. These descriptions are then used to explore the functional logic of motor nerve terminal organization and the structural basis of the low variability of release. This analysis supports the suggestion that the probability of release differs significantly at the different 'active zones' from which quanta are released. Finally, after a brief consideration of how release is maintained in the long term, a comparison is made of the features of NMJs with those of some well-studied neuronal synapses. An important conclusion is that NMJs share some important features with neuronal synapses, so continuing efforts to understand how motor nerve terminals work are likely to have much more general implications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. 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.

  15. CDOM Sources and Photobleaching Control Quantum Yields for Oceanic DMS Photolysis.

    PubMed

    Galí, Martí; Kieber, David J; Romera-Castillo, Cristina; Kinsey, Joanna D; Devred, Emmanuel; Pérez, Gonzalo L; Westby, George R; Marrasé, Cèlia; Babin, Marcel; Levasseur, Maurice; Duarte, Carlos M; Agustí, Susana; Simó, Rafel

    2016-12-20

    Photolysis is a major removal pathway for the biogenic gas dimethylsulfide (DMS) in the surface ocean. Here we tested the hypothesis that apparent quantum yields (AQY) for DMS photolysis varied according to the quantity and quality of its photosensitizers, chiefly chromophoric dissolved organic matter (CDOM) and nitrate. AQY compiled from the literature and unpublished studies ranged across 3 orders of magnitude at the 330 nm reference wavelength. The smallest AQY(330) were observed in coastal waters receiving major riverine inputs of terrestrial CDOM (0.06-0.5 m(3) (mol quanta)(-1)). In open-ocean waters, AQY(330) generally ranged between 1 and 10 m(3) (mol quanta)(-1). The largest AQY(330), up to 34 m(3) (mol quanta)(-1)), were seen in the Southern Ocean potentially associated with upwelling. Despite the large AQY variability, daily photolysis rate constants at the sea surface spanned a smaller range (0.04-3.7 d(-1)), mainly because of the inverse relationship between CDOM absorption and AQY. Comparison of AQY(330) with CDOM spectral signatures suggests there is an interplay between CDOM origin (terrestrial versus marine) and photobleaching that controls variations in AQYs, with a secondary role for nitrate. Our results can be used for regional or large-scale assessment of DMS photolysis rates in future studies.

  16. Corn silage management III: effects of hybrid, maturity, and processing on nitrogen metabolism and ruminal fermentation.

    PubMed

    Johnson, L M; Harrison, J H; Davidson, D; Swift, M; Mahanna, W C; Shinners, K

    2002-11-01

    Two experiments were conducted to evaluate the effects of maturity and mechanical processing of two hybrids of whole plant corn silage on DM and OM digestibility, nitrogen metabolism, ruminal fermentation, and milk production and composition in lactating Holstein cows. In the first experiment, Pioneer hybrid 3845 whole plant corn was harvested at hard dough, one-third milkline, and two-thirds milkline with a theoretical length-of-cut of 6.4 mm. At each stage of maturity, corn was harvested with (1-mm roll clearance) and without (15.9-mm roll clearance) mechanical processing using a John Deere 5830 harvester with an on-board kernel processor. In the second experiment, Pioneer hybrids 3845 and Quanta were harvested at one-third milkline, two-thirds milkline, and blackline stages of maturity with and without mechanical processing. The theoretical length-of-cut was 12.7 mm. Total tract DM and OM digestibilities were lower for cows fed diets containing processed corn silage in experiment 1, and tended to be lower for cows fed diets containing unprocessed corn silage in experiment 2. Ruminal acetate concentrations were greater and ruminal propionate concentrations were lower 2 and 6 h after feeding for cows fed diets containing corn silage harvested at physiological maturity in experiment 2. This was due to decreased digestion of starch at advanced maturities in experiment 2. Ruminal pH tended to decline rapidly after feeding for cows fed hybrid Quanta (2 h) compared to hybrid 3845 (5 h) corn silage based diets. Ruminal acetate concentrations decreased and ruminal propionate concentrations increased 2 and 6 h after feeding for cows fed diets containing hybrid Quanta corn silage compared to hybrid 3845 corn silage. This was related to a greater starch concentration in the corn silage, greater starch intake, and increased rate of starch digestion for cows fed hybrid Quanta corn silage-based diets. Microbial nitrogen flow was lower and feed nitrogen flow was greater for

  17. Cyclic-AMP levels in the lichen Evernia prunastri are modulated by light quantity and quality.

    PubMed

    Segovia, María; Gordillo, Francisco J L; Figueroa, Félix L

    2003-07-01

    Changes in the accumulation of cAMP levels were measured by the isotope dilution assay using protein kinase A in the lichen Evernia prunastri at varying light conditions. cAMP levels decreased following exposure to low irradiance (20 micromol quanta m(-2) s(-1), and below the compensation point for photosynthesis) of red light (600-710-nm wave length) and increased by 50% after far-red light illumination (15 micromol quanta m(-2) s(-1), 710-800-nm wavelength). Far-red partially reverted the effect of red light when the former was supplied after the latter. cAMP increased to its maximum level under high irradiance supplied by a non-photomorphogenic yellow light source (400 micromol quanta m(-2) s(-1), reaching photosynthetic saturation). The addition of small quantities of red and far-red light, however, had profound restricting effects on cAMP accumulation. The addition of inhibitors of electron transport chains did not promote any significant change in cAMP levels in any of the treatments, indicating that cAMP accumulation could not depend on ATP synthesis. We propose that the response of cAMP accumulation at low irradiance comprises the activation of a morphogenic pathway through a red/far-red photoreceptor. In addition, at high irradiance the response would occur most likely through photosystems II and I acting as sensors of light quantity, that can be strongly modified by the red/far-red photomorphogenic system. Thus, cAMP would be involved in sensing the overall light environment.

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

    PubMed

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

    2011-12-01

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

  19. [Influence of elevated atmospheric CO2 concentration on photosynthesis and leaf nitrogen partition in process of photosynthetic carbon cycle in Musa paradisiaca].

    PubMed

    Sun, G; Zhao, P; Zeng, X; Peng, S

    2001-06-01

    The photosynthetic rate (Pn) in leaves of Musa paradisiaca grown under elevated CO2 concentration (700 +/- 56 microliters.L-1) for one week was 5.14 +/- 0.32 mumol.m-2.s-1, 22.1% higher than that under ambient CO2 concentration, while under elevated CO2 concentration for 8 week, the Pn decreased by 18.1%. It can be inferred that the photosynthetic acclimation to elevated CO2 concentration and the Pn inhibition occurred in leaves of M. paradisiaca. The respiration rate in light (Rd) was lower in leaves under higher CO2 concentration, compared with that under ambient CO2 concentration. If the respiration in light was not included, the difference in CO2 compensation point for the leaves of both plants was not significant. Under higher CO2 concentration for 8 weeks, the maximum carboxylation rate(Vcmax) and electron transportation rate (J) in leaves decreased respectively by 30.5% and 14.8%, compared with that under ambient CO2 concentration. The calculated apparent quantum yield (alpha) in leaves under elevated CO2 concentration according to the initial slope of Pn/PAR was reduced to 0.014 +/- 0.010 molCO2.mol-1 quanta, compared with the value of 0.025 +/- 0.005 molCO2.mol-1 quanta in the control. The efficiency of light energy conversion also decreased from 0.203 to 0.136 electrons.quanta-1 in plants under elevated CO2 concentration. A lower partitioning coefficient for leaf nitrogen in Rubisco, bioenergetics and thylakoid light-harvesting components was observed in plants under higher CO2 concentration. The results indicated that the multi-process of photosynthesis was suppressed significantly by a long-term (8 weeks) higher CO2 concentration incubation.

  20. Comparison between different software programs and post-processing techniques for the MRI quantification of liver iron concentration in thalassemia patients.

    PubMed

    Bacigalupo, Lorenzo; Paparo, Francesco; Zefiro, Daniele; Viberti, Carlo Maria; Cevasco, Luca; Gianesin, Barbara; Pinto, Valeria Maria; Rollandi, Gian Andrea; Wood, John C; Forni, Gian Luca

    2016-10-01

    In magnetic resonance imaging (MRI) relaxometry, various software programs are available to perform R2* measurements and to estimate the liver iron concentration (LIC). The main objective of our study was to compare R2* LIC values, obtained with three different software programs based on specific decay models and calibration curves, with LIC estimates provided by R2-relaxometry (FerriScan). This retrospective study included 15 patients with 15 baseline MRIs and 34 serial examinations. R2* LIC estimates were calculated using the FuncTool, CMRtools/Thalassemia Tools and Quanta Hematology programs. Longitudinal LIC changes (ΔLIC) were calculated using the subset of 34 serial MRIs. After Bland-Altman analysis on baseline data, Quanta Hematology, which employs the monoexponential-plus-constant fit, produced the lowest mean difference [0.01 ± 0.14 log(mg/gdw)] with the closest limits of agreement. In the longitudinal setting, Quanta Hematology again gave the lowest mean difference between R2 and R2* LIC (0.1 ± 2.6 mg/gdw). Using FerriScan as reference, the value of concordant directional ΔLIC changes was the same for all programs (27/34, 85.7 %). R2* LICs are higher than R2 LICs at iron levels <7 mg/gdw, while R2 LIC averages higher than R2* LIC with increasing iron load. The monoexponential-plus-constant model provided the best agreement with R2 LIC estimates.

  1. The ontogeny of physiological response to light intensity in early stage spiny lobster (Jasus edwardsii) larvae.

    PubMed

    Bermudes, Michel; Ritar, Arthur J; Carter, Chris G

    2008-05-01

    Early stage phyllosoma larvae of the spiny rock lobster Jasus edwardsii were examined for swimming speed, feeding, oxygen consumption and nitrogen excretion as instantaneous performance indicators when exposed to different irradiance levels. Swimming speed was measured in recently hatched Stage I larvae while all other parameters were measured in larvae from hatch to mid-Stage V. The swimming speed of recently hatched Stage I phyllosoma increased logarithmically between light intensities of 2.9 x 10(14) and 1.8 x 10(16) quanta s(-1) cm(-2) indicating that, within this range, swimming activity was only suppressed at the lowest irradiance level. Larvae examined under dark (no light) conditions showed lower feed intake, oxygen consumption and nitrogen excretion than larvae under low (7.7 x 10(12) q s(-1) cm(-2)) and high (3.9 x 10(14) q s(-1) cm(-2)) light intensities, and this was a consistent pattern observed throughout development from hatch to Stage V. There was no difference in feeding, oxygen consumption and nitrogen excretion between larvae exposed to low and high light intensities. However, from mid-Stage I to mid-Stage V, the metabolic feeding efficiency (feed intake:oxygen consumption ratio) was consistently higher in larvae exposed to low light intensity than in phyllosoma assessed in the dark and under high irradiance. A light intensity of about 7.7 x 10(12) quanta s(-1) cm(-2) and no higher than 3.9 x 10(14) quanta s(-1) cm(-2) is recommended to stimulate feeding and optimise metabolic feeding efficiency in early larval stages of J. edwardsii.

  2. 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.

  3. Comparison of two experiments on radiative neutron decay

    SciTech Connect

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

    2009-12-15

    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) x 10{sup -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) x 10{sup -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.

  4. Pre-slow-roll initial conditions: Large scale power suppression and infrared aspects during inflation

    NASA Astrophysics Data System (ADS)

    Lello, Louis; Boyanovsky, Daniel; Holman, Richard

    2014-03-01

    If the large-scale anomalies in the temperature power spectrum of the cosmic microwave background are of primordial origin, they may herald modifications to the slow-roll inflationary paradigm on the largest scales. We study the possibility that the origin of the large-scale power suppression is a modification of initial conditions during slow roll as a result of a pre-slow-roll phase during which the inflaton evolves rapidly. This stage is manifest in a potential in the equations for the Gaussian fluctuations during slow roll and modifies the power spectra of scalar perturbations via an initial condition transfer function T(k). We provide a general analytical study of its large- and small-scale properties and analyze the impact of these initial conditions on the infrared aspects of typical test scalar fields. The infrared behavior of massless minimally coupled test scalar field theories leads to the dynamical generation of mass and anomalous dimensions, both depending nonanalytically on T(0). During inflation, all quanta decay into many quanta even of the same field because of the lack of kinematic thresholds. The decay leads to a quantum entangled state of subhorizon and superhorizon quanta with correlations across the horizon. We find the modifications of the decay width and the entanglement entropy from the initial conditions. In all cases, initial conditions from a "fast-roll" stage that lead to a suppression in the scalar power spectrum at large scales also result in a suppression of the dynamically generated masses, anomalous dimensions and decay widths.

