Ultracold lithium-6 atoms in the BEC-BCS crossover: experiments and the construction of a new apparatus

International Nuclear Information System (INIS)

Teichmann, M.

2007-09-01

We use a fermionic gas of Lithium-6 as a model system to study superfluidity. The limiting cases of superfluidity are Bose-Einstein condensation (BEC) and superconductivity, described by the theory by Bardeen, Cooper and Schrieffer (BCS). In Lithium-6 gases, we can explore the whole range between the two cases, known as the BEC-BCS crossover, using a Feshbach resonance. We study the change of the momentum distribution of the gas in this cross-over and compare to theoretical models. We also investigate the hydrodynamic expansion, characteristic for a superfluid gas. We observe a sudden change of the ellipticity of the gas close to the transition to the superfluid phase. Moreover, we localized heteronuclear Feshbach resonances between 6 Li and 7 Li. We are currently constructing a second generation of the experimental setup. An new laser system, based on high power laser diodes, was developed. Changes in the vacuum chamber, including a complete reconstruction of the Zeeman slower, have increased the atomic flux, allowing us to increase the repetition rate of our experiment. Modifications of the geometry of the magnetic traps lead to a higher number of trapped atoms. (author)

Ultracold lithium-6 atoms in the BEC-BCS crossover: experiments and the construction of a new apparatus; Atomes de lithium-6 ultra froids dans la transition BEC-BCS: experiences et construction d'un montage experimental

Energy Technology Data Exchange (ETDEWEB)

Teichmann, M

2007-09-15

We use a fermionic gas of Lithium-6 as a model system to study superfluidity. The limiting cases of superfluidity are Bose-Einstein condensation (BEC) and superconductivity, described by the theory by Bardeen, Cooper and Schrieffer (BCS). In Lithium-6 gases, we can explore the whole range between the two cases, known as the BEC-BCS crossover, using a Feshbach resonance. We study the change of the momentum distribution of the gas in this cross-over and compare to theoretical models. We also investigate the hydrodynamic expansion, characteristic for a superfluid gas. We observe a sudden change of the ellipticity of the gas close to the transition to the superfluid phase. Moreover, we localized heteronuclear Feshbach resonances between {sup 6}Li and {sup 7}Li. We are currently constructing a second generation of the experimental setup. An new laser system, based on high power laser diodes, was developed. Changes in the vacuum chamber, including a complete reconstruction of the Zeeman slower, have increased the atomic flux, allowing us to increase the repetition rate of our experiment. Modifications of the geometry of the magnetic traps lead to a higher number of trapped atoms. (author)

Ultracold lithium-6 atoms in the BEC-BCS crossover: experiments and the construction of a new apparatus; Atomes de lithium-6 ultra froids dans la transition BEC-BCS: experiences et construction d'un montage experimental

Energy Technology Data Exchange (ETDEWEB)

Teichmann, M

2007-09-15

We use a fermionic gas of Lithium-6 as a model system to study superfluidity. The limiting cases of superfluidity are Bose-Einstein condensation (BEC) and superconductivity, described by the theory by Bardeen, Cooper and Schrieffer (BCS). In Lithium-6 gases, we can explore the whole range between the two cases, known as the BEC-BCS crossover, using a Feshbach resonance. We study the change of the momentum distribution of the gas in this cross-over and compare to theoretical models. We also investigate the hydrodynamic expansion, characteristic for a superfluid gas. We observe a sudden change of the ellipticity of the gas close to the transition to the superfluid phase. Moreover, we localized heteronuclear Feshbach resonances between {sup 6}Li and {sup 7}Li. We are currently constructing a second generation of the experimental setup. An new laser system, based on high power laser diodes, was developed. Changes in the vacuum chamber, including a complete reconstruction of the Zeeman slower, have increased the atomic flux, allowing us to increase the repetition rate of our experiment. Modifications of the geometry of the magnetic traps lead to a higher number of trapped atoms. (author)

Superfluidity and BCS-BEC crossover of ultracold atomic Fermi gases in mixed dimensions

Science.gov (United States)

Zhang, Leifeng; Chen, Qijin

Atomic Fermi gases have been under active investigation in the past decade. Here we study the superfluid and pairing phenomena of a two-component ultracold atomic Fermi gas in the presence of mixed dimensionality, in which one component is confined on a 1D optical lattice whereas the other is free in the 3D continuum. We assume a short-range pairing interaction and determine the superfluid transition temperature Tc and the phase diagram for the entire BCS-BEC crossover, using a pairing fluctuation theory which includes self-consistently the contributions of finite momentum pairs. We find that, as the lattice depth increases and the lattice spacing decreases, the behavior of Tc becomes very similar to that of a population imbalance Fermi gas in a simple 3D continuum. There is no superfluidity even at T = 0 below certain threshold of pairing strength in the BCS regime. Nonmonotonic Tc behavior and intermediate temperature superfluidity emerge, and for deep enough lattice, the Tc curve will split into two parts. Implications for experiment will be discussed. References: 1. Q.J. Chen, Ioan Kosztin, B. Janko, and K. Levin, Phys. Rev. B 59, 7083 (1999). 2. Chih-Chun Chien, Qijin Chen, Yan He, and K. Levin, Phys. Rev. Lett. 97, 090402(2006). Work supported by NSF of China and the National Basic Research Program of China.

BCS-BEC crossover in a system of microcavity polaritons

International Nuclear Information System (INIS)

Keeling, Jonathan; Eastham, P.R.; Szymanska, M.H.; Littlewood, P.B.

2005-01-01

We investigate the thermodynamics and signatures of a polariton condensate over a range of densities, using a model of microcavity polaritons with internal structure. We determine a phase diagram for this system including fluctuation corrections to the mean-field theory. At low densities the condensation temperature T c behaves like that for point bosons. At higher densities, when T c approaches the Rabi splitting, T c deviates from the form for point bosons, and instead approaches the result of a BCS-like mean-field theory. This crossover occurs at densities much less than the Mott density. We show that current experiments are in a density range where the phase boundary is described by the BCS-like mean-field boundary. We investigate the influence of inhomogeneous broadening and detuning of excitons on the phase diagram

Comparative study of BCS-BEC crossover theories above Tc: The nature of the pseudogap in ultracold atomic Fermi gases

International Nuclear Information System (INIS)

Chien, C.-C.; Guo Hao; He Yan; Levin, K.

2010-01-01

This article presents a comparison of two finite-temperature BCS-Bose-Einstein condensation (BEC) crossover theories above the transition temperature: Nozieres-Schmitt-Rink (NSR) theory and finite-T extended BCS-Leggett theory. The comparison is cast in the form of numerical studies of the behavior of the fermionic spectral function both theoretically and as constrained by (primarily) radio frequency (rf) experiments. Both theories include pair fluctuations and exhibit pseudogap effects, although the nature of this pseudogap is very different. The pseudogap in finite-T extended BCS-Leggett theory is found to follow a BCS-like dispersion which, in turn, is associated with a broadened BCS-like self-energy, rather more similar to what is observed in high-temperature superconductors (albeit, for a d-wave case). The fermionic quasiparticle dispersion is different in NSR theory and the damping is considerably larger. We argue that the two theories are appropriate in different temperature regimes with the BCS-Leggett approach being more suitable nearer to condensation. There should, in effect, be little difference at higher T as the pseudogap becomes weaker and where the simplifying approximations used in the BCS-Leggett approach break down. On the basis of momentum-integrated rf studies of unpolarized gases, it would be difficult to distinguish which theory is the better one. A full comparison for polarized gases is not possible since it is claimed that there are inconsistencies in the NSR approach (not found in the BCS-Leggett scheme). Future experiments along the lines of momentum-resolved experiments look to be very promising in distinguishing the two theories.

Goldstone and Higgs Hydrodynamics in the BCS–BEC Crossover

Directory of Open Access Journals (Sweden)

Luca Salasnich

2017-06-01

Full Text Available We discuss the derivation of a low-energy effective field theory of phase (Goldstone and amplitude (Higgs modes of the pairing field from a microscopic theory of attractive fermions. The coupled equations for Goldstone and Higgs fields are critically analyzed in the Bardeen–Cooper–Schrieffer (BCS-to-Bose–Einstein condensate (BEC crossover—both in three spatial dimensions and in two spatial dimensions. The crucial role of pair fluctuations is investigated, and the beyond-mean-field Gaussian theory of the BCS–BEC crossover is compared with available experimental data of the two-dimensional ultracold Fermi superfluid.

Equation for the superfluid gap obtained by coarse graining the Bogoliubov-de Gennes equations throughout the BCS-BEC crossover

Science.gov (United States)

Simonucci, S.; Strinati, G. C.

2014-02-01

We derive a nonlinear differential equation for the gap parameter of a superfluid Fermi system by performing a suitable coarse graining of the Bogoliubov-de Gennes (BdG) equations throughout the BCS-BEC crossover, with the aim of replacing the time-consuming solution of the original BdG equations by the simpler solution of this novel equation. We perform a favorable numerical test on the validity of this new equation over most of the temperature-coupling phase diagram, by an explicit comparison with the full solution of the original BdG equations for an isolated vortex. We also show that the new equation reduces both to the Ginzburg-Landau equation for Cooper pairs in weak coupling close to the critical temperature and to the Gross-Pitaevskii equation for composite bosons in strong coupling at low temperature.

Phase diagram of dilute nuclear matter: Unconventional pairing and the BCS-BEC crossover

Energy Technology Data Exchange (ETDEWEB)

Stein, Martin; Sedrakian, Armen [Frankfurt Univ. (Germany). Inst. fuer Theoretische Physik

2013-07-01

We report on a comprehensive study of the phase structure of cold, dilute nuclear matter featuring a {sup 3}S{sub 1}-{sup 3}D{sub 1} condensate at non-zero isospin asymmetry, within wide ranges of temperatures and densities. We find a rich phase diagram comprising three superfluid phases, namely a LOFF phase, the ordinary BCS phase, and a heterogeneous, phase-separated BCS phase, with associated crossovers from the latter two phases to a homogeneous or phase-separated Bose-Einstein condensate of deuterons. The phase diagram contains two tri-critical points (one a Lifshitz point), which may degenerate into a single tetra-critical point for some degree of isospin asymmetry.

Role of superconducting energy gap in extended BCS-Bose crossover theory

Science.gov (United States)

Chávez, I.; García, L. A.; de Llano, M.; Grether, M.

2017-10-01

The generalized Bose-Einstein condensation (GBEC) theory of superconductivity (SC) is briefly surveyed. It hinges on three distinct new ingredients: (i) Treatment of Cooper pairs (CPs) as actual bosons since they obey Bose statistics, in contrast to BCS pairs which do not obey Bose commutation relations; (ii) inclusion of two-hole Cooper pairs (2hCPs) on an equal footing with two-electron Cooper pairs (2eCPs), thus making this a complete boson-fermion (BF) model; and (iii) inclusion in the resulting ternary ideal BF gas with particular BF vertex interactions that drive boson formation/disintegration processes. GBEC subsumes as special cases both BCS (having its 50-50 symmetry of both kinds of CPs) and ordinary BEC theories (having no 2hCPs), as well as the now familiar BCS-Bose crossover theory. We extended the crossover theory with the explicit inclusion of 2hCPs and construct a phase diagram of Tc/TF versus n/nf, where Tc and TF are the critical and Fermi temperatures, n is the total number density and nf that of unbound electrons at T = 0. Also, with this extended crossover one can construct the energy gap Δ(T)/Δ(0) versus T/Tc for some elemental SCs by solving at least two equations numerically: a gap-like and a number equation. In 50-50 symmetry, the energy gap curve agrees quite well with experimental data. But ignoring 2hCPs altogether leads to the gap curve falling substantially below that with 50-50 symmetry which already fits the data quite well, showing that 2hCPs are indispensable to describe SCs.

Vortex lattices in a rotating Fermi superfluid in the BCS–BEC crossover with many Landau levels

International Nuclear Information System (INIS)

Song, Tie-ling; Ma, C.R.; Ma, Yong-li

2012-01-01

We present an explicit analytical analysis of the ground state of vortex lattice structure, based on a minimization of the generalized Gross–Pitaevskii energy functional in a trapped rotating Fermi superfluid gas. By a Bogoliubov-like transformation we find that the coarse-grained average of the atomic density varies as inverted parabola in three dimensional cases; the Fermi superfluid in the BEC regime enters into the lowest Landau level at fast rotation, in which the vortices form an almost regular triangular lattice over a central region and the vortex lattice is expanded along the radial direction in the outer region; the fluid in the unitarity and BCS regimes occupies many low-lying Landau levels, in which a trapped gas with a triangular vortex lattice has a superfluid core surrounded by a normal gas. The calculation is qualitatively consistent with recent numerical and experimental data both in the vortex lattice structure and vortex numbers and in the density profiles versus the stirring frequency in the whole BCS–BEC crossover. - Highlights: ► We present an analysis of vortex lattice in an interacting trapped rotating Fermi superfluid gas. ► Decomposing the vortex from the condensate, we can explain the vortex lattice. ► The calculation is consistent with numerical and experimental data. ► It can characterize experimentally properties in different regimes of the BCS–BEC crossover.

BCS-BEC crossover in dense relativistic matter: Collective excitations

Czech Academy of Sciences Publication Activity Database

Brauner, Tomáš

2008-01-01

Roč. 77, č. 9 (2008), 096006/1-096006/11 ISSN 1550-7998 R&D Projects: GA ČR GA202/06/0734 Institutional research plan: CEZ:AV0Z10480505 Keywords : quark matter * dynamical model * gross-neveu Subject RIV: BE - Theoretical Physics Impact factor: 5.050, year: 2008

Conversion of a Degenerate Fermi Gas of 6Li Atoms to a Molecular BEC

International Nuclear Information System (INIS)

Strecker, K.E.; Partridge, G.B.; Kamar, R.I.; Jack, M.W.; Hulet, R.G.

2005-01-01

Atomic Feshbach resonances have recently been used to produce a strongly interacting Fermi gas, where the BCS/BEC crossover can be explored. We have used both narrow and broad Feshbach resonances to convert a quantum degenerate Fermi gas of 6Li atoms into an ultracold gas of Li2 molecules. For the narrow resonances, the molecules are formed by coherent adiabatic passage through the resonance. We find that 50% of the atoms are converted to molecules. Furthermore, the lifetime of these molecules was measured to be surprisingly long, 1 s. We will discuss these measurements in the context of the present theoretical understanding. Molecules can also be formed using static fields near the broad Feshbach resonance. The lifetime of these molecules is again long, and sufficient to enable their evaporation to a Bose-Einstein condensate. Phase contrast images of the molecular condensate are presented. The BCS/BEC crossover may be explored by starting with a pure molecular condensate on the low-field side of the Feshbach resonance, and adiabatically changing the field to any final value around resonance. We combine this ability with optical spectroscopy on a bound-bound molecular transition to probe the nature of the many-body wavefunction in the crossover regime

Splitting and oscillation of Majorana zero modes in the p-wave BCS-BEC evolution with plural vortices

International Nuclear Information System (INIS)

Mizushima, T.; Machida, K.

2010-01-01

We investigate how the vortex-vortex separation changes Majorana zero modes in the vicinity of the BCS-BEC (Bose-Einstein condensation) topological phase transition of p-wave resonant Fermi gases. By analytically and numerically solving the Bogoliubov-de Gennes equation for spinless p-wave superfluids with plural vortices, it is demonstrated that the quasiparticle tunneling between neighboring vortices gives rise to the quantum oscillation of the low-lying spectra on the scale of the Fermi wavelength in addition to the exponential splitting. This rapid oscillation, which appears in the weak-coupling regime as a consequence of quantum oscillations of quasiparticle wave functions, disappears in the vicinity of the BCS-BEC topological phase transition. This is understandable from that the wave function of the Majorana zero modes is described by the modified Bessel function in the strong-coupling regime, and thus it becomes spread over the vortex core region. Due to the exponential divergence of the modified Bessel function, the concrete realization of the Majorana zero modes near the topological phase transition requires the neighboring vortices to be separated beyond the length scale defined by the coherence length and the dimensionless coupling constant. All these behaviors are also confirmed by carrying out the full numerical diagonalization of the nonlocal Bogoliubov-de Gennes equation in a two-dimensional geometry. Furthermore, this argument is expanded into the case of three-vortex systems, where a pair of core-bound and edge-bound Majorana states survive at zero-energy state regardless of the vortex separation.

Extracting the Condensate Density from Projection Experiments with Fermi Gases

International Nuclear Information System (INIS)

Perali, A.; Pieri, P.; Strinati, G.C.

2005-01-01

A debated issue in the physics of the BCS-BEC crossover with trapped Fermi atoms is to identify characteristic properties of the superfluid phase. Recently, a condensate fraction was measured on the BCS side of the crossover by sweeping the system in a fast (nonadiabatic) way from the BCS to the Bose-Einstein condensation (BEC) sides, thus 'projecting' the initial many-body state onto a molecular condensate. We analyze here the theoretical implications of these projection experiments, by identifying the appropriate quantum-mechanical operator associated with the measured quantities and relating them to the many-body correlations occurring in the BCS-BEC crossover. Calculations are presented over wide temperature and coupling ranges, by including pairing fluctuations on top of the mean field

Gray solitons in a strongly interacting superfluid Fermi gas

International Nuclear Information System (INIS)

Spuntarelli, Andrea; Pieri, Pierbiagio; Strinati, Giancarlo C; Carr, Lincoln D

2011-01-01

The Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensate (BEC) crossover problem is solved for stationary gray solitons via the Boguliubov-de Gennes equations at zero temperature. These crossover solitons exhibit a localized notch in the gap and a characteristic phase difference across the notch for all interaction strengths, from BEC to BCS regimes. However, they do not follow the well-known Josephson-like sinusoidal relationship between velocity and phase difference except in the far BEC limit: at unitarity, the velocity has a nearly linear dependence on phase difference over an extended range. For a fixed phase difference, the soliton is of nearly constant depth from the BEC limit to unitarity and then grows progressively shallower into the BCS limit, and on the BCS side, Friedel oscillations are apparent in both gap amplitude and phase. The crossover soliton appears fundamentally in the gap; we show, however, that the density closely follows the gap, and the soliton is therefore observable. We develop an approximate power-law relationship to express this fact: the density of gray crossover solitons varies as the square of the gap amplitude in the BEC limit and as a power of about 1.5 at unitarity.

Crossover from BCS to composite boson (local pair) superconductivity in quasi-2D systems

International Nuclear Information System (INIS)

Gorbar, E.V.; Loktev, V.M.; Sharapov, S.G.

1995-01-01

The crossover from cooperative Cooper pairing to independent bound state (composite bosons) formation and condensation in quasi-2 D systems is studied. It is shown that at low carrier density the critical superconducting temperature is equal to the temperature of Bose-condensation of ideal quasi-2 D Bose-gas with heavy dynamical mass, meanwhile at high densities the BCS result remains valid. 15 refs

Quantitative comparison between theoretical predictions and experimental results for the BCS-BEC crossover

International Nuclear Information System (INIS)

Perali, A.; Pieri, P.; Strinati, G.C.

2004-01-01

Theoretical predictions for the Bardeen-Cooper-Schrieffer-Bose-Einstein condensation crossover of trapped Fermi atoms are compared with recent experimental results for the density profiles of L 6 i. The calculations rest on a single theoretical approach that includes pairing fluctuations beyond mean-field. Excellent agreement with experimental results is obtained. Theoretical predictions for the zero-temperature chemical potential and gap at the unitarity limit are also found to compare extremely well with Quantum Monte Carlo simulations and with recent experimental results

Induced interactions in a superfluid Bose-Fermi mixture

DEFF Research Database (Denmark)

Kinnunen, Jami; Bruun, Georg

2015-01-01

We analyze a Bose-Einstein condensate (BEC) mixed with a superfluid two-component Fermi gas in the whole BCS-BEC crossover. Using a quasiparticle random-phase approximation combined with Beliaev theory to describe the Fermi superfluid and the BEC, respectively, we show that the single-particle an......We analyze a Bose-Einstein condensate (BEC) mixed with a superfluid two-component Fermi gas in the whole BCS-BEC crossover. Using a quasiparticle random-phase approximation combined with Beliaev theory to describe the Fermi superfluid and the BEC, respectively, we show that the single...... shift in the excitation spectrum of the BEC. In addition, the excitation of quasiparticles in the Fermi superfluid leads to damping of the excitations in the BEC. Besides studying induced interactions themselves, we can use these prominent effects to systematically probe the strongly interacting Fermi...

Comparison between a diagrammatic theory for the BCS-BEC crossover and quantum Monte Carlo results

International Nuclear Information System (INIS)

Pieri, P.; Pisani, L.; Strinati, G.C.

2005-01-01

Predictions for the chemical potential and the excitation gap recently obtained by our diagrammatic theory for the Bardeen-Cooper-Schreiffer-Bose-Einstein Condensation crossover in the superfluid phase are compared with quantum Monte Carlo results at zero temperature now available in the literature. A remarkable agreement is found between the results obtained by the two approaches

Crossover between the dense electron-hole phase and the BCS excitonic phase in quantum dots

International Nuclear Information System (INIS)

Rodriguez, B.A.; Gonzalez, A.; Quiroga, L.; Capote, R.; Rodriguez, F.J.

1999-09-01

Second order perturbation theory and a Lipkin-Nogami scheme combined with an exact Monte Carlo projection after variation are applied to compute the ground-state energy of 6 ≤ N ≤ 210 electron-hole pairs confined in a parabolic two-dimensional quantum dot. The energy shows nice scaling properties as N or the confinement strength is varied. A crossover from the high-density electron-hole phase to the BCS excitonic phase is found at a density which is roughly four times the close-packing density of excitons. (author)

Two-body correlation functions in dilute nuclear matter

International Nuclear Information System (INIS)

Isayev, A A

2006-01-01

Finding the distinct features of the crossover from the regime of large overlapping Cooper pairs to the limit of non-overlapping pairs of fermions (Shafroth pairs) in multicomponent Fermi systems remains one of the actual problems in a quantum many-body theory. Here this transition is studied by calculating the two-body density, spin and isospin correlation functions in dilute asymmetric nuclear matter. It is shown that criterion of the crossover (Phys. Rev. Lett. 95, 090402 (2005)), consisting in the change of the sign of the density correlation function at low momentum transfer, fails to describe correctly the density-driven BEC-BCS transition at finite isospin asymmetry or finite temperature. As an unambiguous signature of the BEC-BCS transition, there can be used the presence (BCS regime) or absence (BEC regime) of the singularity in the momentum distribution of the quasiparticle density of states

Study of two-proton radioactivity within the relativistic mean-field plus BCS approach

International Nuclear Information System (INIS)

Singh, D.; Saxena, G.

2012-01-01

Inspired by recent experimental studies of two-proton radioactivity in the light-medium mass region, we have employed relativistic mean-field plus state-dependent BCS approach (RMF+BCS) to study the ground state properties of selected even-Z nuclei in the region 20 ≤ Z ≤ 40. It is found that the effective potential barrier provided by the Coulomb interaction and that due to centrifugal force may cause a long delay in the decay of some of the nuclei even with small negative proton separation energy. This may cause the existence of proton-rich nuclei beyond the proton drip-line. Nuclei 38 Ti, 42 Cr, 45 Fe, 48 Ni, 55 Zn, 60 Ge, 63, 64 Se, 68 Kr, 72 Sr and 76 Zr are found to be the potential candidates for exhibiting two-proton radioactivity in the region 20 ≤ Z ≤ 40. The reliability of these predictions is further strengthened by the agreement of the calculated results for the ground state properties such as binding energy, one- and two-proton separation energy, proton and neutron radii, and deformation with the available experimental data for the entire chain of the isotopes of the nuclei in the region 20 ≤ Z ≤ 40. (author)

Verification of an analytic fit for the vortex core profile in superfluid Fermi gases

International Nuclear Information System (INIS)

Verhelst, Nick; Klimin, Serghei; Tempere, Jacques

2017-01-01

Highlights: • The vortex profile in an imbalanced Fermi condensate is investigated. • The analytic fit for the vortex profile is compared with numerical simulations. • The analytic fit excellently agrees with numeric results in the BCS-BEC crossover. - Abstract: A characteristic property of superfluidity and -conductivity is the presence of quantized vortices in rotating systems. To study the BEC-BCS crossover the two most common methods are the Bogoliubov-De Gennes theory and the usage of an effective field theory. In order to simplify the calculations for one vortex, it is often assumed that the hyperbolic tangent yields a good approximation for the vortex structure. The combination of a variational vortex structure, together with cylindrical symmetry yields analytic (or numerically simple) expressions. The focus of this article is to investigate to what extent this analytic fit truly reflects the vortex structure throughout the BEC-BCS crossover at finite temperatures. The vortex structure will be determined using the effective field theory presented in [Eur. Phys. Journal B 88, 122 (2015)] and compared to the variational analytic solution. By doing this it is possible to see where these two structures agree, and where they differ. This comparison results in a range of applicability where the hyperbolic tangent will be a good fit for the vortex structure.

Verification of an analytic fit for the vortex core profile in superfluid Fermi gases

Energy Technology Data Exchange (ETDEWEB)

Verhelst, Nick, E-mail: nick.verhelst@uantwerpen.be [TQC, Universiteit Antwerpen, Universiteitsplein 1, B-2610 Antwerpen (Belgium); Klimin, Serghei, E-mail: sergei.klimin@uantwerpen.be [TQC, Universiteit Antwerpen, Universiteitsplein 1, B-2610 Antwerpen (Belgium); Department of Theoretical Physics, State University of Moldova, Republic of Moldova (Moldova, Republic of); Tempere, Jacques [TQC, Universiteit Antwerpen, Universiteitsplein 1, B-2610 Antwerpen (Belgium); Lyman Laboratory of Physics, Harvard University (United States)

2017-02-15

Highlights: • The vortex profile in an imbalanced Fermi condensate is investigated. • The analytic fit for the vortex profile is compared with numerical simulations. • The analytic fit excellently agrees with numeric results in the BCS-BEC crossover. - Abstract: A characteristic property of superfluidity and -conductivity is the presence of quantized vortices in rotating systems. To study the BEC-BCS crossover the two most common methods are the Bogoliubov-De Gennes theory and the usage of an effective field theory. In order to simplify the calculations for one vortex, it is often assumed that the hyperbolic tangent yields a good approximation for the vortex structure. The combination of a variational vortex structure, together with cylindrical symmetry yields analytic (or numerically simple) expressions. The focus of this article is to investigate to what extent this analytic fit truly reflects the vortex structure throughout the BEC-BCS crossover at finite temperatures. The vortex structure will be determined using the effective field theory presented in [Eur. Phys. Journal B 88, 122 (2015)] and compared to the variational analytic solution. By doing this it is possible to see where these two structures agree, and where they differ. This comparison results in a range of applicability where the hyperbolic tangent will be a good fit for the vortex structure.

Pairing induced superconductivity in holography

Science.gov (United States)

Bagrov, Andrey; Meszena, Balazs; Schalm, Koenraad

2014-09-01

We study pairing induced superconductivity in large N strongly coupled systems at finite density using holography. In the weakly coupled dual gravitational theory the mechanism is conventional BCS theory. An IR hard wall cut-off is included to ensure that we can controllably address the dynamics of a single confined Fermi surface. We address in detail the interplay between the scalar order parameter field and fermion pairing. Adding an explicitly dynamical scalar operator with the same quantum numbers as the fermion-pair, the theory experiences a BCS/BEC crossover controlled by the relative scaling dimensions. We find the novel result that this BCS/BEC crossover exposes resonances in the canonical expectation value of the scalar operator. This occurs not only when the scaling dimension is degenerate with the Cooper pair, but also with that of higher derivative paired operators. We speculate that a proper definition of the order parameter which takes mixing with these operators into account stays finite nevertheless.

Impurity bubbles in a BEC

Science.gov (United States)

Timmermans, Eddy; Blinova, Alina; Boshier, Malcolm

2013-05-01

Polarons (particles that interact with the self-consistent deformation of the host medium that contains them) self-localize when strongly coupled. Dilute Bose-Einstein condensates (BECs) doped with neutral distinguishable atoms (impurities) and armed with a Feshbach-tuned impurity-boson interaction provide a unique laboratory to study self-localized polarons. In nature, self-localized polarons come in two flavors that exhibit qualitatively different behavior: In lattice systems, the deformation is slight and the particle is accompanied by a cloud of collective excitations as in the case of the Landau-Pekar polarons of electrons in a dielectric lattice. In natural fluids and gases, the strongly coupled particle radically alters the medium, e.g. by expelling the host medium as in the case of the electron bubbles in superfluid helium. We show that BEC-impurities can self-localize in a bubble, as well as in a Landau-Pekar polaron state. The BEC-impurity system is fully characterized by only two dimensionless coupling constants. In the corresponding phase diagram the bubble and Landau-Pekar polaron limits correspond to large islands separated by a cross-over region. The same BEC-impurity species can be adiabatically Feshbach steered from the Landau-Pekar to the bubble regime. This work was funded by the Los Alamos LDRD program.

High-temperature electron-hole superfluidity with strong anisotropic gaps in double phosphorene monolayers

Science.gov (United States)

Saberi-Pouya, S.; Zarenia, M.; Perali, A.; Vazifehshenas, T.; Peeters, F. M.

2018-05-01

Excitonic superfluidity in double phosphorene monolayers is investigated using the BCS mean-field equations. Highly anisotropic superfluidity is predicted where we found that the maximum superfluid gap is in the Bose-Einstein condensate (BEC) regime along the armchair direction and in the BCS-BEC crossover regime along the zigzag direction. We estimate the highest Kosterlitz-Thouless transition temperature with maximum value up to ˜90 K with onset carrier densities as high as 4 ×1012cm-2 . This transition temperature is significantly larger than what is found in double electron-hole few-layers graphene. Our results can guide experimental research toward the realization of anisotropic condensate states in electron-hole phosphorene monolayers.

Tunneling dynamics of superfluid Fermi gases in an accelerating optical lattice

International Nuclear Information System (INIS)

Tie Lu; Xue Jukui

2010-01-01

The nonlinear Landau-Zener tunneling and the nonlinear Rabi oscillations of superfluid Fermi gases between Bloch bands in an accelerating optical lattice are discussed. Within the hydrodynamic theory and a two-level model, the tunneling probability of superfluid Fermi gases between Bloch bands is obtained. We find that, as the system crosses from the Bose-Einstein condensation (BEC) side to the BCS side, the tunneling rate is closely related to the particle density: when the density is smaller (larger) than a critical value, the tunneling rate at unitarity is larger (smaller) than that in the BEC limit. This is well explained in terms of an effective interaction and an effective potential. Furthermore, the nonlinear Rabi oscillations of superfluid Fermi gases between the bands are discussed by imposing a periodic modulation on the level bias and the strength of the lattice. Analytical expressions of the critical density for suppressing or enhancing the Rabi oscillations are obtained. It is shown that, as the system crosses from the BEC side to the BCS side, the critical density strongly depends on the modulation parameters (i.e., the modulation amplitude and the modulation frequency). For a fixed density, a high-frequency or low-frequency modulation can suppress or enhance the Rabi oscillations both at unitarity and in the BEC limit. For an intermediate modulation frequency, the Rabi oscillations are chaotic along the entire BEC-BCS crossover, especially, on the BCS side. Interestingly, we find that the modulation of the lattice strength only with an intermediate modulation frequency has significant effect on the Rabi oscillations both in the BEC limit and at unitarity; that is, an intermediate-frequency modulation can enhance the Rabi oscillations, especially on the BCS side.

Sound waves and dynamics of superfluid Fermi gases in optical lattices

International Nuclear Information System (INIS)

Zhang Aixia; Xue Jukui

2009-01-01

The sound waves, the stability of Bloch waves, the Bloch oscillation, and the self-trapping phenomenon in interacting two-component Fermi gases throughout the BEC-BCS crossover in one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) optical lattices are discussed in detail. Within the hydrodynamical theory and by using the perturbative and tight-binding approximation, sound speed in both weak and tight 1D, 2D, 3D optical lattices, and the criteria for occurrences of instability of Bloch waves and self-trapping of Fermi gases along the whole BEC-BCS crossover in tight 1D, 2D, 3D optical lattices are obtained analytically. The results show that the sound speed, the criteria for occurrences of instability of Bloch waves and self-trapping, and the destruction of Bloch oscillation are modified dramatically by the lattice parameters (lattice dimension and lattice strength), the atom density or atom number, and the atom interaction.

Faraday instability and Faraday patterns in a superfluid Fermi gas

International Nuclear Information System (INIS)

Tang Rongan; Xue Jukui; Li Haocai

2011-01-01

With the consideration of the coupling between the transverse width and the longitudinal density, the parametric excitations related to Faraday waves in a cigar-shaped superfluid Fermi gas are studied. A Mathieu equation is obtained, and it is demonstrated firstly that the excited actual 3D Faraday pattern is the combination of the longitudinal Faraday density wave and the corresponding transverse width fluctuation in the longitudinal direction. The Faraday instability growth index and the kinematic equations of the Faraday density wave and the width fluctuation along the Bose-Einstein condensate (BEC)-Bardeen-Cooper-Schrieffer (BCS) crossover are also given for the first time. It is found that the 3D Faraday pattern presents quite different behaviours (such as the excitations and the motions) when the system crosses from the BEC side to the BCS side. The coupling not only plays an important role in the parametric excitation, but also determines the dominant wavelength of the spatial structure. Along the crossover, the coupling effects are more significant in the BCS side. The final numerical investigation verifies these results and gives a detailed study of the parametric excitations (i.e. Faraday instability) and the 3D pattern formation.

Excitonic condensation for the surface states of topological insulator bilayers

International Nuclear Information System (INIS)

Wang Zhigang; Fu Zhenguo; Zhang Ping; Hao Ningning

2012-01-01

We propose a generic topological insulator bilayer (TIB) system to study the excitonic condensation with self-consistent mean-field (SCMF) theory. We show that the TIB system presents the crossover behavior from the Bardeen-Cooper-Schrieffer (BCS) limit to the Bose-Einstein condensation (BEC) limit. Moreover, in comparison with traditional semiconductor systems, we find that for the present system the superfluid property in the BEC phase is more sensitive to electron-hole density imbalance and the BCS phase is more robust. Applying this TIB model to the Bi 2 Se 3 -family material, we find that the BEC phase is most likely to be observed in experiment. We also calculate the critical temperature for the Bi 2 Se 3 -family TIB system, which is ∼100 K. More interestingly, one can expect this relative high-temperature excitonic condensation, since our calculated SCMF critical temperature is approximately equal to the Kosterlitz-Thouless transition temperature. (paper)

RMF+BCS description of some traditional neutron magic isotones

International Nuclear Information System (INIS)

Saxena, G.; Singh, D.; Kaushik, M.

2014-01-01

The traditional neutron magic nuclei with N = 8, 20, 28, 50, 82 and 126, and those with neutron sub-magic number N = 40 are investigated within the relativistic mean-field plus BCS (RMF+BCS) approach. The results indicate appearance of new proton magic numbers as well as the disappearance of conventional magic numbers for nuclei with extreme isospin values. The calculated energies and densities do not indicate any tendency for the proton halo formations in any of the proton rich isotones due to Coulomb interaction and different single particle spectra. However, the potential barrier provided by the Coulomb interaction and that due to the centrifugal force may cause a long delay in the actual decay of proton rich nucleus resulting in the extended drip line. (authors)

A nucleon-pair and boson coexistent description of nuclei

Science.gov (United States)

Dai, Lianrong; Pan, Feng; Draayer, J. P.

2017-07-01

We study a mixture of s-bosons and like-nucleon pairs with the standard pairing interaction outside an inert core. Competition between the nucleon-pairs and s-bosons is investigated in this scenario. The robustness of the BCS-BEC coexistence and crossover phenomena are examined through an analysis of pf-shell nuclei with realistic single-particle energies, in which two configurations with Pauli blocking of nucleon-pair orbits due to the formation of the s-bosons is taken into account. When the nucleon-pair orbits are considered to be independent of the s-bosons, the BCS-BEC crossover becomes smooth, with the number of the s-bosons noticeably more than that of the nucleon-pairs near the half-shell point, a feature that is demonstrated in the pf-shell for several values of the standard pairing interaction strength. As a further test of the robustness of the BCS-BEC coexistence and crossover phenomena in nuclei, results are given for values of even-even 102-130Sn with 100Sn taken as a core and valence neutron pairs confined within the 1d 5/2, 0g 7/2, 1d 3/2, 2s 1/2, 1h 11/2 orbits in the nucleon-pair orbit and the s-boson independent approximation. The results indicate that the B(E2) values are reproduced well. Supported by National Natural Science Foundation of China (11375080, 11675071), the U.S. National Science Foundation (OCI-0904874 and ACI-1516338), U. S. Department of Energy (DE-SC0005248), the Southeastern Universities Research Association, the China-U. S. Theory Institute for Physics with Exotic Nuclei (CUSTIPEN) (DE-SC0009971), and the LSU-LNNU joint research program (9961) is acknowledged

Strongly interacting Fermi systems in 1/N expansion: From cold atoms to color superconductivity

Czech Academy of Sciences Publication Activity Database

Abuki, H.; Brauner, Tomáš

2008-01-01

Roč. 78, č. 12 (2008), 125010/1-125010/13 ISSN 1550-7998 R&D Projects: GA ČR GA202/06/0734 Institutional research plan: CEZ:AV0Z10480505 Keywords : BCS-BEC crossover * Unitary Fermi gas * Quark matter Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 5.050, year: 2008

RMF+BCS description of N = 32 and N = 34 shell closure

International Nuclear Information System (INIS)

Saxena, G.; Kumawat, M.; Singh, U.K.; Jain, S.K.; Aggarwal, Mamta; Kaushik, M.; Singh, S. Somorendro

2017-01-01

We have employed RMF+BCS (relativistic mean-field plus BCS) approach to study N = 32 and N = 34 shell closure with the help of ground state properties of even-even nuclei. Our present investigations include single particle energies, deformations, separation energies as well as neutron and proton densities etc. Encouraged by the recent experiments showing neutron magicity at N = 32 for Ca isotopes, we have applied RMF theory with delta function pairing along with mass dependency (1/A) for full chain of N = 32 and N = 34 isotones upto drip lines. This study predicts new doubly magic nuclei specially 48 Si which is in the same mass region in 52 Ca as the recent experiments observed

Mesoscopic pairing without superconductivity

Science.gov (United States)

Hofmann, Johannes

2017-12-01

We discuss pairing signatures in mesoscopic nanowires with a variable attractive pairing interaction. Depending on the wire length, density, and interaction strength, these systems realize a simultaneous bulk-to-mesoscopic and BCS-BEC crossover, which we describe in terms of the parity parameter that quantifies the odd-even energy difference and generalizes the bulk Cooper pair binding energy to mesoscopic systems. We show that the parity parameter can be extracted from recent measurements of conductance oscillations in SrTiO3 nanowires by Cheng et al. [Nature (London) 521, 196 (2015), 10.1038/nature14398], where it marks the critical magnetic field that separates pair and single-particle currents. Our results place the experiment in the fluctuation-dominated mesoscopic regime on the BCS side of the crossover.

Description of C isotopes within RMF+BCS approach

International Nuclear Information System (INIS)

Saxena, G.; Singh, D.; Kaushik, M.

2013-01-01

In the present investigations we have employed relativistic mean-field plus BCS (RMF + BCS) approach to carry out a systematic study for the ground state properties of even-even C Isotopes. One of the prime reason of this study has been to look into the role of low lying states in neutron rich reason near neutron drip line. It is found that irrespective of whether any resonant state exists or not, the occupancy of weakly bound neutron single particle states having low orbital angular momentum, (l = 0 or 1), with a well spread wave function due to the absence or very small strength of centrifugal barrier, helps to cause the occurrence of nuclei with widely extended neutron density. Such nuclei are found to have characteristically very small two-neutron separation energy and large neutron rms radius akin to that observed in weakly bound systems.

Bose-Einstein condensation in the relativistic ideal Bose gas.

Science.gov (United States)

Grether, M; de Llano, M; Baker, George A

2007-11-16

The Bose-Einstein condensation (BEC) critical temperature in a relativistic ideal Bose gas of identical bosons, with and without the antibosons expected to be pair-produced abundantly at sufficiently hot temperatures, is exactly calculated for all boson number densities, all boson point rest masses, and all temperatures. The Helmholtz free energy at the critical BEC temperature is lower with antibosons, thus implying that omitting antibosons always leads to the computation of a metastable state.

Bose-Einstein Condensation in the Relativistic Ideal Bose Gas

International Nuclear Information System (INIS)

Grether, M.; Llano, M. de; Baker, George A. Jr.