  5. 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.

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

    NASA Astrophysics Data System (ADS)

    Chiba, Yohei; Kimura, Masaaki

    2014-12-01

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

  7. 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.

  8. Quantum cooperative process in living cells

    NASA Astrophysics Data System (ADS)

    Finkel, Robert

    2006-03-01

    A model of a quantum cooperative process has accurately accounted for various quantitative observations.^1 That investigation considered chemical oscillations to be generated by generic quantum oscillators producing discrete quanta with well-defined energy and wavelength. The current work extends the theory by postulating that these oscillations arise from repetitive electron transfers in membranes. We find this produces a limit cycle completely consistent with the hypothetical generic oscillators, accurately reproduces the results of microwave irradiation experiments on yeast, and addresses limits for the smallest possible cell sizes. Questions of coherence in cells and implications for molecular information transfers are briefly considered. ^1R.W. Finkel, J. Theor. Biol. in press.

  9. Time Characteristics and Odd-Even Effects in Nucleus Deexcitation Process

    SciTech Connect

    Fotina, O.V.; Drozdov, V.A.; Eremenko, D.O.; Platonov, S.Yu.; Yuminov, O.A.

    2004-10-01

    An approach based on the statistical theory of nuclear reactions and Monte Carlo method is used for evaluations of excited nuclear system characteristics like probability of decay channel (light particle, {gamma}-quanta emission, or fission), energy, emission angle of decay products, and time characteristics of deexcitation processes. This method permits the direct simulation of the experimental situation, in particular, nuclear-lifetime measurements by the crystal blocking technique. Decay times of compound nuclei formed in the fusion reactions {sup 12}C + {sup 28}Si {yields} {sup 40}Ca and {sup 19}F + {sup 28}Si {yields} {sup 47}V are estimated.

  10. 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

  11. Electrochemical Potential in Non-Equilibrium Normal Metals and Superconductors

    NASA Astrophysics Data System (ADS)

    van Vechten, Deborah; Wood, K. S.; Nikogosyan, S. V.; Paturyan, A. M.; Gulian

    1997-03-01

    The concept of the electrochemical potential in thermodynamic equilibrium is clearly understood. Moreover, a prescription exists for determining its value from the temperature dependent distribution function. However, when the material absorbs a high energy quanta, the local distribution function is strongly disturbed and in general does not have a Fermi-Dirac shape. We will describe how the underlying definitions of this potential in terms of partial derivatives can be numerically evaluated from the distribution functions generated by applying the kinetic equations. We will also discuss how the equilibrium state of the absorber affects the time evolution of the potential following a high energy event. Implications for detector development will be included.

  12. 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.

  13. 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.

  14. Waiting for the W and the Higgs

    DOE PAGES

    Tannenbaum, Michael J.

    2016-10-06

    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.

  15. Noiseless Quantum Measurement and Squeezing of Microwave Fields Utilizing Mechanical Vibrations

    NASA Astrophysics Data System (ADS)

    Ockeloen-Korppi, C. F.; Damskägg, E.; Pirkkalainen, J.-M.; Heikkilä, T. T.; Massel, F.; Sillanpää, M. A.

    2017-03-01

    A process which strongly amplifies both quadrature amplitudes of an oscillatory signal necessarily adds noise. Alternatively, if the information in one quadrature is lost in phase-sensitive amplification, it is possible to completely reconstruct the other quadrature. Here we demonstrate such a nearly perfect phase-sensitive measurement using a cavity optomechanical scheme, characterized by an extremely small noise less than 0.2 quanta. The device also strongly squeezes microwave radiation by 8 dB below vacuum. A source of bright squeezed microwaves opens up applications in manipulations of quantum systems, and noiseless amplification can be used even at modest cryogenic temperatures.

  16. CO product distributions from the visible photodissociation of HCO

    NASA Astrophysics Data System (ADS)

    Neyer, D. W.; Kable, S. H.; Loison, J.-C.; Houston, P. L.; Burak, I.; Goldfield, E. M.

    1992-12-01

    The CO product distributions following photodissociation of selected quantum levels of the A(tilde) state of HCO are investigated. The effects of differential initial vibrational states on the CO products are presented. Pure bending levels with six to 16 quanta have been investigated in addition to levels involving combinations of either the CH stretch and the HCO bend or the CO stretch and the HCO bend. Classical trajectories using the BBH potential energy surface are attempted in order to understand the underlying dynamics of this dissociation.

  17. Surface acoustic wave modulation of a coherently driven quantum dot in a pillar microcavity

    NASA Astrophysics Data System (ADS)

    Villa, B.; Bennett, A. J.; Ellis, D. J. P.; Lee, J. P.; Skiba-Szymanska, J.; Mitchell, T. A.; Griffiths, J. P.; Farrer, I.; Ritchie, D. A.; Ford, C. J. B.; Shields, A. J.

    2017-07-01

    We report the efficient coherent photon scattering from a semiconductor quantum dot embedded in a pillar microcavity. We show that a surface acoustic wave can periodically modulate the energy levels of the quantum dot but has a negligible effect on the cavity mode. The scattered narrow-band laser is converted into a pulsed single-photon stream, displaying an anti-bunching dip characteristic of single-photon emission. Multiple phonon sidebands are resolved in the emission spectrum, due to the absorption and emission of vibrational quanta in each scattering event.

  18. Model description of photonuclear 13C(γ, p)12B activation detection of carbon

    NASA Astrophysics Data System (ADS)

    Dzhilavyan, L. Z.; Pokotilovski, Yu. N.

    2017-09-01

    A model description of the activation detection of carbon with the use of registering 12B-activity produced in a graphite target by a beam of electrons with an energy of 50 MeV due to the photonuclear reaction 13C(γ, p) is presented. This description is carried out with consideration for the influence of the main background process related to the generation of potoneutrons under radiation and secondary background γ' quanta caused by them. A satisfactory agreement with experimental results is obtained taking into account the incompleteness of data on the conditions of these experiments.

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

    SciTech Connect

    Stipčević, Mario

    2016-03-15

    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.

  1. Achieving optimal rectification using underdamped rocked ratchets.

    PubMed

    Marchesoni, Fabio; Savel'ev, Sergey; Nori, Franco

    2006-02-01

    An underdamped rocked ratchet operated at very low temperatures and damping is shown: (i) to be capable of rectifying the ac input signal more efficiently than in the overdamped regime; (ii) to be insensitive to the initial conditions, at variance with noiseless, or deterministic, ratchets; and (iii) to be characterized by a wide damping "window," where its efficiency is appreciable also for weak input amplitudes. All these properties are rather robust, irrespective of the wave form of the drive and the ratchet potential. Our results relate to recent experiments on current-biased annular Josephson junctions and also on rectifiers of magnetic flux quanta in superconductors.

  2. 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.

  3. 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).

  4. Magnonic Black Holes

    NASA Astrophysics Data System (ADS)

    Roldán-Molina, A.; Nunez, Alvaro S.; Duine, R. A.

    2017-02-01

    We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons—the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.

  5. 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.

  6. Non-LTE astrophysics and the origin of high-energy cosmic rays

    SciTech Connect

    Colgate, S.A.

    1982-01-01

    The most startling aspects of the universe are the departures from the nonuniform, nonthermodynamic equilibrium state. Mass concentrations and high energy electromagnetic quanta and particles are the primary examples. Of these various departures the extremum of nonexplained phenomena is still the acceleration of cosmic rays. The usual explanations involving multiple mechanisms contributing to various regions of the spectrum is suggested as most unlikely. In particular, the suggestion of the acceleration of the very highest energy cosmic rays in distant active galactic nuclei is shown to be untenable because of photon particle interactions.

  7. 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.

  8. Cooling and Autonomous Feedback in a Bose-Hubbard Chain with Attractive Interactions.

    PubMed

    Hacohen-Gourgy, S; Ramasesh, V V; De Grandi, C; Siddiqi, I; Girvin, S M

    2015-12-11

    We engineer a quantum bath that enables entropy and energy exchange with a one-dimensional Bose-Hubbard lattice with attractive on-site interactions. We implement this in an array of three superconducting transmon qubits coupled to a single cavity mode; the transmons represent lattice sites and their excitation quanta embody bosonic particles. Our cooling protocol preserves the particle number-realizing a canonical ensemble-and also affords the efficient preparation of dark states which, due to symmetry, cannot be prepared via coherent drives on the cavity. Furthermore, by applying continuous microwave radiation, we also realize autonomous feedback to indefinitely stabilize particular eigenstates of the array.

  9. Cooling of a Suspended Nanowire by an ac Josephson Current Flow

    NASA Astrophysics Data System (ADS)

    Sonne, Gustav; Peña-Aza, Milton E.; Gorelik, Leonid Y.; Shekhter, Robert I.; Jonson, Mats

    2010-06-01

    We consider a nanoelectromechanical Josephson junction, where a suspended nanowire serves as a superconducting weak link, and show that an applied dc bias voltage can result in suppression of the flexural vibrations of the wire. This cooling effect is achieved through the transfer of vibronic energy quanta first to voltage-driven Andreev states and then to extended quasiparticle electronic states. Our analysis, which is performed for a nanowire in the form of a metallic carbon nanotube and in the framework of the density matrix formalism, shows that such self-cooling is possible down to the ground state of the flexural vibration mode of the nanowire.

  10. 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)

  11. 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.

  12. Insensitivity of Hawking radiation to an invariant Planck-scale cutoff

    SciTech Connect

    Agullo, Ivan; Navarro-Salas, Jose; Olmo, Gonzalo J.; Parker, Leonard

    2009-08-15

    A disturbing aspect of Hawking's derivation of black hole radiance is the need to invoke extreme conditions for the quantum field that originates the emitted quanta. It is widely argued that the derivation requires the validity of the conventional relativistic field theory to arbitrarily high, trans-Planckian scales. We stress in this note that this is not necessarily the case if the question is presented in a covariant way. We point out that Hawking radiation is immediately robust against an invariant Planck-scale cutoff. This important feature of Hawking radiation is relevant for a quantum gravity theory that preserves, in some way, the Lorentz symmetry.

  13. Ratchet effect in Nb films with asymmetric pinning potentials

    NASA Astrophysics Data System (ADS)

    Villegas, Javier E.; Savel'Ev, Sergey; Nori, Franco; Gonzalez, Elvira M.; Anguita, Jose V.; Garcia, Ricardo; Vicent, Jose L.

    2004-03-01

    We fabricated a device that controls the motion of flux quanta in a niobium superconducting film grown on an array of nanoscale triangular pinning potentials (J. E. Villegas et al. Science 302, 1188 (2003).) The controllable rectification of the vortex motion is due to the asymmetry of the fabricated magnetic pinning centers. The reversal in the direction of the vortex flow is explained by the interaction between the vortices trapped on the magnetic nanostructures and the interstitial vortices. The applied magnetic field and input current strength can tune both the polarity and magnitude of the rectified vortex flow. Our ratchet system is explained and modeled theoretically, taking the interactions between particles into consideration.

  14. 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.

  15. 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. .

  16. 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.

  17. Characterization of a high coherence, Brillouin microcavity laser on silicon.

    PubMed

    Li, Jiang; Lee, Hansuek; Chen, Tong; Vahala, Kerry J

    2012-08-27

    Recently, a high efficiency, narrow-linewidth, chip-based stimulated Brillouin laser (SBL) was demonstrated using an ultra-high-Q, silica-on-silicon resonator. In this work, this novel laser is more fully characterized. The Schawlow Townes linewidth formula for Brillouin laser operation is derived and compared to linewidth data, and the fitting is used to measure the mechanical thermal quanta contribution to the Brillouin laser linewidth. A study of laser mode pulling by the Brillouin optical gain spectrum is also presented, and high-order, cascaded operation of the SBL is demonstrated. Potential application of these devices to microwave sources and phase-coherent communication is discussed.

  18. 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.

  19. 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.

  20. Observation of quantum limit of zero sound absorption in normal 3He at 400 MHz

    NASA Astrophysics Data System (ADS)

    Matsumoto, Koichi; Ikegami, Toru; Okuda, Yuichi

    1994-02-01

    We are studying the quantum limit of zero sound absorption in normal 3He in which sound quanta are absorbed or emitted directly by quasiparticles. For that experiment, high frequency ultrasound is required since the condition ℏ;ω ≥ κT must be satisfied. We have succeeded in observing zero sound at the frequency of 400 MHz which is high enough to confirm the quantum effect. In the preliminary experiment, the absorption decreases with the square of temperature as it predicted by Fermi liquid theory and is seen to remain finite at absolute zero temperature.

  1. Pressure dependence of quantum zero sound attenuation in normal liquid3He

    NASA Astrophysics Data System (ADS)

    Matsumoto, Koichi; Ikegami, Toru; Karaki, Koichi; Okuda, Yuichi

    1996-01-01

    In the Fermi liquid theory Landau predicted that sound quanta are absorbed and emitted by directly creating and annihilating quasiparticle-quasihole pairs in normal liquid3He, when the angular frequency of ultrasound satisfies the condition Ћω> kT. In this regime sound attenuation remains finite at absolute zero temperature. We studied this quantum absorption limit as a function of pressure using an ultrasound of 389.1 MHz and have verified that this quantum zero sound absorption does exist.

  2. Classical Physics and the Bounds of Quantum Correlations.

    PubMed

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

    2016-06-24

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

  3. 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 .

  4. [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.

  5. 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.

  6. Aharonov-Bohm superperiod in a Laughlin quasiparticle interferometer.

    PubMed

    Camino, F E; Zhou, Wei; Goldman, V J

    2005-12-09

    We report an Aharonov-Bohm superperiod of five magnetic flux quanta (5h/e) observed in a Laughlin quasiparticle interferometer, where an edge channel of the 1/3 fractional quantum Hall fluid encircles an island of the 2/5 fluid. This result does not violate the gauge invariance argument of the Byers-Yang theorem because the magnetic flux, in addition to affecting the Aharonov-Bohm phase of the encircling 1/3 quasiparticles, creates the 2/5 quasiparticles in the island. The superperiod is accordingly understood as imposed by the anyonic statistical interaction of Laughlin quasiparticles.

  7. 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.

  8. 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.

  9. Waiting for the W. and the Higgs

    NASA Astrophysics Data System (ADS)

    Tannenbaum, M. J.

    2016-12-01

    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.

  10. Electron in a Two Dimensional System with Point Scatterers Amd Magnetic Field

    NASA Astrophysics Data System (ADS)

    Gredeskul, S. A.; Avishai, Y.; Azbel, M. Ya.; Zusman, M.

    We consider non-interacting electrons in two dimensions subject to a perpendicular magnetic field and interacting with point impurities with random strength located on the sites of a square lattice. For very strong magnetic field (such that there are more than n+1 flux quanta per plaque), we obtain (in closed analytic form) extended solutions, which are independent on the strength of disorder, for each Landau level with a number smaller or equal to n. If the rational magnetic flux per plaque is less than one unit, we construct dispersion laws and Hofstadter-like butterfly for all denominators less than ten.

  11. Cooling of a suspended nanowire by an ac Josephson current flow.

    PubMed

    Sonne, Gustav; Peña-Aza, Milton E; Gorelik, Leonid Y; Shekhter, Robert I; Jonson, Mats

    2010-06-04

    We consider a nanoelectromechanical Josephson junction, where a suspended nanowire serves as a superconducting weak link, and show that an applied dc bias voltage can result in suppression of the flexural vibrations of the wire. This cooling effect is achieved through the transfer of vibronic energy quanta first to voltage-driven Andreev states and then to extended quasiparticle electronic states. Our analysis, which is performed for a nanowire in the form of a metallic carbon nanotube and in the framework of the density matrix formalism, shows that such self-cooling is possible down to the ground state of the flexural vibration mode of the nanowire.

  12. A 3000 K laboratory emission spectrum of water.

    PubMed

    Coheur, Pierre-François; Bernath, Peter F; Carleer, Michel; Colin, Reginald; Polyansky, Oleg L; Zobov, Nikolai F; Shirin, Sergei V; Barber, Robert J; Tennyson, Jonathan

    2005-02-15

    An emission spectrum of hot water with a temperature of about 3000 K is obtained using an oxy-acetylene torch. This spectrum contains a very large number of transitions. The spectrum, along with previous cooler laboratory emission spectra and an absorption spectrum recorded from a sunspot, is analyzed in the 500-2000 cm(-1) region. Use of a calculated variational linelist for water allows significant progress to be made on assigning transitions involving highly excited vibrational and rotational states. In particular emission from rotationally excited states up to J=42 and vibrational levels with up to eight quanta of bending motion are assigned.

  13. A 3000 K laboratory emission spectrum of water

    NASA Astrophysics Data System (ADS)

    Coheur, Pierre-François; Bernath, Peter F.; Carleer, Michel; Colin, Reginald; Polyansky, Oleg L.; Zobov, Nikolai F.; Shirin, Sergei V.; Barber, Robert J.; Tennyson, Jonathan

    2005-02-01

    An emission spectrum of hot water with a temperature of about 3000K is obtained using an oxy-acetylene torch. This spectrum contains a very large number of transitions. The spectrum, along with previous cooler laboratory emission spectra and an absorption spectrum recorded from a sunspot, is analyzed in the 500-2000cm-1 region. Use of a calculated variational linelist for water allows significant progress to be made on assigning transitions involving highly excited vibrational and rotational states. In particular emission from rotationally excited states up to J =42 and vibrational levels with up to eight quanta of bending motion are assigned.

  14. Serrated creep and spatio-temporal structures of macrolocalized plastic deformation

    NASA Astrophysics Data System (ADS)

    Shibkov, A. A.; Zolotov, A. E.; Zheltov, M. A.; Gasanov, M. F.; Denisov, A. A.

    2014-05-01

    The dynamics and morphology of macrolocalized deformation bands have been investigated using a complex of high-speed in situ methods under the conditions of serrated creep of flat samples of the aluminum-magnesium alloy 5456 with different aspect ratios. It has been found that, at the front of a macroscopic plastic deformation jump, a complex structure of propagating deformation bands, which are considered as macrolocalized deformation "quanta," is spontaneously formed in the material. It has been shown that, with an increase in the sample length, the deformation behavior of the alloy tends to the state of self-organized criticality.

  15. Decomposition of a unit quantum and isolation of a fractional quantum by an externally injected soliton in an ultra-thin superconducting bi-layer film

    NASA Astrophysics Data System (ADS)

    Tanaka, Y.; Yamamori, H.; Yanagisawa, T.; Nishio, T.; Arisawa, S.

    2017-07-01

    An ultra-thin superconducting bi-layer is an artificial multi-component superconductor in which the magnetic flux can be fractionally quantized. The fractionally quantized state is energetically unfavorable, so it is difficult to realize experimentally. We propose a new method to create fractional quantized states by the reaction of a unit quantized state with an externally injected inter-layer phase-difference soliton. Simulation shows that the unit quantized state splits the soliton and the soliton fragments produce fractional quanta by dissociation of the unit quantum.

  16. [On the issue of non-mutagenic non-targeted effects in low renewable tissues. Analysis of low dose radiation effects on the rat renal tubule epithelium].

    PubMed

    Bychkovskaia, I B; Kirik, O V; Fedortseva, R F

    2014-01-01

    Irradiation of rats with γ-quanta at relatively low doses induces a sustainable dose-independent increase in the occurrence of lethal cytoplasmic disorders in the renal tubules epithelium together with sustainable and as well dose-independent subcelluar compensation and restorative processes. Over the period of research (6 months) these processes led to no population recovery. The detected alterations are referred to the category of non-targeted non-mutagenic effects and they are of interest because they address the issue of the sensitivity of low renewable tissues to radiation.

  17. Equilibrium distributions in entropy driven balanced processes

    NASA Astrophysics Data System (ADS)

    Biró, Tamás S.; Néda, Zoltán

    2017-05-01

    For entropy driven balanced processes we obtain final states with Poisson, Bernoulli, negative binomial and Pólya distributions. We apply this both for complex networks and particle production. For random networks we follow the evolution of the degree distribution, Pn, in a system where a node can activate k fixed connections from K possible partnerships among all nodes. The total number of connections, N, is also fixed. For particle physics problems Pn is the probability of having n particles (or other quanta) distributed among k states (phase space cells) while altogether a fixed number of N particles reside on K states.

  18. An Introduction to Multiphoton Ionization and Study of Ionization Rate of Hydrogen Atom

    SciTech Connect

    Shrestha, N.; Nakarmi, J. J.; Jha, L. N.

    2009-04-19

    From a semiclassical point of view, we discuss the problem of nonlinear interaction between electromagnetic radiation and atoms. The time-dependent Schroedinger equation for single electron systems is solved using perturbative technique to obtain transition probability. We also discuss higher order perturbation used in multiple processes where two or more quanta are emitted instead of a single photon. The approach is based on the assumption that the perturbation is small. From the transition probability ionization rate and absorption, the cross-section of hydrogen atoms is calculated. Variation in photon energy and field strength is analyzed. Variation of cross-section with photon energy is discussed.

  19. Delayed pulses from high-transparency Josephson junctions

    NASA Astrophysics Data System (ADS)

    Xu, Songtao; Mancini, C. A.; Feldman, M. J.

    2001-05-01

    Calculations of the shape and the timing of single-magnetic-flux quanta (SFQs) generated by high-current-density "self-shunted" Josephson junctions are presented. The junction current is assumed to be due in part to multiple Andreev reflections within the high-transparency barrier. The SFQ pulses from these junctions show several differences when compared to those from lower-current-density resistively shunted Josephson junctions, the most important being that the pulses are significantly delayed in the self-shunted junctions, by as much as many times the pulse width.

  20. Light-dependent magnetoreception in birds: increasing intensity of monochromatic light changes the nature of the response

    PubMed Central

    Wiltschko, Roswitha; Stapput, Katrin; Bischof, Hans-Joachim; Wiltschko, Wolfgang

    2007-01-01

    Background The Radical Pair model proposes that magnetoreception is a light-dependent process. Under low monochromatic light from the short-wavelength part of the visual spectrum, migratory birds show orientation in their migratory direction. Under monochromatic light of higher intensity, however, they showed unusual preferences for other directions or axial preferences. To determine whether or not these responses are still controlled by the respective light regimes, European robins, Erithacus rubecula, were tested under UV, Blue, Turquoise and Green light at increasing intensities, with orientation in migratory direction serving as a criterion whether or not magnetoreception works in the normal way. Results The birds were well oriented in their seasonally appropriate migratory direction under 424 nm Blue, 502 nm Turquoise and 565 nm Green light of low intensity with a quantal flux of 8·1015 quanta s-1 m-2, indicating unimpaired magnetoreception. Under 373 nm UV of the same quantal flux, they were not oriented in migratory direction, showing a preference for the east-west axis instead, but they were well oriented in migratory direction under UV of lower intensity. Intensities of above 36·1015 quanta s-1 m-2 of Blue, Turquoise and Green light elicited a variety of responses: disorientation, headings along the east-west axis, headings along the north-south axis or 'fixed' direction tendencies. These responses changed as the intensity was increased from 36·1015 quanta s-1 m-2 to 54 and 72·1015 quanta s-1 m-2. Conclusion The specific manifestation of responses in directions other than the migratory direction clearly depends on the ambient light regime. This implies that even when the mechanisms normally providing magnetic compass information seem disrupted, processes that are activated by light still control the behavior. It suggests complex interactions between different types of receptors, magnetic and visual. The nature of the receptors involved and details of

  1. Light-dependent magnetoreception in birds: increasing intensity of monochromatic light changes the nature of the response.

    PubMed

    Wiltschko, Roswitha; Stapput, Katrin; Bischof, Hans-Joachim; Wiltschko, Wolfgang

    2007-02-15

    The Radical Pair model proposes that magnetoreception is a light-dependent process. Under low monochromatic light from the short-wavelength part of the visual spectrum, migratory birds show orientation in their migratory direction. Under monochromatic light of higher intensity, however, they showed unusual preferences for other directions or axial preferences. To determine whether or not these responses are still controlled by the respective light regimes, European robins, Erithacus rubecula, were tested under UV, Blue, Turquoise and Green light at increasing intensities, with orientation in migratory direction serving as a criterion whether or not magnetoreception works in the normal way. The birds were well oriented in their seasonally appropriate migratory direction under 424 nm Blue, 502 nm Turquoise and 565 nm Green light of low intensity with a quantal flux of 8 x 10(15) quanta s(-1) m(-2), indicating unimpaired magnetoreception. Under 373 nm UV of the same quantal flux, they were not oriented in migratory direction, showing a preference for the east-west axis instead, but they were well oriented in migratory direction under UV of lower intensity. Intensities of above 36 x 10(15) quanta s(-1) m(-2) of Blue, Turquoise and Green light elicited a variety of responses: disorientation, headings along the east-west axis, headings along the north-south axis or 'fixed' direction tendencies. These responses changed as the intensity was increased from 36 x 10(15) quanta s(-1) m(-2) to 54 and 72 x 10(15) quanta s(-1) m(-2). The specific manifestation of responses in directions other than the migratory direction clearly depends on the ambient light regime. This implies that even when the mechanisms normally providing magnetic compass information seem disrupted, processes that are activated by light still control the behavior. It suggests complex interactions between different types of receptors, magnetic and visual. The nature of the receptors involved and details of

  2. ARSA accelerator - small-size source of nanosecond pulses of electron and x-ray radiation

    SciTech Connect

    Elyash, S.L.; Alexandrin, A.I.; Donskoy, E.N.