2007-01-01

The Bose-Einstein condensation (BEC) critical temperature in a relativistic ideal Bose gas of identical bosons, with and without the antibosons expected to be pair-produced abundantly at sufficiently hot temperatures, is exactly calculated for all boson number densities, all boson point rest masses, and all temperatures. The Helmholtz free energy at the critical BEC temperature is lower with antibosons, thus implying that omitting antibosons always leads to the computation of a metastable state

Microscopy of 2D Fermi gases. Exploring excitations and thermodynamics

Energy Technology Data Exchange (ETDEWEB)

Morgener, Kai Henning

2014-12-08

This thesis presents experiments on three-dimensional (3D) and two-dimensional (2D) ultracold fermionic {sup 6}Li gases providing local access to microscopic quantum many-body physics. A broad magnetic Feshbach resonance is used to tune the interparticle interaction strength freely to address the entire crossover between the Bose-Einstein-Condensate (BEC) and Bardeen-Cooper-Schrieffer (BCS) regime. We map out the critical velocity in the crossover from BEC to BCS superfluidity by moving a small attractive potential through the 3D cloud. We compare the results with theoretical predictions and achieve quantitative understanding in the BEC regime by performing numerical simulations. Of particular interest is the regime of strong correlations, where no theoretical predictions exist. In the BEC regime, the critical velocity should be closely related to the speed of sound, according to the Landau criterion and Bogolyubov theory. We measure the sound velocity by exciting a density wave and tracking its propagation. The focus of this thesis is on our first experiments on general properties of quasi-2D Fermi gases. We realize strong vertical confinement by generating a 1D optical lattice by intersecting two blue-detuned laser beams under a steep angle. The large resulting lattice spacing enables us to prepare a single planar quantum gas deeply in the 2D regime. The first measurements of the speed of sound in quasi-2D gases in the BEC-BCS crossover are presented. In addition, we present preliminary results on the pressure equation of state, which is extracted from in-situ density profiles. Since the sound velocity is directly connected to the equation of state, the results provide a crosscheck of the speed of sound. Moreover, we benchmark the derived sound from available equation of state predictions, find very good agreement with recent numerical calculations, and disprove a sophisticated mean field approach. These studies are carried out with a novel apparatus which has

Bec Model of HIGH-Tc Superconductivity in Layered Cuprates

Science.gov (United States)

Lomnitz, M.; Villarreal, C.; de Llano, M.

2013-11-01

High-Tc superconductivity in layered cuprates is described in a BCS-BEC formalism with linearly-dispersive s- and d-wave Cooper pairs moving in quasi-2D finite-width layers around the CuO2 planes. This yields a closed formula for Tc involving the layer width, the Debye frequency, the pairing energy and the in-plane penetration depth. The new formula has no free parameters and reasonably reproduces empirical values of superconducting Tcs for 11 different layered superconductors over a wide doping regime including YBCO itself as well as other compounds like LSCO, BSCCO and TBCCO. In agreement with the London formalism, the formula also yields a fair description of the Tc dependence of the lower critical magnetic field in highly underdoped YBCO.

Spectroscopy of Dipolar Fermions in Layered Two-Dimensional and Three-Dimensional Lattices

Science.gov (United States)

2011-09-06

Moreover, we consider other sources of spectral broadening: interaction-induced quasiparticle lifetimes and the different polarizabilities of the...and study Cooper pair binding [7,8], polaron quasiparticle residue [9], and pseudogap behavior of ultracold fermions across the BEC/BCS crossover [10...imaginary part of this energy is the quasiparticle lifetime, and the only source of quasiparticle decay is the p-wave particle loss. Thus the cloud

Stability of Sarma phases in density imbalanced electron-hole bilayer systems

International Nuclear Information System (INIS)

Subasi, A. L.; Tanatar, B.; Pieri, P.; Senatore, G.

2010-01-01

We study excitonic condensation in an electron-hole bilayer system with unequal layer densities at zero temperature. Using mean-field theory we solve the Bardeen-Cooper-Schrieffer (BCS) gap equations numerically and investigate the effects of intralayer interactions. The electron-hole system evolves from BCS in the weak coupling limit to Bose-Einstein condensation (BEC) in the strong coupling limit. We analyze the stability of the Sarma phase with k,-k pairing by calculating the superfluid mass density and also by checking the compressibility matrix. We find that with bare Coulomb interactions the superfluid density is always positive in the Sarma phase, due to a peculiar momentum structure of the gap function originating from the singular behavior of the Coulomb potential at zero momentum and the presence of a sharp Fermi surface. Introducing a simple model for screening, we find that the superfluid density becomes negative in some regions of the phase diagram, corresponding to an instability toward a Fulde-Ferrel-Larkin-Ovchinnikov-type superfluid phase. Thus, intralayer interaction and screening together can lead to a rich phase diagram in the BCS-BEC crossover regime in electron-hole bilayer systems.

Laser frequency stabilization using bichromatic crossover spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Jeong, Taek; Seb Moon, Han, E-mail: hsmoon@pusan.ac.kr [Department of Physics, Pusan National University, Busan 609-735 (Korea, Republic of)

2015-03-07

We propose a Doppler-free spectroscopic method named bichromatic crossover spectroscopy (BCS), which we then use for the frequency stabilization of an off-resonant frequency that does not correspond to an atomic transition. The observed BCS in the 5S{sub 1/2} → 5P{sub 1/2} transition of {sup 87}Rb is related to the hyperfine structure of the conventional saturated absorption spectrum of this transition. Furthermore, the Doppler-free BCS is numerically calculated by considering all of the degenerate magnetic sublevels of the 5S{sub 1/2} → 5P{sub 1/2} transition in an atomic vapor cell, and is found to be in good agreement with the experimental results. Finally, we successfully achieve modulation-free off-resonant locking at the center frequency between the two 5S{sub 1/2}(F = 1 and 2) → 5P{sub 1/2}(F′ = 1) transitions using a polarization rotation of the BCS. The laser frequency stability was estimated to be the Allan variance of 2.1 × 10{sup −10} at 1 s.

Study of bubble structure in N = 20 isotones within relativistic mean-field plus BCS approach

International Nuclear Information System (INIS)

Kumawat, M.; Singh, U.K.; Jain, S.K.; Saxena, G.; Aggarwal, Mamta; Singh, S. Somorendro; Kaushik, M.

2017-01-01

Guided by various theoretical studies and encouraged with recent first experimental evidence of proton density depletion in "3"4Si, we have applied relativistic mean field plus BCS approach for systematic study of bubble structure in magic nuclei with N = 20 isotones. Our present investigations include single particle energies, deformations, separation energies as well as neutron and proton densities etc. It is found that proton sd shells (1d_5_/_2,2s_1_/_2,1d_3_/_2) in N = 20 isotones play very important role in the formation of bubble structure. The unoccupied 2s_1_/_2 state gives rise to bubble since this 2s_1_/_2 state does not have any centrifugal barrier, therefore for Z = 8 - 14 in the isotonic chain radial distributions of such state is found with peak in the interior of the nucleus with corresponding wave functions extending into the surface region. Consequently, in these nuclei with unoccupied s-state the central density found depleted as compared to the nucleus wherein this state is fully occupied. It is important to note here that in these nuclei depletion in proton density for "3"4Si is found with most significance which is in accord with the recent experiment. Moving further for higher Z value, Z = 16 and Z = 18 the 2s_1_/_2 state remains semi-occupied and contributing partially in the depletion of central density resulting semi-bubble structure for Z = 16 and 18. For Z≥20, 2s_1_/_2 state get fully occupied and no sign of bubble structures are seen for higher isotones

Future Potential for Hydro-Québec and the Québec electricity market

OpenAIRE

Teig, Atle Nedbu

2010-01-01

The purpose of this thesis is to investigate what a restructuring of the Québec electricity market could mean for Hydro-Québec and the Province of Québec. The thesis is divided into four main sections. Section one describes the drivers of electricity markets and we get an introduction to the situation in Québec. The environmental aspect of energy is also explained. Section two describes the electricity market in Norway and the Nordic countries, which works as a benchma...

Relativistic mean field calculations in neutron-rich nuclei

Energy Technology Data Exchange (ETDEWEB)

Gangopadhyay, G.; Bhattacharya, Madhubrata [Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700 009 (India); Roy, Subinit [Saha Institute of Nuclear Physics, Block AF, Sector 1, Kolkata- 700 064 (India)

2014-08-14

Relativistic mean field calculations have been employed to study neutron rich nuclei. The Lagrange's equations have been solved in the co-ordinate space. The effect of the continuum has been effectively taken into account through the method of resonant continuum. It is found that BCS approximation performs as well as a more involved Relativistic Continuum Hartree Bogoliubov approach. Calculations reveal the possibility of modification of magic numbers in neutron rich nuclei. Calculation for low energy proton scattering cross sections shows that the present approach reproduces the density in very light neutron rich nuclei.

Quantum critical scaling of fidelity in BCS-like model

International Nuclear Information System (INIS)

Adamski, Mariusz; Jedrzejewski, Janusz; Krokhmalskii, Taras

2013-01-01

We study scaling of the ground-state fidelity in neighborhoods of quantum critical points in a model of interacting spinful fermions—a BCS-like model. Due to the exact diagonalizability of the model, in one and higher dimensions, scaling of the ground-state fidelity can be analyzed numerically with great accuracy, not only for small systems but also for macroscopic ones, together with the crossover region between them. Additionally, in the one-dimensional case we have been able to derive a number of analytical formulas for fidelity and show that they accurately fit our numerical results; these results are reported in the paper. Besides regular critical points and their neighborhoods, where well-known scaling laws are obeyed, there is the multicritical point and critical points in its proximity where anomalous scaling behavior is found. We also consider scaling of fidelity in neighborhoods of critical points where fidelity oscillates strongly as the system size or the chemical potential is varied. Our results for a one-dimensional version of a BCS-like model are compared with those obtained recently by Rams and Damski in similar studies of a quantum spin chain—an anisotropic XY model in a transverse magnetic field. (paper)

Relativistic mean field theory for deformed nuclei with pairing correlations

International Nuclear Information System (INIS)

Geng, Lisheng; Toki, Hiroshi; Sugimoto, Satoru; Meng, Jie

2003-01-01

We develop a relativistic mean field (RMF) description of deformed nuclei with pairing correlations in the BCS approximation. The treatment of the pairing correlations for nuclei whose Fermi surfaces are close to the threshold of unbound states needs special attention. With this in mind, we use a delta function interaction for the pairing interaction to pick up those states whose wave functions are concentrated in the nuclear region and employ the standard BCS approximation for the single-particle states obtained from the BMF theory with deformation. We apply the RMF + BCS method to the Zr isotopes and obtain a good description of the binding energies and the nuclear radii of nuclei from the proton drip line to the neutron drip line. (author)

Superconducting fluctuations in systems with Rashba-spin-orbit coupling

Energy Technology Data Exchange (ETDEWEB)

Beyl, Stefan [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg (Germany); Orth, Peter P.; Scheurer, Mathias; Schmalian, Joerg [Institut fuer Theorie der Kondensierten Materie, Karlsruher Institut fuer Technologie (Germany)

2015-07-01

We investigate the BEC-BCS crossover in a two-dimensional system with Rashba-spin-orbit coupling. To include the effects of phase and amplitude fluctuations of the superconducting order parameter we perform a loop expansion of the effective field theory. We analyze in particular the probability of a low density superconducting quantum phase transition. The theory is relevant to LaAlO{sub 3}/SrTiO{sub 3} interfaces and two-dimensional cold atom systems with synthetic gauge fields.

Effective and fundamental quantum fields at criticality

Energy Technology Data Exchange (ETDEWEB)

Scherer, Michael

2010-10-28

We employ Wetterich's approach to functional renormalization as a suitable method to investigate universal phenomena in non-perturbative quantum field theories both qualitatively and quantitatively. Therefore we derive and investigate flow equations for a class of chiral Yukawa models with and without gauge bosons and reveal fixed-point mechanisms. In four dimensions chiral Yukawa systems serve as toy models for the standard model Higgs sector and show signatures of asymptotically safe fixed points by a balancing of bosonic and fermionic contributions. In the approximations investigated this renders the theory fundamental and solves the triviality problem. Further, we obtain predictions for the Higgs mass and even for the top mass of our toy model. In three dimensions we compute the critical exponents which define new universality classes and provide benchmark values for systems of strongly correlated chiral fermions. In a Yukawa system of non-relativistic two-component fermions a fixed point dominates the renormalization flow giving rise to universality in the BCS-BEC crossover. We push the functional renormalization method to a quantitative level and we compute the critical temperature and the single-particle gap with a considerable precision for the whole crossover. Finally, we provide further evidence for the asymptotic safety scenario in quantum gravity by confirming the existence of an ultraviolet fixed point under inclusion of a curvature-ghost coupling. (orig.)

Effective and fundamental quantum fields at criticality

International Nuclear Information System (INIS)

Scherer, Michael

2010-01-01

We employ Wetterich's approach to functional renormalization as a suitable method to investigate universal phenomena in non-perturbative quantum field theories both qualitatively and quantitatively. Therefore we derive and investigate flow equations for a class of chiral Yukawa models with and without gauge bosons and reveal fixed-point mechanisms. In four dimensions chiral Yukawa systems serve as toy models for the standard model Higgs sector and show signatures of asymptotically safe fixed points by a balancing of bosonic and fermionic contributions. In the approximations investigated this renders the theory fundamental and solves the triviality problem. Further, we obtain predictions for the Higgs mass and even for the top mass of our toy model. In three dimensions we compute the critical exponents which define new universality classes and provide benchmark values for systems of strongly correlated chiral fermions. In a Yukawa system of non-relativistic two-component fermions a fixed point dominates the renormalization flow giving rise to universality in the BCS-BEC crossover. We push the functional renormalization method to a quantitative level and we compute the critical temperature and the single-particle gap with a considerable precision for the whole crossover. Finally, we provide further evidence for the asymptotic safety scenario in quantum gravity by confirming the existence of an ultraviolet fixed point under inclusion of a curvature-ghost coupling. (orig.)

Some Recent Progress on Quark Pairings in Dense Quark and Nuclear Matter

International Nuclear Information System (INIS)

Pang Jinyi; Wang Jincheng; Wang Qun

2012-01-01

In this review article we give a brief overview on some recent progress in quark pairings in dense quark/nuclear matter mostly developed in the past five years. We focus on following aspects in particular: the BCS-BEC crossover in the CSC phase, the baryon formation and dissociation in dense quark/nuclear matter, the Ginzburg-Landau theory for three-flavor dense matter with U A (1) anomaly, and the collective and Nambu-Goldstone modes for the spin-one CSC. (physics of elementary particles and fields)

Shell-model Monte Carlo simulations of the BCS-BEC crossover in few-fermion systems

DEFF Research Database (Denmark)

Zinner, Nikolaj Thomas; Mølmer, Klaus; Özen, C.

2009-01-01

We study a trapped system of fermions with a zero-range two-body interaction using the shell-model Monte Carlo method, providing ab initio results for the low particle number limit where mean-field theory is not applicable. We present results for the N-body energies as function of interaction...

BCS 50 years

CERN Document Server

Feldman, Dimitri

2011-01-01

The BCS theory of superconductivity developed in 1957 by Bardeen, Cooper and Schrieffer has been remarkably successful in explaining the properties of superconductors. In addition, concepts from BCS have been incorporated into diverse fields of physics, from nuclear physics and dense quark matter to the current standard model. Practical applications include SQUIDs, magnetic resonance imaging, superconducting electronics and the transmission of electricity. This invaluable book is a compilation of both a historical account and a discussion of the current state of theory and experiment. With con

Ultracold atoms and the Functional Renormalization Group

International Nuclear Information System (INIS)

Boettcher, Igor; Pawlowski, Jan M.; Diehl, Sebastian

2012-01-01

We give a self-contained introduction to the physics of ultracold atoms using functional integral techniques. Based on a consideration of the relevant length scales, we derive the universal effective low energy Hamiltonian describing ultracold alkali atoms. We then introduce the concept of the effective action, which generalizes the classical action principle to full quantum status and provides an intuitive and versatile tool for practical calculations. This framework is applied to weakly interacting degenerate bosons and fermions in the spatial continuum. In particular, we discuss the related BEC and BCS quantum condensation mechanisms. We then turn to the BCS-BEC crossover, which interpolates between both phenomena, and which is realized experimentally in the vicinity of a Feshbach resonance. For its description, we introduce the Functional Renormalization Group approach. After a general discussion of the method in the cold atoms context, we present a detailed and pedagogical application to the crossover problem. This not only provides the physical mechanism underlying this phenomenon. More generally, it also reveals how the renormalization group can be used as a tool to capture physics at all scales, from few-body scattering on microscopic scales, through the finite temperature phase diagram governed by many-body length scales, up to critical phenomena dictating long distance physics at the phase transition. The presentation aims to equip students at the beginning PhD level with knowledge on key physical phenomena and flexible tools for their description, and should enable to embark upon practical calculations in this field.

Theoretical Study of Spin Crossover in 30 Iron Complexes

DEFF Research Database (Denmark)

Kepp, Kasper Planeta

2016-01-01

Spin crossover was studied in 30 iron complexes using density functional theory to quantify the direction and magnitude of dispersion, relativistic effects, zero-point energies, and vibrational entropy. Remarkably consistent entropy−enthalpy compensation was identified. Zero-point energies favor...

High-temperature atomic superfluidity in lattice Bose-Fermi mixtures.

Science.gov (United States)

Illuminati, Fabrizio; Albus, Alexander

2004-08-27

We consider atomic Bose-Fermi mixtures in optical lattices and study the superfluidity of fermionic atoms due to s-wave pairing induced by boson-fermion interactions. We prove that the induced fermion-fermion coupling is always attractive if the boson-boson on-site interaction is repulsive, and predict the existence of an enhanced BEC-BCS crossover as the strength of the lattice potential is varied. We show that for direct on-site fermion-fermion repulsion, the induced attraction can give rise to superfluidity via s-wave pairing at striking variance with the case of pure systems of fermionic atoms with direct repulsive interactions.

High-temperature atomic superfluidity in lattice Bose-Fermi mixtures

International Nuclear Information System (INIS)

Illuminati, Fabrizio; Albus, Alexander

2004-01-01

We consider atomic Bose-Fermi mixtures in optical lattices and study the superfluidity of fermionic atoms due to s-wave pairing induced by boson-fermion interactions. We prove that the induced fermion-fermion coupling is always attractive if the boson-boson on-site interaction is repulsive, and predict the existence of an enhanced BEC-BCS crossover as the strength of the lattice potential is varied. We show that for direct on-site fermion-fermion repulsion, the induced attraction can give rise to superfluidity via s-wave pairing at striking variance with the case of pure systems of fermionic atoms with direct repulsive interactions

Vortex Lattices in the Bose-Fermi Superfluid Mixture.

Science.gov (United States)

Jiang, Yuzhu; Qi, Ran; Shi, Zhe-Yu; Zhai, Hui

2017-02-24

In this Letter we show that the vortex lattice structure in the Bose-Fermi superfluid mixture can undergo a sequence of structure transitions when the Fermi superfluid is tuned from the BCS regime to the BEC regime. This is due to the difference in the vortex core structure of a Fermi superfluid in the BCS regime and in the BEC regime. In the BCS regime the vortex core is nearly filled, while the density at the vortex core gradually decreases until it empties out in the BEC regime. Therefore, with the density-density interaction between the Bose and the Fermi superfluids, interaction between the two sets of vortex lattices gets stronger in the BEC regime, which yields the structure transition of vortex lattices. In view of the recent realization of this superfluid mixture and vortices therein, our theoretical predication can be verified experimentally in the near future.

Superconductivity a new approach based on the Bethe-Salpeter equation in the mean-field approximation

CERN Document Server

Malik, G P

2016-01-01

Given the Debye temperature of an elemental superconductor (SC) and its Tc, BCS theory enables one to predict the value of its gap 0 at T = 0, or vice versa. This monograph shows that non-elemental SCs can be similarly dealt with via the generalized BCS equations (GBCSEs) which, given any two parameters of the set {Tc, 10, 20 > 10}, enable one to predict the third. Also given herein are new equations for the critical magnetic field and critical current density of an elemental and a non-elemental SC — equations that are derived directly from those that govern pairing in them. The monograph includes topics that are usually not covered in any one text on superconductivity, e.g., BCS-BEC crossover physics, the long-standing puzzle posed by SrTiO3, and heavy-fermion superconductors — all of which are still imperfectly understood and therefore continue to avidly engage theoreticians. It suggests that addressing the Tcs, s and other properties (e.g., number densities of charge carriers) of high-Tc SCs via GBCSE...

Second sound in a two-dimensional Bose gas: From the weakly to the strongly interacting regime

Science.gov (United States)

Ota, Miki; Stringari, Sandro

2018-03-01

Using Landau's theory of two-fluid hydrodynamics, we investigate first and second sounds propagating in a two-dimensional (2D) Bose gas. We study the temperature and interaction dependence of both sound modes and show that their behavior exhibits a deep qualitative change as the gas evolves from the weakly interacting to the strongly interacting regime. Special emphasis is placed on the jump of both sounds at the Berezinskii-Kosterlitz-Thouless transition, caused by the discontinuity of the superfluid density. We find that the excitation of second sound through a density perturbation becomes weaker and weaker as the interaction strength increases as a consequence of the decrease in the thermal expansion coefficient. Our results could be relevant for future experiments on the propagation of sound on the Bose-Einstein condensate (BEC) side of the BCS-BEC crossover of a 2D superfluid Fermi gas.

Introduction to the functional renormalization group

International Nuclear Information System (INIS)

Kopietz, Peter; Bartosch, Lorenz; Schuetz, Florian

2010-01-01

This book, based on a graduate course given by the authors, is a pedagogic and self-contained introduction to the renormalization group with special emphasis on the functional renormalization group. The functional renormalization group is a modern formulation of the Wilsonian renormalization group in terms of formally exact functional differential equations for generating functionals. In Part I the reader is introduced to the basic concepts of the renormalization group idea, requiring only basic knowledge of equilibrium statistical mechanics. More advanced methods, such as diagrammatic perturbation theory, are introduced step by step. Part II then gives a self-contained introduction to the functional renormalization group. After a careful definition of various types of generating functionals, the renormalization group flow equations for these functionals are derived. This procedure is shown to encompass the traditional method of the mode elimination steps of the Wilsonian renormalization group procedure. Then, approximate solutions of these flow equations using expansions in powers of irreducible vertices or in powers of derivatives are given. Finally, in Part III the exact hierarchy of functional renormalization group flow equations for the irreducible vertices is used to study various aspects of non-relativistic fermions, including the so-called BCS-BEC crossover, thereby making the link to contemporary research topics. (orig.)

A second generation Cs BEC experiment

International Nuclear Information System (INIS)

Gustavsson, M.; Unterwaditzer, P.; Naegerl, H.-C.

2004-01-01

We present a new experiment currently under construction in Innsbruck. A Cs BEC will be produced in a glass cell apparatus, allowing maximum optical access and rapid switching of magnetic fields. A high loading rate and a large-volume optical dipole trap at near infrared wavelengths together with optimized 3D Raman sideband cooling should allow for large condensates with more than 10 6 atoms. We plan to load the BEC into a 3D optical lattice. With precisely two or three atoms per site and s-wave interactions tunable through Feshbach resonances at low magnetic fields, it will be possible to study collisions and molecule formation in a very controlled environment. The formation of a molecular BEC made out of bosonic constituents might be stabilized with help of the lattice. A further possible application is the measurement of clock shifts. Another interesting possibility is to study the regime of zero scattering length. A BEC without perturbing mean-field shifts is ideally suited for atom interferometry and precision measurements. For example, it is possible to determine the fine structure constant alpha via measurement of the photon recoil. (author)

Uncertainty dimension and basin entropy in relativistic chaotic scattering

Science.gov (United States)

Bernal, Juan D.; Seoane, Jesús M.; Sanjuán, Miguel A. F.

2018-04-01

Chaotic scattering is an important topic in nonlinear dynamics and chaos with applications in several fields in physics and engineering. The study of this phenomenon in relativistic systems has received little attention as compared to the Newtonian case. Here we focus our work on the study of some relevant characteristics of the exit basin topology in the relativistic Hénon-Heiles system: the uncertainty dimension, the Wada property, and the basin entropy. Our main findings for the uncertainty dimension show two different behaviors insofar as we change the relativistic parameter β , in which a crossover behavior is uncovered. This crossover point is related with the disappearance of KAM islands in phase space, which happens for velocity values above the ultrarelativistic limit, v >0.1 c . This result is supported by numerical simulations and by qualitative analysis, which are in good agreement. On the other hand, the computation of the exit basins in the phase space suggests the existence of Wada basins for a range of β relevant in galactic dynamics, and it also has important implications in other topics in physics such as as in the Störmer problem, among others.

Condensation for non-relativistic matter in Hořava–Lifshitz gravity

Directory of Open Access Journals (Sweden)

Jiliang Jing

2015-10-01

Full Text Available We study condensation for non-relativistic matter in a Hořava–Lifshitz black hole without the condition of the detailed balance. We show that, for the fixed non-relativistic parameter α2 (or the detailed balance parameter ϵ, it is easier for the scalar hair to form as the parameter ϵ (or α2 becomes larger, but the condensation is not affected by the non-relativistic parameter β2. We also find that the ratio of the gap frequency in conductivity to the critical temperature decreases with the increase of ϵ and α2, but increases with the increase of β2. The ratio can reduce to the Horowitz–Roberts relation ωg/Tc≈8 obtained in the Einstein gravity and Cai's result ωg/Tc≈13 found in a Hořava–Lifshitz gravity with the condition of the detailed balance for the relativistic matter. Especially, we note that the ratio can arrive at the value of the BCS theory ωg/Tc≈3.5 by taking proper values of the parameters.

A new generation all-optical Cs BEC

International Nuclear Information System (INIS)

Gustavsson, M.; Haller, E.; Flir, A.; Rojas Kopeinig, G.; Naegerl, H.C.

2006-01-01

Full text: We have recently produced a Cs BEC in a new generation setup. The condensate is formed in a glass cell, allowing maximum optical access and rapid switching of magnetic fields compared to our first Cs BEC experiment. After a pre-cooling stage consisting of a MOT and 3D Raman sideband cooling, we load 10 7 atoms at a temperature of 1.5 μK in a large-volume crossed optical dipole trap, generated by a high power laser diode stack. To reach degeneracy the atoms are transferred to a focused 'dimple' trap where the density is high enough to allow for efficient evaporation. We report on the progress of loading the BEC in an optical lattice, which together with tunable s-wave scattering length and several Feshbach resonances at low magnetic fields will offer many possibilities for exciting experiments towards the complete control of all degrees of freedom for ultracold molecules. The regime of zero scattering length is another interesting area of study. A BEC without perturbing mean-field shifts is ideally suited for a detailed study of Bloch oscillations in the noninteracting regime. It will also be possible to extend and improve previous BEC based experiments to determine the fine structure constant via a measurement of the photon recoil in an atom interferometer. (author)

Bound states and Cooper pairs of molecules in 2D optical lattices bilayer

Energy Technology Data Exchange (ETDEWEB)

Camacho-Guardian, A.; Dominguez-Castro, G.A.; Paredes, R. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico (Mexico)

2016-08-15

We investigate the formation of Cooper pairs, bound dimers and the dimer-dimer elastic scattering of ultracold dipolar Fermi molecules confined in a 2D optical lattice bilayer configuration. While the energy and their associated bound states are determined in a variational way, the correlated two-molecule pair is addressed as in the original Cooper formulation. We demonstrate that the 2D lattice confinement favors the formation of zero center mass momentum bound states. Regarding the Cooper pairs binding energy, this depends on the molecule populations in each layer. Maximum binding energies occur for non-zero (zero) pair momentum when the Fermi system is polarized (unpolarized). We find an analytic expression for the dimer-dimer effective interaction in the deep BEC regime. The present analysis represents a route for addressing the BCS-BEC crossover in dipolar Fermi gases confined in 2D optical lattices within the current experimental panorama. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Exotic superfluidity and pairing phenomena in atomic Fermi gases in mixed dimensions.

Science.gov (United States)

Zhang, Leifeng; Che, Yanming; Wang, Jibiao; Chen, Qijin

2017-10-11

Atomic Fermi gases have been an ideal platform for simulating conventional and engineering exotic physical systems owing to their multiple tunable control parameters. Here we investigate the effects of mixed dimensionality on the superfluid and pairing phenomena of a two-component ultracold atomic Fermi gas with a short-range pairing interaction, while one component is confined on a one-dimensional (1D) optical lattice whereas the other is in a homogeneous 3D continuum. We study the phase diagram and the pseudogap phenomena throughout the entire BCS-BEC crossover, using a pairing fluctuation theory. We find that the effective dimensionality of the non-interacting lattice component can evolve from quasi-3D to quasi-1D, leading to strong Fermi surface mismatch. Upon pairing, the system becomes effectively quasi-two dimensional in the BEC regime. The behavior of T c bears similarity to that of a regular 3D population imbalanced Fermi gas, but with a more drastic departure from the regular 3D balanced case, featuring both intermediate temperature superfluidity and possible pair density wave ground state. Unlike a simple 1D optical lattice case, T c in the mixed dimensions has a constant BEC asymptote.

Contributions to the mathematical study of BCS theory

International Nuclear Information System (INIS)

Deuchert, Andreas

2016-01-01

The results of this thesis contribute to the mathematical study of BCS theory, that is, to the study of the BCS gap equation and the BCS functional. In the first part, we investigate a recent definition of a generalized relative entropy for bounded and not necessarily compact operators, which, in the second part, is used to define and study a non-periodic version of the BCS functional with an external field. In the third part of this work, we consider the BCS functional in two spatial dimensions with a radial pair interaction and show that the translational symmetry of the model is not broken. The quantum relative entropy plays an important role in statistical mechanics and quantum information theory. Apart from its relevance in quantum physics, it has interesting mathematical properties, such as joint convexity and monotonicity. From a purely mathematical point of view, it can be interpreted as a distance measure between two matrices, or more generally two trace-class operators, A and B. Like Hartree states, BCS states are conveniently described in terms of a generalized one-particle density matrix and so it is no surprise that the need to extend the relative entropy to non-compact operators also plays a role in BCS theory. This was our initial motivation in studying this object. The generalized relative entropy of Lewin and Sabin is defined by a limiting procedure that resembles the thermodynamic limit. An important question left open in their work is whether there exists a simple formula that allows one to compute the limit without having to work with the complicated limiting procedure. Such a formula is necessary for example for trial state arguments. In Chapter 2 we answer this question affirmatively and derive such a formula. Assuming some mild regularity conditions for the operators A and B, we show that it takes a particularly simple form, which is suitable for computations. Our proof is based upon a novel integral representation of the generalized relative

Contributions to the mathematical study of BCS theory

Energy Technology Data Exchange (ETDEWEB)

Deuchert, Andreas

2016-09-29

The results of this thesis contribute to the mathematical study of BCS theory, that is, to the study of the BCS gap equation and the BCS functional. In the first part, we investigate a recent definition of a generalized relative entropy for bounded and not necessarily compact operators, which, in the second part, is used to define and study a non-periodic version of the BCS functional with an external field. In the third part of this work, we consider the BCS functional in two spatial dimensions with a radial pair interaction and show that the translational symmetry of the model is not broken. The quantum relative entropy plays an important role in statistical mechanics and quantum information theory. Apart from its relevance in quantum physics, it has interesting mathematical properties, such as joint convexity and monotonicity. From a purely mathematical point of view, it can be interpreted as a distance measure between two matrices, or more generally two trace-class operators, A and B. Like Hartree states, BCS states are conveniently described in terms of a generalized one-particle density matrix and so it is no surprise that the need to extend the relative entropy to non-compact operators also plays a role in BCS theory. This was our initial motivation in studying this object. The generalized relative entropy of Lewin and Sabin is defined by a limiting procedure that resembles the thermodynamic limit. An important question left open in their work is whether there exists a simple formula that allows one to compute the limit without having to work with the complicated limiting procedure. Such a formula is necessary for example for trial state arguments. In Chapter 2 we answer this question affirmatively and derive such a formula. Assuming some mild regularity conditions for the operators A and B, we show that it takes a particularly simple form, which is suitable for computations. Our proof is based upon a novel integral representation of the generalized relative

The biowaiver extension for BCS class III drugs: the effect of dissolution rate on the bioequivalence of BCS class III immediate-release drugs predicted by computer simulation.

Science.gov (United States)

Tsume, Yasuhiro; Amidon, Gordon L

2010-08-02

The Biopharmaceutical Classification System (BCS) guidance issued by the FDA allows waivers for in vivo bioavailability and bioequivalence studies for immediate-release (IR) solid oral dosage forms only for BCS class I drugs. However, a number of drugs within BCS class III have been proposed to be eligible for biowaivers. The World Health Organization (WHO) has shortened the requisite dissolution time of BCS class III drugs on their Essential Medicine List (EML) from 30 to 15 min for extended biowaivers; however, the impact of the shorter dissolution time on AUC(0-inf) and C(max) is unknown. The objectives of this investigation were to assess the ability of gastrointestinal simulation software to predict the oral absorption of the BCS class I drugs propranolol and metoprolol and the BCS class III drugs cimetidine, atenolol, and amoxicillin, and to perform in silico bioequivalence studies to assess the feasibility of extending biowaivers to BCS class III drugs. The drug absorption from the gastrointestinal tract was predicted using physicochemical and pharmacokinetic properties of test drugs provided by GastroPlus (version 6.0). Virtual trials with a 200 mL dose volume at different drug release rates (T(85%) = 15 to 180 min) were performed to predict the oral absorption (C(max) and AUC(0-inf)) of the above drugs. Both BCS class I drugs satisfied bioequivalence with regard to the release rates up to 120 min. The results with BCS class III drugs demonstrated bioequivalence using the prolonged release rate, T(85%) = 45 or 60 min, indicating that the dissolution standard for bioequivalence is dependent on the intestinal membrane permeability and permeability profile throughout the gastrointestinal tract. The results of GastroPlus simulations indicate that the dissolution rate of BCS class III drugs could be prolonged to the point where dissolution, rather than permeability, would control the overall absorption. For BCS class III drugs with intestinal absorption patterns

THE MEANING OF CANADIAN FEDERALISM IN QUÉBEC: CRITICAL REFLECTIONS

Directory of Open Access Journals (Sweden)

Guy Laforest

2010-10-01

Full Text Available Ever since the federal founding of Canada in 1867, Québec has substantiallycontributed to the various stages in the evolution of the Canadian state and inthe interpretation of Canadian federalism. In the aftermath of the referendumsof 1980 and 1995, and considering that a third sovereignty referendum appearsquite unlikely in Québec, this article provides a survey and critical understandingof current federalist thinking and current academic discourses concerning federalismin Québec. Although the article is mostly about intellectual history, it integratescurrent political developments in the province of Québec, governed bythe Liberals led by Jean Charest since 2003, and in Canada as a whole as well,governed since 2006 by consecutive Conservative minority governments underthe leadership of Stephen Harper. The article shows that in the major academicdiscipines of constitutional law, history, political science and philosophy, Québecinterpretations of Canadian federalism continue to be dominated by a paradigmformulated by the Report of the Tremblay Commission, a forum for enquiry onconstitutional matters created by the Québec government more than fifty yearsago. The dominant paradigm continues to propose an «existential» approachfocusing on greater autonomy and recognition for Québec, while at the sametime adopting an instrumental-utilitarian stance towards Canada. While thisapproach continues to be developed with great academic sophistication, in mostof these disciplines a certain federalist «revival» is under way, attempting topropose a better equilibrium between the requirements of autonomy-recognitionfor Québec and those of solidarity-interdependence with the whole of Canada.

Quasiparticle lifetime in a mixture of Bose and Fermi superfluids.

Science.gov (United States)

Zheng, Wei; Zhai, Hui

2014-12-31

In this Letter, we study the effect of quasiparticle interactions in a Bose-Fermi superfluid mixture. We consider the lifetime of a quasiparticle of the Bose superfluid due to its interaction with quasiparticles in the Fermi superfluid. We find that this damping rate, i.e., the inverse of the lifetime, has quite a different threshold behavior at the BCS and the BEC side of the Fermi superfluid. The damping rate is a constant near the threshold momentum in the BCS side, while it increases rapidly in the BEC side. This is because, in the BCS side, the decay process is restricted by the constraint that the fermion quasiparticle is located near the Fermi surface, while such a restriction does not exist in the BEC side where the damping process is dominated by bosonic quasiparticles of the Fermi superfluid. Our results are related to the collective mode experiment in the recently realized Bose-Fermi superfluid mixture.

Biometrics Enabling Capability Increment 1 (BEC Inc 1)

Science.gov (United States)

2016-03-01

modal biometrics submissions to include iris, face, palm and finger prints from biometrics collection devices, which will support the Warfighter in...2016 Major Automated Information System Annual Report Biometrics Enabling Capability Increment 1 (BEC Inc 1) Defense Acquisition Management...Phone: 227-3119 DSN Fax: Date Assigned: July 15, 2015 Program Information Program Name Biometrics Enabling Capability Increment 1 (BEC Inc 1) DoD

Absence of coherent peaks in a Z2 fractionalized BCS superconducting state

Science.gov (United States)

Zhong, Yin; Lu, Han-Tao; Luo, Hong-Gang

2015-01-01

We explore a Z2 fractionalized Bardeen-Cooper-Schrieffer (BCS) superconducting state, which is a minimal extension of usual BCS framework. It is found that this state has similar thermal and transport properties, but its single-particle feature strongly deviates from the coherent quasiparticle behavior of the classic/conventional BCS superconducting state. The fingerprint of such Z2 BCS state is the absence of the BCS coherent peaks and instead a kink in the local density of state occurs, which in principle could be probed by scanning tunneling microscopy or point-contact spectroscopy experiments. The corresponding exactly soluble models that realize the desirable Z2 fractionalized BCS state are presented. In addition, we also study the extended t-U-J model by using Z2 slave-spin representation and find that the Z2 BCS state may exist when the paring structure is fully gapped or has nodes. The prototypical wave-function of such a Z2 BCS state is also proposed, which could be taken as trial wave-function in current numerical techniques. Furthermore, the pairing mechanism of Z2 BCS state is argued from both weak and strong coupling perspective. The present work may be helpful to further study the unconventional superconductivity and its relation to non-Fermi liquids.

Hot and steamy (but untrue) stories of the boiler emergency cooling system (BECS)

International Nuclear Information System (INIS)

Lorencez, C.; Bramble, A.

2004-01-01

The PNGS 'B' Boiler Emergency Cooling System (BECS) has been designed to provide interim makeup inventory to the boilers following a Loss of Feedwater, Steam Balance Header or Main Steam Line break event. Its objective is to operate as an interim heat sink to remove the excess energy in the Heat Transport System until a long term heat sink can be placed in service. The effectiveness of BECS has been assessed for a range of BECS tank water levels and pressure at the ambient Boiler Room (BR) temperature. Currently, BECS operates at a pressure of 160 kPa(g) and a water level of 2.2 m, and it is assumed that the water temperature is similar to that of the BR because there is no temperature instrumentation in tanks. However, it has been suggested that the coolant temperature in the BECS tanks may be much higher than the BR temperature in several PNGS 'B' units; this is attributed to in-leakage of high pressure and temperature water (at 4.7 Mpa(g) and 250 o C) from the Reheater Drains system into the BECS tanks, as observed by an increasing water tank levels in several units. Thus, to predict and assess the effect of the current in-leakage on the BECS water temperature, a numerical model of the BECS tanks was developed. (author)

Dynamical vanishing of the order parameter in a confined Bardeen-Cooper-Schrieffer Fermi gas after an interaction quench

Science.gov (United States)

Hannibal, S.; Kettmann, P.; Croitoru, M. D.; Axt, V. M.; Kuhn, T.

2018-01-01

We present a numerical study of the Higgs mode in an ultracold confined Fermi gas after an interaction quench and find a dynamical vanishing of the superfluid order parameter. Our calculations are done within a microscopic density-matrix approach in the Bogoliubov-de Gennes framework which takes the three-dimensional cigar-shaped confinement explicitly into account. In this framework, we study the amplitude mode of the order parameter after interaction quenches starting on the BCS side of the BEC-BCS crossover close to the transition and ending in the BCS regime. We demonstrate the emergence of a dynamically vanishing superfluid order parameter in the spatiotemporal dynamics in a three-dimensional trap. Further, we show that the signal averaged over the whole trap mirrors the spatiotemporal behavior and allows us to systematically study the effects of the system size and aspect ratio on the observed dynamics. Our analysis enables us to connect the confinement-induced modifications of the dynamics to the pairing properties of the system. Finally, we demonstrate that the signature of the Higgs mode is contained in the dynamical signal of the condensate fraction, which, therefore, might provide a new experimental access to the nonadiabatic regime of the Higgs mode.

On nonlinear dynamics of a dipolar exciton BEC in two-layer graphene

International Nuclear Information System (INIS)

Berman, O.L.; Kezerashvili, R.Ya.; Kolmakov, G.V.

2012-01-01

The nonlinear dynamics of a Bose–Einstein condensate (BEC) of dipolar excitons in two-layer graphene is studied. It is demonstrated that a steady turbulent state is formed in this system. A comparison between the dynamics of the exciton BEC in two-layer graphene and those in GaAs/AlGaAs coupled quantum wells shows that turbulence is a general effect in a BEC.

Introduction to superfluidity field-theoretical approach and applications

CERN Document Server

Schmitt, Andreas

2015-01-01

Superfluidity – and closely related to it, superconductivity – are very general phenomena that can occur on vastly different energy scales. Their underlying theoretical mechanism of spontaneous symmetry breaking is even more general and applies to a multitude of physical systems.  In these lecture notes, a pedagogical introduction to the field-theory approach to superfluidity is presented. The connection to more traditional approaches, often formulated in a different language, is carefully explained in order to provide a consistent picture that is useful for students and researchers in all fields of physics. After introducing the basic concepts, such as the two-fluid model and the Goldstone mode, selected topics of current research are addressed, such as the BCS-BEC crossover and Cooper pairing with mismatched Fermi momenta.

Advanced evaluation method of SG TSP BEC hole blockage rate

International Nuclear Information System (INIS)

Izumida, Hiroyuki; Nagata, Yasuyuki; Harada, Yutaka; Murakami, Ryuji

2003-01-01

In spite of the control of the water chemistry of SG secondary feed-water in PWR-SG, SG TSP BEC holes, which are the flow path of secondary water, are often clogged. In the past, the trending of BEC hole blockage rate has conducted by evaluating ECT original signals and visual inspections. However, the ECT original signals of deposits are diversified, it becomes difficult to analyze them with the existing evaluation method using the ECT original signals. In this regard, we have developed the secondary side visual inspection system, which enables the high-accuracy evaluation of BEC hole blockage rate, and new ECT signal evaluation method. (author)

Educational Reevaluation, Political Transformation: Québec and Higher Education

Science.gov (United States)

Unger, Zoe

2013-01-01

This paper considers the history of Québec's higher education system and the reforms that have contributed to the role of education in the province. Québec's education system has repeatedly been a site for social and political transformation; most recently, reevaluation of education's role in the province has revealed a tension between…

Mathematical aspects of the BCS theory of superconductivity and related theories

International Nuclear Information System (INIS)

Braeunlich, Gerhard Albert

2014-01-01

The present work starts with a introduction to the BCS theory, describing superconductivity and superfluidity. The main part consist of a collection of three publications and a paper included in a conference proceedings. The introduction (Chapter 1) includes a brief historical review of the research in the field of superconductivity and superfluidity. It ends with a short summary of the technical applications of superconductivity. In Chapter 2, a derivation of the BCS functional from quantum statistics is presented. Chapter 3 explains the results of the publications mentioned above. In a first work, the validity of the negligence of the direct and exchange energy in the derivation of the BCS functional is examined. Another work addresses the connection between the BCS theory and the Gross-Pitaevskii equation.

Beyond the relativistic mean-field approximation. II. Configuration mixing of mean-field wave functions projected on angular momentum and particle number

International Nuclear Information System (INIS)

Niksic, T.; Vretenar, D.; Ring, P.

2006-01-01

The framework of relativistic self-consistent mean-field models is extended to include correlations related to the restoration of broken symmetries and to fluctuations of collective variables. The generator coordinate method is used to perform configuration mixing of angular-momentum and particle-number projected relativistic wave functions. The geometry is restricted to axially symmetric shapes, and the intrinsic wave functions are generated from the solutions of the relativistic mean-field+Lipkin-Nogami BCS equations, with a constraint on the mass quadrupole moment. The model employs a relativistic point-coupling (contact) nucleon-nucleon effective interaction in the particle-hole channel, and a density-independent δ-interaction in the pairing channel. Illustrative calculations are performed for 24 Mg, 32 S, and 36 Ar, and compared with results obtained employing the model developed in the first part of this work, i.e., without particle-number projection, as well as with the corresponding nonrelativistic models based on Skyrme and Gogny effective interactions

Relativistic continuum random phase approximation in spherical nuclei

International Nuclear Information System (INIS)

Daoutidis, Ioannis

2009-01-01

Covariant density functional theory is used to analyze the nuclear response in the external multipole fields. The investigations are based on modern functionals with zero range and density dependent coupling constants. After a self-consistent solution of the Relativistic Mean Field (RMF) equations for the nuclear ground states multipole giant resonances are studied within the Relativistic Random Phase Approximation (RRPA), the small amplitude limit of the time-dependent RMF. The coupling to the continuum is treated precisely by calculating the single particle Greens-function of the corresponding Dirac equation. In conventional methods based on a discretization of the continuum this was not possible. The residual interaction is derived from the same RMF Lagrangian. This guarantees current conservation and a precise decoupling of the Goldstone modes. For nuclei with open shells pairing correlations are taken into account in the framework of BCS theory and relativistic quasiparticle RPA. Continuum RPA (CRPA) presents a robust method connected with an astonishing reduction of the numerical effort as compared to conventional methods. Modes of various multipolarities and isospin are investigated, in particular also the newly discovered Pygmy modes in the vicinity of the neutron evaporation threshold. The results are compared with conventional discrete RPA calculations as well as with experimental data. We find that the full treatment of the continuum is essential for light nuclei and the study of resonances in the neighborhood of the threshold. (orig.)

Relativistic continuum random phase approximation in spherical nuclei

Energy Technology Data Exchange (ETDEWEB)

Daoutidis, Ioannis

2009-10-01

Covariant density functional theory is used to analyze the nuclear response in the external multipole fields. The investigations are based on modern functionals with zero range and density dependent coupling constants. After a self-consistent solution of the Relativistic Mean Field (RMF) equations for the nuclear ground states multipole giant resonances are studied within the Relativistic Random Phase Approximation (RRPA), the small amplitude limit of the time-dependent RMF. The coupling to the continuum is treated precisely by calculating the single particle Greens-function of the corresponding Dirac equation. In conventional methods based on a discretization of the continuum this was not possible. The residual interaction is derived from the same RMF Lagrangian. This guarantees current conservation and a precise decoupling of the Goldstone modes. For nuclei with open shells pairing correlations are taken into account in the framework of BCS theory and relativistic quasiparticle RPA. Continuum RPA (CRPA) presents a robust method connected with an astonishing reduction of the numerical effort as compared to conventional methods. Modes of various multipolarities and isospin are investigated, in particular also the newly discovered Pygmy modes in the vicinity of the neutron evaporation threshold. The results are compared with conventional discrete RPA calculations as well as with experimental data. We find that the full treatment of the continuum is essential for light nuclei and the study of resonances in the neighborhood of the threshold. (orig.)

BCS equations in the continuum

International Nuclear Information System (INIS)

Sandulescu, N.; Liotta, R. J.; Wyss, R.

1998-01-01

The properties of nuclei close to the drip line are significantly influenced by the continuum part of the single-particle spectrum. The main role is played by the resonant states which are largely confined in the region of nuclear potential and therefore stronger coupled with the bound states in an excitation process. Resonant states are also important in the nuclei beyond the drip line. In this case the decay properties of the nucleus can be directly related to the widths of the narrow resonances occupied by the unbound nucleons. The aim of this work is to propose an alternative for evaluating the effect of the resonant part of single-particle spectrum on the pairing correlations calculated within the BCS approximation. We estimated the role of resonances in the case of the isotope 170 Sn. The Resonant-BCS (RBCS) equations are solved for the case of a seniority force. The BCS approximation based on a seniority force cannot be applied in the case of a nucleus immersed in a box if all discrete states simulating the continuum are considered. In such a case the pairing correlations will increase with the number of states in the box. In our case one can still apply a seniority force with RBCS because the effect of the continuum appears here through a finite number of physical resonances, well defined by the given mean field. Because these resonances have a spatial distribution concentrated within the region of the nuclear potential, one expects that the localization probability of nucleons, far out from the nuclear surface, to be small. The gap obtained taking correctly the contribution of resonances, according to RBCS equations, is about 1.3 MeV, while pairing gap calculated only with the bound single-particle spectrum has the value Δ = 1.10 MeV. If we introduce also the resonant states, neglecting completely their widths, the gap will increase to the value Δ = 1.880 MeV. Therefore, one cannot estimate properly the pairing correlations by supplementing the spectrum

Preterm birth in the Inuit and First Nations populations of Québec, Canada, 1981-2008.

Science.gov (United States)

Auger, Nathalie; Fon Sing, Mélanie; Park, Alison L; Lo, Ernest; Trempe, Normand; Luo, Zhong-Cheng

2012-03-24

To evaluate preterm birth (PTB) for Inuit and First Nations vs. non-Indigenous populations in the province of Québec, Canada. Retrospective cohort study. We evaluated singleton live births for Québec residents, 1981-2008 (n = 2,310,466). Municipality of residence (Inuit-inhabited, First Nations-inhabited, rest of Québec) and language (Inuit, First Nations, French/English) were used to identify Inuit and First Nations births. The outcome was PTB (Inuit language speakers in Inuit-inhabited areas and the rest of Québec compared with French/English speakers in the rest of Québec, and disparities persisted over time. Relative to French/English speakers in the rest of Québec, Inuit language speakers in the rest of Québec had the highest risk of PTB (HR 1.98, 95% CI: 1.62-2.41). The risk was also elevated for Inuit language speakers in Inuit-inhabited areas, though to a lesser extent (HR 1.29, 95% CI: 1.18-1.41). In contrast, First Nations language speakers in First Nations-inhabited areas and the rest of Québec had similar or lower risks of PTB relative to French/English speakers in the rest of Québec. Inuit populations, especially those outside Inuit-inhabited areas, have persistently elevated risks of PTB, indicating a need for strategies to prevent PTB in this population.

Considerations for a Pediatric Biopharmaceutics Classification System (BCS): application to five drugs.

Science.gov (United States)

Gandhi, Shivani V; Rodriguez, William; Khan, Mansoor; Polli, James E

2014-06-01

It has been advocated that biopharmaceutic risk assessment should be conducted early in pediatric product development and synchronized with the adult product development program. However, we are unaware of efforts to classify drugs into a Biopharmaceutics Classification System (BCS) framework for pediatric patients. The objective was to classify five drugs into a potential BCS. These five drugs were selected since both oral and intravenous pharmacokinetic data were available for each drug, and covered the four BCS classes in adults. Literature searches for each drug were conducted using Medline and applied to classify drugs with respect to solubility and permeability in pediatric subpopulations. Four pediatric subpopulations were considered: neonates, infants, children, and adolescents. Regarding solubility, dose numbers were calculated using a volume for each subpopulation based on body surface area (BSA) relative to 250 ml for a 1.73 m(2) adult. Dose numbers spanned a range of values, depending upon the pediatric dose formula and subpopulation. Regarding permeability, pharmacokinetic literature data required assumptions and decisions about data collection. Using a devised pediatric BCS framework, there was agreement in adult and pediatric BCS class for two drugs, azithromycin (class 3) and ciprofloxacin (class 4). There was discordance for the three drugs that have high adult permeability since all pediatric permeabilities were low: dolasetron (class 3 in pediatric), ketoprofen (class 4 in pediatric), and voriconazole (class 4 in pediatric). A main contribution of this work is the identification of critical factors required for a pediatric BCS.

Preterm birth in the Inuit and First Nations populations of Québec, Canada, 1981–2008

Science.gov (United States)

Auger, Nathalie; Sing, Mélanie Fon; Park, Alison L.; Lo, Ernest; Trempe, Normand; Luo, Zhong-Cheng

2012-01-01

Objectives To evaluate preterm birth (PTB) for Inuit and First Nations vs. non-Indigenous populations in the province of Québec, Canada. Study design Retrospective cohort study. Methods We evaluated singleton live births for Québec residents, 1981–2008 (n =2,310,466). Municipality of residence (Inuit-inhabited, First Nations-inhabited, rest of Québec) and language (Inuit, First Nations, French/English) were used to identify Inuit and First Nations births. The outcome was PTB (Inuit language speakers in Inuit-inhabited areas and the rest of Québec compared with French/English speakers in the rest of Québec, and disparities persisted over time. Relative to French/English speakers in the rest of Québec, Inuit language speakers in the rest of Québec had the highest risk of PTB (HR 1.98, 95% CI: 1.62–2.41). The risk was also elevated for Inuit language speakers in Inuit-inhabited areas, though to a lesser extent (HR 1.29, 95% CI: 1.18–1.41). In contrast, First Nations language speakers in First Nations-inhabited areas and the rest of Québec had similar or lower risks of PTB relative to French/English speakers in the rest of Québec. Conclusions Inuit populations, especially those outside Inuit-inhabited areas, have persistently elevated risks of PTB, indicating a need for strategies to prevent PTB in this population. PMID:22456035

THE BIOPHARMACEUTICAL CLASSIFICATION SYSTEM (BCS): PRESENT STATUS AND FUTURE PROSPECTIVES

OpenAIRE

Budhwaar Vikaas; Nanda Arun

2012-01-01

The Biopharmaceutical classification system (BCS) was introduced By Amidon et al., (1995) as a method for classifying drug substances based on their dose/solubility ratio and intestinal permeability. It allows predicting the in vivo pharmacokinetic performance of drug products. The drug can be categorized into four classes of BCS, namely, High solubility high permeability, low solubility high permeability, High solubility low permeability and low solubility low permeability. An objective of B...

Balancing BEC and IAQ in civil buildings during rapid urbanization in China: Regulation, interplay and collaboration

International Nuclear Information System (INIS)

Zhang Jiefeng; Bai Zhipeng; Chang, Victor W.C.; Ding Xiao

2011-01-01

Energy consumption by building sector becomes more and more important in a rapid growing economy like China. Tremendous efforts have been made on building energy conservation (BEC) to comply with the national energy-saving policies over the last three decades. At the same time, with the increasing awareness of the importance of indoor air quality (IAQ), Ministry of Health (MoH) also initiates the related standards to fulfill the needs. BEC and IAQ are two main concerns in the current building management practice. This paper makes an attempt, based on the regulations and standards in chronological order, to elaborate the followings: (1) the development history of BEC and IAQ management in civil buildings in China, (2) the interplay and sometimes seeming conflicts of BEC and IAQ management in the real practice, (3) the importance of proper communications between related authorities in setting up cross-linked regulations to ensure the success of better building managements. - Highlights: → The development of BEC and IAQ management follow similar timelines. → Misconducts of building management practice may lead to compromised IAQ. → Ventilation design and thermal insulation have impacts on both BEC and IAQ. → Proper cross-agency communications essentially promote the BEC and IAQ management.

Prediction of solubility and permeability class membership: provisional BCS classification of the world's top oral drugs.

Science.gov (United States)

Dahan, Arik; Miller, Jonathan M; Amidon, Gordon L

2009-12-01

The Biopharmaceutics Classification System (BCS) categorizes drugs into one of four biopharmaceutical classes according to their water solubility and membrane permeability characteristics and broadly allows the prediction of the rate-limiting step in the intestinal absorption process following oral administration. Since its introduction in 1995, the BCS has generated remarkable impact on the global pharmaceutical sciences arena, in drug discovery, development, and regulation, and extensive validation/discussion/extension of the BCS is continuously published in the literature. The BCS has been effectively implanted by drug regulatory agencies around the world in setting bioavailability/bioequivalence standards for immediate-release (IR) oral drug product approval. In this review, we describe the BCS scientific framework and impact on regulatory practice of oral drug products and review the provisional BCS classification of the top drugs on the global market. The Biopharmaceutical Drug Disposition Classification System and its association with the BCS are discussed as well. One notable finding of the provisional BCS classification is that the clinical performance of the majority of approved IR oral drug products essential for human health can be assured with an in vitro dissolution test, rather than empirical in vivo human studies.

[Towards Professionalization : the Editorial Discourse of Québec Pharmacy magazine, 1960-2013 ].

Science.gov (United States)

Savard, Pierre-André; Meunier-Sirois, Alexandre; Marando, Nancy; Bussières, Jean-François

2016-12-01

The second half of the twentieth century and the beginning of the 2000s marked deep changes in the practice of pharmacy in Quebec. The editorials of Québec Pharmacie journal attest these changes on a 50-year period by relating power relationships, conflicts, problems and solutions that concerned pharmacists. This article proposes to analyze the editorial discourse of Québec Pharmacie journal between 1960 and 2013, and to grasp the evolution of the speech. To do so, we analyze the major topics addressed by the editorialists. It appears that Québec Pharmacie’s editorialists aimed the professionalization of pharmacy.

The Development and Preliminary Validation of the Behavior, Environment, and Changeability Survey (BECS)

Science.gov (United States)

Walsh, Jennifer R.; Hebert, Angel; Byrd-Bredbenner, Carol; Carey, Gale; Colby, Sarah; Brown-Esters, Onikia N.; Greene, Geoffrey; Hoerr, Sharon; Horacek, Tanya; Kattelmann, Kendra; Kidd, Tandalayo; Koenings, Mallory; Phillips, Beatrice; Shelnutt, Karla P.; White, Adrienne A.

2012-01-01

Objective: To develop and test the validity of the Behavior, Environment, and Changeability Survey (BECS) for identifying the importance and changeability of nutrition, exercise, and stress management behavior and related aspects of the environment. Design: A cross-sectional, online survey of the BECS and selected validated instruments. Setting:…

Nonequilibrium phenomena in QCD and BEC. Boltzmann and beyond

Energy Technology Data Exchange (ETDEWEB)

Stockamp, T.

2006-12-22

In chapter 2 we chose the real time formalism to discuss some basic principles in quantum field theory at finite temperature. This enables us to derive the quantum Boltzmann equation from the Schwinger-Dyson series. We then shortly introduce the basic concepts of QCD which are needed to understand the physics of QGP formation. After a detailed account on the bottom-up scenario we show the consistency of this approach by a diagramatical analysis of the relevant Boltzmann collision integrals. Chapter 3 deals with BEC dynamics out of equilibrium. After an introduction to the fundamental theoretical tool - namely the Gross-Pitaevskii equation - we focus on a generalization to finite temperature developed by Zaremba, Nikuni and Griffin (ZNG). These authors use a Boltzmann equation to describe the interactions between condensed and excited atoms and manage in this way to describe condensate growth. We then turn to a discussion on the 2PI effective action and derive equations of motion for a relativistic scalar field theory. In the nonrelativistic limit these equations are shown to coincide with the ZNG theory when a quasiparticle approximation is applied. Finally, we perform a numerical analysis of the full 2PI equations. These remain valid even at strong coupling and far from equilibrium, and thus go far beyond Boltzmann's approach. For simplicity, we limit ourselves to a homogeneous system and present the first 3+1 dimensional study of condensate melting. (orig.)

A modified physiological BCS for prediction of intestinal absorption in drug discovery.

Science.gov (United States)

Zaki, Noha M; Artursson, Per; Bergström, Christel A S

2010-10-04

In this study, the influence of physiologically relevant media on the compound position in a biopharmaceutical classification system (BCS) which resembled the intestinal absorption was investigated. Both solubility and permeability limited compounds (n = 22) were included to analyze the importance of each of these on the final absorption. Solubility was determined in three different dissolution media, phosphate buffer pH 6.5 (PhB 6.5), fasted state simulated intestinal fluid (FaSSIF), and fed state simulated intestinal fluid (FeSSIF) at 37 °C, and permeability values were determined using the 2/4/A1 cell line. The solubility data and membrane permeability values were used for sorting the compounds into a BCS modified to reflect the fasted and fed state. Three of the seven compounds sorted as BCS II in PhB 6.5 (high permeability, low solubility) changed their position to BCS I when dissolved in FaSSIF and/or FeSSIF (high permeability, high solubility). These were low dosed (20 mg or less) lipophilic molecules displaying solvation limited solubility. In contrast, compounds having solid-state limited solubility had a minor increase in solubility when dissolved in FaSSIF and/or FeSSIF. Although further studies are needed to enable general cutoff values, our study indicates that low dosed BCS Class II compounds which have solubility normally restricted by poor solvation may behave as BCS Class I compounds in vivo. The large series of compounds investigated herein reveals the importance of investigating solubility and dissolution under physiologically relevant conditions in all stages of the drug discovery process to push suitable compounds forward, to select proper formulations, and to reduce the risk of food effects.

Preterm birth in the Inuit and First Nations populations of Québec, Canada, 1981–2008

Directory of Open Access Journals (Sweden)

Nathalie Auger

2012-03-01

Full Text Available Objectives: To evaluate preterm birth (PTB for Inuit and First Nations vs. non-Indigenous populations in the province of Québec, Canada. Study design: Retrospective cohort study. Methods: We evaluated singleton live births for Québec residents, 1981–2008 (n = 2,310,466. Municipality of residence (Inuit-inhabited, First Nations-inhabited, rest of Québec and language (Inuit, First Nations, French/English were used to identify Inuit and First Nations births. The outcome was PTB (<37 completed weeks. Cox proportional hazards regression was employed to estimate hazard ratios (HR and 95% confidence intervals (CI of PTB, adjusting for maternal age, education, marital status, parity and birth year. Results: PTB rates were higher for Inuit language speakers in Inuit-inhabited areas and the rest of Québec compared with French/English speakers in the rest of Québec, and disparities persisted over time. Relative to French/English speakers in the rest of Québec, Inuit language speakers in the rest of Québec had the highest risk of PTB (HR 1.98, 95% CI: 1.62–2.41. The risk was also elevated for Inuit language speakers in Inuit-inhabited areas, though to a lesser extent (HR 1.29, 95% CI: 1.18–1.41. In contrast, First Nations language speakers in First Nations-inhabited areas and the rest of Québec had similar or lower risks of PTB relative to French/English speakers in the rest of Québec. Conclusions: Inuit populations, especially those outside Inuit-inhabited areas, have persistently elevated risks of PTB, indicating a need for strategies to prevent PTB in this population.

Quantum decoherence of phonons in Bose-Einstein condensates

Science.gov (United States)

Howl, Richard; Sabín, Carlos; Hackermüller, Lucia; Fuentes, Ivette

2018-01-01

We apply modern techniques from quantum optics and quantum information science to Bose-Einstein condensates (BECs) in order to study, for the first time, the quantum decoherence of phonons of isolated BECs. In the last few years, major advances in the manipulation and control of phonons have highlighted their potential as carriers of quantum information in quantum technologies, particularly in quantum processing and quantum communication. Although most of these studies have focused on trapped ion and crystalline systems, another promising system that has remained relatively unexplored is BECs. The potential benefits in using this system have been emphasized recently with proposals of relativistic quantum devices that exploit quantum states of phonons in BECs to achieve, in principle, superior performance over standard non-relativistic devices. Quantum decoherence is often the limiting factor in the practical realization of quantum technologies, but here we show that quantum decoherence of phonons is not expected to heavily constrain the performance of these proposed relativistic quantum devices.

Shear viscosity and imperfect fluidity in bosonic and fermionic superfluids

Science.gov (United States)

Boyack, Rufus; Guo, Hao; Levin, K.

2014-12-01

In this paper we address the ratio of the shear viscosity to entropy density η /s in bosonic and fermionic superfluids. A small η /s is associated with nearly perfect fluidity, and more general measures of the fluidity perfection/imperfection are of wide interest to a number of communities. We use a Kubo approach to concretely address this ratio via low-temperature transport associated with the quasiparticles. Our analysis for bosonic superfluids utilizes the framework of the one-loop Bogoliubov approximation, whereas for fermionic superfluids we apply BCS theory and its BCS-BEC extension. Interestingly, we find that the transport properties of strict BCS and Bogoliubov superfluids have very similar structures, albeit with different quasiparticle dispersion relations. While there is a dramatic contrast between the power law and exponential temperature dependence for η alone, the ratio η /s for both systems is more similar. Specifically, we find the same linear dependence (on the ratio of temperature T to inverse lifetime γ (T ) ) with η /s ∝T /γ (T ) , corresponding to imperfect fluidity. By contrast, near the unitary limit of BCS-BEC superfluids a very different behavior results, which is more consistent with near-perfect fluidity.

Casimir energy of a BEC: from moderate interactions to the ideal gas

International Nuclear Information System (INIS)

Schiefele, J; Henkel, C

2009-01-01

Considering the Casimir effect due to phononic excitations of a weakly interacting dilute Bose-Einstein condensate (BEC), we derive a renormalized expression for the zero-temperature Casimir energy E C of a BEC confined to a parallel plate geometry with periodic boundary conditions. Our expression is formally equivalent to the free energy of a bosonic field at finite temperature, with a nontrivial density of modes that we compute analytically. As a function of the interaction strength, E C smoothly describes the transition from the weakly interacting Bogoliubov regime to the non-interacting ideal BEC. For the weakly interacting case, E C reduces to leading order to the Casimir energy due to zero-point fluctuations of massless phonon modes. In the limit of an ideal Bose gas, our result correctly describes the Casimir energy going to zero

Agitation Rate and Time for Complete Dissolution in BCS Biowaivers Based on Investigation of a BCS Biowaiver for Dexketoprofen Tablets.

Science.gov (United States)

Garcia-Arieta, Alfredo; Gordon, John; Gwaza, Luther; Mangas-Sanjuan, V; Álvarez, Covadonga; Torrado, Juan J

2015-09-08

The objective of the present work is to investigate the validity of the existing requirements for BCS biowaivers of immediate release products containing a class I drug in relation to the agitation rate (50 or 75 rpm in the paddle apparatus) and the time limit for complete dissolution (30 min) in the current biowaivers in vitro dissolution tests. Further, the possibility of extensions will be examined since it has been proposed that the time limit for complete dissolution should be revised to 60 min, and also, if cone formation occurs with apparatus 2 at 50 rpm, then a higher agitation rate is acceptable to eliminate it. The development of four generic dexketoprofen immediate release tablets is described. Dexketoprofen is the eutomer of ketoprofen. According to the BCS, dexketoprofen is a class I drug. Three out of the four products failed to show bioequivalence for Cmax in the initial bioequivalence study conducted with the product despite similar but nonrapid dissolution profiles at 50 rpm in the paddle apparatus, or similar and very rapid dissolution profiles at 75 rpm. In conclusion, these data indicate that BCS biowaivers for class I drugs should be granted only when dissolution with the paddle apparatus is complete in 30 min at 50 rpm. The time limit for complete dissolution should not be extended to 60 min. Furthermore, the agitation rate should not be increased to 75 rpm, even in the case of a coning effect.

Perron-Frobenius theorem on the superfluid transition of an ultracold Fermi gas

Science.gov (United States)

Sakumichi, Naoyuki; Kawakami, Norio; Ueda, Masahito

2014-05-01

The Perron-Frobenius theorem is applied to identify the superfluid transition of the BCS-BEC crossover based on a cluster expansion method of Lee and Yang. Here, the cluster expansion is a systematic expansion of the equation of state (EOS) in terms of the fugacity z = exp (βμ) as βpλ3 = 2 z +b2z2 +b3z3 + ⋯ , with inverse temperature β =(kB T) - 1 , chemical potential μ, pressure p, and thermal de Broglie length λ =(2 πℏβ / m) 1 / 2 . According to the method of Lee and Yang, EOS is expressed by the Lee-Yang graphs. A singularity of an infinite series of ladder-type Lee-Yang graphs is analyzed. We point out that the singularity is governed by the Perron-Frobenius eigenvalue of a certain primitive matrix which is defined in terms of the two-body cluster functions and the Fermi distribution functions. As a consequence, it is found that there exists a unique fugacity at the phase transition point, which implies that there is no fragmentation of Bose-Einstein condensates of dimers and Cooper pairs at the ladder-approximation level of Lee-Yang graphs. An application to a BEC of strongly bounded dimers is also made.

The complexity of intestinal permeability: Assigning the correct BCS classification through careful data interpretation.

Science.gov (United States)

Zur, Moran; Hanson, Allison S; Dahan, Arik

2014-09-30

While the solubility parameter is fairly straightforward when assigning BCS classification, the intestinal permeability (Peff) is more complex than generally recognized. In this paper we emphasize this complexity through the analysis of codeine, a commonly used antitussive/analgesic drug. Codeine was previously classified as a low-permeability compound, based on its lower LogP compared to metoprolol, a marker for the low-high permeability class boundary. In contrast, high fraction of dose absorbed (Fabs) was reported for codeine, which challenges the generally recognized Peff-Fabs correlation. The purpose of this study was to clarify this ambiguity through elucidation of codeine's BCS solubility/permeability class membership. Codeine's BCS solubility class was determined, and its intestinal permeability throughout the small intestine was investigated, both in vitro and in vivo in rats. Codeine was found to be unequivocally a high-solubility compound. All in vitro studies indicated that codeine's permeability is higher than metoprolol's. In vivo studies in rats showed similar permeability for both drugs throughout the entire small-intestine. In conclusion, codeine was found to be a BCS Class I compound. No Peff-Fabs discrepancy is involved in its absorption; rather, it reflects the risk of assigning BCS classification based on merely limited physicochemical characteristics. A thorough investigation using multiple experimental methods is prudent before assigning a BCS classification, to avoid misjudgment in various settings, e.g., drug discovery, formulation design, drug development and regulation. Copyright © 2013 Elsevier B.V. All rights reserved.

Banks-Casher-type relation for the BCS gap at high density

OpenAIRE

Kanazawa, Takuya; Wettig, Tilo; Yamamoto, Naoki

2012-01-01

We derive a new Banks-Casher-type relation which relates the density of complex Dirac eigenvalues at the origin to the BCS gap of quarks at high density. Our relation is applicable to QCD and QCD-like theories without a sign problem, such as two-color QCD and adjoint QCD with baryon chemical potential, and QCD with isospin chemical potential. It provides us with a method to measure the BCS gap through the Dirac spectrum on the lattice.

Body condition score (BCS and metabolic status of shelter dogs

Directory of Open Access Journals (Sweden)

I. Andrighetto

2010-04-01

Full Text Available A group of 147 shelter dogs were weighted and assigned a body condition score (BCS using a 9 point scale system, in order to evaluate the prevalence of obesity in the kennel. More than 60% of the animals showed a BCS³6 (overweight and obese and this condition was mainly attributed to an excess of carbohydrates and fat in the diet. In 67/147 dogs, a blood sample was drawn and the effects of BCS, age and time spent in the shelter were evaluated on biochemical parameters. Obese dogs showed significantly higher levels of triglycerides (P<0.01, while increasing BCS determined only an increasing non significant trend on cholesterol values. Age influenced creatinine (P<0.05 and the oldest dogs scoring BCS³6 registered significant higher NEFA (P<0.05 and CK (P=0.01 levels. Time spent in the shelter did not affect any parameter. The dogs’ metabolic condition reflects the need of taking more care of the quality of feed administered in the shelters to avoid the negative health effects caused by chronic obesity.

Twisting Anderson pseudospins with light: Quench dynamics in THz-pumped BCS superconductors

Science.gov (United States)

Chou, Yang-Zhi; Liao, Yunxiang; Foster, Matthew

We study the preparation and the detection of coherent far-from-equilibrium BCS superconductor dynamics in THz pump-probe experiments. In a recent experiment, an intense monocycle THz pulse with center frequency ω = Δ was injected into a superconductor with BCS gap Δ the post-pump evolution was detected via the optical conductivity. It was argued that nonlinear coupling of the pump to the Anderson pseudospins of the superconductor induces coherent dynamics of the Higgs mode Δ (t) . We validate this picture in a 2D BCS model with a combination of exact numerics and the Lax reduction, and we compute the dynamical phase diagram. The main effect of the pump is to scramble the orientations of Anderson pseudospins along the Fermi surface by twisting them in the xy-plane. We show that more intense pulses can induce a far-from-equilibrium gapless phase (phase I), originally predicted in the context of interaction quenches. We show that the THz pump can reach phase I at much lower energy densities than an interaction quench, and we demonstrate that Lax reduction provides a quantitative tool for computing coherent BCS dynamics. We also compute the optical conductivity for the states discussed here.

Twisting Anderson pseudospins with light: Quench dynamics in terahertz-pumped BCS superconductors

Science.gov (United States)

Chou, Yang-Zhi; Liao, Yunxiang; Foster, Matthew S.

2017-03-01

We study the preparation (pump) and the detection (probe) of far-from-equilibrium BCS superconductor dynamics in THz pump-probe experiments. In a recent experiment [R. Matsunaga, Y. I. Hamada, K. Makise, Y. Uzawa, H. Terai, Z. Wang, and R. Shimano, Phys. Rev. Lett. 111, 057002 (2013), 10.1103/PhysRevLett.111.057002], an intense monocycle THz pulse with center frequency ω ≃Δ was injected into a superconductor with BCS gap Δ ; the subsequent postpump evolution was detected via the optical conductivity. It was argued that nonlinear coupling of the pump to the Anderson pseudospins of the superconductor induces coherent dynamics of the Higgs (amplitude) mode Δ (t ) . We validate this picture in a two-dimensional BCS model with a combination of exact numerics and the Lax reduction method, and we compute the nonequilibrium phase diagram as a function of the pump intensity. The main effect of the pump is to scramble the orientations of Anderson pseudospins along the Fermi surface by twisting them in the x y plane. We show that more intense pump pulses can induce a far-from-equilibrium phase of gapless superconductivity ("phase I"), originally predicted in the context of interaction quenches in ultracold atoms. We show that the THz pump method can reach phase I at much lower energy densities than an interaction quench, and we demonstrate that Lax reduction (tied to the integrability of the BCS Hamiltonian) provides a general quantitative tool for computing coherent BCS dynamics. We also calculate the Mattis-Bardeen optical conductivity for the nonequilibrium states discussed here.

Cooper-pair size and binding energy for unconventional superconducting systems

Science.gov (United States)

Dinóla Neto, F.; Neto, Minos A.; Salmon, Octavio D. Rodriguez

2018-06-01

The main proposal of this paper is to analyze the size of the Cooper pairs composed by unbalanced mass fermions from different electronic bands along the BCS-BEC crossover and study the binding energy of the pairs. We are considering an interaction between fermions with different masses leading to an inter-band pairing. In addiction to the attractive interaction we have an hybridization term to couple both bands, which in general acts unfavorable for the pairing between the electrons. We get first order phase transitions as the hybridization breaks the Cooper pairs for the s-wave symmetry of the gap amplitude. The results show the dependence of the Cooper-pair size as a function of the hybridization for T = 0 . We also propose the structure of the binding energy of the inter-band system as a function of the two-bands quasi-particle energies.

Goldstone mode and pair-breaking excitations in atomic Fermi superfluids

Science.gov (United States)

Hoinka, Sascha; Dyke, Paul; Lingham, Marcus G.; Kinnunen, Jami J.; Bruun, Georg M.; Vale, Chris J.

2017-10-01

Spontaneous symmetry breaking is a central paradigm of elementary particle physics, magnetism, superfluidity and superconductivity. According to Goldstone's theorem, phase transitions that break continuous symmetries lead to the existence of gapless excitations in the long-wavelength limit. These Goldstone modes can become the dominant low-energy excitation, showing that symmetry breaking has a profound impact on the physical properties of matter. Here, we present a comprehensive study of the elementary excitations in a homogeneous strongly interacting Fermi gas through the crossover from a Bardeen-Cooper-Schrieffer (BCS) superfluid to a Bose-Einstein condensate (BEC) of molecules using two-photon Bragg spectroscopy. The spectra exhibit a discrete Goldstone mode, associated with the broken-symmetry superfluid phase, as well as pair-breaking single-particle excitations. Our techniques yield a direct determination of the superfluid pairing gap and speed of sound in close agreement with strong-coupling theories.

Establishing the pharmaceutical quality of Chinese herbal medicine: a provisional BCS classification.

Science.gov (United States)

Fong, Sophia Y K; Liu, Mary; Wei, Hai; Löbenberg, Raimar; Kanfer, Isadore; Lee, Vincent H L; Amidon, Gordon L; Zuo, Zhong

2013-05-06

The Biopharmaceutical Classification System (BCS), which is a scientific approach to categorize active drug ingredient based on its solubility and intestinal permeability into one of the four classes, has been used to set the pharmaceutical quality standards for drug products in western society. However, it has received little attention in the area of Chinese herbal medicine (CHM). This is likely, in part, due to the presence of multiple active components as well as lack of standardization of CHM. In this report, we apply BCS classification to CHMs provisionally as a basis for establishing improved in vitro quality standards. Based on a top-200 drugs selling list in China, a total of 31 CHM products comprising 50 official active marker compounds (AMCs) were provisionally classified according to BCS. Information on AMC content and doses of these CHM products were retrieved from the Chinese Pharmacopoeia. BCS parameters including solubility and permeability of the AMCs were predicted in silico (ACD/Laboratories). A BCS classification of CHMs according to biopharmaceutical properties of their AMCs is demonstrated to be feasible in the current study and can be used to provide a minimum set of quality standards. Our provisional results showed that 44% of the included AMCs were classified as Class III (high solubility, low permeability), followed by Class II (26%), Class I (18%), and Class IV (12%). A similar trend was observed when CHMs were classified in accordance with the BCS class of AMCs. Most (45%) of the included CHMs were classified as Class III, followed by Class II (16%), Class I (10%), and Class IV (6%); whereas 23% of the CHMs were of mixed class due to the presence of multiple individual AMCs with different BCS classifications. Moreover, about 60% of the AMCs were classified as high-solubility compounds (Class I and Class III), suggesting an important role for an in vitro dissolution test in setting quality control standards ensuring consistent

Biowaiver extension potential to BCS Class III high solubility-low permeability drugs: bridging evidence for metformin immediate-release tablet.

Science.gov (United States)

Cheng, Ching-Ling; Yu, Lawrence X; Lee, Hwei-Ling; Yang, Chyun-Yu; Lue, Chang-Sha; Chou, Chen-Hsi

2004-07-01

The biopharmaceutics classification system (BCS) allows biowaiver for rapid dissolving immediate-release (IR) products of Class I drugs (high solubility and high permeability). The possibility of extending biowaivers to Class III high solubility and low permeability drugs is currently under scrutiny. In vivo bioequivalence data of different formulations of Class III drugs would support such an extension. The objective of this work was to demonstrate the bioequivalence of two marketed IR tablet products of a Class III drug, metformin hydrochloride, that are rapidly dissolving and have similar in vitro dissolution profiles. The effect of race on the systemic exposure of metformin was also explored. A randomized, open-label, two-period crossover study was conducted in 12 healthy Chinese male volunteers. Each subject received a single-dose of 500 mg of each product after an overnight fasting. The plasma concentrations of metformin were followed for 24 h. No significant formulation effect was found for the bioequivalence metrics: areas under concentration-time curve (AUC0-t, AUC0-infinity) and maximal concentration (Cmax). The 90% confidence intervals for the ratio of means were found within the acceptance range of 80-125% for the log-transformed data. Based on these results, it was concluded that the two IR products are bioequivalent. The pharmacokinetic parameters of metformin in Chinese for both products were similar and were in good agreement with those reported for metformin IR tablets in other ethnic populations. This study serves as an example for supporting biowaiver for BCS Class III drugs.

Attractive Hubbard model with disorder and the generalized Anderson theorem

International Nuclear Information System (INIS)

Kuchinskii, E. Z.; Kuleeva, N. A.; Sadovskii, M. V.

2015-01-01

Using the generalized DMFT+Σ approach, we study the influence of disorder on single-particle properties of the normal phase and the superconducting transition temperature in the attractive Hubbard model. A wide range of attractive potentials U is studied, from the weak coupling region, where both the instability of the normal phase and superconductivity are well described by the BCS model, to the strong-coupling region, where the superconducting transition is due to Bose-Einstein condensation (BEC) of compact Cooper pairs, formed at temperatures much higher than the superconducting transition temperature. We study two typical models of the conduction band with semi-elliptic and flat densities of states, respectively appropriate for three-dimensional and two-dimensional systems. For the semi-elliptic density of states, the disorder influence on all single-particle properties (e.g., density of states) is universal for an arbitrary strength of electronic correlations and disorder and is due to only the general disorder widening of the conduction band. In the case of a flat density of states, universality is absent in the general case, but still the disorder influence is mainly due to band widening, and the universal behavior is restored for large enough disorder. Using the combination of DMFT+Σ and Nozieres-Schmitt-Rink approximations, we study the disorder influence on the superconducting transition temperature T c for a range of characteristic values of U and disorder, including the BCS-BEC crossover region and the limit of strong-coupling. Disorder can either suppress T c (in the weak-coupling region) or significantly increase T c (in the strong-coupling region). However, in all cases, the generalized Anderson theorem is valid and all changes of the superconducting critical temperature are essentially due to only the general disorder widening of the conduction band

Characteristics and Motivations of Sports Officials in the Province of Québec

OpenAIRE

Denis Auger; Julie Fortier; André Thibault; Daniel Magny; François Gravelle

2010-01-01

Participation in sport and recreation is important for Quebecers’ health, both mentally and physically. Sports in the province of Québec are organised under the tutelage of Sports-Québec. This is a non-profit organization composed of and representing 63 provincial sports federations, supporting 90 sports and 17 regional leisure and sport units. Federations are responsible for the development of their coaches, instructors and officials. Most federations and associations identify difficulties i...