    1993-12-31

    ARSA miniature accelerator is notable for high intensity of radiation and characteristics stability. Near the output window the electron an x ray dose in the air constitutes in a 10 ns pulse 3 x 10{sup 4} Gy and 3 Gy, respectively. Maximal electron and x-ray quanta energy of 700 keV provides high permeability. Dimensions of the accelerator high-voltage unit are small: 250 x 1000 mm and 50 kg weight. It operates in a single pulse regime or generates a pulse series according to the specified program.

  3. Emission of electrons with energies from 10/sup 4/ to 10/sup 5/ eV upon the fracture of. gamma. -irradiated NaCl crystals

    SciTech Connect

    Khrustalev, Yu.A.; Serdyuk, O.M.; Savenko, V.I.; Bardyshev, I.I.; Deryagin, B.V.

    1986-11-01

    The influence of gamma quanta (in doses up to 100 Mrd) on the parameters of the emission of high-energy electrons upon the fracture of preliminarily irradiated samples of sodium chloride has been studied. No correlation between the concentration of the F color centers, which is linearly dependent on the dose, and the flux of electrons emitted by the freshly formed surface has been discovered. The appearance of vacancy lattice defects of a type more complicated than F centers upon irradiation has an effect on the process of fracture of the crystal, which results in considerable changes in the parameters of the electrons emitted.

  4. Cavity sideband cooling of a single trapped ion.

    PubMed

    Leibrandt, David R; Labaziewicz, Jaroslaw; Vuletić, Vladan; Chuang, Isaac L

    2009-09-04

    We report a demonstration and quantitative characterization of one-dimensional cavity cooling of a single trapped (88)Sr(+) ion in the resolved-sideband regime. We measure the spectrum of cavity transitions, the rates of cavity heating and cooling, and the steady-state cooling limit. The cavity cooling dynamics and cooling limit of 22.5(3) motional quanta, limited by the moderate coupling between the ion and the cavity, are consistent with a simple model [Phys. Rev. A 64, 033405 (2001)] without any free parameters, validating the rate equation model for cavity cooling.

  5. Nondestructive identification of isotopes using nuclear resonance fluorescence

    SciTech Connect

    Shizuma, Toshiyuki; Hayakawa, Takehito; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Ohgaki, Hideaki; Toyokawa, Hiroyuki

    2012-01-15

    Nondestructive identification of heavy isotopes concealed in a thick iron box has been demonstrated by using nuclear resonance fluorescence. A quasi-monochromatic photon beam produced by the collision of laser quanta with high energy electrons was used for resonant excitation of nuclear levels in {sup 206}Pb and {sup 208}Pb. By measuring the resonant {gamma} rays emitted from {sup 206}Pb and {sup 208}Pb, each of these isotopes were clearly identified. The ratio of the effective thickness, i.e., concentration distribution, of these isotopes was deduced from the relative intensities of the measured nuclear resonance fluorescence strengths.

  6. Multiphoton stimulated bremsstrahlung for broad (in the momentum representation) electron wave packets in an ultrashort laser pulse field

    SciTech Connect

    Burenkov, I. A.; Tikhonova, O. V.

    2010-06-15

    We consider features of absorption and emission of external laser field quanta by a broad (in the momentum representation) electron wave packet during its scattering from a potential center. Various scattering modes for the electron wave packet in a high-intensity laser field are analyzed using perturbation theory of potential energy. It is found that the absorption of laser field energy by an electron is substantially more effective as compared to the case of a plane wave. The important role of a number of interference effects associated with the large width of the initial electron momentum distribution is demonstrated.

  7. 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.

  8. POSSIBLE EXPERIMENTS ON WAVE FUNCTION LOCALIZATION DUE TO COMPTON SCATTERING

    SciTech Connect

    Aleksandrov, Alexander V; Danilov, Viatcheslav V; Gorlov, Timofey V; Liu, Yun; Shishlo, Andrei P; Nagaitsev,

    2013-01-01

    The reduction of a particle s wave function in the process of radiation or light scattering is a longstanding problem. Its solution will give a clue on processes that form, for example, wave functions of electrons constantly emitting synchrotron radiation quanta in storage rings. On a more global scale, it may shed light on wave function collapse due to the process of measurement. In this paper we consider various experimental options using Fermilab electron beams and a possible electron beam from the SNS linac and lasers to detect electron wave function change due to Compton scattering.

  9. Electrical conductivity of {gamma}-irradiated crystals of La{sub 0.95}Ba{sub 0.05}F{sub 2.95} superionic conductor

    SciTech Connect

    Sorokin, N. I. Sobolev, B. P.

    2012-03-15

    The electrical conductivity of single crystals of the La{sub 0.95}Ba{sub 0.05}F{sub 2.95} superionic conductor subjected to irradiation by {gamma} quanta (source {gamma}-{sup 60}Co, dose 2 Multiplication-Sign 10{sup 6} rad) has been investigated. It is shown that the radiation defects do not have a great effect on the ionic conductivity of nonstoichiometric La{sub 0.95}Ba{sub 0.05}F{sub 2.95} crystals, which is caused by the heterovalent replacements of La{sup 3+} cations with Ba{sup 2+} cations.

  10. Observation of Soliton Fusion in a Josephson Array

    SciTech Connect

    Pfeiffer, J.; Schuster, M.; Abdumalikov, A.A. Jr.; Ustinov, A.V.

    2006-01-27

    The behavior of topological solitons in a parallel array of a Josephson junction is studied experimentally. We observe the fusion of two relativistic 2{pi} solitons of the same polarity into a single 4{pi} soliton. The 4{pi} soliton carries two quanta of magnetic flux and, most strikingly, travels 18% faster than an ordinary 2{pi} soliton under the same driving force. We also find a variety of bunched states composed of 2{pi} solitons of the same polarity, moving with fixed separation.

  11. Entanglement generation in planar Penning traps

    SciTech Connect

    Martins, Ana M.; Mendonca, J. T.; Guerreiro, A.; Vieira, V. R.

    2010-07-15

    We investigate the generation of entanglement between the axial degrees of freedom of electrons confined in separated locations in planar Penning traps. We show that there are two different sources of entanglement: one is related with the mechanism of switching on and off the electrical coupling between the two electrons, and the other is due to the two-quanta-transition term of the coupling interaction. We show that the degree of entanglement can be controlled by adjusting the strength of the coupling between the traps and the time of interaction. We show that the coupled electrons behave as a temporal active interferometer.

  12. Estimation of {sup 237}U Level Density and Radiative Strength Functions from the (n-bar,{gamma}) Reaction

    SciTech Connect

    Sukhovoj, Anatoly M.; Khitrov, Valery A.; Maslov, Vladimir M.

    2009-01-28

    Intensity distribution of the primary {gamma}-transitions following resonance neutron capture in {sup 236}U about the mean value was approximated in different energy intervals of these quanta and neutrons. Extrapolation of the obtained functions to zero registration threshold of {gamma}-transitions allowed independent estimation of the expected level number of both parities for spin values J = 1/2, 3/2 and sum of radiative widths for both electric and magnetic gamma-transitions to levels with excitation energy up to {approx_equal}2.3 MeV.

  13. A new apparatus for the study of nuclear Bragg scattering

    SciTech Connect

    Siddons, D.P.; Hastings, J.B.; Faigel, G.

    1987-01-01

    A new monochromator system has been constructed which provides an energy resolution of 0.005 eV and an angular divergence of 0.4 arc seconds at an energy of 14.413 keV. In conjunction with a highly perfect crystal of isotopically enriched /sup 57/Fe/sub 2/O/sub 3/, a beam of nuclear resonant photons was extracted from the synchrotron continuum with signal to noise ratio of 100:1, and an intensity of >2 quanta/sec. 14 refs., 9 figs.

  14. Rotational Spectrum of a Dark State in 2-Fluoroethanol Using Microwave/ Radiofrequency-Infrared Multiple Resonance.

    DTIC Science & Technology

    1993-10-26

    the related compound 1,2- difluoroethane suggest that 2-fluoroethanol may also have high toxicity [19]. After the skimmer the molecular beam enters a 56...anharmonic shifts by using the experimentally determined anharmonicity of the C-C torsion in the relited 1,2- difluoroethane molecule in which the...number of C-C torsional quanta. A near linear behavior is observed for the C-C torsion in 1,2- difluoroethane [29]. One complication in the dynamics of 2

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

    NASA Astrophysics Data System (ADS)

    Borisov, A. Yu.

    2010-11-01

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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. Dynamics of quantum vortices in a quasi-two-dimensional Bose-Einstein condensate with two "holes"

    NASA Astrophysics Data System (ADS)

    Ruban, V. P.

    2017-04-01

    The dynamics of interacting quantum vortices in a quasi-two-dimensional spatially inhomogeneous Bose-Einstein condensate, whose equilibrium density vanishes at two points of the plane with a possible presence of an immobile vortex with a few circulation quanta at each point, has been considered in a hydrodynamic approximation. A special class of density profiles has been chosen, so that it proves possible to calculate analytically the velocity field produced by point vortices. The equations of motion have been given in a noncanonical Hamiltonian form. The theory has been generalized to the case where the condensate forms a curved quasi-two-dimensional shell in the three-dimensional space.

  1. Fast scintillation light from CaMoO4 crystals

    NASA Astrophysics Data System (ADS)

    Veresnikova, A. V.; Lubsandorzhiev, B. K.; Barabanov, I. R.; Grabmayr, P.; Greiner, D.; Jochum, J.; Knapp, M.; Oßwald, C.; Poleshuk, R. V.; Ritter, F.; Shaibonov, B. A. M.; Vyatchin, Y. E.; Meierhofer, G.

    2009-05-01

    We report the observation of multi-exponential scintillation light emission from a CaMoO4 crystal with slow and fast components after both α-particles or γ-quanta irradiation. The slow components with decay times of ˜5 and ˜15 μs produce the main contribution to the light yield. Whereas the fast components with ˜10-50 ns decay times observed for the first time with such a crystal at room temperature contribute <1% to the crystal total light yield.

  2. Effects of nitrogen source and UV radiation on the growth, chlorophyll fluorescence and fatty acid composition of Phaeodactylum tricornutum and Chaetoceros muelleri (Bacillariophyceae).

    PubMed

    Liang, Ying; Beardall, John; Heraud, Philip

    2006-03-01

    Cultures of the marine diatoms Phaeodactylum tricornutum and Chaetoceros muelleri were grown in f/2 medium supplied with either nitrate (N-Nt), ammonium (N-Am) or urea (N-Ur) as the nitrogen (N) source at the same final N concentration (0.88 mM). Exponential growth phase cultures of the two diatoms were exposed to four different light regimes for 2 days: (UVAR) PAR (60 micromol quanta m-2 s-1) plus 8.22 W m-2 (unweighted) UVAR; (high UVBR) PAR (60 micromol quanta m-2 s-1) plus 1.04 W m-2 (unweighted) UVBR plus 13.73 W m-2 (unweighted) UVAR; (low UVBR) PAR (60 micromol quanta m-2 s-1) plus 0.19 W m-2 (unweighted) UVBR plus 2.76 W m-2 (unweighted) UVAR and (PAR) PAR (60 micromol quanta m-2 s-1) alone (control). No significant effects of N source on the growth rates of the two diatoms were detected. The maximum effective quantum yield of PSII, PhiPSIIe-max, and the initial slope of the light curve, alpha, of P. tricornutum and C. muelleri were all inhibited, whereas Ik was somewhat increased, as a consequence of 2 days of exposure to all the UVR treatments. Multiple factor ANOVA revealed that all the major fatty acids, both in P. tricornutum and C. muelleri, were influenced more strongly by N source than by UVR. The composition of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) in P. tricornutum and C. muelleri exhibited almost the same pattern of variation with N source and UVR. The maximum value of SFA was found in the N-Am treatment, that of MUFA in the N-Nt treatment and for PUFA in the N-Ur treatment irrespective of the UV radiation. On the other hand, the impact of UVR resulted in an increase of PUFA and a reduction of SFA both in P. tricornutum and C. muelleri under all N sources.