Twisting Anderson pseudospins with light: Quench dynamics in THz-pumped BCS superconductors

OpenAIRE

Chou, Yang-Zhi; Liao, Yunxiang; Foster, Matthew S.

2016-01-01

We study the preparation (pump) and the detection (probe) of far-from-equilibrium BCS superconductor dynamics in THz pump-probe experiments. In a recent experiment [R. Matsunaga, Y. I. Hamada, K. Makise, Y. Uzawa, H. Terai, Z. Wang, and R. Shimano, Phys. Rev. Lett. {\\bf 111}, 057002 (2013)], an intense monocycle THz pulse with center frequency $\\omega \\simeq \\Delta$ was injected into a superconductor with BCS gap $\\Delta$; the subsequent post-pump evolution was detected via the optical conduc...

Measurement of gender inequality in neighbourhoods of Québec, Canada

Directory of Open Access Journals (Sweden)

Tamambang Lum

2011-11-01

Full Text Available Abstract Introduction Few studies have measured gender inequality at levels lower than the country. We sought to develop neighbourhood indicators of gender inequality, and assess their ability to capture variability in gender inequality across Québec, Canada. Methods Aggregate 2001 census data for 11,564 neighbourhoods were obtained for men and women. Twelve indicators of gender inequality representing demographic/household characteristics, education, income, work/leisure, and political participation were selected. Neighbourhood-level gender inequality scores were computed for each indicator, and examined across parts of Québec (metropolitan areas, mid-sized cities, rural areas. Monte Carlo simulations were used to assess the ability of indicators to capture heterogeneity in gender inequality across neighbourhoods. Results Male-dominant neighbourhood-level gender inequality tended to be present for average employment income, labour force participation, employment rate, and employment in managerial positions. Female-dominant gender inequality tended to be present for divorce, single-headed households, and participation in unpaid housework, child and elderly care. Neighbourhood-level gender inequality tended to vary across metropolitan areas, mid-sized cities, and rural areas. Gender inequality scores also varied within these geographic areas. For example, there was greater income-related gender inequality in high than low income neighbourhoods. Monte Carlo simulations suggested that the variation in gender inequality across neighbourhoods was greater than expected with chance alone. Conclusion Neighbourhood-level gender inequality tended to be present in Québec, and varied across parts of the province. Greater awareness of and research on neighbourhood-level gender inequality may be warranted to inform gender policies in Québec and other nations.

Spin Superfluidity and Magnone BEC in He-3

Science.gov (United States)

Bunkov, Yury

2011-03-01

The spin superfluidity -- superfluidity in the magnetic subsystem of a condensed matter -- is manifested as the spontaneous phase-coherent precession of spins first discovered in 1984 in 3 He-B. This superfluid current of spins -- spin supercurrent -- is one more representative of superfluid currents known or discussed in other systems, such as the superfluid current of mass and atoms in superfluid 4 He; superfluid current of electric charge in superconductors; superfluid current of hypercharge in Standard Model of particle physics; superfluid baryonic current and current of chiral charge in quark matter; etc. Spin superfluidity can be described in terms of the Bose condensation of spin waves -- magnons. We discuss different states of magnon superfluidity with different types of spin-orbit coupling: in bulk 3 He-B; magnetically traped `` Q -balls'' at very low temperatures; in 3 He-A and 3 He-B immerged in deformed aerogel; etc. Some effects in normal 3 He can also be treated as a magnetic BEC of fermi liquid. A very similar phenomena can be observed also in a magnetic systems with dinamical frequensy shift, like MnC03 . We will discuss the main experimental signatures of magnons superfluidity: (i) spin supercurrent, which transports the magnetization on a macroscopic distance more than 1 cm long; (ii) spin current Josephson effect which shows interference between two condensates; (iii) spin current vortex -- a topological defect which is an analog of a quantized vortex in superfluids, of an Abrikosov vortex in superconductors, and cosmic strings in relativistic theories; (iv) Goldstone modes related to the broken U (1) symmetry -- phonons in the spin-superfluid magnon gas; etc. For recent review see Yu. M. Bunkov and G. E. Volovik J. Phys. Cond. Matter. 22, 164210 (2010) This work is partly supported by the Ministry of Education and Science of the Russian Federation (contract N 02.740.11.5217).

Interacting bosons model and relation with BCS theory

International Nuclear Information System (INIS)

Diniz, R.

1990-01-01

The Nambu mechanism for BCS theory is extended with inclusion of quadrupole pairing in addition to the usual monopole pairing. An effective Hamiltonian is constructed and its relation to the IBM is discussed. The faced difficulties and a possible generalization of this model are discussed. (author)

A simplified generator coordinate treatment with analytical projected-BCS solutions for isovector pairing collective motions

International Nuclear Information System (INIS)

Kyotoku, M.; Chen, H.T.

1979-01-01

Analytical expressions for the projected-BCS energies and reaction transition rates among the isovector pairing collective states are obtained by the recognition of symmetry properties in a class of BCS wave functions. As a consequence, a simplified generator coordinate treatment is suggested [pt

Coherence factors beyond the BCS expressions—a derivation

International Nuclear Information System (INIS)

Gorohovsky, G; Bettelheim, E

2014-01-01

We present a derivation of a previously announced result for matrix elements between exact eigenstates of the pairing Hamiltonian. Our results, which generalize the well-known Bardeen–Cooper–Schrieffer (BCS) (Bardeen et al 1957 Phys. Rev. 108 1175; 1957 Phys. Rev. 106 162) expressions for what are known as ‘coherence factors’, are derived based on the Slavnov (1989 Theor. Math. Phys. 79 502) formula for overlaps between Bethe-ansatz states, thus making use of the known connection between the exact diagonalization of the BCS Hamiltonian, due to Richardson (1963 Phys. Lett. 3 277; 1964 Nucl. Phys. A 52 221), and the algebraic Bethe ansatz. The resulting formula has a compact form after a suitable parameterization of the energy plane. Although we apply our method here to the pairing Hamiltonian, it may be adjusted to study what is termed the ‘Sutherland limit’ (Sutherland 1995 Phys. Rev. Lett. 74 816) for exactly solvable models, namely where a macroscopic number of rapidities form a large string. (paper)

Dark matter as a Bose-Einstein Condensate: the relativistic non-minimally coupled case

International Nuclear Information System (INIS)

Bettoni, Dario; Colombo, Mattia; Liberati, Stefano

2014-01-01

Bose-Einstein Condensates have been recently proposed as dark matter candidates. In order to characterize the phenomenology associated to such models, we extend previous investigations by studying the general case of a relativistic BEC on a curved background including a non-minimal coupling to curvature. In particular, we discuss the possibility of a two phase cosmological evolution: a cold dark matter-like phase at the large scales/early times and a condensed phase inside dark matter halos. During the first phase dark matter is described by a minimally coupled weakly self-interacting scalar field, while in the second one dark matter condensates and, we shall argue, develops as a consequence the non-minimal coupling. Finally, we discuss how such non-minimal coupling could provide a new mechanism to address cold dark matter paradigm issues at galactic scales

BCS superconductivity for weakly coupled clusters

International Nuclear Information System (INIS)

Friedel, J.

1992-01-01

BCS superconductivity is expected to have fairly high critical temperatures when clusters of moderate sizes are weakly coupled to form a crystal. This remark extends to quasi zerodimensional cases, a remark initially made by Labbe for quasi one-dimensional ones and by Hirsch, Bok and Labbe for quasi twodimensional ones. Possible applications are envisaged for twodimensional clusters (fullerene) or threedimensional ones (metal clusters, Chevrel phases). Conditions for optimal applicability of the scheme are somewhat restricted. (orig.)

Immunization services offered in Québec (Canada) pharmacies

Science.gov (United States)

Sauvageau, Chantal; Dubé, Eve; Bradet, Richard; Mondor, Myrto; Lavoie, France; Moisan, Jocelyne

2013-01-01

Canadian Pharmacists are easy to reach. Although Québec pharmacists are not allowed to administer vaccines, they can: (1) promote vaccination, (2) counsel patients on vaccination, (3) sell vaccines and (4) provide vaccine administration by a nurse. Our objectives were to describe immunization services given in Québec pharmacies and assess the potential relation between, on one hand, pharmacy characteristics and difficulties perceived by pharmacists and, on the other hand, vaccine administration. In 2008–09, an anonymous questionnaire was mailed to all Québec pharmacy owners (n = 1663). Among the 1102 (66%) respondents, 90% stated that vaccines were sold, 27% that a nurse administered vaccines in their pharmacy and 44% were planning to offer vaccine administration in the next five years. Three out of four stated they were doing vaccine promotion and 65%, vaccine counselling. Half of respondents said they would be willing to administer vaccines themselves if legislative modifications were made. Recommendations for cold chain maintenance were followed in 23% of pharmacies selling vaccines. Presence of another health professional in the pharmacy, higher number of opening hours, not being located in the same building than a medical clinic and having an agreement to collaborate with a public health unit or a medical clinic for immunization were positively associated with vaccine administration in multivariate analysis. Higher perceived difficulties with lack of demand from patients were negatively associated with vaccine administration. Most pharmacists are willing to increase their involvement in immunization. Collaboration between public health professionals and pharmacists should be reinforced. PMID:23782530

Modern trends in superconductivity and superfluidity

CERN Document Server

Kagan, M Yu

2013-01-01

This book concisely presents the latest trends in the physics of superconductivity and superfluidity and magnetism in novel systems, as well as the problem of BCS-BEC crossover in ultracold quantum gases and high-Tc superconductors. It further illuminates the intensive exchange of ideas between these closely related fields of condensed matter physics over the last 30 years of their dynamic development. The content is based on the author’s original findings obtained at the Kapitza Institute, as well as advanced lecture courses he held at the Moscow Engineering Physical Institute, Amsterdam University, Loughborough University and LPTMS Orsay between 1994 and 2011. In addition to the findings of his group, the author discusses the most recent concepts in these fields, obtained both in Russia and in the West. The book consists of 16 chapters which are divided into four parts. The first part describes recent developments in superfluid hydrodynamics of quantum fluids and solids, including the fashionable subject...

The Effect of Excipients on the Permeability of BCS Class III Compounds and Implications for Biowaivers.

Science.gov (United States)

Parr, Alan; Hidalgo, Ismael J; Bode, Chris; Brown, William; Yazdanian, Mehran; Gonzalez, Mario A; Sagawa, Kazuko; Miller, Kevin; Jiang, Wenlei; Stippler, Erika S

2016-01-01

Currently, the FDA allows biowaivers for Class I (high solubility and high permeability) and Class III (high solubility and low permeability) compounds of the Biopharmaceutics Classification System (BCS). Scientific evidence should be provided to support biowaivers for BCS Class I and Class III (high solubility and low permeability) compounds. Data on the effects of excipients on drug permeability are needed to demonstrate that commonly used excipients do not affect the permeability of BCS Class III compounds, which would support the application of biowaivers to Class III compounds. This study was designed to generate such data by assessing the permeability of four BCS Class III compounds and one Class I compound in the presence and absence of five commonly used excipients. The permeability of each of the compounds was assessed, at three to five concentrations, with each excipient in two different models: Caco-2 cell monolayers, and in situ rat intestinal perfusion. No substantial increases in the permeability of any of the compounds were observed in the presence of any of the tested excipients in either of the models, with the exception of disruption of Caco-2 cell monolayer integrity by sodium lauryl sulfate at 0.1 mg/ml and higher. The results suggest that the absorption of these four BCS Class III compounds would not be greatly affected by the tested excipients. This may have implications in supporting biowaivers for BCS Class III compounds in general.

Collision of BEC dark matter structures and comparison with the collision of ideal gas structures

International Nuclear Information System (INIS)

Guzman, F. S.; Gonzalez, J. A.

2010-01-01

In this work we present an important feature of the Bose Einstein Condensate (BEC) dark matter model, that is, the head-on collision of BEC dark matter virialized structures. This model of dark matter is assumed to be ruled by the Schroedinger-Poisson system of equations, which is interpreted as the Gross-Pitaevskii equation with a gravitational potential sourced by the density of probability. It has been shown recently that during the collision of two structures a pattern formation in the density of probability appears. We explore the pattern formation for various initial dynamical conditions during the collision. In order to know whether or not the pattern formation is a particular property of the BEC dark matter, we compare with the collision of two structures of virialized ideal gas under similar dynamical initial conditions, which is a model more consistent with usual models of dark matter. In order to do so, we also solve Euler's equations using a smoothed particle hydrodynamics approach. We found that the collision of the ideal gas structures does not show interference patterns, which in turn implies that the pattern formation is a property of the BEC dark matter.

Electric crossover

International Nuclear Information System (INIS)

Schuster, R.M.; Luria, N.G.

1977-01-01

This invention concerns an electric crossover that makes a steam and pressure-tight seal for a conductor crossing two separate walls of a nuclear reactor vessel that seismic tremors or thermal expansion of the walls and conductor subject to relative displacements. The conductors, that have to cross the vessels, are fixed to the walls of the vessel in crossover systems fitted in crossover channels made in the walls of the vessel on their initial manufacture. The separate walls of the vessel move independently when they undergo an earth tremor or a temperature change between the walls or between the conductor. This shift can damage the conductor or the crossover system and this could give rise to cause steam or other materials to leak in the reactor should leaks occur in the primary system. Furthermore, in the case of medium or high power conductors, which are relatively rigid, the non-alignment of the crossover channels can bring about awkward stresses in the conductors or their protective sheathing. The aims of this invention are fulfilled by designing an electric crossover to pass at least one conductor through the two separate walls of a vessels, that includes an initial sub-assembly crossover, secured in a leak-tight manner to the first wall and a second sub-sessembly crossover in sliding or rolling contact with the second wall, whilst forming a leak-tight seal with it [fr

Mathematical analysis of the multiband BCS gap equations in superconductivity

Science.gov (United States)

Yang, Yisong

2005-01-01

In this paper, we present a mathematical analysis for the phonon-dominated multiband isotropic and anisotropic BCS gap equations at any finite temperature T. We establish the existence of a critical temperature T so that, when TT, the only nonnegative gap solution is the zero solution, representing the normal phase. Furthermore, when T=T, we prove that the only gap solution is the zero solution and that the positive gap solution depend on the temperature TMarkowitz-Kadanoff model and we prove that the presence of anisotropic fluctuations enhances T as in the single-band case. A special consequence of these results is that the half-unity exponent isotope effect may rigorously be proved in the multiband BCS theory, isotropic or anisotropic.

What is strange about high-temperature superconductivity in cuprates?

Science.gov (United States)

Božović, I.; He, X.; Wu, J.; Bollinger, A. T.

2017-10-01

Cuprate superconductors exhibit many features, but the ultimate question is why the critical temperature (Tc) is so high. The fundamental dichotomy is between the weak-pairing, Bardeen-Cooper-Schrieffer (BCS) scenario, and Bose-Einstein condensation (BEC) of strongly-bound pairs. While for underdoped cuprates it is hotly debated which of these pictures is appropriate, it is commonly believed that on the overdoped side strongly-correlated fermion physics evolves smoothly into the conventional BCS behavior. Here, we test this dogma by studying the dependence of key superconducting parameters on doping, temperature, and external fields, in thousands of cuprate samples. The findings do not conform to BCS predictions anywhere in the phase diagram.

The Combination of GIS and Biphasic to Better Predict In Vivo Dissolution of BCS Class IIb Drugs, Ketoconazole and Raloxifene.

Science.gov (United States)

Tsume, Yasuhiro; Igawa, Naoto; Drelich, Adam J; Amidon, Gregory E; Amidon, Gordon L

2018-01-01

The formulation developments and the in vivo assessment of Biopharmaceutical Classification System (BCS) class II drugs are challenging due to their low solubility and high permeability in the human gastrointestinal (GI) tract. Since the GI environment influences the drug dissolution of BCS class II drugs, the human GI characteristics should be incorporated into the in vitro dissolution system to predict bioperformance of BCS class II drugs. An absorptive compartment may be important in dissolution apparatus for BCS class II drugs, especially for bases (BCS IIb) because of high permeability, precipitation, and supersaturation. Thus, the in vitro dissolution system with an absorptive compartment may help predicting the in vivo phenomena of BCS class II drugs better than compendial dissolution apparatuses. In this study, an absorptive compartment (a biphasic device) was introduced to a gastrointestinal simulator. This addition was evaluated if this in vitro system could improve the prediction of in vivo dissolution for BCS class IIb drugs, ketoconazole and raloxifene, and subsequent absorption. The gastrointestinal simulator is a practical in vivo predictive tool and exhibited an improved in vivo prediction utilizing the biphasic format and thus a better tool for evaluating the bioperformance of BCS class IIb drugs than compendial apparatuses. Copyright © 2018. Published by Elsevier Inc.

Relativistic and non-relativistic studies of nuclear matter

NARCIS (Netherlands)

Banerjee, MK; Tjon, JA

2002-01-01

We point out that the differences between the results of the non-relativistic lowest order Brueckner theory (LOBT) and the relativistic Dirac-Brueckner analysis predominantly arise from two sources. Besides effects from a nucleon mass modification M* in nuclear medium we have in a relativistic

Software testing an ISTQB-BCS certified tester foundation guide

CERN Document Server

Hambling, Brian; Samaroo, Angelina; Thompson, Geoff; Williams, Peter; Hambling, Brian

2015-01-01

This practical guide provides insight into software testing, explaining the basics of the testing process and how to perform effective tests. It provides an overview of different techniques and how to apply them. It is the best-selling official textbook of the ISTQB-BCS Certified Tester Foundation Level.

Relativistic quasiparticle time blocking approximation: Dipole response of open-shell nuclei

International Nuclear Information System (INIS)

Litvinova, E.; Ring, P.; Tselyaev, V.

2008-01-01

The self-consistent relativistic quasiparticle random-phase approximation (RQRPA) is extended by the quasiparticle-phonon coupling (QPC) model using the quasiparticle time blocking approximation (QTBA). The method is formulated in terms of the Bethe-Salpeter equation (BSE) in the two-quasiparticle space with an energy-dependent two-quasiparticle residual interaction. This equation is solved either in the basis of Dirac states forming the self-consistent solution of the ground state or in the momentum representation. Pairing correlations are treated within the Bardeen-Cooper-Schrieffer (BCS) model with a monopole-monopole interaction. The same NL3 set of the coupling constants generates the Dirac-Hartree-BCS single-quasiparticle spectrum, the static part of the residual two-quasiparticle interaction and the quasiparticle-phonon coupling amplitudes. A quantitative description of electric dipole excitations in the chain of tin isotopes (Z=50) with the mass numbers A=100,106,114,116,120, and 130 and in the chain of isotones with (N=50) 88 Sr, 90 Zr, 92 Mo is performed within this framework. The RQRPA extended by the coupling to collective vibrations generates spectra with a multitude of 2q x phonon (two quasiparticles plus phonon) states providing a noticeable fragmentation of the giant dipole resonance as well as of the soft dipole mode (pygmy resonance) in the nuclei under investigation. The results obtained for the photo absorption cross sections and for the integrated contributions of the low-lying strength to the calculated dipole spectra agree very well with the available experimental data

Relativistic mean field theory with density dependent coupling constants for nuclear matter and finite nuclei with large charge asymmetry

Energy Technology Data Exchange (ETDEWEB)

Typel, S; Wolter, H H [Sektion Physik, Univ. Muenchen, Garching (Germany)

1998-06-01

Nuclear matter and ground state properties for (proton and neutron) semi-closed shell nuclei are described in relativistic mean field theory with coupling constants which depend on the vector density. The parametrization of the density dependence for {sigma}-, {omega}- and {rho}-mesons is obtained by fitting to properties of nuclear matter and some finite nuclei. The equation of state for symmetric and asymmetric nuclear matter is discussed. Finite nuclei are described in Hartree approximation, including a charge and an improved center-of-mass correction. Pairing is considered in the BCS approximation. Special attention is directed to the predictions for properties at the neutron and proton driplines, e.g. for separation energies, spin-orbit splittings and density distributions. (orig.)

Influence of the projection of BCS functions on the M1 and E2 transitions in rare earths

International Nuclear Information System (INIS)

Fellah, M.; Hammann, T.F.

1975-01-01

E2 and M1 transition probabilities for odd-mass rare earth nuclei, have been calculated using both the usual BCS wave functions and the strict particle conserving, projected BCS functions. The blocking effect has been exactly and systematically taken into account. The influence of the Coriolis interaction has been studied using the first order perturbation theory. Allowance has been made for the β and γ vibrations. The unphysical effects, due to particle fluctuation in the BCS theory, are not always negligible, but are in most cases, less important than the Coriolis effect [fr

Experiments with BECs in a Painted Potential: Atom SQUID, Matter Wave Bessel Beams, and Matter Wave Circuits

Science.gov (United States)

Boshier, Malcolm; Ryu, Changhyun; Blackburn, Paul; Blinova, Alina; Henderson, Kevin

2014-05-01

The painted potential is a time-averaged optical dipole potential which is able to create arbitrary and dynamic two dimensional potentials for Bose Einstein condensates (BECs). This poster reports three recent experiments using this technique. First, we have realized the dc atom SQUID geometry of a BEC in a toroidal trap with two Josephson junctions. We observe Josephson effects, measure the critical current of the junctions, and find dynamic behavior that is in good agreement with the simple Josephson equations for a tunnel junction with the ideal sinusoidal current-phase relation expected for the parameters of the experiment. Second, we have used free expansion of a rotating toroidal BEC to create matter wave Bessel beams, which are of interest because perfect Bessel beams (plane waves with amplitude profiles described by Bessel functions) propagate without diffraction. Third, we have realized the basic circuit elements necessary to create complex matter wave circuits. We launch BECs at arbitrary velocity along straight waveguides, propagate them around curved waveguides and stadium-shaped waveguide traps, and split them coherently at y-junctions that can also act as switches. Supported by LANL/LDRD.

Korteweg de Vries Description of One-Dimensional Superfluid Fermi Gases

International Nuclear Information System (INIS)

Xu Yan-Xia; Duan Wen-Shan

2011-01-01

We study one-dimensional matter-wave pulses in cigar-shaped superfluid Fermi gases, including the linear and nonlinear waves of the system. A Korteweg de Vries (KdV) solitary wave is obtained for the superfluid Fermi gases in the limited case of a BEC regime, a BCS regime and unitarity. The dependences of the propagation velocity, amplitude and the width of the solitary wave on the dimensionless interaction parameter y = 1/(k F a sc ) are given for the limited cases of BEC and unitarity. (physics of gases, plasmas, and electric discharges)

Particle–hole duality, integrability, and Russian doll BCS model

Energy Technology Data Exchange (ETDEWEB)

Bork, L.V. [Center for Fundamental and Applied Research, N. L. Dukhov All-Russia Research Institute of Automatics, 127055 Moscow (Russian Federation); Institute for Theoretical and Experimental Physics, 117218 Moscow (Russian Federation); Pogosov, W.V., E-mail: walter.pogosov@gmail.com [Center for Fundamental and Applied Research, N. L. Dukhov All-Russia Research Institute of Automatics, 127055 Moscow (Russian Federation); Institute for Theoretical and Applied Electrodynamics, Russian Academy of Sciences, 125412 Moscow (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region 141700 (Russian Federation)

2015-08-15

We address a generalized Richardson model (Russian doll BCS model), which is characterized by the breaking of time-reversal symmetry. This model is known to be exactly solvable and integrable. We point out that the Russian doll BCS model, on the level of Hamiltonian, is also particle–hole symmetric. This implies that the same state can be expressed both in the particle and hole representations with two different sets of Bethe roots. We then derive exact relations between Bethe roots in the two representations, which can hardly be obtained staying on the level of Bethe equations. In a quasi-classical limit, similar identities for usual Richardson model, known from literature, are recovered from our results. We also show that these relations for Richardson roots take a remarkably simple form at half-filling and for a symmetric with respect to the middle of the interaction band distribution of one-body energy levels, since, in this special case, the rapidities in the particle and hole representations up to the translation satisfy the same system of equations.

Density and spin linear response of atomic Fermi superfluids with population imbalance in the BCS–BEC crossover

International Nuclear Information System (INIS)

Guo, Hao; Li, Yang; He, Yan; Chien, Chih-Chun

2014-01-01

We present a theoretical study of the density and spin (representing the two components) linear response of Fermi superfluids with tunable attractive interactions and population imbalance. In both linear response theories, we find that the fluctuations of the order parameter must be treated on equal footing with the gauge transformations associated with the symmetries of the Hamiltonian so that important constraints including various sum rules can be satisfied. Both theories can be applied to the whole BCS–Bose–Einstein condensation crossover. The spin linear responses are qualitatively different with and without population imbalance because collective-mode effects from the fluctuations of the order parameter survive in the presence of population imbalance, even though the associated symmetry is not broken by the order parameter. Since a polarized superfluid becomes unstable at low temperatures in the weak and intermediate coupling regimes, we found that the density and spin susceptibilities diverge as the system approaches the unstable regime, but the emergence of phase separation preempts the divergence. (paper)

Relativistic equations

International Nuclear Information System (INIS)

Gross, F.

1986-01-01

Relativistic equations for two and three body scattering are discussed. Particular attention is paid to relativistic three body kinetics because of recent form factor measurements of the Helium 3 - Hydrogen 3 system recently completed at Saclay and Bates and the accompanying speculation that relativistic effects are important for understanding the three nucleon system. 16 refs., 4 figs

Application of the relativistic mean-field mass model to the r-process and the influence of mass uncertainties

International Nuclear Information System (INIS)

Sun, B.; Montes, F.; Geng, L. S.; Geissel, H.; Litvinov, Yu. A.; Meng, J.

2008-01-01

A new mass table calculated by the relativistic mean-field approach with the state-dependent BCS method for the pairing correlation is applied for the first time to study r-process nucleosynthesis. The solar r-process abundance is well reproduced within a waiting-point approximation approach. Using an exponential fitting procedure to find the required astrophysical conditions, the influence of mass uncertainty is investigated. The r-process calculations using the FRDM, ETFSI-Q, and HFB-13 mass tables have been used for that purpose. It is found that the nuclear physical uncertainty can significantly influence the deduced astrophysical conditions for the r-process site. In addition, the influence of the shell closure and shape transition have been examined in detail in the r-process simulations

Enhancement of crystallinity of cellulose produced by Escherichia coli through heterologous expression of bcsD gene from Gluconacetobacter xylinus.

Science.gov (United States)

Sajadi, Elaheh; Babaipour, Valiollah; Deldar, Ali Asghar; Yakhchali, Bagher; Fatemi, Seyed Safa-Ali

2017-09-01

To evaluate the crystallinity index of the cellulose produced by Escherichia coli Nissle 1917 after heterologous expression of the cellulose synthase subunit D (bcsD) gene of Gluconacetobacter xylinus BPR2001. The bcsD gene of G. xylinus BPR2001 was expressed in E. coli and its protein product was visualized using SDS-PAGE. FTIR analysis showed that the crystallinity index of the cellulose produced by the recombinants was 0.84, which is 17% more than that of the wild type strain. The increased crystallinity index was also confirmed by X-ray diffraction analysis. The cellulose content was not changed significantly after over-expressing the bcsD. The bcsD gene can improve the crystalline structure of the bacterial cellulose but there is not any significant difference between the amounts of cellulose produced by the recombinant and wild type E. coli Nissle 1917.

Development of HANARO human factors management plan and evaluation of BCS display

International Nuclear Information System (INIS)

Oh, I. S.; Lee, J. W.; Lee, Y. H.

2004-01-01

In this study, human factors evaluation of BCS display design was performed. We adopted the suitability of design elements of BCS display as human factors evaluation measure. And, we also adopted guideline based evaluation, field survey and expert evaluation as evaluation method. The checklist was utilized for the evaluation, and the results of evaluation were well arranged in the evaluation format. We did not find out the HED (Human Engineering Discrepancy) impede safety of HANARO, except some necessary items to improve during short periods. We also provide some items of improvement for the enhancement of safety and operator's performance in the aspect of long periods. If the proposed improvement items were completely fulfilled, the more improved safety of HANARO will be secured

Stability of the graviton Bose–Einstein condensate in the brane-world

Energy Technology Data Exchange (ETDEWEB)

Casadio, Roberto, E-mail: casadio@bo.infn.it [Dipartimento di Fisica e Astronomia, Università di Bologna, via Irnerio 46, 40126 Bologna (Italy); INFN, Sezione di Bologna, viale B. Pichat 6, 40127 Bologna (Italy); Rocha, Roldão da, E-mail: roldao.rocha@ufabc.edu.br [CMCC, Universidade Federal do ABC, 09210-580, Santo André, SP (Brazil)

2016-12-10

We consider a solution of the effective four-dimensional Einstein equations, obtained from the general relativistic Schwarzschild metric through the principle of Minimal Geometric Deformation (MGD). Since the brane tension can, in general, introduce new singularities on a relativistic Eötvös brane model in the MGD framework, we require the absence of observed singularities, in order to constrain the brane tension. We then study the corresponding Bose–Einstein condensate (BEC) gravitational system and determine the critical stability region of BEC MGD stellar configurations. Finally, the critical stellar densities are shown to be related with critical points of the information entropy.

Point form relativistic quantum mechanics and relativistic SU(6)

Science.gov (United States)

Klink, W. H.

1993-01-01

The point form is used as a framework for formulating a relativistic quantum mechanics, with the mass operator carrying the interactions of underlying constituents. A symplectic Lie algebra of mass operators is introduced from which a relativistic harmonic oscillator mass operator is formed. Mass splittings within the degenerate harmonic oscillator levels arise from relativistically invariant spin-spin, spin-orbit, and tensor mass operators. Internal flavor (and color) symmetries are introduced which make it possible to formulate a relativistic SU(6) model of baryons (and mesons). Careful attention is paid to the permutation symmetry properties of the hadronic wave functions, which are written as polynomials in Bargmann spaces.

A unified treatment of the non-relativistic and relativistic hydrogen atom: Pt. 2

International Nuclear Information System (INIS)

Swainson, R.A.; Drake, G.W.F.

1991-01-01

This is the second in a series of three papers in which it is shown how the radial part of non-relativistic and relativistic hydrogenic bound-state calculations involving the Green functions can be presented in a unified manner. In this paper the non-relativistic Green function is examined in detail; new functional forms are presented and a clear mathematical progression is show to link these and most other known forms. A linear transformation of the four radial parts of the relativistic Green function is given which allows for the presentation of this function as a simple generalization of the non-relativistic Green function. Thus, many properties of the non-relativistic Green function are shown to have simple relativistic generalizations. In particular, new recursion relations of the radial parts of both the non-relativistic and relativistic Green functions are presented, along with new expressions for the double Laplace transforms and recursion relations between the radial matrix elements. (author)

The Effect of Excipients on the Permeability of BCS Class III Compounds and Implications for Biowaivers

OpenAIRE

Parr, Alan; Hidalgo, Ismael J.; Bode, Chris; Brown, William; Yazdanian, Mehran; Gonzalez, Mario A.; Sagawa, Kazuko; Miller, Kevin; Jiang, Wenlei; Stippler, Erika S.

2015-01-01

Purpose Currently, the FDA allows biowaivers for Class I (high solubility and high permeability) and Class III (high solubility and low permeability) compounds of the Biopharmaceutics Classification System (BCS). Scientific evidence should be provided to support biowaivers for BCS Class I and Class III (high solubility and low permeability) compounds. Methods Data on the effects of excipients on drug permeability are needed to demonstrate that commonly used excipients do not affect the permea...

Perception, understanding and initiatives with regard to sustainable development: A profile of Québec tourism organizations

OpenAIRE

Auger, Denis; Bélanger, Vincent

2011-01-01

The concept of sustainable development is not new. However, its application in the field of tourism in Québec needs to be clarified. This way, this study is aimed at drawing the profile of Québec tourist organizations, at comparing the initiatives developed according to various perspectives (environmental, social and economic) and finally, to verify the coherence between the level of importance these organizations give to the concepts of sustainable development and the application of these wi...

Dispersion properties of transverse waves in electrically polarized BECs

International Nuclear Information System (INIS)

Andreev, Pavel A; Kuz'menkov, L S

2014-01-01

Further development of the method of quantum hydrodynamics in applications for Bose–Einstein condensates (BECs) is presented. To consider the evolution of polarization direction along with particle movement, we have developed a corresponding set of quantum hydrodynamic equations. It includes equations of the polarization evolution and the polarization-current evolution along with the continuity equation and the Euler equation (the momentum-balance equation). Dispersion properties of the transverse waves, including the electromagnetic waves propagating through the BECs, are considered. To this end, we consider a full set of the Maxwell equations for the description of electromagnetic field dynamics. This approximation gives us the possibility of considering the electromagnetic waves along with the matter waves. We find a splitting of the electromagnetic-wave dispersion on two branches. As a result, we have four solutions, two for the electromagnetic waves and two for the matter waves; the last two are the concentration-polarization waves appearing as a generalization of the Bogoliubov mode. We also find that if the matter wave propagates perpendicular to the external electric field then the dipolar contribution does not disappear (as it follows from our generalization of the Bogoliubov spectrum). A small dipolar frequency shift exists in this case due to the transverse electric field of perturbation. (paper)

Thinking Interculturally: Decolonizing History and Citizenship Education in Québec

Science.gov (United States)

DesRoches, Sarah J.

2016-01-01

The main objective of this article is to offer an alternative discursive framework for teaching history and citizenship education in Québec, Canada. Enabling a more inclusive discussion around how citizenship is constructed, thinking interculturally allows us begin thinking about practical ways in which citizenship and history education might…

Relativistic astrophysics

CERN Document Server

Demianski, Marek

2013-01-01

Relativistic Astrophysics brings together important astronomical discoveries and the significant achievements, as well as the difficulties in the field of relativistic astrophysics. This book is divided into 10 chapters that tackle some aspects of the field, including the gravitational field, stellar equilibrium, black holes, and cosmology. The opening chapters introduce the theories to delineate gravitational field and the elements of relativistic thermodynamics and hydrodynamics. The succeeding chapters deal with the gravitational fields in matter; stellar equilibrium and general relativity

Relativistic quantum logic

International Nuclear Information System (INIS)

Mittelstaedt, P.

1983-01-01

on the basis of the well-known quantum logic and quantum probability a formal language of relativistic quantum physics is developed. This language incorporates quantum logical as well as relativistic restrictions. It is shown that relativity imposes serious restrictions on the validity regions of propositions in space-time. By an additional postulate this relativistic quantum logic can be made consistent. The results of this paper are derived exclusively within the formal quantum language; they are, however, in accordance with well-known facts of relativistic quantum physics in Hilbert space. (author)

BCS wave function, matrix product states, and the Ising conformal field theory

Science.gov (United States)

Montes, Sebastián; Rodríguez-Laguna, Javier; Sierra, Germán

2017-11-01

We present a characterization of the many-body lattice wave functions obtained from the conformal blocks (CBs) of the Ising conformal field theory (CFT). The formalism is interpreted as a matrix product state using continuous ancillary degrees of freedom. We provide analytic and numerical evidence that the resulting states can be written as BCS states. We give a complete proof that the translationally invariant 1D configurations have a BCS form and we find suitable parent Hamiltonians. In particular, we prove that the ground state of the finite-size critical Ising transverse field (ITF) Hamiltonian can be obtained with this construction. Finally, we study 2D configurations using an operator product expansion (OPE) approximation. We associate these states to the weak pairing phase of the p +i p superconductor via the scaling of the pairing function and the entanglement spectrum.

Relativistic quantum mechanics; Mecanique quantique relativiste

Energy Technology Data Exchange (ETDEWEB)

Ollitrault, J.Y. [CEA Saclay, 91 - Gif-sur-Yvette (France). Service de Physique Theorique]|[Universite Pierre et Marie Curie, 75 - Paris (France)

1998-12-01

These notes form an introduction to relativistic quantum mechanics. The mathematical formalism has been reduced to the minimum in order to enable the reader to calculate elementary physical processes. The second quantification and the field theory are the logical followings of this course. The reader is expected to know analytical mechanics (Lagrangian and Hamiltonian), non-relativistic quantum mechanics and some basis of restricted relativity. The purpose of the first 3 chapters is to define the quantum mechanics framework for already known notions about rotation transformations, wave propagation and restricted theory of relativity. The next 3 chapters are devoted to the application of relativistic quantum mechanics to a particle with 0,1/5 and 1 spin value. The last chapter deals with the processes involving several particles, these processes require field theory framework to be thoroughly described. (A.C.) 2 refs.

Current and evolving approaches for improving the oral permeability of BCS Class III or analogous molecules.

Science.gov (United States)

Dave, Vivek S; Gupta, Deepak; Yu, Monica; Nguyen, Phuong; Varghese Gupta, Sheeba

2017-02-01

The Biopharmaceutics Classification System (BCS) classifies pharmaceutical compounds based on their aqueous solubility and intestinal permeability. The BCS Class III compounds are hydrophilic molecules (high aqueous solubility) with low permeability across the biological membranes. While these compounds are pharmacologically effective, poor absorption due to low permeability becomes the rate-limiting step in achieving adequate bioavailability. Several approaches have been explored and utilized for improving the permeability profiles of these compounds. The approaches include traditional methods such as prodrugs, permeation enhancers, ion-pairing, etc., as well as relatively modern approaches such as nanoencapsulation and nanosizing. The most recent approaches include a combination/hybridization of one or more traditional approaches to improve drug permeability. While some of these approaches have been extremely successful, i.e. drug products utilizing the approach have progressed through the USFDA approval for marketing; others require further investigation to be applicable. This article discusses the commonly studied approaches for improving the permeability of BCS Class III compounds.

Dissipative relativistic hydrodynamics

International Nuclear Information System (INIS)

Imshennik, V.S.; Morozov, Yu.I.

1989-01-01

Using the comoving reference frame in the general non-inertial case, the relativistic hydrodynamics equations are derived with an account for dissipative effects in the matter. From the entropy production equation, the exact from for the dissipative tensor components is obtained. As a result, the closed system of equations of dissipative relativistic hydrodynamics is obtained in the comoving reference frame as a relativistic generalization of the known Navier-Stokes equations for Lagrange coordinates. Equations of relativistic hydrodynamics with account for dissipative effects in the matter are derived using the assocoated reference system in general non-inertial case. True form of the dissipative tensor components is obtained from entropy production equation. Closed system of equations for dissipative relativistic hydrodynamics is obtained as a result in the assocoated reference system (ARS) - relativistic generalization of well-known Navier-Stokes equations for Lagrange coordinates. Equation system, obtained in this paper for ARS, may be effectively used in numerical models of explosive processes with 10 51 erg energy releases which are characteristic for flashes of supernovae, if white dwarf type compact target suggested as presupernova

Variation spatiotemporelle de la cryptorchidie et de l'hypospadias au Québec : Une étude exploratoire.

Science.gov (United States)

Guertin, Sophie; Lemieux, Karine-Sylvie; Makhoulian, Natalie; Michaud, Sébastien; Patry, Rose-Marie; Côté, Anne-Andrée; Gagnon, Fabien; Ayotte, Pierre; Bolduc, Stéphane

2011-06-01

RéSUMé: : La majorité des études effectuées au cours des dernières décennies ont mis en évidence une augmentation du nombre de cas de cryptorchidie et d'hypospadias entre 1970 et 1990. De plus, l'importante variabilité géographique de ces anomalies est bien décrite. Cette étude vise à mesurer la prévalence à la naissance de la cryptorchidie et de l'hypospadias au Québec, à vérifier si ces anomalies sont en augmentation et à en évaluer la répartition interrégionale. MéTHODE :: Une étude épidémiologique descriptive a été réalisée à partir du nombre de garçons de cinq ans et moins hospitalisés pour une cryptorchidie ou un hypospadias au Québec de 1989 à 2004 selon les données du fichier administratif d'hospitalisation MED-ÉCHO. Les données sur les naissances provenaient de l'Institut de la statistique du Québec. RéSULTATS :: La prévalence annuelle moyenne pour 1000 naissances vivantes de sexe masculin est de 19,1 (IC à 95 % : 18,8-19,4) pour la cryptorchidie et 11,4 (IC à 95 % 11,1-11,6) pour l'hypospadias au Québec. Au cours de la période étudiée, la prévalence de cryptorchidie a légèrement diminué, alors que celle de l'hypospadias est demeurée stable. Comparativement à la province du Québec, des régions présentent une prévalence significativement différente de cryptorchidie et/ou d'hypospadias. . : Au Québec, la prévalence de cryptorchidie est en légère diminution alors que celle de l'hypospadias est stable. Des variations régionales significatives sont observables. D'autres études sont nécessaires afin d'évaluer l'hypothèse d'un lien avec les contaminants environnementaux en émergence. L'implantation d'un système de surveillance des anomalies congénitales permettrait une représentation plus valide de la situation.

Variation spatiotemporelle de la cryptorchidie et de l’hypospadias au Québec : Une étude exploratoire

Science.gov (United States)

Guertin, Sophie; Lemieux, Karine-Sylvie; Makhoulian, Natalie; Michaud, Sébastien; Patry, Rose-Marie; Côté, Anne-Andrée; Gagnon, Fabien; Ayotte, Pierre; Bolduc, Stéphane

2011-01-01

Résumé Objectifs : La majorité des études effectuées au cours des dernières décennies ont mis en évidence une augmentation du nombre de cas de cryptorchidie et d’hypospadias entre 1970 et 1990. De plus, l’importante variabilité géographique de ces anomalies est bien décrite. Cette étude vise à mesurer la prévalence à la naissance de la cryptorchidie et de l’hypospadias au Québec, à vérifier si ces anomalies sont en augmentation et à en évaluer la répartition interrégionale. Méthode : Une étude épidémiologique descriptive a été réalisée à partir du nombre de garçons de cinq ans et moins hospitalisés pour une cryptorchidie ou un hypospadias au Québec de 1989 à 2004 selon les données du fichier administratif d’hospitalisation MED-ÉCHO. Les données sur les naissances provenaient de l’Institut de la statistique du Québec. Résultats : La prévalence annuelle moyenne pour 1000 naissances vivantes de sexe masculin est de 19,1 (IC à 95 % : 18,8–19,4) pour la cryptorchidie et 11,4 (IC à 95 % 11,1–11,6) pour l’hypospadias au Québec. Au cours de la période étudiée, la prévalence de cryptorchidie a légèrement diminué, alors que celle de l’hypospadias est demeurée stable. Comparativement à la province du Québec, des régions présentent une prévalence significativement différente de cryptorchidie et/ou d’hypospadias. . Conclusion : Au Québec, la prévalence de cryptorchidie est en légère diminution alors que celle de l’hypospadias est stable. Des variations régionales significatives sont observables. D’autres études sont nécessaires afin d’évaluer l’hypothèse d’un lien avec les contaminants environnementaux en émergence. L’implantation d’un système de surveillance des anomalies congénitales permettrait une représentation plus valide de la situation. PMID:21672476

Theoretical Study of Spin Crossover in 30 Iron Complexes.

Science.gov (United States)

Kepp, Kasper P

2016-03-21

Iron complexes are important spin crossover (SCO) systems with vital roles in oxidative metabolism and promising technological potential. The SCO tendency depends on the free energy balance of high- and low-spin states, which again depends on physical effects such as dispersion, relativistic effects, and vibrational entropy. This work studied 30 different iron SCO systems with experimentally known thermochemical data, using 12 different density functionals. Remarkably general entropy-enthalpy compensation across SCO systems was identified (R = 0.82, p = 0.002) that should be considered in rational SCO design. Iron(II) complexes displayed higher ΔH and ΔS values than iron(III) complexes and also less steep compensation effects. First-coordination sphere ΔS values computed from numerical frequencies reproduce most of the experimental entropy and should thus be included when modeling spin-state changes in inorganic chemistry (R = 0.52, p = 3.4 × 10(-3); standard error in TΔS ≈ 4.4 kJ/mol at 298 K vs 16 kJ/mol of total TΔS on average). Zero-point energies favored high-spin states by 9 kJ/mol on average. Interestingly, dispersion effects are surprisingly large for the SCO process (average: 9 kJ/mol, but up to 33 kJ/mol) and favor the more compact low-spin state. Relativistic effects favor low-spin by ∼9 kJ/mol on average, but up to 24 kJ/mol. B3LYP*, TPSSh, B2PLYP, and PW6B95 performed best for the typical calculation scheme that includes ZPE. However, if relativistic and dispersion effects are included, only B3LYP* remained accurate. On average, high-spin was favored by LYP by 11-15 kJ/mol relative to other correlation functionals, and by 4.2 kJ/mol per 1% HF exchange in hybrids. 13% HF exchange was optimal without dispersion, and 15% was optimal with all effects included for these systems.

Measurement of gender inequality in neighbourhoods of Qu?bec, Canada

OpenAIRE

Tamambang, Lum; Auger, Nathalie; Lo, Ernest; Raynault, Marie-France

2011-01-01

Abstract Introduction Few studies have measured gender inequality at levels lower than the country. We sought to develop neighbourhood indicators of gender inequality, and assess their ability to capture variability in gender inequality across Québec, Canada. Methods Aggregate 2001 census data for 11,564 neighbourhoods were obtained for men and women. Twelve indicators of gender inequality representing demographic/household characteristics, education, income, work/leisure, and political parti...

Detecting the BCS pairing amplitude via a sudden lattice ramp in a honeycomb lattice

Science.gov (United States)

Tiesinga, Eite; Nuske, Marlon; Mathey, Ludwig

2016-05-01

We determine the exact time evolution of an initial Bardeen-Cooper-Schrieffer (BCS) state of ultra-cold atoms in a hexagonal optical lattice. The dynamical evolution is triggered by ramping the lattice potential up, such that the interaction strength Uf is much larger than the hopping amplitude Jf. The quench initiates collective oscillations with frequency | Uf | /(2 π) in the momentum occupation numbers and imprints an oscillating phase with the same frequency on the order parameter Δ. The latter is not reproduced by treating the time evolution in mean-field theory. The momentum density-density or noise correlation functions oscillate at frequency | Uf | /(2 π) as well as its second harmonic. For a very deep lattice, with negligible tunneling energy, the oscillations of momentum occupation numbers are undamped. Non-zero tunneling after the quench leads to dephasing of the different momentum modes and a subsequent damping of the oscillations. This occurs even for a finite-temperature initial BCS state, but not for a non-interacting Fermi gas. We therefore propose to use this dephasing to detect a BCS state. Finally, we predict that the noise correlation functions in a honeycomb lattice will develop strong anti-correlations near the Dirac point. We acknowledge funding from the National Science Foundation.

Radiatively driven relativistic spherical winds under relativistic radiative transfer

Science.gov (United States)

Fukue, J.

2018-05-01

We numerically investigate radiatively driven relativistic spherical winds from the central luminous object with mass M and luminosity L* under Newtonian gravity, special relativity, and relativistic radiative transfer. We solve both the relativistic radiative transfer equation and the relativistic hydrodynamical equations for spherically symmetric flows under the double-iteration processes, to obtain the intensity and velocity fields simultaneously. We found that the momentum-driven winds with scattering are quickly accelerated near the central object to reach the terminal speed. The results of numerical solutions are roughly fitted by a relation of \\dot{m}=0.7(Γ _*-1)\\tau _* β _* β _out^{-2.6}, where \\dot{m} is the mass-loss rate normalized by the critical one, Γ* the central luminosity normalized by the critical one, τ* the typical optical depth, β* the initial flow speed at the central core of radius R*, and βout the terminal speed normalized by the speed of light. This relation is close to the non-relativistic analytical solution, \\dot{m} = 2(Γ _*-1)\\tau _* β _* β _out^{-2}, which can be re-expressed as β _out^2/2 = (Γ _*-1)GM/c^2 R_*. That is, the present solution with small optical depth is similar to that of the radiatively driven free outflow. Furthermore, we found that the normalized luminosity (Eddington parameter) must be larger than unity for the relativistic spherical wind to blow off with intermediate or small optical depth, i.e. Γ _* ≳ \\sqrt{(1+β _out)^3/(1-β _out)}. We briefly investigate and discuss an isothermal wind.

Handbook of relativistic quantum chemistry

International Nuclear Information System (INIS)

Liu, Wenjian

2017-01-01

This handbook focuses on the foundations of relativistic quantum mechanics and addresses a number of fundamental issues never covered before in a book. For instance: How can many-body theory be combined with quantum electrodynamics? How can quantum electrodynamics be interfaced with relativistic quantum chemistry? What is the most appropriate relativistic many-electron Hamiltonian? How can we achieve relativistic explicit correlation? How can we formulate relativistic properties? - just to name a few. Since relativistic quantum chemistry is an integral component of computational chemistry, this handbook also supplements the ''Handbook of Computational Chemistry''. Generally speaking, it aims to establish the 'big picture' of relativistic molecular quantum mechanics as the union of quantum electrodynamics and relativistic quantum chemistry. Accordingly, it provides an accessible introduction for readers new to the field, presents advanced methodologies for experts, and discusses possible future perspectives, helping readers understand when/how to apply/develop the methodologies.

Validity of congenital malformation diagnostic codes recorded in Québec's administrative databases.

Science.gov (United States)

Blais, Lucie; Bérard, Anick; Kettani, Fatima-Zohra; Forget, Amélie

2013-08-01

To assess the validity of the diagnostic codes of congenital malformations (CMs) recorded in two of Québec's administrative databases. A cohort of pregnancies and infants born to asthmatic and non-asthmatic women in 1990-2002 was reconstructed using Québec's administrative databases. From this cohort, we selected 269 infants with a CM and 144 without CM born to asthmatic women, together with 284 and 138 infants, respectively, born to non-asthmatic women. The diagnoses of CMs recorded in the databases were compared with the diagnoses written by the physicians in the infants' medical charts. The positive predictive values (PPV) and negative predictive values (NPV) for all, major, and several specific CMs were estimated. The PPVs for all CMs and major CMs were 82.2% (95% confidence interval (CI): 78.5%-85.9%) and 78.1% (74.1%-82.1%), respectively, in the asthmatic group and were 79.2% (75.4%-83.1%) and 69.0% (64.6%-73.4%), respectively, in the non-asthmatic group. PPVs >80% were found for several specific CMs, including cardiac, cleft, and limb CMs in both groups. The NPV for any CM was 88.2% (95% CI: 85.1%-91.3%) in the asthmatic group and 94.2% (92.2%-96.2%) in the non-asthmatic group. Québec's administrative databases are valid tools for epidemiological research of CMs. The results were similar between infants born to women with and without asthma. Copyright © 2013 John Wiley & Sons, Ltd.

Many-body pairing in a two-dimensional Fermi gas

Energy Technology Data Exchange (ETDEWEB)

Neidig, Mathias

2017-05-24

This thesis reports on experiments conducted in a single layer, quasi two-dimensional, two-component ultracold Fermi gas in the strongly interacting regime. Ultracold gases can be used to simulate key aspects of more complicated systems like for example cuprates which show high-T{sub c} superconductivity. The momentum distribution of a sample of bosonic dimers in a quasi-2D square lattice geometry was measured to obtain the coherence properties. For shallow lattices, sharp peaks in the momentum distribution, indicating coherence, were observed at zero momentum as well as at positive and negative lattice momenta along each axis. For deeper lattices, heating impeded the ability to prepare a Mott-insulator. A spatially resolved radio-frequency spectroscopy was employed for a quasi-2D Fermi gas in the normal phase throughout the BEC-BCS crossover. The interaction induced energy shifts were measured in the strongly interacting region where they can be on the order of the Fermi energy and thus the local resolution is crucial. Furthermore, the onset of pairing in the strongly interacting region was measured as a function of temperature and it was shown that the fraction of free atoms decreases faster than expected from thermal non-interacting theory. At last, the pairing gap was measured using an imbalanced sample. On the BEC side it was found to be in very good agreement with two-body physics as expected. In the strongly interacting regime, however, a deviation from two-body physics indicates that here many-body effects play a role and thus further studies are required.

Relativistic many-body theory of atomic transitions. The relativistic equation-of-motion approach

International Nuclear Information System (INIS)

Huang, K.

1982-01-01

An equation-of-motion approach is used to develop the relativistic many-body theory of atomic transitions. The relativistic equations of motion for transition matrices are formulated with the use of techniques of quantum-field theory. To reduce the equations of motion to a tractable form which is appropriate for numerical calculations, a graphical method to resolve the complication arising from the antisymmetrization and angular-momentum coupling is employed. The relativistic equation-of-motion method allows an ab initio treatment of correlation and relativistic effects in both closed- and open-shell many-body systems. A special case of the present formulation reduces to the relativistic random-phase approximation

Relativistic many-body theory of atomic transitions: the relativistic equation-of-motion approach

International Nuclear Information System (INIS)

Huang, K.N.

1981-01-01

An equation-of-motion approach is used to develop the relativistic many-body theory of atomic transitions. The relativistic equations of motion for transition matrices are formulated using techniques of quantum field theory. To reduce the equation of motion to a tractable form which is appropriate for numerical calculations, a graphical method is employed to resolve the complication arising from the antisymmetrization and angular momentum coupling. The relativistic equation-of-motion method allows an ab initio treatment of correlation and relativistic effects in both closed- and open-shell many-body systems. A special case of the present formulation reduces to the relativistic random-phase approximation

The energetic state of mitochondria modulates complex III biogenesis through the ATP-dependent activity of Bcs1.

Science.gov (United States)

Ostojić, Jelena; Panozzo, Cristina; Lasserre, Jean-Paul; Nouet, Cécile; Courtin, Florence; Blancard, Corinne; di Rago, Jean-Paul; Dujardin, Geneviève

2013-10-01

Our understanding of the mechanisms involved in mitochondrial biogenesis has continuously expanded during the last decades, yet little is known about how they are modulated to optimize the functioning of mitochondria. Here, we show that mutations in the ATP binding domain of Bcs1, a chaperone involved in the assembly of complex III, can be rescued by mutations that decrease the ATP hydrolytic activity of the ATP synthase. Our results reveal a Bcs1-mediated control loop in which the biogenesis of complex III is modulated by the energy-transducing activity of mitochondria. Although ATP is well known as a regulator of a number of cellular activities, we show here that ATP can be also used to modulate the biogenesis of an enzyme by controlling a specific chaperone involved in its assembly. Our study further highlights the intramitochondrial adenine nucleotide pool as a potential target for the treatment of Bcs1-based disorders. Copyright © 2013 Elsevier Inc. All rights reserved.

Relativistic duality, and relativistic and radiative corrections for heavy-quark systems

International Nuclear Information System (INIS)

Durand, B.; Durand, L.

1982-01-01

We give a JWKB proof of a relativistic duality relation which relates an appropriate energy average of the physical cross section for e + e - →qq-bar bound states→hadrons to the same energy average of the perturbative cross section for e + e - →qq-bar. We show that the duality relation can be used effectively to estimate relativistic and radiative corrections for bound-quark systems to order α/sub s//sup ts2/. We also present a formula which relates the square of the ''large'' 3 S 1 Salpeter-Bethe-Schwinger wave function for zero space-time separation of the quarks to the square of the nonrelativistic Schroedinger wave function at the origin for an effective potential which reproduces the relativistic spectrum. This formula allows one to use the nonrelativistic wave functions obtained in potential models fitted to the psi and UPSILON spectra to calculate relativistic leptonic widths for qq-bar states via a relativistic version of the van Royen--Weisskopf formula

In silico prediction of drug dissolution and absorption with variation in intestinal pH for BCS class II weak acid drugs: ibuprofen and ketoprofen.

Science.gov (United States)

Tsume, Yasuhiro; Langguth, Peter; Garcia-Arieta, Alfredo; Amidon, Gordon L

2012-10-01

The FDA Biopharmaceutical Classification System guidance allows waivers for in vivo bioavailability and bioequivalence studies for immediate-release solid oral dosage forms only for BCS class I. Extensions of the in vivo biowaiver for a number of drugs in BCS class III and BCS class II have been proposed, in particular, BCS class II weak acids. However, a discrepancy between the in vivo BE results and in vitro dissolution results for BCS class II acids was recently observed. The objectives of this study were to determine the oral absorption of BCS class II weak acids via simulation software and to determine if the in vitro dissolution test with various dissolution media could be sufficient for in vitro bioequivalence studies of ibuprofen and ketoprofen as models of carboxylic acid drugs. The oral absorption of these BCS class II acids from the gastrointestinal tract was predicted by GastroPlus™. Ibuprofen did not satisfy the bioequivalence criteria at lower settings of intestinal pH of 6.0. Further the experimental dissolution of ibuprofen tablets in a low concentration phosphate buffer at pH 6.0 (the average buffer capacity 2.2 mmol l (-1) /pH) was dramatically reduced compared with the dissolution in SIF (the average buffer capacity 12.6 mmol l (-1) /pH). Thus these predictions for the oral absorption of BCS class II acids indicate that the absorption patterns depend largely on the intestinal pH and buffer strength and must be considered carefully for a bioequivalence test. Simulation software may be a very useful tool to aid the selection of dissolution media that may be useful in setting an in vitro bioequivalence dissolution standard. Copyright © 2012 John Wiley & Sons, Ltd.

Handbook of relativistic quantum chemistry

Energy Technology Data Exchange (ETDEWEB)

Liu, Wenjian (ed.) [Peking Univ., Beijing (China). Center for Computational Science and Engineering

2017-03-01

This handbook focuses on the foundations of relativistic quantum mechanics and addresses a number of fundamental issues never covered before in a book. For instance: How can many-body theory be combined with quantum electrodynamics? How can quantum electrodynamics be interfaced with relativistic quantum chemistry? What is the most appropriate relativistic many-electron Hamiltonian? How can we achieve relativistic explicit correlation? How can we formulate relativistic properties? - just to name a few. Since relativistic quantum chemistry is an integral component of computational chemistry, this handbook also supplements the ''Handbook of Computational Chemistry''. Generally speaking, it aims to establish the 'big picture' of relativistic molecular quantum mechanics as the union of quantum electrodynamics and relativistic quantum chemistry. Accordingly, it provides an accessible introduction for readers new to the field, presents advanced methodologies for experts, and discusses possible future perspectives, helping readers understand when/how to apply/develop the methodologies.

Relativistic non-Hamiltonian mechanics

International Nuclear Information System (INIS)

Tarasov, Vasily E.

2010-01-01

Relativistic particle subjected to a general four-force is considered as a nonholonomic system. The nonholonomic constraint in four-dimensional space-time represents the relativistic invariance by the equation for four-velocity u μ u μ + c 2 = 0, where c is the speed of light in vacuum. In the general case, four-forces are non-potential, and the relativistic particle is a non-Hamiltonian system in four-dimensional pseudo-Euclidean space-time. We consider non-Hamiltonian and dissipative systems in relativistic mechanics. Covariant forms of the principle of stationary action and the Hamilton's principle for relativistic mechanics of non-Hamiltonian systems are discussed. The equivalence of these principles is considered for relativistic particles subjected to potential and non-potential forces. We note that the equations of motion which follow from the Hamilton's principle are not equivalent to the equations which follow from the variational principle of stationary action. The Hamilton's principle and the principle of stationary action are not compatible in the case of systems with nonholonomic constraint and the potential forces. The principle of stationary action for relativistic particle subjected to non-potential forces can be used if the Helmholtz conditions are satisfied. The Hamilton's principle and the principle of stationary action are equivalent only for a special class of relativistic non-Hamiltonian systems.

Cosmological BCS mechanism and the big bang singularity

Science.gov (United States)

Alexander, Stephon; Biswas, Tirthabir

2009-07-01

We provide a novel mechanism that resolves the big bang singularity present in Friedman-Lemaitre-Robertson-Walker space-times without the need for ghost fields. Building on the fact that a four-fermion interaction arises in general relativity when fermions are covariantly coupled, we show that at early times the decrease in scale factor enhances the correlation between pairs of fermions. This enhancement leads to a BCS-like condensation of the fermions and opens a gap dynamically driving the Hubble parameter H to zero and results in a nonsingular bounce, at least in some special cases.

In Silico Prediction of Drug Dissolution and Absorption with variation in Intestinal pH for BCS Class II Weak Acid Drugs: Ibuprofen and Ketoprofen§

Science.gov (United States)

Tsume, Yasuhiro; Langguth, Peter; Garcia-Arieta, Alfredo; Amidon, Gordon L.

2012-01-01

The FDA Biopharmaceutical Classification System guidance allows waivers for in vivo bioavailability and bioequivalence studies for immediate-release solid oral dosage forms only for BCS class I. Extensions of the in vivo biowaiver for a number of drugs in BCS Class III and BCS class II have been proposed, particularly, BCS class II weak acids. However, a discrepancy between the in vivo- BE results and in vitro- dissolution results for a BCS class II acids was recently observed. The objectives of this study were to determine the oral absorption of BCS class II weak acids via simulation software and to determine if the in vitro dissolution test with various dissolution media could be sufficient for in vitro bioequivalence studies of ibuprofen and ketoprofen as models of carboxylic acid drugs. The oral absorption of these BCS class II acids from the gastrointestinal tract was predicted by GastroPlus™. Ibuprofen did not satisfy the bioequivalence criteria at lower settings of intestinal pH=6.0. Further the experimental dissolution of ibuprofen tablets in the low concentration phosphate buffer at pH 6.0 (the average buffer capacity 2.2 mmol L-1/pH) was dramatically reduced compared to the dissolution in SIF (the average buffer capacity 12.6 mmol L -1/pH). Thus these predictions for oral absorption of BCS class II acids indicate that the absorption patterns largely depend on the intestinal pH and buffer strength and must be carefully considered for a bioequivalence test. Simulation software may be very useful tool to aid the selection of dissolution media that may be useful in setting an in vitro bioequivalence dissolution standard. PMID:22815122

Separable Crossover-Promoting and Crossover-Constraining Aspects of Zip1 Activity during Budding Yeast Meiosis.

Directory of Open Access Journals (Sweden)

Karen Voelkel-Meiman

2015-06-01

Full Text Available Accurate chromosome segregation during meiosis relies on the presence of crossover events distributed among all chromosomes. MutSγ and MutLγ homologs (Msh4/5 and Mlh1/3 facilitate the formation of a prominent group of meiotic crossovers that mature within the context of an elaborate chromosomal structure called the synaptonemal complex (SC. SC proteins are required for intermediate steps in the formation of MutSγ-MutLγ crossovers, but whether the assembled SC structure per se is required for MutSγ-MutLγ-dependent crossover recombination events is unknown. Here we describe an interspecies complementation experiment that reveals that the mature SC is dispensable for the formation of Mlh3-dependent crossovers in budding yeast. Zip1 forms a major structural component of the budding yeast SC, and is also required for MutSγ and MutLγ-dependent crossover formation. Kluyveromyces lactis ZIP1 expressed in place of Saccharomyces cerevisiae ZIP1 in S. cerevisiae cells fails to support SC assembly (synapsis but promotes wild-type crossover levels in those nuclei that progress to form spores. While stable, full-length SC does not assemble in S. cerevisiae cells expressing K. lactis ZIP1, aggregates of K. lactis Zip1 displayed by S. cerevisiae meiotic nuclei are decorated with SC-associated proteins, and K. lactis Zip1 promotes the SUMOylation of the SC central element protein Ecm11, suggesting that K. lactis Zip1 functionally interfaces with components of the S. cerevisiae synapsis machinery. Moreover, K. lactis Zip1-mediated crossovers rely on S. cerevisiae synapsis initiation proteins Zip3, Zip4, Spo16, as well as the Mlh3 protein, as do the crossovers mediated by S. cerevisiae Zip1. Surprisingly, however, K. lactis Zip1-mediated crossovers are largely Msh4/Msh5 (MutSγ-independent. This separation-of-function version of Zip1 thus reveals that neither assembled SC nor MutSγ is required for Mlh3-dependent crossover formation per se in budding yeast

Investigation of the coupling of the momentum distribution of a BEC with its collective of modes

Science.gov (United States)

Henn, Emanuel; Tavares, Pedro; Fritsch, Amilson; Vivanco, Franklin; Telles, Gustavo; Bagnato, Vanderlei

In our group we have a strong research line on quantum turbulence and the general investigation of Bose-Einstein condensates (BEC) subjected to oscillatory excitations. Inside this research line we investigate first the behavior of the normal modes of the BEC under this excitation and observe a non-linear behavior in the amplitude of the quadrupolar mode. Also, inside this same procedure of investigation we study the momentum distribution of a BEC to understand if it is possible to extract Kolmogorov like excitation spectra which would point to a turbulent state of matter. The condensate is perturbed, and we let it evolve in-trap after which we perform standard time-of- flight absorption imaging. The momentum distribution is extracted and analyzed as a function of the in-trap free evolution time for a 2D projected cloud. We show that the momentum distribution has its features varying periodically with the same frequency as the quadrupolar mode displayed by the atomic gas hinting at a strong coupling of both. The main consequence of that one cannot be assertive about the quantitative features of the extract spectrum of momentum and we can only rely on its qualitative features. Financial Support: FAPESP, CNPq.

BCS @ 50: derivation of gap equations in different lattice geometries

International Nuclear Information System (INIS)

Saurabh Basu

2007-07-01

We rigorously derive BCS gap equations for a square, triangular and a honeycomb lattice using a two-dimensional t-J model. The gap equations in all the three lattice geometries look usual, with band indices appearing and a minor modification in the separable pair potential for the (two band) honeycomb lattice. In each case, the gap equation is solved (self consistently with the number equation) at low densities assuming singlet pairing. (author)

Recent development of relativistic molecular theory

International Nuclear Information System (INIS)

Takahito, Nakajima; Kimihiko, Hirao

2005-01-01

Today it is common knowledge that relativistic effects are important in the heavy-element chemistry. The continuing development of the relativistic molecular theory is opening up rows of the periodic table that are impossible to treat with the non-relativistic approach. The most straightforward way to treat relativistic effects on heavy-element systems is to use the four-component Dirac-Hartree-Fock approach and its electron-correlation methods based on the Dirac-Coulomb(-Breit) Hamiltonian. The Dirac-Hartree-Fock (DHF) or Dirac-Kohn-Sham (DKS) equation with the four-component spinors composed of the large- and small-components demands severe computational efforts to solve, and its applications to molecules including heavy elements have been limited to small- to medium-size systems. Recently, we have developed a very efficient algorithm for the four-component DHF and DKS approaches. As an alternative approach, several quasi-relativistic approximations have also been proposed instead of explicitly solving the four-component relativistic equation. We have developed the relativistic elimination of small components (RESC) and higher-order Douglas-Kroll (DK) Hamiltonians within the framework of the two-component quasi-relativistic approach. The developing four-component relativistic and approximate quasi-relativistic methods have been implemented into a program suite named REL4D. In this article, we will introduce the efficient relativistic molecular theories to treat heavy-atomic molecular systems accurately via the four-component relativistic and the two-component quasi-relativistic approaches. We will also show several chemical applications including heavy-element systems with our relativistic molecular approaches. (author)

On the limits of consistency of Eliashberg theory and the density of states of high-Tc superconductors

International Nuclear Information System (INIS)

Varelogiannis, G.

1997-01-01

We make a detailed study of the Eliashberg theory in the coupling region where some fundamental qualitative deviations from the conventional BCS- like behavior begin to appear. These deviations are identified as the onset of a cross-over from BCS superconductivity to Bose condensation. We point out that the beginning of this cross-over occurs when the gap Δ g becomes comparable to the boson energies Ω ph . This condition traduces the physical constraint that the distance the paired electron covers during the absorption of the virtual boson, cannot be larger than the coherence length. The frontier region of couplings is of the order of λ∼3, and high-T c , materials are concerned. A clear qualitative indication of the occurrence of a cross-over regime should be a dip structure above the gap in the density of states of excitations, and this is one of the most robust characteristics of the high-T c , superconducting state. Comparing our results with tunneling and photoemission experiments we conclude that high-T c materials (cuprates and fullerides) are indeed at the beginning of a cross-over from BCS superconductivity to Bose condensation, even though the fermionic nature still prevails. If the Uemura plot is relevant, then the dip should also be present in the other materials that are close to the cross-over regime like heavy Fermion and organic superconductors. In all these materials Ginzburg Landau equations are irrelevant. (orig.)

Dynamical description of the fission process using the TD-BCS theory

Energy Technology Data Exchange (ETDEWEB)

Scamps, Guillaume, E-mail: scamps@nucl.phys.tohoku.ac.jp [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Simenel, Cédric [Department of Nuclear Physics, Research School of Physics and Engineering Australian National University, Canberra, Australian Capital Territory 2601 (Australia); Lacroix, Denis [Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, F-91406 Orsay Cedex (France)

2015-10-15

The description of fission remains a challenge for nuclear microscopic theories. The time-dependent Hartree-Fock approach with BCS pairing is applied to study the last stage of the fission process. A good agreement is found for the one-body observables: the total kinetic energy and the average mass asymmetry. The non-physical dependence of two-body observables with the initial shape is discussed.

Relativistic Kinetic Theory

Science.gov (United States)

Vereshchagin, Gregory V.; Aksenov, Alexey G.

2017-02-01

Preface; Acknowledgements; Acronyms and definitions; Introduction; Part I. Theoretical Foundations: 1. Basic concepts; 2. Kinetic equation; 3. Averaging; 4. Conservation laws and equilibrium; 5. Relativistic BBGKY hierarchy; 6. Basic parameters in gases and plasmas; Part II. Numerical Methods: 7. The basics of computational physics; 8. Direct integration of Boltzmann equations; 9. Multidimensional hydrodynamics; Part III. Applications: 10. Wave dispersion in relativistic plasma; 11. Thermalization in relativistic plasma; 12. Kinetics of particles in strong fields; 13. Compton scattering in astrophysics and cosmology; 14. Self-gravitating systems; 15. Neutrinos, gravitational collapse and supernovae; Appendices; Bibliography; Index.

Quantifying the Chasm: Exploring the Impact of the BCS on Total Football Revenues for Division One Football Programs from 2002-2012

Science.gov (United States)

Caro, Cary A.

2014-01-01

The Bowl Championship Series served as a collection of bowl games that were designed to crown the national champion in Division One football. The BCS created two classifications of institutions in Division football, those that were granted automatic access (AQ) to the post-season games, and those that were not (non-AQ). The BCS also generated…

Relativistic Linear Restoring Force

Science.gov (United States)

Clark, D.; Franklin, J.; Mann, N.

2012-01-01

We consider two different forms for a relativistic version of a linear restoring force. The pair comes from taking Hooke's law to be the force appearing on the right-hand side of the relativistic expressions: d"p"/d"t" or d"p"/d["tau"]. Either formulation recovers Hooke's law in the non-relativistic limit. In addition to these two forces, we…

Relativistic decay widths of autoionization processes: The relativistic FanoADC-Stieltjes method

Energy Technology Data Exchange (ETDEWEB)

Fasshauer, Elke, E-mail: Elke.Fasshauer@uit.no [Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø–The Arctic University of Norway, N-9037 Tromsø (Norway); Theoretische Chemie, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany); Kolorenč, Přemysl [Institute of Theoretical Physics, Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, 180 00 Prague (Czech Republic); Pernpointner, Markus [Theoretische Chemie, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany)

2015-04-14

Electronic decay processes of ionized systems are, for example, the Auger decay or the Interatomic/ Intermolecular Coulombic Decay. In both processes, an energetically low lying vacancy is filled by an electron of an energetically higher lying orbital and a secondary electron is instantaneously emitted to the continuum. Whether or not such a process occurs depends both on the energetic accessibility and the corresponding lifetime compared to the lifetime of competing decay mechanisms. We present a realization of the non-relativistically established FanoADC-Stieltjes method for the description of autoionization decay widths including relativistic effects. This procedure, being based on the Algebraic Diagrammatic Construction (ADC), was adapted to the relativistic framework and implemented into the relativistic quantum chemistry program package Dirac. It is, in contrast to other existing relativistic atomic codes, not limited to the description of autoionization lifetimes in spherically symmetric systems, but is instead also applicable to molecules and clusters. We employ this method to the Auger processes following the Kr3d{sup −1}, Xe4d{sup −1}, and Rn5d{sup −1} ionization. Based on the results, we show a pronounced influence of mainly scalar-relativistic effects on the decay widths of autoionization processes.

Regional-dependent intestinal permeability and BCS classification: elucidation of pH-related complexity in rats using pseudoephedrine.

Science.gov (United States)

Fairstein, Moran; Swissa, Rotem; Dahan, Arik

2013-04-01

Based on its lower Log P value relative to metoprolol, a marker for the low/high-permeability (P(eff)) class boundary, pseudoephedrine was provisionally classified as BCS low-permeability compound. On the other hand, following oral administration, pseudoephedrine fraction dose absorbed (F(abs)) and systemic bioavailability approaches 100%. This represents a challenge to the generally recognized P(eff)-F(abs) correlation. The purpose of this study was to elucidate the underlying mechanisms behind the confusion in pseudoephedrine's BCS classification. Pseudoephedrine's BCS solubility class was determined, and its physicochemical properties and intestinal permeability were thoroughly investigated, both in vitro and in vivo in rats, considering the complexity of the whole of the small intestine. Pseudoephedrine was found to be unequivocally a high-solubility compound. All of the permeability studies revealed similar phenomenon; at any given intestinal segment/pH, the permeability of metoprolol was higher than that of pseudoephedrine, however, as the intestinal region becomes progressively distal, and the pH gradually increases, pseudoephedrine's permeability rises above that of metoprolol in the former segment. This unique permeability pattern likely explains pseudoephedrine's complete absorption. In conclusion, pseudoephedrine is a BCS Class I compound; no discrepancy between P(eff) and F(abs) is involved in its absorption. Rather, it reflects the complexity behind P(eff) when considering the whole of the intestine. We propose to allow high-permeability classification to drugs with P(eff) that matches/exceeds the low/high class benchmark anywhere throughout the intestinal tract and not restricted necessarily to the jejunum.

Relativistic positioning systems: perspectives and prospects

Science.gov (United States)

Coll Bartolomé

2013-11-01

Relativistic positioning systems are interesting technical objects for applications around the Earth and in the Solar system. But above all else, they are basic scientific objects allowing developing relativity from its own concepts. Some past and future features of relativistic positioning sys- tems, with special attention to the developments that they suggest for an epistemic relativity (relativistic experimental approach to physics), are analyzed. This includes relativistic stereometry, which, together with relativistic positioning systems, allows to introduce the general relativistic notion of (finite) laboratory (space-time region able to perform experiments of finite size).

Electronic structure of FeTiSb using relativistic and scalar-relativistic approaches

Energy Technology Data Exchange (ETDEWEB)

Sahariya, Jagrati [Department of Physics, Manipal University Jaipur, Jaipur-303007, Rajasthan (India); Mund, H. S., E-mail: hmoond@gmail.com [Department of Physics, M. L. Sukhadia University, Udaipur-313001, Rajasthan (India)

2016-05-06

Electronic and magnetic properties of FeTiSb have been reported. The calculations are performed using spin polarized relativistic Korringa-Kohn-Rostoker scheme based on Green’s function method. Within SPR-KKR a fully relativistic and scalar-relativistic approaches have been used to investigate electronic structure of FeTiSb. Energy bands, total and partial density of states, atom specific magnetic moment along with total moment of FeTiSb alloys are presented.

Relativistic entanglement from relativistic quantum mechanics in the rest-frame instant form of dynamics

International Nuclear Information System (INIS)

Lusanna, Luca

2011-01-01

After a review of the problems induced by the Lorentz signature of Minkowski space-time, like the need of a clock synchronization convention for the definition of 3-space and the complexity of the notion of relativistic center of mass, there is the introduction of a new formulation of relativistic quantum mechanics compatible with the theory of relativistic bound states. In it the zeroth postulate of non-relativistic quantum mechanics is not valid and the physics is described in the rest frame by a Hilbert space containing only relative variables. The non-locality of the Poincare' generators imply a kinematical non-locality and non-separability influencing the theory of relativistic entanglement and not connected with the standard quantum non-locality.

Dark lump excitations in superfluid Fermi gases

Science.gov (United States)

Xu, Yan-Xia; Duan, Wen-Shan

2012-11-01

We study the linear and nonlinear properties of two-dimensional matter-wave pulses in disk-shaped superfluid Fermi gases. A Kadomtsev—Petviashvili I (KPI) solitary wave has been realized for superfluid Fermi gases in the limited cases of Bardeen—Cooper—Schrieffer (BCS) regime, Bose—Einstein condensate (BEC) regime, and unitarity regime. One-lump solution as well as one-line soliton solutions for the KPI equation are obtained, and two-line soliton solutions with the same amplitude are also studied in the limited cases. The dependence of the lump propagating velocity and the sound speed of two-dimensional superfluid Fermi gases on the interaction parameter are investigated for the limited cases of BEC and unitarity.

Dark lump excitations in superfluid Fermi gases

International Nuclear Information System (INIS)

Xu Yan-Xia; Duan Wen-Shan

2012-01-01

We study the linear and nonlinear properties of two-dimensional matter-wave pulses in disk-shaped superfluid Fermi gases. A Kadomtsev—Petviashvili I (KPI) solitary wave has been realized for superfluid Fermi gases in the limited cases of Bardeen—Cooper—Schrieffer (BCS) regime, Bose—Einstein condensate (BEC) regime, and unitarity regime. One-lump solution as well as one-line soliton solutions for the KPI equation are obtained, and two-line soliton solutions with the same amplitude are also studied in the limited cases. The dependence of the lump propagating velocity and the sound speed of two-dimensional superfluid Fermi gases on the interaction parameter are investigated for the limited cases of BEC and unitarity

Stability of BEC galactic dark matter halos

Energy Technology Data Exchange (ETDEWEB)

Guzmán, F.S.; Lora-Clavijo, F.D.; González-Avilés, J.J.; Rivera-Paleo, F.J., E-mail: guzman@ifm.umich.mx, E-mail: fadulora@ifm.umich.mx, E-mail: javiles@ifm.umich.mx, E-mail: friverap@ifm.umich.mx [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Cd. Universitaria, 58040 Morelia, Michoacán (Mexico)

2013-09-01

In this paper we show that spherically symmetric BEC dark matter halos, with the sin r/r density profile, that accurately fit galactic rotation curves and represent a potential solution to the cusp-core problem are unstable. We do this by introducing back the density profiles into the fully time-dependent Gross-Pitaevskii-Poisson system of equations. Using numerical methods to track the evolution of the system, we found that these galactic halos lose mass at an approximate rate of half of its mass in a time scale of dozens of Myr. We consider this time scale is enough as to consider these halos are unstable and unlikely to be formed. We provide some arguments to show that this behavior is general and discuss some other drawbacks of the model that restrict its viability.

Gravitationally bound BCS state as dark matter

Energy Technology Data Exchange (ETDEWEB)

Alexander, Stephon [Department of Physics, Brown University, Providence, RI 20912 (United States); Cormack, Sam, E-mail: stephon_alexander@brown.edu, E-mail: samuel.c.cormack.gr@dartmouth.edu [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States)

2017-04-01

We explore the possibility that fermionic dark matter undergoes a BCS transition to form a superfluid. This requires an attractive interaction between fermions and we describe a possible source of this interaction induced by torsion. We describe the gravitating fermion system with the Bogoliubov-de Gennes formalism in the local density approximation. We solve the Poisson equation along with the equations for the density and gap energy of the fermions to find a self-gravitating, superfluid solution for dark matter halos. In order to produce halos the size of dwarf galaxies, we require a particle mass of ∼ 200 eV. We find a maximum attractive coupling strength before the halo becomes unstable. If dark matter halos do have a superfluid component, this raises the possibility that they contain vortex lines.