  3. Long-term survival of decentralized axons and incorporation of satellite cells in motor neurons of rock lobsters.

    PubMed

    Atwood, H L; Dudel, J; Feinstein, N; Parnas, I

    1989-06-19

    Previous electrophysiological experiments have shown that in the abdominal extensor muscles of rock lobsters, axons which were cut in surviving animals do not degenerate peripherally for several months, but conduct action potentials and release transmitter quanta on stimulation closely distal to the scar. Electron micrographs from the axon distal to the scar (in a reliably conducting region) show invasion of the axoplasmic space by nucleated cells, probably glia. After several months, the cell membranes of the invaders have vanished and apparently functional multiple nuclei remain. We suggest that decentralized axons may survive for months with the help of 'donated' nuclei.

  4. Dirac

    NASA Astrophysics Data System (ADS)

    Kragh, Helge

    2005-07-01

    Preface; 1. Early years; 2. Discovery of quantum mechanics; 3. Relativity and spinning electrons; 4. Travels and thinking; 5. The dream of philosophers; 6. Quanta and fields; 7. Fifty years of a physicist's life; 8. 'The so-called quantum electrodynamics'; 9. Electrons and ether; 10. Just a disappointment; 11. Adventures in cosmology; 12. The purest soul; 13. Philosophy in physics; 14. The principle of mathematical beauty; Appendices; Bibliography of P. A. M. Dirac; Notes and references; General bibliography; Index of names; Index of subjects.

  5. 3D Sisyphus Cooling of Trapped Ions

    NASA Astrophysics Data System (ADS)

    Ejtemaee, S.; Haljan, P. C.

    2017-07-01

    Using a laser polarization gradient, we realize 3D Sisyphus cooling of Yb+ 171 ions confined in and near the Lamb-Dicke regime in a linear Paul trap. The cooling rate and final mean motional energy of a single ion are characterized as a function of laser intensity and compared to semiclassical and quantum simulations. Sisyphus cooling is also applied to a linear string of four ions to obtain a mean energy of 1-3 quanta for all vibrational modes, an approximately order of magnitude reduction below Doppler cooled energies. This is used to enable subsequent, efficient sideband laser cooling.

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

    NASA Astrophysics Data System (ADS)

    Cockett, Martin C.; Watkins, Mark J.

    2004-01-01

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

  7. Magnonic Black Holes.

    PubMed

    Roldán-Molina, A; Nunez, Alvaro S; Duine, R A

    2017-02-10

    We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons-the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.

  8. Dark-energy thermodynamic models

    SciTech Connect

    Besprosvany, Jaime; Izquierdo, German

    2010-12-07

    We study cosmological consequences of dark-energy thermodynamic models. The assumption that dark energy is conformed of quanta, and an extensivity argument generalize its equation of state. This implies that dark energy and another key component exchange energy. The energy densities of dark energy and the other component then tend asymptotically to a constant, thus explaining the coincidence of dark matter and dark energy today. On the other hand, a model of non-relativistic particles in a Bose-Einstein condensate, with a short-range attractive interaction, produces acceleration. It is shown that the phantom-acceleration regime, at the beginning of the universe, solves the horizon problem.

  9. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2006-06-01

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

  11. Generation of two-mode squeezed states for two separated atomic ensembles via coupled cavities

    SciTech Connect

    Zheng Shibiao; Yang Zhenbiao; Xia Yan

    2010-01-15

    We propose an efficient scheme for the generation of two-mode squeezed states for two separated atomic ensembles trapped in distant cavities. The scheme is based on selective couplings between the collective atomic modes and two linearly transformed common field modes mediated by an optical fiber or a third cavity. The quanta of the transformed atomic modes are exhausted due to the linear coupling with the transformed field modes, bringing the original atomic modes into the two-mode squeezed states. The experimental implementation of the scheme would be an important step toward quantum communication and networking with continuous variables.

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

    SciTech Connect

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

    2014-12-15

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

  13. Noiseless Quantum Measurement and Squeezing of Microwave Fields Utilizing Mechanical Vibrations.

    PubMed

    Ockeloen-Korppi, C F; Damskägg, E; Pirkkalainen, J-M; Heikkilä, T T; Massel, F; Sillanpää, M A

    2017-03-10

    A process which strongly amplifies both quadrature amplitudes of an oscillatory signal necessarily adds noise. Alternatively, if the information in one quadrature is lost in phase-sensitive amplification, it is possible to completely reconstruct the other quadrature. Here we demonstrate such a nearly perfect phase-sensitive measurement using a cavity optomechanical scheme, characterized by an extremely small noise less than 0.2 quanta. The device also strongly squeezes microwave radiation by 8 dB below vacuum. A source of bright squeezed microwaves opens up applications in manipulations of quantum systems, and noiseless amplification can be used even at modest cryogenic temperatures.

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

    NASA Astrophysics Data System (ADS)

    Yang, Chun-Wei; Hwang, Tzonelih

    2013-11-01

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

  15. J-PET detector system for studies of the electron-positron annihilations

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    Jagiellonian Positron Emission Tomograph (J-PET) has been recently constructed at the Jagiellonian University as a prototype of a cost-effective scanner for the metabolic imaging of the whole human body. J-PET detector is optimized for the measurement of momentum and polarization of photons from the electron-positron annihilations. It is built out of strips of plastic scintillators, forming three cylindrical layers. As detector of gamma quanta it will be used for studies of discrete symmetries and multiparticle entanglement of photons originating from the decays of ortho-positronium atoms.

  16. 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

    2016-07-20

    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.

  17. In search of the black swans

    NASA Astrophysics Data System (ADS)

    Buchanan, Mark

    2009-04-01

    In 1890 an electricity company enticed the German physicist Max Planck to help it in its efforts to make more efficient light bulbs. Planck, as a theorist, naturally started with the fundamentals and soon became enmeshed in the thorny problem of explaining the spectrum of black-body radiation, which he eventually did by introducing the idea - a "purely formal" assumption, as he then considered it - that electromagnetic energy can only be emitted or absorbed in discrete quanta. The rest is history. Electric light bulbs and mathematical necessity led Planck to discover quantum theory and to kick start the most significant scientific revolution of the 20th century.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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).

  4. Modeling a Living Cell as a Physical System

    NASA Astrophysics Data System (ADS)

    Finkel, Robert

    2003-11-01

    The organization and synchrony of a living cell suggests that a cooperative process may enable the cell to act as a unit for some functions. This is an old and unproven idea, although some findings seem to be best interpreted as cooperative behavior. Here we propose a model based on cooperative behavior originating from metabolism-behavior not immediately evident from the component molecules or biochemical sequences. The model follows from treating energy cycles as quantum oscillators that give rise to associated chemical waves and quanta much as lattice vibrations in solids give rise to phonons. Model parameters are determined from established data for a specific bacterium. We find average wavelengths for the quanta of chemical oscillations are 115 nm at 310 K agreeing closely with the diameter of the smallest free-living cells. We analyze experimental results where yeast cells experienced resonant changes in growth at specific microwave frequencies. These frequencies are accurately reproduced with the model and other critical frequencies are predicted.

  5. Old and new research on the Absolute Parallelism theory

    NASA Astrophysics Data System (ADS)

    Zhogin, I. L.

    2004-12-01

    Compatible equations, Singularities of solutions, Topological charges and quasi-charges. PhD thesis (translated frorm Russian). The book shows the sights of Absolute Parallelism (AP), and contains useful information on the problem of singularities, compatibility theory, homotopy groups (also relative and k-ad), topological quasi-charge groups and their morphisms. AP is a single (frame) field theory proposed by Einstein some 80 years ago; it embraces symmetries of both Special and General Relativity. The compatibility theory, if applied to the cases when the frame matrix degenerates, gives a covariant test on singularities of solutions. This gives a single variant (missed in Einstein-Mayer's list of compatible equations), the unique 5D equation (nothing, nor D, can be changed), which solutions are free of emerging singularities. SO4-symmetrical nonstationary solutions give rise to a cosmological model (relativistic surfing; anti-Milne model in FRW framework) with a specific reduction of the extra-dimension. Topological classification of localized field configurations, combinatorics of topological quasi-charges (quanta), is discussed in an attempt to imagine the Standard Model (and quantum theory itself; and, perhaps, to make some qualitative predictions, like the absence of spin zero elementary quanta).

  6. Cosmic ray contribution in extragalactic background gamma-ray emission at an energy of 0.1 TeV

    NASA Astrophysics Data System (ADS)

    Uryson, Anna

    2017-06-01

    We estimate the intensity of gamma-quanta at the energy 0.1 TeV that is generated in extragalactic space in interactions of ultra-high energy cosmic rays with the cosmic background emission. Energy of 0.1 TeV is chosen because the Universe is mostly transparent for these quanta. In the paper three types of cosmic ray sources are analyzed: objects with red shifts up to z = 1.1 having monoenergetic particle spectra, E = 1021 eV; the same objects with exponential particle spectra; objects with red shifts 0 < z ≤ 0.0092 i.e. located at distances less than ≈ 50 Mpc, also with exponential particle spectra. It is found that the cosmic ray contribution in extragalactic background emission at 0.1 TeV ranges from f ≤ 10-4 to f ≈ 0.1 depending on the source characteristics. Thus the cosmic ray contribution in extragalactic background emission can be used for studying cosmic ray sources.

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

    PubMed

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

    2015-10-01

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

  8. 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 PAGES

    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

  9. 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 }.

  10. Solar cosmic ray bursts and solar neutrino fluxes

    NASA Technical Reports Server (NTRS)

    Basilevakaya, G. A.; Nikolsky, S. I.; Stozhkov, Y. I.; Charakhchyan, T. N.

    1985-01-01

    The neutrino flux detected in the C1-Ar experiment seems to respond to the powerful solar cosmic ray bursts. The ground-based detectors, the balloons and the satellites detect about 50% of the bursts of soalr cosmic ray generated on the Sun's visible side. As a rule, such bursts originate from the Western side of the visible solar disk. Since the solar cosmic ray bursts are in opposite phase withthe 11-year galactic cosmic ray cycle which also seems to be reflected by neutrino experiment. The neutrino generation in the bursts will flatten the possible 11-year behavior of the AR-37 production rate, Q, in the Cl-Ar experiment. The detection of solar-flare-generated gamma-quanta with energies above tens of Mev is indicative of the generation of high-energy particles which in turn may produce neutrinos. Thus, the increased Q during the runs, when the flare-generated high energy gamma-quanta have been registered, may be regarded as additional evidence for neutrino geneation in the solar flare processes.

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

    NASA Astrophysics Data System (ADS)

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

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

  12. Suppression of the Landau-Zener transition probability by weak classical noise

    NASA Astrophysics Data System (ADS)

    Malla, Rajesh K.; Mishchenko, E. G.; Raikh, M. E.

    2017-08-01

    When the drive, which causes the level crossing in a qubit, is slow, the probability PL Z of the Landau-Zener transition is close to 1. In this regime, which is most promising for applications, the noise due to the coupling to the environment reduces the average PL Z. At the same time, the survival probability, 1 -PL Z , which is exponentially small for a slow drive, can be completely dominated by noise-induced correction. Our main message is that the effect of weak classical noise can be captured analytically by treating it as a perturbation in the Schrödinger equation. This allows us to study the dependence of the noise-induced correction to PL Z on the correlation time of the noise. As this correlation time exceeds the bare Landau-Zener transition time, the effect of noise becomes negligible. On the physical level, the mechanism of enhancement of the survival probability can be viewed as an absorption of the "noise quanta" across the gap. With characteristic energy of the quantum governed by the noise spectrum, the slower the noise is, the lower the number of quanta for which absorption is allowed energetically is. We consider two conventional realizations of noise: Gaussian noise and telegraph noise.

  13. Quantum entanglement of angular momentum states with quantum numbers up to 10,010

    PubMed Central

    Fickler, Robert; Campbell, Geoff; Buchler, Ben; Lam, Ping Koy; Zeilinger, Anton

    2016-01-01

    Photons with a twisted phase front carry a quantized amount of orbital angular momentum (OAM) and have become important in various fields of optics, such as quantum and classical information science or optical tweezers. Because no upper limit on the OAM content per photon is known, they are also interesting systems to experimentally challenge quantum mechanical prediction for high quantum numbers. Here, we take advantage of a recently developed technique to imprint unprecedented high values of OAM, namely spiral phase mirrors, to generate photons with more than 10,000 quanta of OAM. Moreover, we demonstrate quantum entanglement between these large OAM quanta of one photon and the polarization of its partner photon. To our knowledge, this corresponds to entanglement with the largest quantum number that has been demonstrated in an experiment. The results may also open novel ways to couple single photons to massive objects, enhance angular resolution, and highlight OAM as a promising way to increase the information capacity of a single photon. PMID:27856742

  14. 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.

  15. Nonperturbative production of matter and rapid thermalization after MSSM inflation

    NASA Astrophysics Data System (ADS)

    Allahverdi, Rouzbeh; Ferrantelli, Andrea; Garcia-Bellido, Juan; Mazumdar, Anupam

    2011-06-01

    A gauge invariant combination of LLe sleptons within the minimal supersymmetric standard model is one of the few inflaton candidates that can naturally explain population of the observable sector and creation of matter after inflation. After the end of inflation, the inflaton oscillates coherently about the minimum of its potential, which is a point of enhanced gauged symmetry. This results in bursts of nonperturbative production of the gauge/gaugino and (s)lepton quanta. The subsequent decay of these quanta is very fast and leads to an extremely efficient transfer of the inflaton energy to (s)quarks via instant preheating. Around 20% of the inflaton energy density is drained during every inflaton oscillation. However, all of the standard model degrees of freedom (and their supersymmetric partners) do not thermalize immediately, since the large inflaton vacuum expectation value breaks the electroweak symmetry. After about 100 oscillations—albeit within one Hubble time—the amplitude of inflaton oscillations becomes sufficiently small, and all of the degrees of freedom will thermalize. This provides by far the most efficient reheating of the universe with the observed degrees of freedom.

  16. 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.

  17. 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.

  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

    2013-05-05

    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. Experimental Investigations of Changes in β-Decay Rate of 60Co and 137Cs

    NASA Astrophysics Data System (ADS)

    Baurov, Yu. A.; Konradov, A. A.; Kushniruk, V. F.; Kuznetsov, E. A.; Sobolev, Yu. G.; Ryabov, Yu. V.; Senkevich, A. P.; Zadorozsny, S. V.

    Results of simultaneous measurements of β-decay rate with the aid of Ge(Li)-detectors performed at two laboratories 140 km apart (INR RAS, Troitsk, 60Co, and JINR, Dubna, 137Cs) from 15 March 2000 to 10 April 2000 are presented. Regular deviations of the count rate of γ-quanta following the β-decay of ~0.7% (INR RAS, 60Co) and ~0.2% (JINR, 137Cs) from the statistical average, are observed. The analysis of extremum deviations of γ--quanta count rate shows that the set of directions of tangents to the Earth's parallels of latitude at the extremum points of trajectories of motion in the space of each laboratory clearly forms three separate compact subsets of directions which agree, for two laboratories, to an accuracy of +/-10°. This phenomenon is shown not to be explained on the basis of traditional notion. A possible explanation is suggested based on the hypothesis that there exists a new anisotropic interaction caused by the cosmological vectorial potential Ag, a new fundamental constant having, according to the experiments carried out, the coordinate of right ascension α ~ 285° in the second equatorial system. This is in agreement with earlier experiments.

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

    PubMed

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

    2016-04-01

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

  1. Superluminal radiation by uniformly moving charges

    NASA Astrophysics Data System (ADS)

    Tomaschitz, Roman

    2003-03-01

    The emission of superluminal quanta (tachyons) by freely propagating particles is scrutinized. Estimates are derived for spontaneous superluminal radiation from electrons moving close to the speed of the Galaxy in the microwave background. This is the threshold velocity for tachyon radiation to occur, a lower bound. Quantitative estimates are also given for the opposite limit, tachyon radiation emitted by ultra-relativistic electrons in linear colliders and supernova shock waves. The superluminal energy flux is studied and the spectral energy density of the radiation is derived, classically as well as in second quantization. There is a transversal bosonic and a longitudinal fermionic component of the radiation. We calculate the power radiated, its angular dependence, the mean energy of the radiated quanta, absorption and emission rates, as well as tachyonic number counts. We explain how the symmetry of the Einstein /A-coefficients connects to time-symmetric wave propagation and to the Wheeler-Feynman absorber theory. A relation between the tachyon mass and the velocity of the Local Group of galaxies is suggested.

  2. 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

    SciTech Connect

    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 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 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°.

  3. Quantum Synchronization Blockade: Energy Quantization Hinders Synchronization of Identical Oscillators.

    PubMed

    Lörch, Niels; Nigg, Simon E; Nunnenkamp, Andreas; Tiwari, Rakesh P; Bruder, Christoph

    2017-06-16

    Classically, the tendency towards spontaneous synchronization is strongest if the natural frequencies of the self-oscillators are as close as possible. We show that this wisdom fails in the deep quantum regime, where the uncertainty of amplitude narrows down to the level of single quanta. Under these circumstances identical self-oscillators cannot synchronize and detuning their frequencies can actually help synchronization. The effect can be understood in a simple picture: Interaction requires an exchange of energy. In the quantum regime, the possible quanta of energy are discrete. If the extractable energy of one oscillator does not exactly match the amount the second oscillator may absorb, interaction, and thereby synchronization, is blocked. We demonstrate this effect, which we coin quantum synchronization blockade, in the minimal example of two Kerr-type self-oscillators and predict consequences for small oscillator networks, where synchronization between blocked oscillators can be mediated via a detuned oscillator. We also propose concrete implementations with superconducting circuits and trapped ions. This paves the way for investigations of new quantum synchronization phenomena in oscillator networks both theoretically and experimentally.

  4. 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.

  5. Quantum Synchronization Blockade: Energy Quantization Hinders Synchronization of Identical Oscillators

    NASA Astrophysics Data System (ADS)

    Lörch, Niels; Nigg, Simon E.; Nunnenkamp, Andreas; Tiwari, Rakesh P.; Bruder, Christoph

    2017-06-01

    Classically, the tendency towards spontaneous synchronization is strongest if the natural frequencies of the self-oscillators are as close as possible. We show that this wisdom fails in the deep quantum regime, where the uncertainty of amplitude narrows down to the level of single quanta. Under these circumstances identical self-oscillators cannot synchronize and detuning their frequencies can actually help synchronization. The effect can be understood in a simple picture: Interaction requires an exchange of energy. In the quantum regime, the possible quanta of energy are discrete. If the extractable energy of one oscillator does not exactly match the amount the second oscillator may absorb, interaction, and thereby synchronization, is blocked. We demonstrate this effect, which we coin quantum synchronization blockade, in the minimal example of two Kerr-type self-oscillators and predict consequences for small oscillator networks, where synchronization between blocked oscillators can be mediated via a detuned oscillator. We also propose concrete implementations with superconducting circuits and trapped ions. This paves the way for investigations of new quantum synchronization phenomena in oscillator networks both theoretically and experimentally.

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

    PubMed

    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

    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 [Formula: see text] decays with angular and energy resolution equal to [Formula: see text] and [Formula: see text], 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.

  7. Influences of Variations of Characteristic Parameters of Protein Molecules on States of Soliton Transported Bio-Energy

    NASA Astrophysics Data System (ADS)

    Pang, Xiao-Feng; Zhang, Huai-Wu; Yu, Jia-Feng; Luo, Yu-Hui

    We simulate numerically the dynamic properties of new soliton with quasi-coherent two quanta in the improved model by fourth-order Runge-Kutta way. We observed that the window of formation of new soliton is shifted toward smaller values of coupling constants when compared with the Davydov's soliton with one quantum and Förner's soliton with two quantum model. The new soliton formation starts at (χ1+χ2)=20 PN, and pinning starts from (χ1+χ2)=86 PN. The pinned solitons are also observed if both quanta are on the same end of the chain in the initial state. The behaviors of new soliton are varied under influences for variations of characteristic parameters arising from the structure nonuniformity of protein molecules. Although the new soliton is also sensitive to the dipole-dipole interaction and diagonal disorder, the sensitivity to the impurity is weaker than that of the Davydov's and Förner's solitons. Therefore, the new soliton is robust against the fluctuations of coupled constant, dipole-dipole interaction and diagonal disorder arising from the impurity or structure nonuniformity, when compared with that of the Davydov's and Förner's solitons.

  8. Ten shades of black

    NASA Astrophysics Data System (ADS)

    Hod, Shahar

    2015-09-01

    The holographic principle has taught us that, as far as their entropy content is concerned, black holes in (3 + 1)-dimensional curved spacetimes behave as ordinary thermodynamic systems in flat (2 + 1)-dimensional spacetimes. In this paper, we point out that the opposite behavior can also be observed in black-hole physics. To show this we study the quantum Hawking evaporation of near-extremal Reissner-Nordström (RN) black holes. We first point out that the black-hole radiation spectrum departs from the familiar radiation spectrum of genuine (3 + 1)-dimensional perfect black-body emitters. In particular, the would be black-body thermal spectrum is distorted by the curvature potential which surrounds the black-hole and effectively blocks the emission of low-energy quanta. Taking into account the energy-dependent gray-body factors which quantify the imprint of passage of the emitted radiation quanta through the black-hole curvature potential, we reveal that the (3 + 1)-dimensional black holes effectively behave as perfect black-body emitters in a flat (9 + 1)-dimensional spacetime.

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

    SciTech Connect

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

    1995-12-31

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

  11. The MARS15-based FermiCORD Code System for Calculation of the Accelerator-Induced Residual Dose

    SciTech Connect

    Grebe, A.; Leveling, A.; Lu, T.; Mokhov, N.; Pronskikh, V.

    2016-09-01

    The FermiCORD code system, a set of codes based on MARS15 that calculates the accelerator-induced residual doses at experimental facilities of arbitrary configurations, has been developed. FermiCORD is written in C++ as an add-on to Fortran-based MARS15. The FermiCORD algorithm consists of two stages: 1) simulation of residual doses on contact with the surfaces surrounding the studied location and of radionuclide inventories in the structures surrounding those locations using MARS15, and 2) simulation of the emission of the nuclear decay gamma-quanta by the residuals in the activated structures and scoring the prompt doses of these gamma-quanta at arbitrary distances from those structures. The FermiCORD code system has been benchmarked against similar algorithms based on other code systems and showed a good agreement. The code system has been applied for calculation of the residual dose of the target station for the Mu2e experiment and the results have been compared to approximate dosimetric approaches.

  12. 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

  13. Quantum entanglement of angular momentum states with quantum numbers up to 10,010

    NASA Astrophysics Data System (ADS)

    Fickler, Robert; Campbell, Geoff; Buchler, Ben; Lam, Ping Koy; Zeilinger, Anton

    2016-11-01

    Photons with a twisted phase front carry a quantized amount of orbital angular momentum (OAM) and have become important in various fields of optics, such as quantum and classical information science or optical tweezers. Because no upper limit on the OAM content per photon is known, they are also interesting systems to experimentally challenge quantum mechanical prediction for high quantum numbers. Here, we take advantage of a recently developed technique to imprint unprecedented high values of OAM, namely spiral phase mirrors, to generate photons with more than 10,000 quanta of OAM. Moreover, we demonstrate quantum entanglement between these large OAM quanta of one photon and the polarization of its partner photon. To our knowledge, this corresponds to entanglement with the largest quantum number that has been demonstrated in an experiment. The results may also open novel ways to couple single photons to massive objects, enhance angular resolution, and highlight OAM as a promising way to increase the information capacity of a single photon.

  14. Magnetic-field-influenced nonequilibrium transport through a quantum ring with correlated electrons in a photon cavity

    NASA Astrophysics Data System (ADS)

    Arnold, Thorsten; Tang, Chi-Shung; Manolescu, Andrei; Gudmundsson, Vidar

    2013-01-01

    We investigate magnetic-field-influenced time-dependent transport of Coulomb interacting electrons through a two-dimensional quantum ring in an electromagnetic cavity under nonequilibrium conditions described by a time-convolutionless non-Markovian master equation formalism. We take into account the full electromagnetic interaction of electrons and cavity photons. A bias voltage is applied to semi-infinite leads along the x axis, which are connected to the quantum ring. The magnetic field is tunable to manipulate the time-dependent electron transport coupled to a photon field with either x or y polarization. We find that the lead-system-lead current is strongly suppressed by the y-polarized photon field at magnetic field with two flux quanta due to a degeneracy of the many-body energy spectrum of the mostly occupied states. On the other hand, the lead-system-lead current can be significantly enhanced by the y-polarized field at magnetic field with half-integer flux quanta. Furthermore, the y-polarized photon field perturbs the periodicity of the persistent current with the magnetic field and suppresses the magnitude of the persistent current. The spatial and temporal density distributions reflect the characteristics of the many-body spectrum. The vortex formation in the contact areas to the leads influences the charge circulation in the ring.