Quantum dynamics of a BEC interacting with a single-mode quantized field in the presence of interatom collisions

Energy Technology Data Exchange (ETDEWEB)

Ghasemian, E. [Atomic and Molecular Group, Faculty of Physics, Yazd University, Yazd (Iran, Islamic Republic of); Tavassoly, M.K., E-mail: mktavassoly@yazd.ac.ir [Atomic and Molecular Group, Faculty of Physics, Yazd University, Yazd (Iran, Islamic Republic of); Photonics Research Group, Engineering Research Center, Yazd University, Yazd (Iran, Islamic Republic of); The Laboratory of Quantum Information Processing, Yazd University, Yazd (Iran, Islamic Republic of)

2016-09-23

In this paper, we consider a model in which N two-level atoms in a Bose–Einstein condensate (BEC) interact with a single-mode quantized laser field. Our goal is to investigate the quantum dynamics of atoms in the BEC in the presence of interatom interactions. To achieve the purpose, at first, using the collective angular momentum operators, we try to reduce the dynamical Hamiltonian of the system to a well-known Jaynes–Cummings like model (JCM). We also use the Dicke model to construct the state of atomic subsystem, by which the analytical solution of the system may be obtained. Then, we analyze the atomic population inversion, the degree of entanglement between the “atoms in BEC” and the “field” as well as the Mandel parameter. Numerical results show that, the atomic population inversion, atom-field entanglement and quantum statistics of photons are very sensitive to the evolved parameters in the model (and so can be well-adjusted), such as the number of atoms in BEC, the intensity of initial field, the interatom coupling constant and detuning. To investigate the entanglement properties, we pay attention to the entropy and linear entropy. It is shown that, oscillations in the two entropy criteria may be seen, with some maxima of entanglement at some moments of time. Finally, looking for the quantum statistics, we evaluate the Mandel parameter, by which we demonstrate the sub-Poissonian statistics and so the nonclassical characteristics of the field state of system. Collapse-revival phenomenon, which is a distinguishable nonclassical characteristic of the system, can be apparently observed in the atomic population inversion and the Mandel parameter. - Highlights: • N two-level atoms in a BEC interacting with a laser field in the presence of interatom interactions is considered. • The atomic population inversion, degree of entanglement between the “atoms in BEC” and the “field” and the Mandel parameter are investigated. • Collapse

Non-BCS superconductivity for underdoped cuprates by spin-vortex attraction

OpenAIRE

Marchetti, P. A.; Ye, F.; Su, Z. B.; Yu, L.

2011-01-01

Within a gauge approach to the t-J model, we propose a new, non-BCS mechanism of superconductivity for underdoped cuprates. The gluing force of the superconducting mechanism is an attraction between spin vortices on two different N\\'eel sublattices, centered around the empty sites described in terms of fermionic holons. The spin fluctuations are described by bosonic spinons with a gap generated by the spin vortices. Due to the no-double occupation constraint, there is a gauge attraction betwe...

Energy dependence of sputtering yields of Be, Be-C and Be-W films by Be{sup +}-ions

Energy Technology Data Exchange (ETDEWEB)

Korshunov, S.N.; Guseva, M.I.; Gureev, V.M.; Neumoin, V.E.; Stoljarova, V.G. [Russian Research Center Kurchatov Inst., Moscow (Russian Federation)

1998-01-01

The energy dependence measurements of Be, Be-C and Be-W deposited layer sputtering yields by Be{sup +}-ions were performed. The ion energy was varied in the range (0.3-5.0) keV. The temperature in the process of irradiation was sustained at the level of 670 K. The mixed layers were prepared by simultaneous sputtering of pair targets, Be and C, Be and W, and Be-targets with Ar{sup +}- and Be{sup +}-ions and codeposition of the sputtered atoms on silicon collectors The codeposited layer thickness was changed in the range of (500-1000) nm. The content of oxigen in the Be, Be-C, Be-W deposited layers did not exceed 20 at.%. The mixed layer sputtering yields were compared with the experimental and calculated data, obtained for the self-sputtering yields of beryllium and carbon. It was found that the sputtering yields of the Be-C and Be deposited layers by Be{sup +}-ions in the energy range (0.3-5.0) keV are within the range between the corresponding self-sputtering yields for Be and C. The sputtering yields for the mixture Be-W are close to the corresponding self-sputtering yields of beryllium. (author)

Climatic changes and caribou abundance in northern Québec over the last century

Directory of Open Access Journals (Sweden)

Michel Crête

1990-09-01

Full Text Available The temperature increase observed in the Northern hemisphere during the first half of this century was also detectable in Québec; it affected both summer and winter. In northern Québec, warmer summers stimulated growth and favored range expansion of trees and shurbs. Based on black spruce krummholz height and water level in lakes, the warmer period was also characterized by greater snowfall and deeper snow cover. This period of deep snow coincided with apparent caribou scarcity. Three hypotheses were explored to relate increased temperature with caribou decline: 1 destruction of winter habitat due to high frequency of forest fires, 2 increased energy cost to obtain forage in deep snow and 3 delayed melting of snow on calving grounds that shortened the time to raise calves. The combined effect of the 3 mechanism could explain caribou scarcity, particularly for the Rivière George herd whose calving ground becomes snow free in late June. Ways to test the third hypothesis are proposed.

DMFT+Σ approach to disordered Hubbard model

International Nuclear Information System (INIS)

Kuchinskii, E. Z.; Sadovskii, M. V.

2016-01-01

We briefly review the generalized dynamic mean-field theory DMFT+Σ applied to both repulsive and attractive disordered Hubbard models. We examine the general problem of metal–insulator transition and the phase diagram in the repulsive case, as well as the BCS–BEC crossover region of the attractive model, demonstrating a certain universality of single-electron properties under disordering in both models. We also discuss and compare the results for the density of states and dynamic conductivity in the repulsive and attractive cases and the generalized Anderson theorem behavior of the superconducting critical temperature in the disordered attractive case. A brief discussion of the behavior of Ginzburg–Landau coefficients under disordering in the BCS–BEC crossover region is also presented.

Relativistic Descriptions of Few-Body Systems

International Nuclear Information System (INIS)

Karmanov, V. A.

2011-01-01

A brief review of relativistic effects in few-body systems, of theoretical approaches, recent developments and applications is given. Manifestations of relativistic effects in the binding energies, in the electromagnetic form factors and in three-body observables are demonstrated. The three-body forces of relativistic origin are also discussed. We conclude that relativistic effects in nuclei can be important in spite of small binding energy. At high momenta they clearly manifest themselves and are necessary to describe the deuteron e.m. form factors. At the same time, there is still a discrepancy in three-body observables which might be a result of less clarity in understanding the corresponding relativistic effects, the relativistic NN kernel and the three-body forces. Relativistic few-body physics remains to be a field of very intensive and fruitful researches. (author)

The Relevance of the Carnivalesque in the Québec Novel

Directory of Open Access Journals (Sweden)

Maroussia Ahmed

1984-09-01

Full Text Available The Bakhtinian concept of space is topological rather than topographic, and encompasses the cosmic, the social and the corporeal; its function in the Québec novel consists in debasing the hierarchical verticality of Lent and of the "official feast." As Carnival is an anti-law,"law" in the Québec novel will be defined as the chronotope of the sacred space (the land or "terre" of Québec in the genre known as the "novel of the land" ("le roman de Ia terre". Until the Second World War, this chronotope transforms an Augustinian political view of the civitas dei into literary proselytism, via the ideology of agricultural messianism. Sanctification implies closure of space and of the text; the "outside" is debased, as is textual "difference," that is, carnivalesque writing as it appears, for example, in La Scouine by Albert Laberge or in Marie Calumet by Rodolphe Girard. During the 1940s, the "introspective novel" (Robert Charbonneau, Robert Elie, Robert Choquette also connotes the "upper" euphorically and the "lower" dysphorically, but at this historical point as a function of the sanctification of the individual according to a Thomist hierarchy. The quest of the hero can be seen as the ascent of a vertical ladder of time/space/society/values. The novel of the 1960s takes on a carnivalesque air: former sacred spaces are diminished in number and importance or are debased; new spaces appear where the body communicates with other bodies and the world. The space of knowledge is not God, but the land. Novels of this period (by M.C. Blais, R. Carrier, A. Hébert are constructed around two paradigms according to a Manichean view of the world, and bear a great predictability, thus leading to a new set of "upside down" cliches. The carnivalesque multiple is completely realized in Hubert Aquin's first two novels. Space ceases to bear meaning other than as a metaphor for horizontal kinetic writing. The text becomes the open space of a continuous game between

Bcs1p can rescue a large and productive cytochrome bc(1) complex assembly intermediate in the inner membrane of yeast mitochondria.

Science.gov (United States)

Conte, Laura; Trumpower, Bernard L; Zara, Vincenzo

2011-01-01

The yeast cytochrome bc(1) complex, a component of the mitochondrial respiratory chain, is composed of ten distinct protein subunits. In the assembly of the bc(1) complex, some ancillary proteins, such as the chaperone Bcs1p, are actively involved. The deletion of the nuclear gene encoding this chaperone caused the arrest of the bc(1) assembly and the formation of a functionally inactive bc(1) core structure of about 500-kDa. This immature bc(1) core structure could represent, on the one hand, a true assembly intermediate or, on the other hand, a degradation product and/or an incorrect product of assembly. The experiments here reported show that the gradual expression of Bcs1p in the yeast strain lacking this protein was progressively able to rescue the bc(1) core structure leading to the formation of the functional homodimeric bc(1) complex. Following Bcs1p expression, the mature bc(1) complex was also progressively converted into two supercomplexes with the cytochrome c oxidase complex. The capability of restoring the bc(1) complex and the supercomplexes was also possessed by the mutated yeast R81C Bcsp1. Notably, in the human ortholog BCS1L, the corresponding point mutation (R45C) was instead the cause of a severe bc(1) complex deficiency. Differently from the yeast R81C Bcs1p, two other mutated Bcs1p's (K192P and F401I) were unable to recover the bc(1) core structure in yeast. This study identifies for the first time a productive assembly intermediate of the yeast bc(1) complex and gives new insights into the molecular mechanisms involved in the last steps of bc(1) assembly. Copyright © 2010 Elsevier B.V. All rights reserved.

LENR BEC Clusters on and below Wires through Cavitation and Related Techniques

Science.gov (United States)

Stringham, Roger; Stringham, Julie

2011-03-01

During the last two years I have been working on BEC cluster densities deposited just under the surface of wires, using cavitation, and other techniques. If I get the concentration high enough before the clusters dissipate, in addition to cold fusion related excess heat (and other effects, including helium-4 formation) I anticipate that it may be possible to initiate transient forms of superconductivity at room temperature.

The Pedagogical Practices of Québec High School Teachers Relative to Sexual Diversity

Science.gov (United States)

Richard, Gabrielle

2015-01-01

This article explores the ways in which teachers describe their pedagogical and intervention practices relative to sexual diversity in Québec (Canada). Three variables closely associated with teachers who report inclusive practices emerge: experiential training (based on the experience of a lesbian, gay, or bisexual [LGB] teacher), contact…

Sensitivity of relativistic impulse approximation proton-nucleus elastic scattering calculations on relativistic mean-field parameterizations

International Nuclear Information System (INIS)

Hojsik, M.; Gmuca, S.

1998-01-01

Relativistic microscopic calculations are presented for proton elastic scattering from 40 Ca at 500 MeV. The underlying target densities are calculated within the framework of the relativistic mean-field theory with several parameter sets commonly in use. The self consistency of the scalar and vector densities (and thus to relativistic mean-field parameters) is investigated. Recently, the relativistic impulse approximation (RIA) has been widely and repeatedly used for the calculations of proton-nucleus scattering at intermediate energies. These calculations have exhibited significant improvements over the nonrelativistic approaches. The relativistic impulse approximation calculations. in particular, provide a dramatically better description of the spin observables, namely the analyzing power, A y , and the spin-rotation function, Q, at least for energies higher than 400 MeV. In the relativistic impulse approximation, the Dirac optical potential is obtained by folding of the local Lorentz-invariant amplitudes with the corresponding nuclear densities. For the spin zero targets the scalar and vector terms give the dominant contributions. Thus the scalar and vector nuclear densities (both, proton and neutron ones) play the dominant role in the relativistic impulse approximation. While the proton vector densities can be obtained by unfolding from the empirically known charge densities, all other densities used rely to a great extent on theoretical models. The various recipes are used to construct the neutron vector densities and the scalar densities for both, neutrons and protons. In this paper we will study the sensitivity of the relativistic impulse approximation results on the various sets of relativistic mean-field parameters currently in use

Environmental exposure to polychlorinated biphenyls and placental CYP1A1 activity in Inuit women from northern Québec.

OpenAIRE

Pereg, Daria; Dewailly, Eric; Poirier, Guy G; Ayotte, Pierre

2002-01-01

Some polychlorinated biphenyl (PCB) congeners are CYP1A1 inducers, and induction of this enzyme in the placenta has been linked to adverse effects on fetal development. The objective of this study was to determine if the body burden of PCBs is related to placental CYP1A1 activity in Inuit women from Nunavik (northern Québec), a population highly exposed to organochlorines. Placenta and cord blood samples were obtained from 35 Inuit women and 30 women from a southern Québec community exposed t...

Response Functions for the Two-Dimensional Ultracold Fermi Gas: Dynamical BCS Theory and Beyond

Science.gov (United States)

Vitali, Ettore; Shi, Hao; Qin, Mingpu; Zhang, Shiwei

2017-12-01

Response functions are central objects in physics. They provide crucial information about the behavior of physical systems, and they can be directly compared with scattering experiments involving particles such as neutrons or photons. Calculations of such functions starting from the many-body Hamiltonian of a physical system are challenging and extremely valuable. In this paper, we focus on the two-dimensional (2D) ultracold Fermi atomic gas which has been realized experimentally. We present an application of the dynamical BCS theory to obtain response functions for different regimes of interaction strengths in the 2D gas with zero-range attractive interaction. We also discuss auxiliary-field quantum Monte Carlo (AFQMC) methods for the calculation of imaginary time correlations in these dilute Fermi gas systems. Illustrative results are given and comparisons are made between AFQMC and dynamical BCS theory results to assess the accuracy of the latter.

Inflationary Quasiparticle Creation and Thermalization Dynamics in Coupled Bose-Einstein Condensates.

Science.gov (United States)

Posazhennikova, Anna; Trujillo-Martinez, Mauricio; Kroha, Johann

2016-06-03

A Bose gas in a double-well potential, exhibiting a true Bose-Einstein condensate (BEC) amplitude and initially performing Josephson oscillations, is a prototype of an isolated, nonequilibrium many-body system. We investigate the quasiparticle (QP) creation and thermalization dynamics of this system by solving the time-dependent Keldysh-Bogoliubov equations. We find avalanchelike QP creation due to a parametric resonance between BEC and QP oscillations, followed by slow, exponential relaxation to a thermal state at an elevated temperature, controlled by the initial excitation energy of the oscillating BEC above its ground state. The crossover between the two regimes occurs because of an effective decoupling of the QP and BEC oscillations. This dynamics is analogous to elementary particle creation in models of the early universe. The thermalization in our setup occurs because the BEC acts as a grand canonical reservoir for the quasiparticle system.

Inflationary Quasiparticle Creation and Thermalization Dynamics in Coupled Bose-Einstein Condensates

Science.gov (United States)

Posazhennikova, Anna; Trujillo-Martinez, Mauricio; Kroha, Johann

2016-06-01

A Bose gas in a double-well potential, exhibiting a true Bose-Einstein condensate (BEC) amplitude and initially performing Josephson oscillations, is a prototype of an isolated, nonequilibrium many-body system. We investigate the quasiparticle (QP) creation and thermalization dynamics of this system by solving the time-dependent Keldysh-Bogoliubov equations. We find avalanchelike QP creation due to a parametric resonance between BEC and QP oscillations, followed by slow, exponential relaxation to a thermal state at an elevated temperature, controlled by the initial excitation energy of the oscillating BEC above its ground state. The crossover between the two regimes occurs because of an effective decoupling of the QP and BEC oscillations. This dynamics is analogous to elementary particle creation in models of the early universe. The thermalization in our setup occurs because the BEC acts as a grand canonical reservoir for the quasiparticle system.

The relativistic virial theorem

International Nuclear Information System (INIS)

Lucha, W.; Schoeberl, F.F.

1989-11-01

The relativistic generalization of the quantum-mechanical virial theorem is derived and used to clarify the connection between the nonrelativistic and (semi-)relativistic treatment of bound states. 12 refs. (Authors)

ATM promotes the obligate XY crossover and both crossover control and chromosome axis integrity on autosomes.

Directory of Open Access Journals (Sweden)

Marco Barchi

2008-05-01

Full Text Available During meiosis in most sexually reproducing organisms, recombination forms crossovers between homologous maternal and paternal chromosomes and thereby promotes proper chromosome segregation at the first meiotic division. The number and distribution of crossovers are tightly controlled, but the factors that contribute to this control are poorly understood in most organisms, including mammals. Here we provide evidence that the ATM kinase or protein is essential for proper crossover formation in mouse spermatocytes. ATM deficiency causes multiple phenotypes in humans and mice, including gonadal atrophy. Mouse Atm-/- spermatocytes undergo apoptosis at mid-prophase of meiosis I, but Atm(-/- meiotic phenotypes are partially rescued by Spo11 heterozygosity, such that ATM-deficient spermatocytes progress to meiotic metaphase I. Strikingly, Spo11+/-Atm-/- spermatocytes are defective in forming the obligate crossover on the sex chromosomes, even though the XY pair is usually incorporated in a sex body and is transcriptionally inactivated as in normal spermatocytes. The XY crossover defect correlates with the appearance of lagging chromosomes at metaphase I, which may trigger the extensive metaphase apoptosis that is observed in these cells. In addition, control of the number and distribution of crossovers on autosomes appears to be defective in the absence of ATM because there is an increase in the total number of MLH1 foci, which mark the sites of eventual crossover formation, and because interference between MLH1 foci is perturbed. The axes of autosomes exhibit structural defects that correlate with the positions of ongoing recombination. Together, these findings indicate that ATM plays a role in both crossover control and chromosome axis integrity and further suggests that ATM is important for coordinating these features of meiotic chromosome dynamics.

San Juanico, BCS, Mexico, hybrid electric plant renewable energies in the rural communities development; Planta electrica hibrida San Juanico, B.C.S., Mexico, las energias renovables en el desarrollo de las comunidades rurales

Energy Technology Data Exchange (ETDEWEB)

Lopez Rios, Serafin [Gerencia de Proyectos Geotermoelectricos, Comision Federal de Electricidad (Mexico)

1999-08-01

The hybrid electric plant of San Juanico, B.C.S., Mexico, is described in terms of its environmental goals, operating process and contribution to the development of that rural community of the Baja California Peninsula. San Juanico hybrid electric plant is organized in three electrical generation systems that work in parallel: one uses solar energy, another wind energy and a third one uses diesel fuel. [Spanish] Se describe la planta hibrida de San Juanico, BCS, Mexico, en terminos de los objetivos ambientales que condujeron a su realizacion, asi como de su proceso operativo y de la participacion que tiene en el desarrollo de esa comunidad rural de la peninsula de Baja California, Mexico. La planta hibrida de San Juanico esta constituida por tres sistemas de generacion de electrcicidad que operan en paralelo: uno utiliza energia radiante del sol, otro energia del viento y un tercero utiliza diesel.

Cultura, identidad política y multiculturalidad en Todos Santos, BCS1

Directory of Open Access Journals (Sweden)

Rossana Almada

2005-01-01

Full Text Available Este ensayo tiene como objetivo hablar del desbordamiento institucional de la política y su desplazamiento hacia la sociedad civil. Desde luego, no es la intención negar la importancia de instituciones políticas tales como partidos, sino señalar cómo la morfología de la complejidad social desdibuja las fronteras de la representación y traslada las demandas a las calles, a las cantinas,a las casas de los interesados. El trabajo forma parte de una investigación mayor a la que he llamado Juntos, pero no revueltos. Multiculturalidad e identidad local en Todos Santos, BCS, es por eso que presento como ejemplo de este fenómeno el caso del conflicto latente en Todos Santos, Baja California Sur (BCS tanto por el uso de los espacios como por las formas que tendrá que adquirir la identidad local que construyen, a partir de sus convergencias y negociaciones, los tres grupos en lucha por la hegemonía social todosanteña: extranjeros, principalmente estadounidenses y canadienses, mexicanos no sudcalifornianos y todosanteños.

Contraint's theory and relativistic dynamics

International Nuclear Information System (INIS)

Longhi, G.; Lusanna, L.

1987-01-01

The purpose of this Workshop was to examine the current situation of relativistic dynamics. In particular, Dirac-Bergmann's theory of constraints, which lies at the heart of gauge theories, general relativity, relativistic mechanics and string theories, was chosen as the unifying theoretical framework best suited to investigate such a field. The papers discussed were on general relativity; relativistic mechanics; particle physics and mathematical physics. Also discussed were the problems of classical and quantum level, namely the identification of the classical observables of constrained systems, the equivalence of the nonequivalence of the various ways to quantize such systems; the problem of the anomalies; the best geometrical approach to the theory of constraints; the possibility of unifying all the treatments of relativistic mechanics. This book compiles the papers presented at proceedings of relativistic dynamics and constraints theory

Multiwavelength Observations of Relativistic Jets from General Relativistic Magnetohydrodynamic Simulations

Directory of Open Access Journals (Sweden)

Richard Anantua

2018-03-01

Full Text Available This work summarizes a program intended to unify three burgeoning branches of the high-energy astrophysics of relativistic jets: general relativistic magnetohydrodynamic (GRMHD simulations of ever-increasing dynamical range, the microphysical theory of particle acceleration under relativistic conditions, and multiwavelength observations resolving ever-decreasing spatiotemporal scales. The process, which involves converting simulation output into time series of images and polarization maps that can be directly compared to observations, is performed by (1 self-consistently prescribing models for emission, absorption, and particle acceleration and (2 performing time-dependent polarized radiative transfer. M87 serves as an exemplary prototype for this investigation due to its prominent and well-studied jet and the imminent prospect of learning much more from Event Horizon Telescope (EHT observations this year. Synthetic observations can be directly compared with real observations for observational signatures such as jet instabilities, collimation, relativistic beaming, and polarization. The simplest models described adopt the standard equipartition hypothesis; other models calculate emission by relating it to current density or shear. These models are intended for application to the radio jet instead of the higher frequency emission, the disk and the wind, which will be subjects of future investigations.

The Ne3LS Network, Québec's initiative to evaluate the impact and promote a responsible and sustainable development of nanotechnology

Science.gov (United States)

Endo, Charles-Anica; Emond, Claude; Battista, Renaldo; Parizeau, Marie-Hélène; Beaudry, Catherine

2011-07-01

The spectacular progress made by nanosciences and nanotechnologies elicits as much hope and fear. Consequently, a great number of research and training initiatives on the ethical, environmental, economic, legal and social issues regarding nanotechnology development (Ne3LS) are emerging worldwide. In Québec, Canada, a Task Force was mandated by NanoQuébec to conceive a Ne3LS research and training strategy to assess those issues. This Task Force brought together experts from universities, governments or industry working in nanosciences and nanotechnologies or in Ne3LS. Their resulting action plan, made public in November 2006, contained several recommendations, including the creation of a knowledge network (Ne3LS Network). In the following years, after consulting with numerous key players concerned with the possible impacts of nanosciences and nanotechnologies in Québec, the Ne3LS Network was launched in January 2010 in partnership with the Fonds québécois de la recherche sur la nature et les technologies, the Fonds québécois de la recherche sur la société et la culture and the Fonds de la recherche en santé du Québec, NanoQuébec, the Institut de recherche Robert-Sauvé en santé et en sécurité du travail as well as the University of Montreal. Its objectives are to 1) Foster the development of Ne3LS research activities (grants and fellowships); 2) Spearhead the Canadian and international Ne3LS network; 3) Take part in the training of researchers and experts; 4) Encourage the creation of interactive tools for the general public; 5) Facilitate collaboration between decision-makers and experts; 6) Involve the scientific community through a host of activities (symposium, conferences, thematic events); 7) Build multidisciplinary research teams to evaluate the impact of nanotechnology.

An introduction to relativistic hydrodynamics

Energy Technology Data Exchange (ETDEWEB)

Font, Jose A [Departamento de AstronomIa y AstrofIsica, Universidad de Valencia, Dr. Moliner 50, 46100 Burjassot (Valencia) (Spain)

2007-11-15

We review formulations of the equations of (inviscid) general relativistic hydrodynamics and (ideal) magnetohydrodynamics, along with methods for their numerical solution. Both systems can be cast as first-order, hyperbolic systems of conservation laws, following the explicit choice of an Eulerian observer and suitable fluid and magnetic field variables. During the last fifteen years, the so-called (upwind) high-resolution shock-capturing schemes based on Riemann solvers have been successfully extended from classical to relativistic fluid dynamics, both special and general. Nowadays, general relativistic hydrodynamical simulations in relativistic astrophysics are routinely performed, particularly within the test-fluid approximation but also for dynamical spacetimes. While such advances also hold true in the case of the MHD equations, the astrophysical applications investigated so far are still limited, yet the field is bound to witness major developments in the near future. The article also presents a brief overview of numerical techniques, providing state-of-the-art examples of their applicability to general relativistic fluids and magneto-fluids in characteristic scenarios of relativistic astrophysics.

Holographic energy loss in non-relativistic backgrounds

Energy Technology Data Exchange (ETDEWEB)

Atashi, Mahdi; Fadafan, Kazem Bitaghsir; Farahbodnia, Mitra [Shahrood University of Technology, Physics Department, P.O. Box 3619995161, Shahrood (Iran, Islamic Republic of)

2017-03-15

In this paper, we study some aspects of energy loss in non-relativistic theories from holography. We analyze the energy lost by a rotating heavy point particle along a circle of radius l with angular velocity ω in theories with general dynamical exponent z and hyperscaling violation exponent θ. It is shown that this problem provides a novel perspective on the energy loss in such theories. A general computation at zero and finite temperature is done and it is shown how the total energy loss rate depends non-trivially on two characteristic exponents (z,θ). We find that at zero temperature there is a special radius l{sub c} where the energy loss is independent of different values of (θ,z). Also at zero temperature, there is a crossover between a regime in which the energy loss is dominated by the linear drag force and by the radiation because of the acceleration of the rotating particle. We find that the energy loss of the particle decreases by increasing θ and z. We note that, unlike in the zero temperature, there is no special radius l{sub c} at finite temperature case. (orig.)

Plasma relativistic microwave electronics

International Nuclear Information System (INIS)

Kuzelev, M.V.; Loza, O.T.; Rukhadze, A.A.; Strelkov, P.S.; Shkvarunets, A.G.

2001-01-01

One formulated the principles of plasma relativistic microwave electronics based on the induced Cherenkov radiation of electromagnetic waves at interaction of a relativistic electron beam with plasma. One developed the theory of plasma relativistic generators and accelerators of microwave radiation, designed and studied the prototypes of such devices. One studied theoretically the mechanisms of radiation, calculated the efficiencies and the frequency spectra of plasma relativistic microwave generators and accelerators. The theory findings are proved by the experiment: intensity of the designed sources of microwave radiation is equal to 500 μW, the frequency of microwave radiation is increased by 7 times (from 4 up to 28 GHz), the width of radiation frequency band may vary from several up to 100%. The designed sources of microwave radiation are no else compared in the electronics [ru

A Possible Path from BCS through HTS to VHTS

Science.gov (United States)

Chu, C. W.

2010-03-01

Three years after celebrating the 50th anniversary of the BCS theory and the 20th anniversary of the discovery of high temperature superconductivity (HTS), it appears to be most fitting for us to contemplate the possibility of very high temperature superconductivity (VHTS). VHTS, preferably at room temperature, if achieved, could change the world both scientifically and technologically. Unfortunately, it has long been considered by some to belong to the domain of science fiction and to occur only ``at an astronomical distance and under an astronomical pressure.'' With the advent of liquid nitrogen superconductivity in 1987, the outlook has become much brighter. Currently, there appears to be no reason, either theoretical or experimental, why VHTS would be impossible, in spite of the 2006 prediction of the death of HTS by 2010-2015 through the so-called scientometric analysis of the publication record of the previous 20 years. The recent discovery of the new class of Fe-pnictide HTSs fuels more cautious optimism. Since its inception, BCS theory has provided the basic framework for the occurrence and understanding of superconductivity, but it has failed to show where and how to find superconductivity at a higher temperature. This may be attributed to the small energy scale of superconductivity in comparison with those of other excitations in the solids. After examining existing data, we believe that a holistic multidisciplinary enlightened empirical approach appears to be the most effective way to discover novel superconductors with higher transition temperatures. In this talk, I shall present several possible approaches toward VHTS that we are currently pursuing, after briefly summarizing what has happened in the long search for HTS and VHTS.

Relativistic Quantum Mechanics

International Nuclear Information System (INIS)

Antoine, J-P

2004-01-01

The aim of relativistic quantum mechanics is to describe the finer details of the structure of atoms and molecules, where relativistic effects become nonnegligible. It is a sort of intermediate realm, between the familiar nonrelativistic quantum mechanics and fully relativistic quantum field theory, and thus it lacks the simplicity and elegance of both. Yet it is a necessary tool, mostly for quantum chemists. Pilkuhn's book offers to this audience an up-to-date survey of these methods, which is quite welcome since most previous textbooks are at least ten years old. The point of view of the author is to start immediately in the relativistic domain, following the lead of Maxwell's equations rather than classical mechanics, and thus to treat the nonrelativistic version as an approximation. Thus Chapter 1 takes off from Maxwell's equations (in the noncovariant Coulomb gauge) and gradually derives the basic aspects of Quantum Mechanics in a rather pedestrian way (states and observables, Hilbert space, operators, quantum measurement, scattering,. Chapter 2 starts with the Lorentz transformations, then continues with the Pauli spin equation and the Dirac equation and some of their applications (notably the hydrogen atom). Chapter 3 is entitled 'Quantum fields and particles', but falls short of treating quantum field theory properly: only creation/annihilation operators are considered, for a particle in a box. The emphasis is on two-electron states (the Pauli principle, the Foldy--Wouthuysen elimination of small components of Dirac spinors, Breit projection operators. Chapter 4 is devoted to scattering theory and the description of relativistic bound states. Chapter 5, finally, covers hyperfine interactions and radiative corrections. As we said above, relativistic quantum mechanics is by nature limited in scope and rather inelegant and Pilkuhn's book is no exception. The notation is often heavy (mostly noncovariant) and the mathematical level rather low. The central topic

Relativistic particle in a box

OpenAIRE

Alberto, P.; Fiolhais, Carlos; Gil, Victor

1996-01-01

The problem of a relativistic spin 1/2 particle confined to a one-dimensional box is solved in a way that resembles closely the solution of the well known quantum-mechanical textbook problem of a non-relativistic particle in a box. The energy levels and probability density are computed and compared with the non-relativistic case

Relativistic hydrodynamics

CERN Document Server

Luciano, Rezzolla

2013-01-01

Relativistic hydrodynamics is a very successful theoretical framework to describe the dynamics of matter from scales as small as those of colliding elementary particles, up to the largest scales in the universe. This book provides an up-to-date, lively, and approachable introduction to the mathematical formalism, numerical techniques, and applications of relativistic hydrodynamics. The topic is typically covered either by very formal or by very phenomenological books, but is instead presented here in a form that will be appreciated both by students and researchers in the field. The topics covered in the book are the results of work carried out over the last 40 years, which can be found in rather technical research articles with dissimilar notations and styles. The book is not just a collection of scattered information, but a well-organized description of relativistic hydrodynamics, from the basic principles of statistical kinetic theory, down to the technical aspects of numerical methods devised for the solut...

Study of quantum spin correlations of relativistic electron pairs - Testing nonlocality of relativistic quantum mechanics

International Nuclear Information System (INIS)

Bodek, K.; Rozpędzik, D.; Zejma, J.; Caban, P.; Rembieliński, J.; Włodarczyk, M.; Ciborowski, J.; Enders, J.; Köhler, A.; Kozela, A.

2013-01-01

The Polish-German project QUEST aims at studying relativistic quantum spin correlations of the Einstein-Rosen-Podolsky-Bohm type, through measurement of the correlation function and the corresponding probabilities for relativistic electron pairs. The results will be compared to theoretical predictions obtained by us within the framework of relativistic quantum mechanics, based on assumptions regarding the form of the relativistic spin operator. Agreement or divergence will be interpreted in the context of non-uniqueness of the relativistic spin operator in quantum mechanics as well as dependence of the correlation function on the choice of observables representing the spin. Pairs of correlated electrons will originate from the Mo/ller scattering of polarized 15 MeV electrons provided by the superconducting Darmstadt electron linear accelerator S-DALINAC, TU Darmstadt, incident on a Be target. Spin projections will be determined using the Mott polarimetry technique. Measurements (starting 2013) are planned for longitudinal and transverse beam polarizations and different orientations of the beam polarization vector w.r.t. the Mo/ller scattering plane. This is the first project to study relativistic spin correlations for particles with mass

La précarité au Québec : un concept parmi d’autres pour parler des jeunes

Directory of Open Access Journals (Sweden)

Madeleine Gauthier

2011-04-01

Full Text Available Ce texte met en contexte l’usage du concept de précarité au Québec. Celui-ci a surtout été utilisé parmi beaucoup d’autres pour décrire la situation des jeunes au moment de la crise de l’emploi des décennies 1970 et 1980. Il a parfois contribué, par son attribution à l’ensemble des jeunes, à laisser les plus vulnérables dans l’ombre et à amplifier l’effet du travail atypique sur l’avenir de toute une génération. Un usage plus modéré du concept s’est imposé progressivement en présence de faits plus justement vérifiés. Sa force de persuasion a pu susciter des stratégies tant individuelles que collectives en faveur des jeunes. Ce retour dans le temps a permis de montrer que les jeunes sont sensibles à la conjoncture mais n’en restent pas pour autant les victimes. Est-ce à cause du type d’État (de Gøsta Esping-Anderson, évoqué par Mircea Vultur que le concept n’a eu qu’une importance relative au Québec ? La question se pose-t-elle dans une approche pragmatique du changement ?"Precariousness" in Québec: one of several concepts applied to young peopleThis paper examines the concept of "precariousness" in a Québec context. This concept was one of several used to describe the situation of young people during the employment crisis of the 1970s and 1980s. It was applied to young people as a whole and thus sometimes favoured a tendency to gloss over the highly vulnerable situations and to amplify the effect of non-standard employment on the future of an entire generation. More moderate use of the concept gradually prevailed with more accurate data. It was a persuasive concept that did bring about individual and collective strategies to help young people. This look backward in time shows that young people are sensitive to the economy and its performance. They are nonetheless not permanently victims of economic downturn. Is the type of welfare state (Esping-Anderson as argued by Vultur the reason why

Relativistic viscoelastic fluid mechanics

International Nuclear Information System (INIS)

Fukuma, Masafumi; Sakatani, Yuho

2011-01-01

A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski space-time become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.

Relativistic viscoelastic fluid mechanics.

Science.gov (United States)

Fukuma, Masafumi; Sakatani, Yuho

2011-08-01

A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski space-time become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.

Relativistic Coulomb Fission

Science.gov (United States)

Norbury, John W.

1992-01-01

Nuclear fission reactions induced by the electromagnetic field of relativistic nuclei are studied for energies relevant to present and future relativistic heavy ion accelerators. Cross sections are calculated for U-238 and Pu-239 fission induced by C-12, Si-28, Au-197, and U-238 projectiles. It is found that some of the cross sections can exceed 10 b.

Relativistic Shock Acceleration

International Nuclear Information System (INIS)

Duffy, P.; Downes, T.P.; Gallant, Y.A.; Kirk, J.G.

1999-01-01

In this paper we briefly review the basic theory of shock waves in relativistic hydrodynamics and magneto-hydrodynamics, emphasising some astrophysically interesting cases. We then present an overview of the theory of particle acceleration at such shocks describing the methods used to calculate the spectral indices of energetic particles. Recent results on acceleration at ultra-relativistic shocks are discussed. (author)

Relativistic impulse dynamics.

Science.gov (United States)

Swanson, Stanley M

2011-08-01

Classical electrodynamics has some annoying rough edges. The self-energy of charges is infinite without a cutoff. The calculation of relativistic trajectories is difficult because of retardation and an average radiation reaction term. By reconceptuallizing electrodynamics in terms of exchanges of impulses rather than describing it by forces and potentials, we eliminate these problems. A fully relativistic theory using photonlike null impulses is developed. Numerical calculations for a two-body, one-impulse-in-transit model are discussed. A simple relationship between center-of-mass scattering angle and angular momentum was found. It reproduces the Rutherford cross section at low velocities and agrees with the leading term of relativistic distinguishable-particle quantum cross sections (Møller, Mott) when the distance of closest approach is larger than the Compton wavelength of the particle. Magnetism emerges as a consequence of viewing retarded and advanced interactions from the vantage point of an instantaneous radius vector. Radiation reaction becomes the local conservation of energy-momentum between the radiating particle and the emitted impulse. A net action is defined that could be used in developing quantum dynamics without potentials. A reinterpretation of Newton's laws extends them to relativistic motion.

Optimizing solubility and permeability of a biopharmaceutics classification system (BCS) class 4 antibiotic drug using lipophilic fragments disturbing the crystal lattice.

Science.gov (United States)

Tehler, Ulrika; Fagerberg, Jonas H; Svensson, Richard; Larhed, Mats; Artursson, Per; Bergström, Christel A S

2013-03-28

Esterification was used to simultaneously increase solubility and permeability of ciprofloxacin, a biopharmaceutics classification system (BCS) class 4 drug (low solubility/low permeability) with solid-state limited solubility. Molecular flexibility was increased to disturb the crystal lattice, lower the melting point, and thereby improve the solubility, whereas lipophilicity was increased to enhance the intestinal permeability. These structural changes resulted in BCS class 1 analogues (high solubility/high permeability) emphasizing that simple medicinal chemistry may improve both these properties.

Turismo y Sustentabilidad en Pequeñas Localidades Localidades Costeras de Baja California Sur (BCS

Directory of Open Access Journals (Sweden)

Reyna Ibañez Pérez

2014-01-01

Full Text Available El fomento del turismo se realiza en sitios que, aunque pequeños, cuentan con atractivos naturales y culturales, tal es el caso de las zonas costeras. Tan solo en México, se estima que existen más de 1,100 comunidades que dependen directamente de dicha actividad, esta te ndencia se refleja, de igual manera, en pequeñas localidades costeras de Baja California Sur (BCS. En este sentido, el objetivo de este trabajo fue realizar un an álisis exploratorio que permitió detectar a las comunidades costeras de BCS, donde el turismo genera un aporte importante a su economía local, además , se buscó identificar la problemática general que éstas enfrentan. Para realizar dicho estudio se revisó literatura, se organizó información estadística y se elaboró un análisis Fortalezas, Oportunidades, Debilidades y Amenazas (FODA. Los resultad os apuntan a que, en BCS, existen más de 35 localidades ru rales vinculadas con dicha actividad que comparten como problemática la escasa in fraestructura y la carencia de medidas de control de la afluencia turística. La principal recomendación es desarrollar líneas de investigación que permitan aportar elementos para medir la sustentabilidad turística a nivel local y, co n base en ello, diseñar medidas para la adecuada conducción de tan importante actividad.

Scattering in relativistic particle mechanics

International Nuclear Information System (INIS)

De Bievre, S.

1986-01-01

The problem of direct interaction in relativistic particle mechanics has been extensively studied and a variety of models has been proposed avoiding the conclusions of the so-called no-interaction theorems. In this thesis the authors studied scattering in the relativistic two-body problem. He uses the results to analyze gauge invariance in Hamiltonian constraint models and the uniqueness of the symplectic structure in manifestly covariant relativistic particle mechanics. A general geometric framework that underlies approaches to relativistic particle mechanics is presented and the kinematic properties of the scattering transformation, i.e., those properties that arise solely from the invariance of the theory under the Poincare group are studied. The second part of the analysis of the relativistic two-body scattering problem is devoted to the dynamical properties of the scattering process. Using general geometric arguments, gauge invariance of the scattering transformation in the Todorov-Komar Hamiltonian constraint model is proved. Finally, quantization of the models is discussed

Relativistic finite-temperature Thomas-Fermi model

Science.gov (United States)

Faussurier, Gérald

2017-11-01

We investigate the relativistic finite-temperature Thomas-Fermi model, which has been proposed recently in an astrophysical context. Assuming a constant distribution of protons inside the nucleus of finite size avoids severe divergence of the electron density with respect to a point-like nucleus. A formula for the nuclear radius is chosen to treat any element. The relativistic finite-temperature Thomas-Fermi model matches the two asymptotic regimes, i.e., the non-relativistic and the ultra-relativistic finite-temperature Thomas-Fermi models. The equation of state is considered in detail. For each version of the finite-temperature Thomas-Fermi model, the pressure, the kinetic energy, and the entropy are calculated. The internal energy and free energy are also considered. The thermodynamic consistency of the three models is considered by working from the free energy. The virial question is also studied in the three cases as well as the relationship with the density functional theory. The relativistic finite-temperature Thomas-Fermi model is far more involved than the non-relativistic and ultra-relativistic finite-temperature Thomas-Fermi models that are very close to each other from a mathematical point of view.