  15. Kinetics of neurotransmitter release in neuromuscular synapses of newborn and adult rats.

    PubMed

    Khuzakhmetova, Venera; Samigullin, Dmitry; Nurullin, Leniz; Vyskočil, Frantisek; Nikolsky, Evgeny; Bukharaeva, Ellya

    2014-05-01

    The kinetics of the phasic synchronous and delayed asynchronous release of acetylcholine quanta was studied at the neuromuscular junctions of aging rats from infant to mature animals at various frequencies of rhythmic stimulation of the motor nerve. We found that in infants 6 (P6) and 10 (P10) days after birth a strongly asynchronous phase of quantal release was observed, along with a reduced number of quanta compared to the synapses of adults. The rise time and decay of uni-quantal end-plate currents were significantly longer in infant synapses. The presynaptic immunostaining revealed that the area of the synapses in infants was significantly (up to six times) smaller than in mature junctions. The intensity of delayed asynchronous release in infants increased with the frequency of stimulation more than in adults. A blockade of the ryanodine receptors, which can contribute to the formation of delayed asynchronous release, had no effect on the kinetics of delayed secretion in the infants unlike synapses of adults. Therefore, high degree of asynchrony of quantal release in infants is not associated with the activity of ryanodine receptors and with the liberation of calcium ions from intracellular calcium stores. Copyright © 2014 ISDN. Published by Elsevier Ltd. All rights reserved.

  16. 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.

  17. 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

  18. 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.

  19. Multiple x-ray bursts from long discharges in air

    NASA Astrophysics Data System (ADS)

    Nguyen, C. V.; van Deursen, A. P. J.; Ebert, U.

    2008-12-01

    A lightning surge generator generates a high-voltage surge with a 1.2 µs rise time. The generator fed a spark gap of two pointed electrodes at 0.7 to 1.2 m distances. Gap breakdown occurred between 0.1 and 3 µs after the maximum generator voltage of approximately 850 kV. Various scintillator detectors with different response times recorded bursts of hard radiation in nearly all surges. The bursts were detected over the time span between approximately half of the maximum surge voltage and full gap breakdown. The consistent timing of the bursts with the high-voltage surge excluded background radiation as the source for the high intensity pulses. In spite of the symmetry of the gap, negative surges produced more intense radiation than positive. This has been attributed to additional positive discharges from the measurement cabinet which occurred for negative surges. Some hard radiation signals were equivalent to several megaelectronvolts. Pile-up occurs of lesser energy x-ray quanta, but still with a large fraction of these with an energy of the order of 100 keV. The bursts occurred within the 4 ns time resolution of the fastest detector. The relation between the energy of the x-ray quanta and the signal from the scintillation detector is quite complicated, as shown by the measurements.

  20. Unidentified EGRET sources and their possible Fermi counterparts

    NASA Astrophysics Data System (ADS)

    Lyapin, A. R.; Arkhangelskaja, I. V.; Larin, D. S.

    2017-01-01

    Unidentified EGRET sources from 3EG catalog have been analyzed. Preliminary data analysis has shown at least 23 of these sources coincide with those in 3FGL Fermi catalogue within 1, 2 and 3 sigma error intervals of the coordinates and fluxes. Their properties are discussed in the presented work. Even 3-sigma difference allows supposing sources similarity because of more than 3-sigma distinctions in values of fluxes between identified EGRET sources and their Fermi counterparts. For instance, the coincidence between 3EG J1255-0549 and 3FGL J1256.1-0547 was reported in Fermi catalogues 1FGL, 2FGL, 3FGL. However, these sources fluxes (in units of 10‑8 photons × cm‑2 × s‑1) in the energy band E > 100 MeV were 179.7 ± 6.7 (3EG), 44.711 ± 0.724 (3FGL), 53.611 ± 0.997 (2FGL) and 67.939 ± 1.861 (1FGL). Such effect was observed for sufficient portion of identified EGRET sources. It could cause by troubles of particles identification by Fermi/LAT trigger system. Very often charged particles recognized as gamma-quanta because of wrong backsplash analysis. Nevertheless, gammas counts as charged particles due analogous reason and rejected during ground data processing. For example, it appears as geomagnetic modulation presence on gamma-quanta count rate latitudinal profiles in energy band E > 20 MeV.

  1. Polarization spectral synthesis for Type Ia supernova explosion models

    NASA Astrophysics Data System (ADS)

    Bulla, M.; Sim, S. A.; Kromer, M.

    2015-06-01

    We present a Monte Carlo radiative transfer technique for calculating synthetic spectropolarimetry for multidimensional supernova explosion models. The approach utilizes `virtual-packets' that are generated during the propagation of the Monte Carlo quanta and used to compute synthetic observables for specific observer orientations. Compared to extracting synthetic observables by direct binning of emergent Monte Carlo quanta, this virtual-packet approach leads to a substantial reduction in the Monte Carlo noise. This is not only vital for calculating synthetic spectropolarimetry (since the degree of polarization is typically very small) but also useful for calculations of light curves and spectra. We first validate our approach via application of an idealized test code to simple geometries. We then describe its implementation in the Monte Carlo radiative transfer code ARTIS and present test calculations for simple models for Type Ia supernovae. Specifically, we use the well-known one-dimensional W7 model to verify that our scheme can accurately recover zero polarization from a spherical model, and to demonstrate the reduction in Monte Carlo noise compared to a simple packet-binning approach. To investigate the impact of aspherical ejecta on the polarization spectra, we then use ARTIS to calculate synthetic observables for prolate and oblate ellipsoidal models with Type Ia supernova compositions.

  2. Determining the vibrational pattern via overtone cold spectra: C-H methyl stretches of propyne.

    PubMed

    Portnov, Alex; Bespechansky, Evgeny; Ganot, Yuval; Rosenwaks, Salman; Bar, Ilana

    2005-06-08

    Vibrationally mediated photodissociation and photoacoustic (PA) spectroscopy were employed for studying the intramolecular dynamics of propyne initially excited to the first through fourth overtone of methyl C-H stretching modes. Room-temperature PA and jet-cooled action spectra, monitoring the absorption of the parent and the yield of the ensuing H photofragments, respectively, were obtained. The PA spectra exhibit mainly broad features, while the action spectra, due to inhomogeneous structure reduction, expose multiple peaks of recognizable shapes in the differing overtone manifolds. Symmetric rotor simulations of the band contours of the action spectra allowed retrieving of band origins and linewidths. The linewidths of the bands in each manifold enabled estimates for energy redistribution times out of the corresponding states to the bath states, the times ranging from 18+/-6 ps for two quanta of C-H excitation to subpicosecond for five quanta. The data were also analyzed in terms of a normal-mode model and a joint local-/normal-mode model. These models enabled determination of harmonic frequencies, anharmonicities, and interaction parameters reproducing the observed data in all monitored regions and provided spectral assignments. The measured Doppler profiles were well fitted by Gaussians with widths suggesting low average translational energies for the released H photofragments. These low energies and their similarities to those for dissociation of propyne isotopomers preexcited to acetylenic C-H stretches were ascribed to an indirect dissociation process occurring after internal conversion to the ground electronic state and isomerization to allene.

  3. Fulling-Unruh effect in general stationary accelerated frames

    SciTech Connect

    Korsbakken, Jan Ivar; Leinaas, Jon Magne

    2004-10-15

    We study the generalized Unruh effect for accelerated reference frames that include rotation in addition to acceleration. We focus particularly on the case where the motion is planar, with the presence of a static limit in addition to the event horizon. Possible definitions of an accelerated vacuum state are examined and the interpretation of the Minkowski vacuum state as a thermodynamic state is discussed. Such a thermodynamic state is shown to depend on two parameters, the acceleration temperature and a drift velocity, which are determined by the acceleration and angular velocity of the accelerated frame. We relate the properties of the Minkowski vacuum in the accelerated frame to the excitation spectrum of a detector that is stationary in this frame. The detector can be excited both by absorbing positive energy quanta in the 'hot' vacuum state and by emitting negative energy quanta into the 'ergosphere' between the horizon and the static limit. The effects are related to similar effects in the gravitational field of a rotating black hole.

  4. Baryonic States in QCD From Gauge/String Duality at Large N{sub C}

    SciTech Connect

    De Teramond, G.

    2004-09-08

    We have computed the baryon spectrum in the framework of {Nu} = 4 super-conformal Yang-Mills theory using AdS/CFT duality. Baryons are included in the theory by adding an open string sector, corresponding to quarks in the fundamental representation of {Nu} = 4. The hadron mass scale is introduced by imposing boundary conditions at the AdS{sub 5} coordinate r{sub 0} = {Lambda}{sub QCD} R{sup 2}, which is the only parameter. The quantum numbers of each baryon, are identified by matching the fall-off of the string wavefunction {Psi}(x,r) at the asymptotic 3+1 boundary to the operator dimension of the lowest three-quark Fock state, subject to appropriate boundary conditions. Higher Fock states are matched quanta to quanta with quantum fluctuations of the bulk geometry about the AdS background. We limit our discussion to massless quarks. The resulting four-dimensional spectrum displays a remarkable resemblance to the physical baryon spectrum of QCD, including the suppression of spin-orbit interactions.

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

    SciTech Connect

    Semenov, Alexander; Babikov, Dmitri

    2014-01-28

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

  6. Pump and amplification dynamics of gamma rays in a nuclear medium with the hidden population inversion

    SciTech Connect

    Rivlin, Lev A

    2009-12-31

    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. (active media)

  7. Quantum entanglement of angular momentum states with quantum numbers up to 10,010.

    PubMed

    Fickler, Robert; Campbell, Geoff; Buchler, Ben; Lam, Ping Koy; Zeilinger, Anton

    2016-11-29

    Photons with a twisted phase front carry a quantized amount of orbital angular momentum (OAM) and have become important in various fields of optics, such as quantum and classical information science or optical tweezers. Because no upper limit on the OAM content per photon is known, they are also interesting systems to experimentally challenge quantum mechanical prediction for high quantum numbers. Here, we take advantage of a recently developed technique to imprint unprecedented high values of OAM, namely spiral phase mirrors, to generate photons with more than 10,000 quanta of OAM. Moreover, we demonstrate quantum entanglement between these large OAM quanta of one photon and the polarization of its partner photon. To our knowledge, this corresponds to entanglement with the largest quantum number that has been demonstrated in an experiment. The results may also open novel ways to couple single photons to massive objects, enhance angular resolution, and highlight OAM as a promising way to increase the information capacity of a single photon.

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

  9. Evaluation of thermal acclimation capacity in corals with different thermal histories based on catalase concentrations and antioxidant potentials.

    PubMed

    Griffin, Sean P; Bhagooli, Ranjeet; Weil, Ernesto

    2006-06-01

    Colonies of Pocillopora damicornis from Kaneohe Bay and colonies of Pocillopora meandrina from a thermal outfall site and a control site at Kahe were exposed to three different temperatures (29, 32 and 33 degrees C) in outdoor aquaria on running water tables for five days. Samples (n=3) were taken from each treatment at 0800, 1200 and 1600 h. ELISAs using catalase antibodies and ferric reducing/antioxidant potential (FRAP) assays were run on the samples to determine how antioxidant levels changed throughout the experiment. Light levels during the experiment were highest in the morning ( approximately 1000-1500 micromol quanta m(-2) s(-1)) and decreased to 25-60 micromol quanta m(-2) s(-1) by 1100 h and remained low until sunset. Antioxidant concentrations were highest in the morning for P. damicornis from Kaneohe and P. meandrina outfall samples. There was no significant change through the day for P. meandrina samples from the control site. The difference in response between the outfall samples and the control samples suggests that P. meandrina has acclimated to elevated temperatures found at the outfall site.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  11. 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.

  12. Monte Carlo framework for noncontinuous interactions between particles and classical fields.

    PubMed

    Wesp, Christian; van Hees, Hendrik; Meistrenko, Alex; Greiner, Carsten

    2015-04-01

    Particles and fields are standard components in numerical calculations like transport simulations in nuclear physics and have well-understood dynamics. Still, a common problem is the interaction between particles and fields due to their different formal description. Particle interactions are discrete, pointlike events while field dynamics is described with continuous partial-differential equations of motion. A workaround is the use of effective theories like the Langevin equation with the drawback of energy conservation violation. We present a method, which allows us to model noncontinuous interactions between particles and scalar fields, allowing us to simulate scattering-like interactions which exchange discrete "quanta" of energy and momentum between fields and particles while obeying energy and momentum conservation and allowing control over interaction strengths and times. In this paper we apply this method to different model systems, starting with a simple harmonic oscillator, which is damped by losing discrete energy quanta. The second and third system consists of an oscillator and a one-dimensional field, which are damped via discrete energy loss and are coupled to a stochastic force, leading to equilibrium states which correspond to statistical Langevin-like systems. The last example is a scalar field in (1 + 3) space-time dimensions, which is coupled to a microcanonical ensemble of particles by incorporating particle production and annihilation processes. Obeying the detailed-balance principle, the system equilibrates to thermal and chemical equilibrium with dynamical fluctuations on the fields, generated dynamically by the discrete interactions.

  13. 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.

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

    PubMed Central

    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

  15. 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.

  16. Synaptophysin (p38) at the frog neuromuscular junction: its incorporation into the axolemma and recycling after intense quantal secretion

    PubMed Central

    1988-01-01

    Recycling of synaptophysin (p38), a synaptic vesicle integral membrane protein, was studied by the use of antisera raised against the protein purified from frog brain. When frog cutaneous pectoris muscles were fixed at rest, a bright, specific immunofluorescent signal was observed in nerve-terminal regions only if their plasma membranes had been previously permeabilized. When muscles were fixed after they had been treated for 1 h with a low dose of alpha-latrotoxin in Ca2+-free medium, an equally intense fluorescence could be observed without previous permeabilization. Under this condition, alpha-latrotoxin depletes nerve terminals of their quantal store of acetylcholine and of synaptic vesicles. These results indicate that fusion of synaptic vesicles leads to the exposure of intravesicular antigenic determinants of synaptophysin on the outer surface of the axolemma, and provide direct support for the vesicle hypothesis of neurotransmitter release. After 1 h treatment with the same dose of alpha-latrotoxin in the presence of 1.8 mM extracellular Ca2+, immunofluorescent images were obtained only after permeabilization with detergents. Under this condition, the vesicle population was maintained by an active process of recycling and more than two times the initial store of quanta were secreted. Thus, despite the active turnover of synaptic vesicles and of quanta of neurotransmitter, no extensive intermixing occurs between components of the vesicle and presynaptic plasma membrane. PMID:3144557

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

    PubMed

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

    2013-04-01

    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. 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. 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. 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.

  18. 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.

  19. 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°.

  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. 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.

  2. 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

  3. A symmetry relating certain processes in 2-and 4-dimensional space-times and the value {alpha}{sub 0} = 1/4{pi} of the bare fine structure constant

    SciTech Connect

    Ritus, V. I.

    2006-04-15

    The symmetry manifests itself in exact relations between the Bogoliubov coefficients for processes induced by an accelerated point mirror in 1 + 1 dimensional space and the current (charge) densities for the processes caused by an accelerated point charge in 3 + 1 dimensional space. The spectra of pairs of Bose (Fermi) massless quanta emitted by the mirror coincide with the spectra of photons (scalar quanta) emitted by the electric (scalar) charge up to the factor e{sup 2}/{Dirac_h}c. The integral relation between the propagator of a pair of oppositely directed massless particles in 1 + 1 dimensional space and the propagator of a single particle in 3 + 1 dimensional space leads to the equality of the vacuum-vacuum amplitudes for the charge and the mirror if the mean number of created particles is small and the charge e = {radical}{Dirac_h}c. Due to the symmetry, the mass shifts of electric and scalar charges (the sources of Bose fields with spin 1 and 0 in 3 + 1 dimensional space) for the trajectories with a subluminal relative velocity {beta}{sub 12} of the ends and the maximum proper acceleration w{sub 0} are expressed in terms of the heat capacity (or energy) spectral densities of Bose and Fermi gases of massless particles with the temperature w{sub 0}/2{pi} in 1 + 1 dimensional space. Thus, the acceleration excites 1-dimensional oscillation in the proper field of a charge, and the energy of oscillation is partly deexcited in the form of real quanta and partly remains in the field. As a result, the mass shift of an accelerated electric charge is nonzero and negative, while that of a scalar charge is zero. The symmetry is extended to the mirror and charge interactions with the fields carrying spacelike momenta and defining the Bogoliubov coefficients {alpha}{sup B,F}. The traces tr{alpha}{sup B,F}, which describe the vector and scalar interactions of the accelerated mirror with a uniformly moving detector, were found in analytic form for two mirror trajectories

  4. Novel dual 'small' vesicle model of ATP- and noradrenaline-mediated sympathetic neuromuscular transmission.

    PubMed

    Stjärne, L

    2001-02-20

    triggers the twitch. The working hypothesis is proposed that these nerves use two classes of 'small vesicles' (SVs) to store and release either 'big' or 'small' ATP and noradrenaline 'quanta', and that differences in properties (Ca2+ affinity, capacity) of Ca2+ receptors in the SV membranes enable the nerves to selectively secrete 'big quanta' at low frequency and 'small quanta' during trains at high frequency.

  5. Performance evaluation of a novel chemiluminescence assay for detection of anti-GBM antibodies: an international multicenter study.

    PubMed

    Mahler, Michael; Radice, Antonella; Sinico, Renato A; Damoiseaux, Jan; Seaman, Andrea; Buckmelter, Kristen; Vizjak, Alenka; Buchner, Carol; Binder, Walter L; Fritzler, Marvin J; Cui, Zhao

    2012-01-01

    Autoantibodies to the non-collagen region (NC1) of the alpha-3 subunit of collagen IV represent a serological hallmark in the diagnosis of Goodpasture's syndrome (GPS). The objective of our study was to carefully analyze the performance characteristics of a novel anti-glomerular basement membrane (GBM) chemiluminescence immunoassay (CIA). Sera from patients with GPS (n = 90) were collected from four clinical centers. Samples from different disease groups (n = 397) and healthy individuals (n = 400) were used as controls. All samples were tested for anti-GBM antibodies by a rapid, random access CIA (QUANTA Flash™ GBM). Most of the samples were also tested using other methods including different commercial anti-GBM IgG assays and research assays for anti-GBM IgA and IgM. The sensitivity and specificity of the novel CIA was 95.6% [95% confidence interval (CI) 89.0-98.8%] and 99.6% (95% CI 98.9-99.9%), respectively. Receiver operating characteristic analysis showed good discrimination between GPS patients and controls. The area under the curve was 0.98 (CI 0.96-1.0). The three anti-GBM antibody-positive samples from the control group were from two healthy individuals and one human immunodeficiency virus (HIV)-infected patient. All three individuals had low levels of anti-GBM antibodies [20, 24 and 25 chemiluminescent unit (CU), cutoff 20 CU]. When the results of the new CIA were compared to other methods, good agreement was observed: 95.8% (kappa = 0.92) versus EliA™ GBM, 97.4% (kappa = 0.95) versus both BINDAZYME™ Anti-GBM and QUANTA Lite® GBM. Anti-GBM IgA was detectable in low concentrations in patients with GPS and was associated with anti-GBM IgG but was less useful in discriminating GPS patients and controls. No discrimination was found for anti-GBM IgM. The novel QUANTA Flash™ GBM CIA demonstrated good sensitivity and specificity and had good agreement with other methods. Our data confirm that ∼5% of patients with GPS do not have detectable levels of

  6. A charge-driven molecular water pump

    NASA Astrophysics Data System (ADS)

    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.

  7. 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

  8. Detecting neutrons by forward recoil protons at the Energy & Transmutation facility: Detector development and calibration with 14.1-MeV neutrons

    NASA Astrophysics Data System (ADS)

    Afanasev, S.; Vishnevskiy, A.; Vishnevskiy, D.; Rogachev, A.; Tyutyunnikov, S.

    2017-05-01

    As part of the Energy & Transmutation project, we are developing a detector for neutrons with energies in the 10-100 MeV range emitted from the target irradiated by a charged-particle beam. The neutron is detected by measuring the time-of-flight and total kinetic energy of the forward-going recoil proton [1] knocked out at a small angle from a thin layer of plastic scintillator, which has to be selected against an intense background created by γ quanta, scattered neutrons, and charged particles. On the other hand, neutron energy has to be measured over the full range with no extra tuning of the detector operation regime. Initial measurements with a source of 14.1-MeV neutrons are reported.

  9. Search for neutrino generated air shower candidates with energy ≥ 1019 eV and Zenith angle θ

    NASA Astrophysics Data System (ADS)

    Knurenko, Stanislav; Petrov, Igor; Sabourov, Artem

    2017-06-01

    The description of the methodology and results of searching for air showers generated by neutral particles such as high energy gamma quanta and astroneutrinos are presented. For this purpose, we conducted a comprehensive analysis of the data: the electron, the muon and the EAS Cerenkov light, and their response time in scintillation and Cherenkov detectors. Air showers with energy more than 5·1018 eV and zenith angle θ ≥ 55∘ are selected and analyzed. Search results indicate a lack of air shower events formed by gamma-rays or high-energy neutrinos, but it does not mean that such air showers do not exist in nature; for example, experiments that recorded showers having a marked low muon content, i.e., "Muonless", are likely to be candidates for showers produced by neutral primary particles.

  10. Effect of synchrotron radiation in the proposed 4 GeV Argonne microtron

    SciTech Connect

    Crosbie, E.A.

    1983-01-01

    Synchrotron radiation in the sector magnets of the 4-GeV microtron designed at the Argonne National Laboratory produces a small but noticeable distortion of the closed orbits of the system and a very-significant growth of the horizontal and longitudinal phase-space emittances. Because of the small apertures in the three 25-meter linacs, it is important that the expected growth of the beam be calculated as accurately as possible. For this reason, a computer program has been written which follows the motions of individual electrons in the four dimensional horizontal and longitudinal phase space as they are accelerated in the system. As the electrons go through the sector magnets, they emit quanta at random with randomly chosen energies. The final results show 63% emittance (area ..pi..) values of 0.15 mm mrad and 630 keV degrees for the horizontal and longitudinal phase spaces, respectively. The 99% values are about 4.6 times larger.

  11. Absorption Band Shapes of a Push-Pull Dye Approaching the Cyanine Limit: A Challenging Case for First Principle Calculations.

    PubMed

    Capobianco, Amedeo; Borrelli, Raffaele; Landi, Alessandro; Velardo, Amalia; Peluso, Andrea

    2016-07-21

    The absorption band shapes of a solvent tunable donor-acceptor dye have been theoretically investigated by using Kubo's generating function approach, with minimum energy geometries and normal coordinates computed at the DFT level of theory. The adopted computational procedure allows us to include in the computation of Franck-Condon factors the whole set of normal modes, without any limitation on excitation quanta, allowing for an almost quantitative reproduction of the absorption band shape when the equilibrium geometries of the ground and the excited states are well predicted by electronic computations. Noteworthy, the functionals that yield more accurate band shapes also provide good prediction of the moment variations upon excitation; because the latter quantities are rarely available, theoretical simulation of band shapes could be a powerful tool for choosing the most appropriate computational method for predictive purposes.

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  13. Localization and coherent states in a quantum DNLS trimer

    NASA Astrophysics Data System (ADS)

    Martínez-Galicia, Ricardo; Panayotaros, Panayotis

    2016-11-01

    We compare quantum states obtained from the integration of exact and approximate evolution equations for a quantized discrete nonlinear Schrödinger system (DNLS) with three lattice sites (trimer). The initial conditions are Glauber coherent states, and their projections to subspaces with a definite number of particles, and we are especially interested in coherent states that correspond to classical states that are in the neighborhood of breather solutions of the classical system. The breathers are well defined periodic orbits of the classical DNLS that we heuristically view as examples of spatially localized solutions. The two evolution equations give converging results in the subspaces with an increasing number of particles. This is no longer the case for normalized projections of Glauber states, where we see that the distance between the quantum states obtained by the exact and approximate equations shows recurrence phenomena that depend on the number of quanta and on the dynamical properties of the classical trajectory.

  14. 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.

  15. 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.

  16. 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

  17. 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).

  18. 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.

  19. On the first Solvay Congress in 1911

    NASA Astrophysics Data System (ADS)

    Straumann, Norbert

    2011-11-01

    Late in October 1911, eighteen leading scientists from all over Europe met to the first of a famous sequence of Solvay conferences in Brussels. This historical meeting was mainly devoted to "The Theory of Radiation and the Quanta", at a time when the foundations of physics were totally shaken. Although "nothing positive came out" (Einstein), it is interesting to see the diverging attitudes of Europe's most famous scientists in the middle of the quantum revolution. After a few general remarks about the conference, I shall focus on some of the most interesting contributions and discussions. Einstein, at 32 the youngest, was clearly most aware of the profound nature of the crises. He gave the final talk entitled "The Present State of the Problem of Specific Heats", but he put his theme into the larger context of the quantum problem, and caused a barrage of challenges, in particular from Lorentz, Planck, Poincaré, and others.

  20. 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.