Language Learning Styles Used By Students Of Basic English Course (Bec) Pare

OpenAIRE

HIDAYAH, ULFA NURUL

2013-01-01

Learning styles are the important factors to help students to learn a second or foreign language. A learning habit of every individual is needed to support the student's learning to be more effective, for example by taking an English course. Learning styles can be classified into: visual, auditory, kinesthetic, tactile, group, and individual. This study is conducted to examine the language learning styles applied by the students of Basic English Course (BEC) in Pare, Kediri. This study applie...

Relativistic description of atomic nuclei

International Nuclear Information System (INIS)

Krutov, V.A.

1985-01-01

Papers on the relativistic description of nuclei are reviewed. The Brown and Rho ''small'' bag'' model is accepted for hardrons. Meson exchange potentials of the nucleon-nucleon interaction have been considered. Then the transition from a system of two interacting nucleons has been performed to the relativistic nucleus description as a multinucleon system on the basis of OBEP (one-boson exchange potential). The proboem of OPEP (one-pion-exchange potential) inclusion to a relativistic scheme is discussed. Simplicity of calculations and attractiveness of the Walecka model for specific computations and calculations was noted. The relativistic model of nucleons interacting through ''effective'' scalar and vector boson fields was used in the Walacka model for describing neutronaand nuclear mater matters

Effect on cavity optomechanics of the interaction between a cavity field and a one-dimensional interacting bosonic gas

International Nuclear Information System (INIS)

Sun Qing; Hu Xinghua; Liu, W. M.; Xie, X. C.; Ji Anchun

2011-01-01

We investigate optomechanical coupling between one-dimensional interacting bosons and the electromagnetic field in a high-finesse optical cavity. We show that by tuning interatomic interactions, one can realize effective optomechanics with mechanical resonators ranging from side-mode excitations of a Bose-Einstein condensate (BEC) to particle-hole excitations of a Tonks-Girardeau (TG) gas. We propose that this unique feature can be formulated to detect the BEC-TG gas crossover and measure the sine-Gordon transition continuously and nondestructively.

La teoría de la historia del derecho en Ricardo Zorraquín Becú

OpenAIRE

Vilches Fuentes,Hugo

2005-01-01

El artículo estudia las ideas del profesor Ricardo Zorraquín Becú, historiador del derecho indiano y del derecho argentino, que desde ambas especialidades salta a la historia del derecho como ciencia en sus relaciones con la historia y con el derecho.

Relativistic Jahn-Teller effect in tetrahedral systems

International Nuclear Information System (INIS)

Opalka, Daniel; Domcke, Wolfgang; Segado, Mireia; Poluyanov, Leonid V.

2010-01-01

It is shown that orbitally degenerate states in highly symmetric systems are split by Jahn-Teller forces which are of relativistic origin (that is, they arise from the spin-orbit coupling operator). For the example of tetrahedral systems, the relativistic Jahn-Teller Hamiltonians of orbitally degenerate electronic states with spin 1/2 are derived. While both electrostatic and relativistic forces contribute to the Jahn-Teller activity of vibrational modes of E and T 2 symmetry in 2 T 2 states of tetrahedral systems, the electrostatic and relativistic Jahn-Teller couplings are complementary for 2 E states: The E mode is Jahn-Teller active through electrostatic forces, while the T 2 mode is Jahn-Teller active through the relativistic forces. The relativistic Jahn-Teller parameters have been computed with ab initio relativistic electronic-structure methods. It is shown for the example of the tetrahedral cluster cations of the group V elements that the relativistic Jahn-Teller couplings can be of the same order of magnitude as the familiar electrostatic Jahn-Teller couplings for the heavier elements.

Ten years of integrated care: backwards and forwards. The case of the province of Québec, Canada

Directory of Open Access Journals (Sweden)

Isabelle Vedel

2011-02-01

Full Text Available Introduction: Québec's rapidly growing elderly and chronically ill population represents a major challenge to its healthcare delivery system, attributable in part to the system's focus on acute care and fragmented delivery. Description of policy practice: Over the past few years, reforms have been implemented at the provincial policy level to integrate hospital-based, nursing home, homecare and social services in 95 catchment areas. Recent organizational changes in primary care have also resulted in the implementation of family medicine groups and network clinics. Several localized initiatives were also developed to improve integration of care for older persons or persons with chronic diseases. Conclusion and discussion: Québec has a history of integration of health and social services at the structural level. Recent evaluations of the current reform show that the care provided by various institutions in the healthcare system is becoming better integrated. The Québec health care system nevertheless continues to face three important challenges in its management of chronic diseases: implementing the reorganization of primary care, successfully integrating primary and secondary care at the clinical level, and developing effective governance and change management. Efforts should focus on strengthening primary care by implementing nurse practitioners, developing a shared information system, and achieving better collaboration between primary and secondary care.

Ten years of integrated care: backwards and forwards. The case of the province of Québec, Canada

Directory of Open Access Journals (Sweden)

Isabelle Vedel

2011-02-01

Full Text Available Introduction: Québec's rapidly growing elderly and chronically ill population represents a major challenge to its healthcare delivery system, attributable in part to the system's focus on acute care and fragmented delivery. Description of policy practice: Over the past few years, reforms have been implemented at the provincial policy level to integrate hospital-based, nursing home, homecare and social services in 95 catchment areas. Recent organizational changes in primary care have also resulted in the implementation of family medicine groups and network clinics. Several localized initiatives were also developed to improve integration of care for older persons or persons with chronic diseases.Conclusion and discussion: Québec has a history of integration of health and social services at the structural level. Recent evaluations of the current reform show that the care provided by various institutions in the healthcare system is becoming better integrated. The Québec health care system nevertheless continues to face three important challenges in its management of chronic diseases: implementing the reorganization of primary care, successfully integrating primary and secondary care at the clinical level, and developing effective governance and change management.Efforts should focus on strengthening primary care by implementing nurse practitioners, developing a shared information system, and achieving better collaboration between primary and secondary care.

The relativistic rocket

Energy Technology Data Exchange (ETDEWEB)

Antippa, Adel F [Departement de Physique, Universite du Quebec a Trois-Rivieres, Trois-Rivieres, Quebec G9A 5H7 (Canada)

2009-05-15

We solve the problem of the relativistic rocket by making use of the relation between Lorentzian and Galilean velocities, as well as the laws of superposition of successive collinear Lorentz boosts in the limit of infinitesimal boosts. The solution is conceptually simple, and technically straightforward, and provides an example of a powerful method that can be applied to a wide range of special relativistic problems of linear acceleration.

Relativistic length agony continued

Directory of Open Access Journals (Sweden)

Redžić D.V.

2014-01-01

Full Text Available We made an attempt to remedy recent confusing treatments of some basic relativistic concepts and results. Following the argument presented in an earlier paper (Redžić 2008b, we discussed the misconceptions that are recurrent points in the literature devoted to teaching relativity such as: there is no change in the object in Special Relativity, illusory character of relativistic length contraction, stresses and strains induced by Lorentz contraction, and related issues. We gave several examples of the traps of everyday language that lurk in Special Relativity. To remove a possible conceptual and terminological muddle, we made a distinction between the relativistic length reduction and relativistic FitzGerald-Lorentz contraction, corresponding to a passive and an active aspect of length contraction, respectively; we pointed out that both aspects have fundamental dynamical contents. As an illustration of our considerations, we discussed briefly the Dewan-Beran-Bell spaceship paradox and the ‘pole in a barn’ paradox. [Projekat Ministarstva nauke Republike Srbije, br. 171028

An investigation of relativistic microscopic optical potential in terms of relativistic Brueckner-Bethe-Goldstone equation

International Nuclear Information System (INIS)

Chen Baoqiu; Ma Zhongyu

1992-01-01

Relativistic microscopic optical potential of nucleon-nucleus is derived from the relativistic Brueckner-Bethe-Goldstone (RBBG) equation. The complex effective mass of a nucleon is determined by a fit to 200 MeV p- 40 Ca scattering data. The relativistic microscopic optical potentials with this effective mass are obtained from RBBG for p- 16O , 40 Ca, 90 Zr and 208 Pb scattering in energy range from 160 to 800 MeV. The microscopic optical potential is used to study the proton- 40 Ca scattering problem at 200 MeV. The results, such as differential cross section, analyzing power and spin rotation function are compared with those calculated from phenomenological relativistic optical potential

Leading order relativistic chiral nucleon-nucleon interaction

Science.gov (United States)

Ren, Xiu-Lei; Li, Kai-Wen; Geng, Li-Sheng; Long, Bingwei; Ring, Peter; Meng, Jie

2018-01-01

Motivated by the successes of relativistic theories in studies of atomic/molecular and nuclear systems and the need for a relativistic chiral force in relativistic nuclear structure studies, we explore a new relativistic scheme to construct the nucleon-nucleon interaction in the framework of covariant chiral effective field theory. The chiral interaction is formulated up to leading order with covariant power counting and a Lorentz invariant chiral Lagrangian. We find that the relativistic scheme induces all six spin operators needed to describe the nuclear force. A detailed investigation of the partial wave potentials shows a better description of the {}1S0 and {}3P0 phase shifts than the leading order Weinberg approach, and similar to that of the next-to-leading order Weinberg approach. For the other partial waves with angular momenta J≥slant 1, the relativistic results are almost the same as their leading order non-relativistic counterparts. )

RANKINE-HUGONIOT RELATIONS IN RELATIVISTIC COMBUSTION WAVES

International Nuclear Information System (INIS)

Gao Yang; Law, Chung K.

2012-01-01

As a foundational element describing relativistic reacting waves of relevance to astrophysical phenomena, the Rankine-Hugoniot relations classifying the various propagation modes of detonation and deflagration are analyzed in the relativistic regime, with the results properly degenerating to the non-relativistic and highly relativistic limits. The existence of negative-pressure downstream flows is noted for relativistic shocks, which could be of interest in the understanding of the nature of dark energy. Entropy analysis for relativistic shock waves is also performed for relativistic fluids with different equations of state (EoS), denoting the existence of rarefaction shocks in fluids with adiabatic index Γ < 1 in their EoS. The analysis further shows that weak detonations and strong deflagrations, which are rare phenomena in terrestrial environments, are expected to exist more commonly in astrophysical systems because of the various endothermic reactions present therein. Additional topics of relevance to astrophysical phenomena are also discussed.

Dimensional crossover in fluids under nanometer-scale confinement.

Science.gov (United States)

Das, Amit; Chakrabarti, J

2012-05-01

Several earlier studies have shown signatures of crossover in various static and dynamics properties of a confined fluid when the confining dimension decreases to about a nanometer. The density fluctuations govern the majority of such properties of a fluid. Here, we illustrate the crossover in density fluctuation in a confined fluid, to provide a generic understanding of confinement-induced crossover of fluid properties, using computer simulations. The crossover can be understood as a manifestation of changes in the long-wavelength behavior of fluctuation in density due to geometrical constraints. We further show that the confining potential significantly affects the crossover behavior.

Relativistic quantum mechanics

International Nuclear Information System (INIS)

Ollitrault, J.Y.

1998-12-01

These notes form an introduction to relativistic quantum mechanics. The mathematical formalism has been reduced to the minimum in order to enable the reader to calculate elementary physical processes. The second quantification and the field theory are the logical followings of this course. The reader is expected to know analytical mechanics (Lagrangian and Hamiltonian), non-relativistic quantum mechanics and some basis of restricted relativity. The purpose of the first 3 chapters is to define the quantum mechanics framework for already known notions about rotation transformations, wave propagation and restricted theory of relativity. The next 3 chapters are devoted to the application of relativistic quantum mechanics to a particle with 0,1/5 and 1 spin value. The last chapter deals with the processes involving several particles, these processes require field theory framework to be thoroughly described. (A.C.)

Relativistic Quantum Revivals

International Nuclear Information System (INIS)

Strange, P.

2010-01-01

Quantum revivals are now a well-known phenomena within nonrelativistic quantum theory. In this Letter we display the effects of relativity on revivals and quantum carpets. It is generally believed that revivals do not occur within a relativistic regime. Here we show that while this is generally true, it is possible, in principle, to set up wave packets with specific mathematical properties that do exhibit exact revivals within a fully relativistic theory.

Towards relativistic quantum geometry

Energy Technology Data Exchange (ETDEWEB)

Ridao, Luis Santiago [Instituto de Investigaciones Físicas de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Mar del Plata (Argentina); Bellini, Mauricio, E-mail: mbellini@mdp.edu.ar [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, C.P. 7600, Mar del Plata (Argentina); Instituto de Investigaciones Físicas de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Mar del Plata (Argentina)

2015-12-17

We obtain a gauge-invariant relativistic quantum geometry by using a Weylian-like manifold with a geometric scalar field which provides a gauge-invariant relativistic quantum theory in which the algebra of the Weylian-like field depends on observers. An example for a Reissner–Nordström black-hole is studied.

[FR] Le developpment du Travail Social et le pluralisme au Québec

Directory of Open Access Journals (Sweden)

André Jacob

2011-06-01

Full Text Available Normal 0 21 false false false ES X-NONE X-NONE MicrosoftInternetExplorer4 Au Canada et au Québec, traiter des questions liées à la diversité culturelle et au racisme a été un défi pour les gouvernements depuis les années soixante. Auparavant et jusqu'à présent, une grande partie des responsabilités en termes de développement ethnoculturel sensible des services publics (services sociaux, des programmes de formation en travail social, etc. ont été laissés aux mains d’organismes de charité non-lucratifs. Cependant, peu à peu, depuis les années soixante, le gouvernement fédéral et le gouvernement provincial, ont dû développer des politiques et des programmes d'action. Au Québec, le travail social a fait partie du débat face à deux grands courants politiques, l’un canadien basé sur le multiculturalisme, et l’autre québécois basé sur l'interculturalisme. L'article vise à donner une perspective historique

pH-Dependent solubility and permeability criteria for provisional biopharmaceutics classification (BCS and BDDCS) in early drug discovery.

Science.gov (United States)

Varma, Manthena V; Gardner, Iain; Steyn, Stefanus J; Nkansah, Paul; Rotter, Charles J; Whitney-Pickett, Carrie; Zhang, Hui; Di, Li; Cram, Michael; Fenner, Katherine S; El-Kattan, Ayman F

2012-05-07

The Biopharmaceutics Classification System (BCS) is a scientific framework that provides a basis for predicting the oral absorption of drugs. These concepts have been extended in the Biopharmaceutics Drug Disposition Classification System (BDDCS) to explain the potential mechanism of drug clearance and understand the effects of uptake and efflux transporters on absorption, distribution, metabolism, and elimination. The objective of present work is to establish criteria for provisional biopharmaceutics classification using pH-dependent passive permeability and aqueous solubility data generated from high throughput screening methodologies in drug discovery settings. The apparent permeability across monolayers of clonal cell line of Madin-Darby canine kidney cells, selected for low endogenous efflux transporter expression, was measured for a set of 105 drugs, with known BCS and BDDCS class. The permeability at apical pH 6.5 for acidic drugs and at pH 7.4 for nonacidic drugs showed a good correlation with the fraction absorbed in human (Fa). Receiver operating characteristic (ROC) curve analysis was utilized to define the permeability class boundary. At permeability ≥ 5 × 10(-6) cm/s, the accuracy of predicting Fa of ≥ 0.90 was 87%. Also, this cutoff showed more than 80% sensitivity and specificity in predicting the literature permeability classes (BCS), and the metabolism classes (BDDCS). The equilibrium solubility of a subset of 49 drugs was measured in pH 1.2 medium, pH 6.5 phosphate buffer, and in FaSSIF medium (pH 6.5). Although dose was not considered, good concordance of the measured solubility with BCS and BDDCS solubility class was achieved, when solubility at pH 1.2 was used for acidic compounds and FaSSIF solubility was used for basic, neutral, and zwitterionic compounds. Using a cutoff of 200 μg/mL, the data set suggested a 93% sensitivity and 86% specificity in predicting both the BCS and BDDCS solubility classes. In conclusion, this study identified

Radiation dominated relativistic current sheets

International Nuclear Information System (INIS)

Jaroschek, C.H.

2008-01-01

Relativistic Current Sheets (RCS) feature plasma instabilities considered as potential key to magnetic energy dissipation and non-thermal particle generation in Poynting flux dominated plasma flows. We show in a series of kinetic plasma simulations that the physical nature of non-linear RCS evolution changes in the presence of incoherent radiation losses: In the ultra-relativistic regime (i.e. magnetization parameter sigma = 104 defined as the ratio of magnetic to plasma rest frame energy density) the combination of non-linear RCS dynamics and synchrotron emission introduces a temperature anisotropy triggering the growth of the Relativistic Tearing Mode (RTM). As direct consequence the RTM prevails over the Relativistic Drift Kink (RDK) Mode as competitive RCS instability. This is in contrast to the previously studied situation of weakly relativistic RCS (sigma ∼ 1) where the RDK is dominant and most of the plasma is thermalized. The simulations witness the typical life cycle of ultra-relativistic RCS evolving from a violent radiation induced collapse towards a radiation quiescent state in rather classical Sweet-Parker topology. Such a transition towards Sweet-Parker configuration in the late non-linear evolution has immediate consequences for the efficiency of magnetic energy dissipation and non-thermal particle generation. Ceasing dissipation rates directly affect our present understanding of non-linear RCS evolution in conventional striped wind scenarios. (author)

Inmigración y educación intercultural en Québec : programas y debates

Directory of Open Access Journals (Sweden)

Josefina Rossel

2000-01-01

Full Text Available Este artículo, marcado por una perspectiva de comparación implícita, presenta una infonnación descriptiva del estado de los programas y debates que conciernen las medidas educativas adoptadas en favor de la integración de los inmigrantes y de la educación intercultural en Québec. Éste describe el contexto general dentro del cual se insertan las cuestiones de educación y de inmigración en Québec, los diferentes programas creados para favorecer la integración escolar de los alumnos de origen inmigrante y discute asimismo sobre algunos debates que conciernen diversas opciones de políticas y programas en este área. En conclusión, la autora propone una reflexión comparativa sobre el esclarecimiento que el caso quebequense es susceptible de aportar a la situación vivida en ciertos estados autónomos de España, sobre todo a aquellos donde la lengua propia no es el castellano. 

Relativistic gas in a Schwarzschild metric

International Nuclear Information System (INIS)

Kremer, Gilberto M

2013-01-01

A relativistic gas in a Schwarzschild metric is studied within the framework of a relativistic Boltzmann equation in the presence of gravitational fields, where Marle’s model for the collision operator of the Boltzmann equation is employed. The transport coefficients of the bulk and shear viscosities and thermal conductivity are determined from the Chapman–Enskog method. It is shown that the transport coefficients depend on the gravitational potential. Expressions for the transport coefficients in the presence of weak gravitational fields in the non-relativistic (low temperature) and ultra-relativistic (high temperature) limiting cases are given. Apart from the temperature gradient the heat flux has two relativistic terms. The first one, proposed by Eckart, is due to the inertia of energy and represents an isothermal heat flux when matter is accelerated. The other, suggested by Tolman, is proportional to the gravitational potential gradient and indicates that—in the absence of an acceleration field—a state of equilibrium of a relativistic gas in a gravitational field can be attained only if the temperature gradient is counterbalanced by a gravitational potential gradient. (paper)

Extended Galilean symmetries of non-relativistic strings

Energy Technology Data Exchange (ETDEWEB)

Batlle, Carles [Departament de Matemàtiques and IOC, Universitat Politècnica de Catalunya, EPSEVG,Av. V. Balaguer 1, E-08808 Vilanova i la Geltrú (Spain); Gomis, Joaquim; Not, Daniel [Departament de Física Quàntica i Astrofísica and Institut de Ciències del Cosmos (ICCUB),Universitat de Barcelona,Martí i Franquès 1, E-08028 Barcelona (Spain)

2017-02-09

We consider two non-relativistic strings and their Galilean symmetries. These strings are obtained as the two possible non-relativistic (NR) limits of a relativistic string. One of them is non-vibrating and represents a continuum of non-relativistic massless particles, and the other one is a non-relativistic vibrating string. For both cases we write the generator of the most general point transformation and impose the condition of Noether symmetry. As a result we obtain two sets of non-relativistic Killing equations for the vector fields that generate the symmetry transformations. Solving these equations shows that NR strings exhibit two extended, infinite dimensional space-time symmetries which contain, as a subset, the Galilean symmetries. For each case, we compute the associated conserved charges and discuss the existence of non-central extensions.

Relativistic generalization of strong plasma turbulence

International Nuclear Information System (INIS)

Chian, A.C.-L.

1982-01-01

Two fundamental electrostatic modes of an unmagnetized plasma, namely, ion acoustic mode and Langumir mode are studied. Previous theories are generalized to include the effect of relativistic mass variations. The existence of relativistic ion acoustic solitons is demonstrated. In addition, it is shown that simple, relativistic Langumir solitons do not exist in a infinite plasma. (L.C.) [pt

The Wigner function in the relativistic quantum mechanics

Energy Technology Data Exchange (ETDEWEB)

Kowalski, K., E-mail: kowalski@uni.lodz.pl; Rembieliński, J.

2016-12-15

A detailed study is presented of the relativistic Wigner function for a quantum spinless particle evolving in time according to the Salpeter equation. - Highlights: • We study the Wigner function for a quantum spinless relativistic particle. • We discuss the relativistic Wigner function introduced by Zavialov and Malokostov. • We introduce relativistic Wigner function based on the standard definition. • We find analytic expressions for relativistic Wigner functions.

New relativistic generalization of the Heisenberg commutation relations

International Nuclear Information System (INIS)

Bohm, A.; Loewe, M.; Magnollay, P.; Tarlini, M.; Aldinger, R.R.; Kielanowski, P.

1984-01-01

A relativistic generalization of the Heisenberg commutation relations is suggested which is different from the conventional ones used for the intrinsic coordinates and momenta in the relativistic oscillator model and the relativistic string. This new quantum relativistic oscillator model is determined by the requirement that it gives a unified description of relativistic vibrations and rotations and contracts in the nonrelativistic limit c -1 →0 into the usual nonrelativistic harmonic oscillator

Topical treatment of malignant and premalignant skin lesions by very low concentrations of a standard mixture (BEC) of solasodine glycosides.

Science.gov (United States)

Cham, B E; Daunter, B; Evans, R A

1991-09-01

A cream formulation containing high concentrations (10%) of a standard mixture of solasodine glycosides (BEC) has been shown to be effective in the treatment of malignant and benign human skin tumours. We now report that a preparation (Curaderm) which contains very low concentrations of BEC (0.005%) is effective in the treatment of keratoses, basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) of the skin of humans. In an open study, clinical and histological observations indicated that all lesions (56 keratoses, 39 BCCs and 29 SCCs) treated with Curaderm had regressed. A placebo formulation had no effect on a smaller number of treated lesions. Curaderm had no adverse effect on the liver, kidneys or haematopoietic system.

Random phase approximation in relativistic approach

International Nuclear Information System (INIS)

Ma Zhongyu; Yang Ding; Tian Yuan; Cao Ligang

2009-01-01

Some special issues of the random phase approximation(RPA) in the relativistic approach are reviewed. A full consistency and proper treatment of coupling to the continuum are responsible for the successful application of the RPA in the description of dynamical properties of finite nuclei. The fully consistent relativistic RPA(RRPA) requires that the relativistic mean filed (RMF) wave function of the nucleus and the RRPA correlations are calculated in a same effective Lagrangian and the consistent treatment of the Dirac sea of negative energy states. The proper treatment of the single particle continuum with scattering asymptotic conditions in the RMF and RRPA is discussed. The full continuum spectrum can be described by the single particle Green's function and the relativistic continuum RPA is established. A separable form of the paring force is introduced in the relativistic quasi-particle RPA. (authors)

Further test of new pairing scheme used in overhaul of BCS theory

International Nuclear Information System (INIS)

Zheng, X.H.; Walmsley, D.G.

2014-01-01

Highlights: • Explanation of a new pairing scheme to overhaul BCS theory. • Prediction of superconductor properties from normal state resistivity. • Applications to Nb, Pb, Al, Ta, Mo, Ir and W, T c between 9.5 and 0.012 K. • High accuracy compared with measured energy gap of Nb, Pb, Al and Ta. • Prediction of energy gap for Mo, Ir and W (so far not measured). - Abstract: A new electron pairing scheme, rectifying a fundamental flaw of the BCS theory, is tested extensively. It postulates that superconductivity arises solely from residual umklapp scattering when it is not in competition for the same destination electron states with normal scattering. It reconciles a long standing theoretical discrepancy in the strength of the electron–phonon interaction between the normal and superconductive states. The new scheme is exploited to calculate the superconductive electron–phonon spectral density, α 2 F(ν), entirely on the basis of normal state electrical resistivity. This leads to first principles superconductive properties (zero temperature energy gap and tunnelling conductance) in seven metals which turn out to be highly accurate when compared with known data; in other cases experimental verification is invited. The transition temperatures involved vary over almost three orders of magnitude: from 9.5 K for niobium to 0.012 K for tungsten

Relativistic mean field model for entrainment in general relativistic superfluid neutron stars

International Nuclear Information System (INIS)

Comer, G.L.; Joynt, R.

2003-01-01

General relativistic superfluid neutron stars have a significantly more intricate dynamics than their ordinary fluid counterparts. Superfluidity allows different superfluid (and superconducting) species of particles to have independent fluid flows, a consequence of which is that the fluid equations of motion contain as many fluid element velocities as superfluid species. Whenever the particles of one superfluid interact with those of another, the momentum of each superfluid will be a linear combination of both superfluid velocities. This leads to the so-called entrainment effect whereby the motion of one superfluid will induce a momentum in the other superfluid. We have constructed a fully relativistic model for entrainment between superfluid neutrons and superconducting protons using a relativistic σ-ω mean field model for the nucleons and their interactions. In this context there are two notions of 'relativistic': relativistic motion of the individual nucleons with respect to a local region of the star (i.e. a fluid element containing, say, an Avogadro's number of particles), and the motion of fluid elements with respect to the rest of the star. While it is the case that the fluid elements will typically maintain average speeds at a fraction of that of light, the supranuclear densities in the core of a neutron star can make the nucleons themselves have quite high average speeds within each fluid element. The formalism is applied to the problem of slowly rotating superfluid neutron star configurations, a distinguishing characteristic being that the neutrons can rotate at a rate different from that of the protons

Quantum gates via relativistic remote control

Energy Technology Data Exchange (ETDEWEB)

Martín-Martínez, Eduardo, E-mail: emartinm@uwaterloo.ca [Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Dept. Applied Math., University of Waterloo, Ontario, N2L 3G1 (Canada); Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada); Sutherland, Chris [Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)

2014-12-12

We harness relativistic effects to gain quantum control on a stationary qubit in an optical cavity by controlling the non-inertial motion of a different probe atom. Furthermore, we show that by considering relativistic trajectories of the probe, we enhance the efficiency of the quantum control. We explore the possible use of these relativistic techniques to build 1-qubit quantum gates.

Thin accretion disks around cold Bose-Einstein condensate stars

Energy Technology Data Exchange (ETDEWEB)

Danila, Bogdan [Babes-Bolyai University, Department of Physics, Cluj-Napoca (Romania); Harko, Tiberiu [University College London, Department of Mathematics, London (United Kingdom); Kovacs, Zoltan

2015-05-15

Due to their superfluid properties some compact astrophysical objects, like neutron or quark stars, may contain a significant part of their matter in the form of a Bose-Einstein condensate (BEC). Observationally distinguishing between neutron/quark stars and BEC stars is a major challenge for this latter theoretical model. An observational possibility of indirectly distinguishing BEC stars from neutron/quark stars is through the study of the thin accretion disks around compact general relativistic objects. In the present paper, we perform a detailed comparative study of the electromagnetic and thermodynamic properties of the thin accretion disks around rapidly rotating BEC stars, neutron stars and quark stars, respectively. Due to the differences in the exterior geometry, the thermodynamic and electromagnetic properties of the disks (energy flux, temperature distribution, equilibrium radiation spectrum, and efficiency of energy conversion) are different for these classes of compact objects. Hence in this preliminary study we have pointed out some astrophysical signatures that may allow one to observationally discriminate between BEC stars and neutron/quark stars. (orig.)

RELATIVISTIC CYCLOTRON INSTABILITY IN ANISOTROPIC PLASMAS

Energy Technology Data Exchange (ETDEWEB)

López, Rodrigo A.; Moya, Pablo S.; Muñoz, Víctor; Valdivia, J. Alejandro [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Navarro, Roberto E.; Araneda, Jaime A. [Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Viñas, Adolfo F., E-mail: rlopez186@gmail.com [NASA Goddard Space Flight Center, Heliophysics Science Division, Geospace Physics Laboratory, Mail Code 673, Greenbelt, MD 20771 (United States)

2016-11-20

A sufficiently large temperature anisotropy can sometimes drive various types of electromagnetic plasma micro-instabilities, which can play an important role in the dynamics of relativistic pair plasmas in space, astrophysics, and laboratory environments. Here, we provide a detailed description of the cyclotron instability of parallel propagating electromagnetic waves in relativistic pair plasmas on the basis of a relativistic anisotropic distribution function. Using plasma kinetic theory and particle-in-cell simulations, we study the influence of the relativistic temperature and the temperature anisotropy on the collective and noncollective modes of these plasmas. Growth rates and dispersion curves from the linear theory show a good agreement with simulations results.

Approximate energy correction for particle number summetry breaking in constrained Hartree-Fock plus BCS calculations

International Nuclear Information System (INIS)

Redon, N.; Meyer, J.; Meyer, M.

1989-01-01

An approximate restoration of the particle number symmetry, a la Lipkin-Nogami, is numerically investigated in the context of Constrained Hartree-Fock plus BCS calculations. Its effect is assessed in a variety of physical situations like potential energy landscapes in transitional nuclei, shape isomerism at low spin and fission barriers of actinide nuclei

Relativistic quantum mechanics

CERN Document Server

Horwitz, Lawrence P

2015-01-01

This book describes a relativistic quantum theory developed by the author starting from the E.C.G. Stueckelberg approach proposed in the early 40s. In this framework a universal invariant evolution parameter (corresponding to the time originally postulated by Newton) is introduced to describe dynamical evolution. This theory is able to provide solutions for some of the fundamental problems encountered in early attempts to construct a relativistic quantum theory. A relativistically covariant construction is given for which particle spins and angular momenta can be combined through the usual rotation group Clebsch-Gordan coefficients. Solutions are defined for both the classical and quantum two body bound state and scattering problems. The recently developed quantum Lax-Phillips theory of semigroup evolution of resonant states is described. The experiment of Lindner and coworkers on interference in time is discussed showing how the property of coherence in time provides a simple understanding of the results. Th...

Apparent unambiguousness of relativistic time dilation

International Nuclear Information System (INIS)

Strel'tsov, V.N.

1992-01-01

It is indicated on the definite analogy between the dependence of visible sizes of relativistic objects and period of the wave, emitted by the moving source from the observation conditions ('retradition factor'). It is noted that the definition of time for moving extended objects, led to relativistic dilation, corresponds to the definition of the relativistic (radar) length led to the 'elongation formula'. 10 refs

Slowly rotating general relativistic superfluid neutron stars with relativistic entrainment

International Nuclear Information System (INIS)

Comer, G.L.

2004-01-01

Neutron stars that are cold enough should have two or more superfluids or supercondutors in their inner crusts and cores. The implication of superfluidity or superconductivity for equilibrium and dynamical neutron star states is that each individual particle species that forms a condensate must have its own, independent number density current and equation of motion that determines that current. An important consequence of the quasiparticle nature of each condensate is the so-called entrainment effect; i.e., the momentum of a condensate is a linear combination of its own current and those of the other condensates. We present here the first fully relativistic modeling of slowly rotating superfluid neutron stars with entrainment that is accurate to the second-order in the rotation rates. The stars consist of superfluid neutrons, superconducting protons, and a highly degenerate, relativistic gas of electrons. We use a relativistic σ-ω mean field model for the equation of state of the matter and the entrainment. We determine the effect of a relative rotation between the neutrons and protons on a star's total mass, shape, and Kepler, mass-shedding limit

Balance equations for a relativistic plasma. Pt. 1

International Nuclear Information System (INIS)

Hebenstreit, H.

1983-01-01

Relativistic power moments of the four-momentum are decomposed according to a macroscopic four-velocity. The thus obtained quantities are identified as relativistic generalization of the nonrelativistic orthogonal moments, e.g. diffusion flow, heat flow, pressure, etc. From the relativistic Boltzmann equation we then derive balance equations for these quantities. Explicit expressions for the relativistic mass conservation, energy balance, pressure balance, heat flow balance are presented. The weak relativistic limit is discussed. The derivation of higher order balance equations is sketched. (orig.)

Structure of even-odd spherical nuclei using the BCS approximations and the ACQPV model: application to isotones with N=82 and Ni, Zn and Cs'' isotopes

International Nuclear Information System (INIS)

Losano, L.

1986-01-01

Calculations of the (E,J Π ) spectra and the electromagnetic properties (fe,Q,BEZ,BM1) are made for Ni odd isotopes, and odd isotones with N=82, using the Shell Model (SM), the usual BCS approximation (one and three quasiparticles), blocking BCS (BBCS) and projected BCS (PBCS). The importance of the five quasiparticle correlations and of the correlation introduced in BCS are examined in detail. The collective degrees of freedom of the core are introduced through the quasiparticle-cluster-vibrator coupling (QPCVC), so that this formalism permits as well the inclusion of blocking as the projection in number of particles in the cluster of one and three quasiparticles. Comparative calculations are made between the version with blocking (BQPCV) and with projection (PQPCV) for spectra and electromagnetic properties of Zn old isotopes. The projected version is applied to the cesium isotopes in the description of the 5/2 + states generated by the anomalous coupling. In all examined cases, the comparison with the available experimental data is also shown. (L.C.) [pt

Loading relativistic Maxwell distributions in particle simulations

Science.gov (United States)

Zenitani, S.

2015-12-01

In order to study energetic plasma phenomena by using particle-in-cell (PIC) and Monte-Carlo simulations, we need to deal with relativistic velocity distributions in these simulations. However, numerical algorithms to deal with relativistic distributions are not well known. In this contribution, we overview basic algorithms to load relativistic Maxwell distributions in PIC and Monte-Carlo simulations. For stationary relativistic Maxwellian, the inverse transform method and the Sobol algorithm are reviewed. To boost particles to obtain relativistic shifted-Maxwellian, two rejection methods are newly proposed in a physically transparent manner. Their acceptance efficiencies are 􏰅50% for generic cases and 100% for symmetric distributions. They can be combined with arbitrary base algorithms.

Relativistic solitons and pulsars

Energy Technology Data Exchange (ETDEWEB)

Karpman, V I [Inst. of Terrestrial Magnetism, Ionosphere, and Radio-Wave Propagation, Moscow; Norman, C A; ter Haar, D; Tsytovich, V N

1975-05-01

A production mechanism for stable electron bunches or sheets of localized electric fields is investigated which may account for pulsar radio emission. Possible soliton phenomena in a one-dimensional relativistic plasma are analyzed, and it is suggested that the motion of a relativistic soliton, or ''relaton'', along a curved magnetic-field line may produce radio emission with the correct polarization properties. A general MHD solution is obtained for relatons, the radiation produced by a relativistic particle colliding with a soliton is evaluated, and the emission by a soliton moving along a curved field line is estimated. It is noted that due to a number of severe physical restrictions, curvature radiation is not a very likely solution to the problem of pulsar radio emission. (IAA)

Mechanistic investigation of food effect on disintegration and dissolution of BCS class III compound solid formulations: the importance of viscosity.

Science.gov (United States)

Radwan, Asma; Amidon, Gordon L; Langguth, Peter

2012-10-01

A negative food effect, i.e. a decrease in bioavailability upon the co-administration of compounds together with food, has been attributed particularly with high solubility/low permeability compounds (BCS class III). Different mechanisms have been proposed including intestinal dilution leading to a lower concentration gradient across the intestinal wall as well as binding of the active pharmaceutical ingredient to food components in the intestine and thereby decreasing the fraction of the dose available for absorption. These mechanisms refer primarily to the compound and not to the dosage form. An increase in viscosity of the dissolution fluid will in particular affect the absorption of BCS type III compounds with preferential absorption in the upper small intestine if the API release is delayed from the dosage form. The present study demonstrated that the increase in viscosity of the dissolution medium, following ingestion of a solid meal, may drastically reduce disintegration and dissolution. For that purpose the viscosity of the standard FDA meal was determined and simulated by solutions of HPMC in buffer. As model formulations, three commercially available tablets containing trospium chloride, a BCS class III m-cholinoreceptor antagonist was used. Trospium chloride drug products have been described to undergo a negative food effect of more than 80% following ingestion with food. The tablets showed prolonged disintegration times and reduced dissolution rates in viscous media, which could be attributed to changes in the liquid penetration rates. The effect was particularly significant for film-coated tablets relative to uncoated dosage forms. The results show the necessity of considering media viscosity when designing in vitro models of drug release for BCS type III drug formulations. Copyright © 2012 John Wiley & Sons, Ltd.

Non-relativistic Limit of a Dirac Polaron in Relativistic Quantum Electrodynamics

CERN Document Server

Arai, A

2006-01-01

A quantum system of a Dirac particle interacting with the quantum radiation field is considered in the case where no external potentials exist. Then the total momentum of the system is conserved and the total Hamiltonian is unitarily equivalent to the direct integral $\\int_{{\\bf R}^3}^\\oplus\\overline{H({\\bf p})}d{\\bf p}$ of a family of self-adjoint operators $\\overline{H({\\bf p})}$ acting in the Hilbert space $\\oplus^4{\\cal F}_{\\rm rad}$, where ${\\cal F}_{\\rm rad}$ is the Hilbert space of the quantum radiation field. The fibre operator $\\overline{H({\\bf p})}$ is called the Hamiltonian of the Dirac polaron with total momentum ${\\bf p} \\in {\\bf R}^3$. The main result of this paper is concerned with the non-relativistic (scaling) limit of $\\overline{H({\\bf p})}$. It is proven that the non-relativistic limit of $\\overline{H({\\bf p})}$ yields a self-adjoint extension of a Hamiltonian of a polaron with spin $1/2$ in non-relativistic quantum electrodynamics.

Nonlinear dynamics of the relativistic standard map

International Nuclear Information System (INIS)

Nomura, Y.; Ichikawa, Y.H.; Horton, W.

1991-04-01

Heating and acceleration of charged particles by RF fields have been extensively investigated by the standard map. The question arises as to how the relativistic effects change the nonlinear dynamical behavior described by the classical standard map. The relativistic standard map is a two parameter (K, Β = ω/kc) family of dynamical systems reducing to the standard map when Β → 0. For Β ≠ 0 the relativistic mass increase suppresses the onset of stochasticity. It shown that the speed of light limits the rate of advance of the phase in the relativistic standard map and introduces KAM surfaces persisting in the high momentum region. An intricate structure of mixing in the higher order periodic orbits and chaotic orbits is analyzed using the symmetry properties of the relativistic standard map. The interchange of the stability of the periodic orbits in the relativistic standard map is also observed and is explained by the local linear stability of the orbits. 12 refs., 16 figs

How one can construct a consistent relativistic quantum mechanics on the base of a relativistic wave equation

Energy Technology Data Exchange (ETDEWEB)

Gavrilov, S.P. [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil); Gitman, D.M. [Sao Paulo Univ. (USP), SP (Brazil). Inst. de Fisica

2000-07-01

Full text follows: There is a common opinion that the construction of a consistent relativistic quantum mechanics on the base of a relativistic wave equation meets well-known difficulties related to the existence of infinite number of negative energy levels, to the existence of negative vector norms, and so on, which may be only solved in a second-quantized theory, see, for example, two basic papers devoted to the problem L.Foldy, S.Wouthuysen, Phys. Rep.78 (1950) 29; H.Feshbach, F.Villars, Rev. Mod. Phys. 30 (1958) 24, whose arguments are repeated in all handbooks in relativistic quantum theory. Even Dirac trying to solve the problem had turned last years to infinite-component relativistic wave equations, see P.A.M. Dirac, Proc. R. Soc. London, A328 (1972) 1. We believe that a consistent relativistic quantum mechanics may be constructed on the base of an extended (charge symmetric) equation, which unite both a relativistic wave equation for a particle and for an antiparticle. We present explicitly the corresponding construction, see for details hep-th/0003112. We support such a construction by two demonstrations: first, in course of a careful canonical quantization of the corresponding classical action of a relativistic particle we arrive just to such a consistent quantum mechanics; second, we demonstrate that a reduction of the QFT of a corresponding field (scalar, spinor, etc.) to one-particle sector, if such a reduction may be done, present namely this quantum mechanics. (author)

Some problems in relativistic thermodynamics

International Nuclear Information System (INIS)

Veitsman, E. V.

2007-01-01

The relativistic equations of state for ideal and real gases, as well as for various interface regions, have been derived. These dependences help to eliminate some controversies in the relativistic thermodynamics based on the special theory of relativity. It is shown, in particular, that the temperature of system whose velocity tends to the velocity of light in vacuum varies in accordance with the Ott law T = T 0 /√1 - v 2 /c 2 . Relativistic dependences for heat and mass transfer, for Ohm's law, and for a viscous flow of a liquid have also been derived

Myocardial infarction in Québec rural and urban populations between 1995 and 1997.

Science.gov (United States)

Loslier, Julie; Vanasse, Alain; Niyonsenga, Théophile; Courteau, Josiane; Orzanco, Gabriela; Hemiari, Abbas

2007-01-01

There is abundant evidence of health inequities between urban and rural populations. The purpose of this paper is to describe the socioeconomic characteristics of Québec urban and rural populations and the relation between rurality and incidence of myocardial infarction (MI), care management and outcomes. Socioeconomic data by census subdivisions were available from the 1996 Canadian census, representing 7,137,245 individuals. Data on patients with MI were taken from the provincial administrative health database (MED-ECHO), which is managed by the Ministry of Health and contains clinical and demographic information collected when patients are released from acute care hospitals in Québec. We included a total of 37,678 cases compiled over the 3 years of follow-up in the analyses. Residents of rural areas with low urban influence have higher MI incidence rates than all of the other populations in the study. In comparison with urban populations, their observed rural counterparts are at a disadvantage with regard to education, employment and income. Although angioplasty and coronary artery bypass graft surgery rates were higher in more urban areas, the survival rate was lower than in rural areas. This study revealed geographic heterogeneity of MI incidence, revascularization rates and survival rates among urban and rural populations.

Dimensional crossover in fragmentation

Science.gov (United States)

Sotolongo-Costa, Oscar; Rodriguez, Arezky H.; Rodgers, G. J.

2000-11-01

Experiments in which thick clay plates and glass rods are fractured have revealed different behavior of fragment mass distribution function in the small and large fragment regions. In this paper we explain this behavior using non-extensive Tsallis statistics and show how the crossover between the two regions is caused by the change in the fragments’ dimensionality during the fracture process. We obtain a physical criterion for the position of this crossover and an expression for the change in the power-law exponent between the small and large fragment regions. These predictions are in good agreement with the experiments on thick clay plates.

The Cauchy problem for the Bogolyubov hierarchy of equations. The BCS model

International Nuclear Information System (INIS)

Vidybida, A.K.

1975-01-01

A chain of Bogolyubov's kinetic equations for an infinite quantum system of particles distributed in space with the mean density 1/V and interacting with the BCS model operator is considered as a single abstract equation in some countable normalized space bsup(v) of sequences of integral operators. In this case an unique solution of the Cauchy problem has been obtained at arbitrary initial conditions from bsup(v), stationary solutions of the equation have been derived, and the class of the initial conditions which approach to stationary ones is indicated

Relativistic ion acceleration by ultraintense laser interactions

International Nuclear Information System (INIS)

Nakajima, K.; Koga, J.K.; Nakagawa, K.

2001-01-01

There has been a great interest in relativistic particle generation by ultraintense laser interactions with matter. We propose the use of relativistically self-focused laser pulses for the acceleration of ions. Two dimensional PIC simulations are performed, which show the formation of a large positive electrostatic field near the front of a relativistically self-focused laser pulse. Several factors contribute to the acceleration including self-focusing distance, pulse depletion, and plasma density. Ultraintense laser-plasma interactions are capable of generating enormous electrostatic fields of ∼3 TV/m for acceleration of protons with relativistic energies exceeding 1 GeV

Breast cancer screening (BCS) chart: a basic and preliminary model for making screening mammography more productive and efficient.

Science.gov (United States)

Poorolajal, Jalal; Akbari, Mohammad Esmaeil; Ziaee, Fatane; Karami, Manoochehr; Ghoncheh, Mahshid

2017-05-15

The breast cancer screening (BCS) chart is suggested as a basic and preliminary tool to improve efficiency of screening mammography. We conducted this case-control study in 2016 and enrolled 1422 women aged 30-75 years, including 506 women with breast cancer (cases) and 916 women without breast cancer (controls). We developed the BCS chart using a multiple logistic regression analysis. We combined the risks of breast cancer to predict the individual risk of breast cancer. Then, we stratified and colored the predicted risk probabilities as follows: green), 05-09% (yellow), 10-14% (orange), 15-19% (red), 20-24% (brown) and ≥25% (black). The BCS chart provides the risk probability of breast cancer, based on age, body mass index, late menopause, having a benign breast disease and a positive family history of breast cancer among the first-degree or the second/third-degree relatives. According to this chart, an individual can be classified in a category of low risk (green), medium risk (yellow and orange), high risk (red and brown) and very high risk (black) for breast cancer. This chart is a flexible and easy to use tool that can detect high-risk subjects and make the screening program more efficient and productive. © The Author 2017. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Hysteretic behavior of spin-crossover noise driven system

Energy Technology Data Exchange (ETDEWEB)

Gudyma, Iurii [Department of General Physics, Chernivtsi National University, Chernivtsi 58012 (Ukraine); Maksymov, Artur, E-mail: maxyartur@gmail.com [Department of General Physics, Chernivtsi National University, Chernivtsi 58012 (Ukraine); Advanced Materials Research Institute, University of New Orleans, LA 70148 (United States); Dimian, Mihai [Department of Electrical and Computer Engineering, Howard University, Washington DC, 20059 (United States); Faculty of Electrical Engineering and Computer Science, Stefan cel Mare University, Suceava 720229 (Romania)

2016-04-01

The influence of white Gaussian noise on hysteretic behavior of spin-crossover system is analyzed in the framework of stochastic Langevin dynamics. Various stochastic simulations are performed and several important properties of spin-transition in spin-crossover system driven by noise are reproduced. The numerical results are tested against the stationary probability function and the associated dynamic potential obtained from Fokker–Planck equation corresponding to spin-crossover Langevin dynamics. The dependence of light-induced optical hysteresis width and non-hysteretic transition curve slope on the noise intensity is illustrated. The role of low-spin and high-spin phase stabilities in the hysteretic behavior of noise-driven spin-crossover system is discussed.

Relativistic collective diffusion in one-dimensional systems

Science.gov (United States)

Lin, Gui-Wu; Lam, Yu-Yiu; Zheng, Dong-Qin; Zhong, Wei-Rong

2018-05-01

The relativistic collective diffusion in one-dimensional molecular system is investigated through nonequilibrium molecular dynamics with Monte Carlo methods. We have proposed the relationship among the speed, the temperature, the density distribution and the collective diffusion coefficient of particles in a relativistic moving system. It is found that the relativistic speed of the system has no effect on the temperature, but the collective diffusion coefficient decreases to zero as the velocity of the system approaches to the speed of light. The collective diffusion coefficient is modified as D‧ = D(1 ‑w2 c2 )3 2 for satisfying the relativistic circumstances. The present results may contribute to the understanding of the behavior of the particles transport diffusion in a high speed system, as well as enlighten the study of biological metabolism at relativistic high speed situation.

Exact Relativistic `Antigravity' Propulsion

Science.gov (United States)

Felber, Franklin S.

2006-01-01

The Schwarzschild solution is used to find the exact relativistic motion of a payload in the gravitational field of a mass moving with constant velocity. At radial approach or recession speeds faster than 3-1/2 times the speed of light, even a small mass gravitationally repels a payload. At relativistic speeds, a suitable mass can quickly propel a heavy payload from rest nearly to the speed of light with negligible stresses on the payload.

Relativistic Boltzmann theory for a plasma

International Nuclear Information System (INIS)

Erkelens, H. van.

1984-01-01

This thesis gives a self-contained treatment of the relativistic Boltzmann theory for a plasma. Here plasma means any mixture containing electrically charged particles. The relativistic Boltzmann equation is linearized for the case of a plasma. The Chapman-Enskog method is elaborated further for transport phenomena. Linear laws for viscous phenomena are derived. Then the collision term in the Boltzmann theory is dealt with. Using the transport equation, a kinetic theory of wave phenomena is developed and the dissipation of hydromagnetic waves in a relativistic plasma is investigated. In the final chapter, it is demonstrated how the relativistic Boltzmann theory can be applied in cosmology. In doing so, expressions are derived for the electric conductivity of the cosmological plasma in the lepton era, the plasma era and the annihilation era. (Auth.)

Many-Body Coulomb Gauge Exotic and Charmed Hybrids

OpenAIRE

Llanes-Estrada, Felipe J.; Cotanch, Stephen R.

2000-01-01

Utilizing a QCD Coulomb gauge Hamiltonian with linear confinement specified by lattice, we report a relativistic many-body calculation for the light exotic and charmed hybrid mesons. The Hamiltonian successfully describes both quark and gluon sectors, with vacuum and quasiparticle properties generated by a BCS transformation and more elaborate TDA and RPA diagonalizations for the meson ($q\\bar{q}$) and glueball ($gg$) masses. Hybrids entail a computationally intense relativistic three quasipa...

Relativistic effects in the Thomas--Fermi atom

International Nuclear Information System (INIS)

Waber, J.T.; Canfield, J.M.

1975-01-01

Two methods of applying relativistic corrections to the Thomas--Fermi atom are considered, and numerical calculations are discussed. Radial charge distributions calculated from a relativistic Thomas--Fermi equation agree in gross form with those from more complicated self-consistent calculations. Energy eigenvalues for mercury, as determined from the relativistic Thomas--Fermi solution, are compared with other calculated and experimental values

Relativistic klystron research for linear colliders

International Nuclear Information System (INIS)

Allen, M.A.; Callin, R.S.; Deruyter, H.; Eppley, K.R.; Fant, K.S.; Fowkes, W.R.; Herrmannsfeldt, W.B.; Hoag, H.A.; Koontz, R.F.; Lavine, T.L.; Lee, T.G.; Loew, G.A.; Miller, R.H.; Morton, P.L.; Palmer, R.B.; Paterson, J.M.; Ruth, R.D.; Schwarz, H.D.; Vlieks, A.E.; Wilson, P.B.

1989-01-01

Relativistic klystrons are being developed as a power source for high gradient accelerator applications which include large linear electron-positron colliders, compact accelerators, and FEL sources. The authors have attained 200 MW peak power at 11.4 GHz from a relativistic klystron, and 140 MV/m longitudinal gradient in a short 11.4 GHz accelerator section. In this paper the authors report on the design of our relativistic klystrons, the results of our experiments so far, and some of our plans for the near future

Relativistic klystron research for linear colliders

International Nuclear Information System (INIS)

Allen, M.A.; Callin, R.S.; Deruyter, H.

1988-09-01

Relativistic klystrons are being developed as a power source for high gradient accelerator applications which include large linear electron-positron colliders, compact accelerators, and FEL sources. We have attained 200 MW peak power at 11.4 GHz from a relativistic klystron, and 140 MV/m longitudinal gradient in a short 11.4 GHz accelerator section. We report here on the design of our relativistic klystrons, the results of our experiments so far, and some of our plans for the near future. 5 refs., 9 figs., 1 tab

Relativistic approach to nuclear structure

International Nuclear Information System (INIS)

Nguyen Van Giai; Bouyssy, A.

1987-03-01

Some recent works related with relativistic models of nuclear structure are briefly reviewed. The Dirac-Hartree-Fock and Dirac-Brueckner-Hartree-Fock are recalled and illustrated by some examples. The problem of isoscalar current and magnetic moments of odd nuclei is discussed. The application of the relativistic model to the nuclear response function is examined

A Comprehensive Comparison of Relativistic Particle Integrators

Science.gov (United States)

Ripperda, B.; Bacchini, F.; Teunissen, J.; Xia, C.; Porth, O.; Sironi, L.; Lapenta, G.; Keppens, R.

2018-03-01

We compare relativistic particle integrators commonly used in plasma physics, showing several test cases relevant for astrophysics. Three explicit particle pushers are considered, namely, the Boris, Vay, and Higuera–Cary schemes. We also present a new relativistic fully implicit particle integrator that is energy conserving. Furthermore, a method based on the relativistic guiding center approximation is included. The algorithms are described such that they can be readily implemented in magnetohydrodynamics codes or Particle-in-Cell codes. Our comparison focuses on the strengths and key features of the particle integrators. We test the conservation of invariants of motion and the accuracy of particle drift dynamics in highly relativistic, mildly relativistic, and non-relativistic settings. The methods are compared in idealized test cases, i.e., without considering feedback onto the electrodynamic fields, collisions, pair creation, or radiation. The test cases include uniform electric and magnetic fields, {\\boldsymbol{E}}× {\\boldsymbol{B}} fields, force-free fields, and setups relevant for high-energy astrophysics, e.g., a magnetic mirror, a magnetic dipole, and a magnetic null. These tests have direct relevance for particle acceleration in shocks and in magnetic reconnection.

Simultaneous projection of particle-number and angular momentum BCS wave-functions in the rare-earth nuclei

International Nuclear Information System (INIS)

Oudih, M.R.; Benhamouda, N.; Fellah, M.; Allal, N.H.

2000-01-01

A method of simultaneous particle-number and angular-momentum projection of the BCS wave-function is presented. The particle number projection method is of FBCS type. In the frame work of the adiabatic approximation, the rotational energies of the axially symmetric even-even nuclei are established and numerically calculated for the rare-earth region. (author)

Relativistic heavy-ion physics

CERN Document Server

Herrera Corral, G

2010-01-01

The study of relativistic heavy-ion collisions is an important part of the LHC research programme at CERN. This emerging field of research focuses on the study of matter under extreme conditions of temperature, density, and pressure. Here we present an introduction to the general aspects of relativistic heavy-ion physics. Afterwards we give an overview of the accelerator facility at CERN and then a quick look at the ALICE project as a dedicated experiment for heavy-ion collisions.

Contextual herd factors associated with cow culling risk in Québec dairy herds: A multilevel analysis.

Science.gov (United States)

Haine, Denis; Delgado, Hector; Cue, Roger; Sewalem, Asheber; Wade, Kevin; Lacroix, René; Lefebvre, Daniel; Arsenault, Julie; Bouchard, Émile; Dubuc, Jocelyn

2017-09-01

Several health disorders, such as milk fever, displaced abomasum, and mastitis, as well as impaired reproductive performance, are known risk factors for the removal of affected cows from a dairy herd. While cow-level risk factors are well documented in the literature, herd-level associations have been less frequently investigated. The objective of this study was to investigate the effect of cow- and herd-level determinants on variations in culling risk in Québec dairy herds: whether herd influences a cow's culling risk. For this, we assessed the influence of herd membership on cow culling risk according to displaced abomasum, milk fever, and retained placenta. A retrospective longitudinal study was conducted on data from dairy herds in the Province of Québec, Canada, by extracting health information events from the dairy herd health management software used by most Québec dairy producers and their veterinarians. Data were extracted for all lactations starting between January 1st and December 31st, 2010. Using multilevel logistic regression, we analysed a total of 10,529 cows from 201 herds that met the inclusion criteria. Milk fever and displaced abomasum were demonstrated to increase the cow culling risk. A minor general herd effect was found for the culling risk (i.e. an intra-class correlation of 1.0% and median odds ratio [MOR] of 1.20). The proportion of first lactation cows was responsible for this significant, but weak herd effect on individual cow culling risk, after taking into account the cow-level factors. On the other hand, the herd's average milk production was a protective factor. The planning and management of forthcoming replacement animals has to be taken into consideration when assessing cow culling risks and herd culling rates. Copyright © 2017 Elsevier B.V. All rights reserved.

Relativistic theories of materials

CERN Document Server

Bressan, Aldo

1978-01-01

The theory of relativity was created in 1905 to solve a problem concerning electromagnetic fields. That solution was reached by means of profound changes in fundamental concepts and ideas that considerably affected the whole of physics. Moreover, when Einstein took gravitation into account, he was forced to develop radical changes also in our space-time concepts (1916). Relativistic works on heat, thermodynamics, and elasticity appeared as early as 1911. However, general theories having a thermodynamic basis, including heat conduction and constitutive equations, did not appear in general relativity until about 1955 for fluids and appeared only after 1960 for elastic or more general finitely deformed materials. These theories dealt with materials with memory, and in this connection some relativistic versions of the principle of material indifference were considered. Even more recently, relativistic theories incorporating finite deformations for polarizable and magnetizable materials and those in which couple s...

Relativistic dynamics without conservation laws

OpenAIRE

Rothenstein, Bernhard; Popescu, Stefan

2006-01-01

We show that relativistic dynamics can be approached without using conservation laws (conservation of momentum, of energy and of the centre of mass). Our approach avoids collisions that are not easy to teach without mnemonic aids. The derivations are based on the principle of relativity and on its direct consequence, the addition law of relativistic velocities.

Polynomial Similarity Transformation Theory: A smooth interpolation between coupled cluster doubles and projected BCS applied to the reduced BCS Hamiltonian

Energy Technology Data Exchange (ETDEWEB)

Degroote, M. [Rice Univ., Houston, TX (United States); Henderson, T. M. [Rice Univ., Houston, TX (United States); Zhao, J. [Rice Univ., Houston, TX (United States); Dukelsky, J. [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Estructura de la Materia; Scuseria, G. E. [Rice Univ., Houston, TX (United States)

2018-01-03

We present a similarity transformation theory based on a polynomial form of a particle-hole pair excitation operator. In the weakly correlated limit, this polynomial becomes an exponential, leading to coupled cluster doubles. In the opposite strongly correlated limit, the polynomial becomes an extended Bessel expansion and yields the projected BCS wavefunction. In between, we interpolate using a single parameter. The e ective Hamiltonian is non-hermitian and this Polynomial Similarity Transformation Theory follows the philosophy of traditional coupled cluster, left projecting the transformed Hamiltonian onto subspaces of the Hilbert space in which the wave function variance is forced to be zero. Similarly, the interpolation parameter is obtained through minimizing the next residual in the projective hierarchy. We rationalize and demonstrate how and why coupled cluster doubles is ill suited to the strongly correlated limit whereas the Bessel expansion remains well behaved. The model provides accurate wave functions with energy errors that in its best variant are smaller than 1% across all interaction stengths. The numerical cost is polynomial in system size and the theory can be straightforwardly applied to any realistic Hamiltonian.

Time Operator in Relativistic Quantum Mechanics

Science.gov (United States)

Khorasani, Sina

2017-07-01

It is first shown that the Dirac’s equation in a relativistic frame could be modified to allow discrete time, in agreement to a recently published upper bound. Next, an exact self-adjoint 4 × 4 relativistic time operator for spin-1/2 particles is found and the time eigenstates for the non-relativistic case are obtained and discussed. Results confirm the quantum mechanical speculation that particles can indeed occupy negative energy levels with vanishingly small but non-zero probablity, contrary to the general expectation from classical physics. Hence, Wolfgang Pauli’s objection regarding the existence of a self-adjoint time operator is fully resolved. It is shown that using the time operator, a bosonic field referred here to as energons may be created, whose number state representations in non-relativistic momentum space can be explicitly found.

Relativistic klystron research for linear colliders

International Nuclear Information System (INIS)

Allen, M.A.; Callin, R.S.; Deruyter, H.; Eppley, K.R.; Fant, K.S.; Fowkes, W.R.; Herrmannesfeldt, W.B.; Higo, T.; Hoag, H.A.; Koontz, R.F.; Lavine, T.L.; Lee, T.G.; Loew, G.A.; Miller, R.H.; Morton, P.L.; Palmer, R.B.; Paterson, J.M.; Ruth, R.D.; Schwarz, H.D.; Takeuchi, Y.; Vlieks, A.E.; Wang, J.W.; Wilson, P.B.; Hopkins, D.B.; Sessler, A.M.; Ryne, R.D.; Westenskow, G.A.; Yu, S.S.

1989-01-01

Relativistic klystrons are being developed as a power source for high gradient accelerator applications which include large linear electron-positron colliders, compact accelerators, and FEL sources. The authors have attained 200MW peak power at 11.4 GHz from a relativistic klystron, and 140 MV/m longitudinal gradient in a short 11.4 GHz accelerator section. They report here on the design of our relativistic klystrons, the results of our experiments so far, and some of our plans for the near future. 5 refs., 9 figs., 1 tab

Relativistic Theory of Few Body Systems

Energy Technology Data Exchange (ETDEWEB)

Franz Gross

2002-11-01

Very significant advances have been made in the relativistic theory of few body systems since I visited Peter Sauer and his group in Hannover in 1983. This talk provides an opportunity to review the progress in this field since then. Different methods for the relativistic calculation of few nucleon systems are briefly described. As an example, seven relativistic calculations of the deuteron elastic structure functions, A, B, and T{sub 20}, are compared. The covariant SPECTATOR {copyright} theory, among the more successful and complete of these methods, is described in more detail.

Crossover ensembles of random matrices and skew-orthogonal polynomials

International Nuclear Information System (INIS)

Kumar, Santosh; Pandey, Akhilesh

2011-01-01

Highlights: → We study crossover ensembles of Jacobi family of random matrices. → We consider correlations for orthogonal-unitary and symplectic-unitary crossovers. → We use the method of skew-orthogonal polynomials and quaternion determinants. → We prove universality of spectral correlations in crossover ensembles. → We discuss applications to quantum conductance and communication theory problems. - Abstract: In a recent paper (S. Kumar, A. Pandey, Phys. Rev. E, 79, 2009, p. 026211) we considered Jacobi family (including Laguerre and Gaussian cases) of random matrix ensembles and reported exact solutions of crossover problems involving time-reversal symmetry breaking. In the present paper we give details of the work. We start with Dyson's Brownian motion description of random matrix ensembles and obtain universal hierarchic relations among the unfolded correlation functions. For arbitrary dimensions we derive the joint probability density (jpd) of eigenvalues for all transitions leading to unitary ensembles as equilibrium ensembles. We focus on the orthogonal-unitary and symplectic-unitary crossovers and give generic expressions for jpd of eigenvalues, two-point kernels and n-level correlation functions. This involves generalization of the theory of skew-orthogonal polynomials to crossover ensembles. We also consider crossovers in the circular ensembles to show the generality of our method. In the large dimensionality limit, correlations in spectra with arbitrary initial density are shown to be universal when expressed in terms of a rescaled symmetry breaking parameter. Applications of our crossover results to communication theory and quantum conductance problems are also briefly discussed.

Contrasted patterns of crossover and non-crossover at Arabidopsis thaliana meiotic recombination hotspots.

Directory of Open Access Journals (Sweden)

Jan Drouaud

2013-11-01

Full Text Available The vast majority of meiotic recombination events (crossovers (COs and non-crossovers (NCOs cluster in narrow hotspots surrounded by large regions devoid of recombinational activity. Here, using a new molecular approach in plants, called "pollen-typing", we detected and characterized hundreds of CO and NCO molecules in two different hotspot regions in Arabidopsis thaliana. This analysis revealed that COs are concentrated in regions of a few kilobases where their rates reach up to 50 times the genome average. The hotspots themselves tend to cluster in regions less than 8 kilobases in size with overlapping CO distribution. Non-crossover (NCO events also occurred in the two hotspots but at very different levels (local CO/NCO ratios of 1/1 and 30/1 and their track lengths were quite small (a few hundred base pairs. We also showed that the ZMM protein MSH4 plays a role in CO formation and somewhat unexpectedly we also found that it is involved in the generation of NCOs but with a different level of effect. Finally, factors acting in cis and in trans appear to shape the rate and distribution of COs at meiotic recombination hotspots.

Relativistic few body calculations

International Nuclear Information System (INIS)

Gross, F.

1988-01-01

A modern treatment of the nuclear few-body problem must take into account both the quark structure of baryons and mesons, which should be important at short range, and the relativistic exchange of mesons, which describes the long range, peripheral interactions. A way to model both of these aspects is described. The long range, peripheral interactions are calculated using the spectator model, a general approach in which the spectators to nucleon interactions are put on their mass-shell. Recent numerical results for a relativistic OBE model of the NN interaction, obtained by solving a relativistic equation with one-particle on mass-shell, will be presented and discussed. Two meson exchange models, one with only four mesons (π,σ,/rho/,ω) but with a 25% admixture of γ 5 coupling for the pion, and a second with six mesons (π,σ,/rho/,ω,δ,/eta/) but pure γ 5 γ/sup μ/ pion coupling, are shown to give very good quantitative fits to the NN scattering phase shifts below 400 MeV, and also a good description of the /rvec p/ 40 Ca elastic scattering observables. Applications of this model to electromagnetic interactions of the two body system, with emphasis on the determination of relativistic current operators consistent with the dynamics and the exact treatment of current conservation in the presence of phenomenological form factors, will be described. 18 refs., 8 figs

Einstein Critical-Slowing-Down is Siegel CyberWar Denial-of-Access Queuing/Pinning/ Jamming/Aikido Via Siegel DIGIT-Physics BEC ``Intersection''-BECOME-UNION Barabasi Network/GRAPH-Physics BEC: Strutt/Rayleigh-Siegel Percolation GLOBALITY-to-LOCALITY Phase-Transition Critical-Phenomenon

Science.gov (United States)

Buick, Otto; Falcon, Pat; Alexander, G.; Siegel, Edward Carl-Ludwig

2013-03-01

Einstein[Dover(03)] critical-slowing-down(CSD)[Pais, Subtle in The Lord; Life & Sci. of Albert Einstein(81)] is Siegel CyberWar denial-of-access(DOA) operations-research queuing theory/pinning/jamming/.../Read [Aikido, Aikibojitsu & Natural-Law(90)]/Aikido(!!!) phase-transition critical-phenomenon via Siegel DIGIT-Physics (Newcomb[Am.J.Math. 4,39(1881)]-{Planck[(1901)]-Einstein[(1905)])-Poincare[Calcul Probabilités(12)-p.313]-Weyl [Goett.Nachr.(14); Math.Ann.77,313 (16)]-{Bose[(24)-Einstein[(25)]-Fermi[(27)]-Dirac[(1927)]}-``Benford''[Proc.Am.Phil.Soc. 78,4,551 (38)]-Kac[Maths.Stat.-Reasoning(55)]-Raimi[Sci.Am. 221,109 (69)...]-Jech[preprint, PSU(95)]-Hill[Proc.AMS 123,3,887(95)]-Browne[NYT(8/98)]-Antonoff-Smith-Siegel[AMS Joint-Mtg.,S.-D.(02)] algebraic-inversion to yield ONLY BOSE-EINSTEIN QUANTUM-statistics (BEQS) with ZERO-digit Bose-Einstein CONDENSATION(BEC) ``INTERSECTION''-BECOME-UNION to Barabasi[PRL 876,5632(01); Rev.Mod.Phys.74,47(02)...] Network /Net/GRAPH(!!!)-physics BEC: Strutt/Rayleigh(1881)-Polya(21)-``Anderson''(58)-Siegel[J.Non-crystalline-Sol.40,453(80)

Relativistic Gas Drag on Dust Grains and Implications

Energy Technology Data Exchange (ETDEWEB)

Hoang, Thiem, E-mail: thiemhoang@kasi.re.kr [Korea Astronomy and Space Science Institute, Daejeon 34055 (Korea, Republic of); Korea University of Science and Technology, Daejeon, 34113 (Korea, Republic of)

2017-09-20

We study the drag force on grains moving at relativistic velocities through interstellar gas and explore its application. First, we derive a new analytical formula of the drag force at high energies and find that it is significantly reduced compared to the classical model. Second, we apply the obtained drag force to calculate the terminal velocities of interstellar grains by strong radiation sources such as supernovae and active galactic nuclei (AGNs). We find that grains can be accelerated to relativistic velocities by very luminous AGNs. We then quantify the deceleration of relativistic spacecraft proposed by the Breakthrough Starshot initiative due to gas drag on a relativistic lightsail. We find that the spacecraft’s decrease in speed is negligible because of the suppression of gas drag at relativistic velocities, suggesting that the lightsail may be open for communication during its journey to α Centauri without causing a considerable delay. Finally, we show that the damage to relativistic thin lightsails by interstellar dust is a minor effect.

A microscopic model of ballistic-diffusive crossover

International Nuclear Information System (INIS)

Bagchi, Debarshee; Mohanty, P K

2014-01-01

Several low-dimensional systems show a crossover from diffusive to ballistic heat transport when system size is decreased. Although there is some phenomenological understanding of this crossover phenomenon at the coarse-grained level, a microscopic picture that consistently describes both the ballistic and the diffusive transport regimes has been lacking. In this work we derive a scaling form for the thermal current in a class of one dimensional systems attached to heat baths at boundaries and rigorously show that the crossover occurs when the characteristic length scale of the system competes with the system size. (paper)

Relativistic heavy ion collisions

International Nuclear Information System (INIS)

Barz, H.W.; Kaempfer, B.; Schulz, H.

1984-12-01

An elementary introduction is given into the scenario of relativistic heavy ion collisions. It deals with relativistic kinematics and estimates of energy densities, extrapolations of the present knowledge of hadron-hadron and hadron-nuleus to nucleus-nucleus collisions, the properties of the quark-gluon plasma and the formation of the plasma and possible experimental signatures. Comments are made on a cosmic ray experiment which could be interpreted as a first indication of the quark-gluon phase of the matter. (author)

Thermodynamic laws and equipartition theorem in relativistic Brownian motion.

Science.gov (United States)

Koide, T; Kodama, T

2011-06-01

We extend the stochastic energetics to a relativistic system. The thermodynamic laws and equipartition theorem are discussed for a relativistic Brownian particle and the first and the second law of thermodynamics in this formalism are derived. The relation between the relativistic equipartition relation and the rate of heat transfer is discussed in the relativistic case together with the nature of the noise term.

Relativistic quantum similarities in atoms in position and momentum spaces

International Nuclear Information System (INIS)

Maldonado, P.; Sarsa, A.; Buendia, E.; Galvez, F.J.

2011-01-01

A study of different quantum similarity measures and their corresponding quantum similarity indices is carried out for the atoms from H to Lr (Z=1-103). Relativistic effects in both position and momentum spaces have been studied by comparing the relativistic values to the non-relativistic ones. We have used the atomic electron density in both position and momentum spaces obtained within relativistic and non-relativistic numerical-parameterized optimized effective potential approximations. -- Highlights: → Quantum similarity measures and indices in electronic structure of atoms. → Position and momentum electronic densities. → Similarity of relativistic and non-relativistic densities. → Similarity of core and valence regions of different atoms. → Dependence with Z along the Periodic Table.

Kinetic analysis of thermally relativistic flow with dissipation

International Nuclear Information System (INIS)

Yano, Ryosuke; Suzuki, Kojiro

2011-01-01

Nonequilibrium flow of thermally relativistic matter with dissipation is considered in the framework of the relativistic kinetic theory. As an object of the analysis, the supersonic rarefied flow of thermally relativistic matter around the triangle prism is analyzed using the Anderson-Witting model. Obtained numerical results indicate that the flow field changes in accordance with the flow velocity and temperature of the uniform flow owing to both effects derived from the Lorentz contraction and thermally relativistic effects, even when the Mach number of the uniform flow is fixed. The profiles of the heat flux along the stagnation streamline can be approximated on the basis of the relativistic Navier-Stokes-Fourier (NSF) law except for a strong nonequilibrium regime such as the middle of the shock wave and the vicinity of the wall, whereas the profile of the heat flux behind the triangle prism cannot be approximated on the basis of the relativistic NSF law owing to rarefied effects via the expansion behind the triangle prism. Additionally, the heat flux via the gradient of the static pressure is non-negligible owing to thermally relativistic effects. The profile of the dynamic pressure is different from that approximated on the basis of the NSF law, which is obtained by the Eckart decomposition. Finally, variations of convections of the mass and momentum owing to the effects derived from the Lorentz contraction and thermally relativistic effects are numerically confirmed.

Investigating the Discriminatory Power of BCS-Biowaiver in Vitro Methodology to Detect Bioavailability Differences between Immediate Release Products Containing a Class I Drug.

Science.gov (United States)

Colón-Useche, Sarin; González-Álvarez, Isabel; Mangas-Sanjuan, Victor; González-Álvarez, Marta; Pastoriza, Pilar; Molina-Martínez, Irene; Bermejo, Marival; García-Arieta, Alfredo

2015-09-08

The purpose of this work is to investigate the discriminatory power of the Biopharmaceutics Classification System (BCS)-biowaiver in vitro methodology, i.e., to investigate if a BCS-biowaiver approach would have detected the Cmax differences observed between two zolpidem tablets and to identify the cause of the in vivo difference. Several dissolution conditions were tested with three zolpidem formulations: the reference (Stilnox), a bioequivalent formulation (BE), and a nonbioequivalent formulation (N-BE). Zolpidem is highly soluble at pH 1.2, 4.5, and 6.8. Its permeability in Caco-2 cells is higher than that of metoprolol and its transport mechanism is passive diffusion. None of the excipients (alone or in combination) showed any effect on permeability. All formulations dissolved more than 85% in 15 min in the paddle apparatus at 50 rpm in all dissolution media. However, at 30 rpm the nonbioequivalent formulation exhibited a slower dissolution rate. A slower gastric emptying rate was also observed in rats for the nonbioequivalent formulation. A slower disintegration and dissolution or a delay in gastric emptying might explain the Cmax infra-bioavailability for a highly permeable drug with short half-life. The BCS-biowaiver approach would have declared bioequivalence, although the in vivo study was not conclusive but detected a 14% mean difference in Cmax that precluded the bioequivalence demonstration. Nonetheless, these findings suggest that a slower dissolution rate is more discriminatory and that rotation speeds higher than 50 rpm should not be used in BCS-biowaivers, even if a coning effect occurs.

Theoretical study of the relativistic molecular rotational g-tensor

International Nuclear Information System (INIS)

Aucar, I. Agustín; Gomez, Sergio S.; Giribet, Claudia G.; Ruiz de Azúa, Martín C.

2014-01-01

An original formulation of the relativistic molecular rotational g-tensor valid for heavy atom containing compounds is presented. In such formulation, the relevant terms of a molecular Hamiltonian for non-relativistic nuclei and relativistic electrons in the laboratory system are considered. Terms linear and bilinear in the nuclear rotation angular momentum and an external uniform magnetic field are considered within first and second order (relativistic) perturbation theory to obtain the rotational g-tensor. Relativistic effects are further analyzed by carrying out the linear response within the elimination of the small component expansion. Quantitative results for model systems HX (X=F, Cl, Br, I), XF (X=Cl, Br, I), and YH + (Y=Ne, Ar, Kr, Xe, Rn) are obtained both at the RPA and density functional theory levels of approximation. Relativistic effects are shown to be small for this molecular property. The relation between the rotational g-tensor and susceptibility tensor which is valid in the non-relativistic theory does not hold within the relativistic framework, and differences between both molecular parameters are analyzed for the model systems under study. It is found that the non-relativistic relation remains valid within 2% even for the heavy HI, IF, and XeH + systems. Only for the sixth-row Rn atom a significant deviation of this relation is found

Theoretical study of the relativistic molecular rotational g-tensor

Energy Technology Data Exchange (ETDEWEB)

Aucar, I. Agustín, E-mail: agustin.aucar@conicet.gov.ar; Gomez, Sergio S., E-mail: ssgomez@exa.unne.edu.ar [Institute for Modeling and Technological Innovation, IMIT (CONICET-UNNE) and Faculty of Exact and Natural Sciences, Northeastern University of Argentina, Avenida Libertad 5400, W3404AAS Corrientes (Argentina); Giribet, Claudia G.; Ruiz de Azúa, Martín C. [Physics Department, Faculty of Exact and Natural Sciences, University of Buenos Aires and IFIBA CONICET, Ciudad Universitaria, Pab. I, 1428 Buenos Aires (Argentina)

2014-11-21

An original formulation of the relativistic molecular rotational g-tensor valid for heavy atom containing compounds is presented. In such formulation, the relevant terms of a molecular Hamiltonian for non-relativistic nuclei and relativistic electrons in the laboratory system are considered. Terms linear and bilinear in the nuclear rotation angular momentum and an external uniform magnetic field are considered within first and second order (relativistic) perturbation theory to obtain the rotational g-tensor. Relativistic effects are further analyzed by carrying out the linear response within the elimination of the small component expansion. Quantitative results for model systems HX (X=F, Cl, Br, I), XF (X=Cl, Br, I), and YH{sup +} (Y=Ne, Ar, Kr, Xe, Rn) are obtained both at the RPA and density functional theory levels of approximation. Relativistic effects are shown to be small for this molecular property. The relation between the rotational g-tensor and susceptibility tensor which is valid in the non-relativistic theory does not hold within the relativistic framework, and differences between both molecular parameters are analyzed for the model systems under study. It is found that the non-relativistic relation remains valid within 2% even for the heavy HI, IF, and XeH{sup +} systems. Only for the sixth-row Rn atom a significant deviation of this relation is found.

Loading relativistic Maxwell distributions in particle simulations

Energy Technology Data Exchange (ETDEWEB)

Zenitani, Seiji, E-mail: seiji.zenitani@nao.ac.jp [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

2015-04-15

Numerical algorithms to load relativistic Maxwell distributions in particle-in-cell (PIC) and Monte-Carlo simulations are presented. For stationary relativistic Maxwellian, the inverse transform method and the Sobol algorithm are reviewed. To boost particles to obtain relativistic shifted-Maxwellian, two rejection methods are proposed in a physically transparent manner. Their acceptance efficiencies are ≈50% for generic cases and 100% for symmetric distributions. They can be combined with arbitrary base algorithms.

Loading relativistic Maxwell distributions in particle simulations

International Nuclear Information System (INIS)

Zenitani, Seiji

2015-01-01

Numerical algorithms to load relativistic Maxwell distributions in particle-in-cell (PIC) and Monte-Carlo simulations are presented. For stationary relativistic Maxwellian, the inverse transform method and the Sobol algorithm are reviewed. To boost particles to obtain relativistic shifted-Maxwellian, two rejection methods are proposed in a physically transparent manner. Their acceptance efficiencies are ≈50% for generic cases and 100% for symmetric distributions. They can be combined with arbitrary base algorithms

The de Sitter relativistic top theory

International Nuclear Information System (INIS)

Armenta, J.; Nieto, J.A.

2005-01-01

We discuss the relativistic top theory from the point of view of the de Sitter (or anti-de Sitter) group. Our treatment rests on the Hanson-Regge spherical relativistic top Lagrangian formulation. We propose an alternative method for studying spinning objects via Kaluza-Klein theory. In particular, we derive the relativistic top equations of motion starting with the geodesic equation for a point particle in 4+N dimensions. We compare our approach with Fukuyama's formulation of spinning objects, which is also based on Kaluza-Klein theory. We also report a generalization of our approach to a 4+N+D dimensional theory

Biquaternions and relativistic kinematics

International Nuclear Information System (INIS)

Bogush, A.A.; Kurochkin, Yu.A.; Fedorov, F.I.

1979-01-01

The problems concerning the use of quaternion interpretation of the Lorentz group vector parametrization are considered for solving relativistic kinematics problems. A vector theory convenient for describing the characteristic features of the Lobachevsky space is suggested. The kinematics of elementary particle scattering is investigated on the basis of this theory. A synthesis of vector parametrization and of quaternion calculation has been shown to lead to natural formulation of the theory of vectors in the three-dimensional Lobachevsky space, realized on mass hyperboloids of relativistic particles

Hartree-Fock+BCS approach to unstable nuclei with the Skyrme force

International Nuclear Information System (INIS)

Tajima, Naoki

2001-01-01

We reanalyze the results of our extensive Hartree-Fock+BCS calculation from new points of view paying attention to the properties of unstable nuclei. The calculation has been done with the Skyrme SIII force for the ground and shape isomeric states of 1029 even-even nuclei ranging 2≤Z≤114. We also discuss the advantages of the employed three-dimensional Cartesian-mesh representation, especially on its remarkably high precision with apparently coarse meshes when applied to atomic nuclei. In Appendices we give the coefficients of finite-point numerical differentiation and integration formulae suitable for Cartesian mesh representation and elucidate the features of each formula and the differences from a method based on the Fourier transformation. (author)

Liouville equation of relativistic charged fermion

International Nuclear Information System (INIS)

Wang Renchuan; Zhu Dongpei; Huang Zhuoran; Ko Che-ming

1991-01-01

As a form of density martrix, the Wigner function is the distribution in quantum phase space. It is a 2 X 2 matrix function when one uses it to describe the non-relativistic fermion. While describing the relativistic fermion, it is usually represented by 4 x 4 matrix function. In this paper authors obtain a Wigner function for the relativistic fermion in the form of 2 x 2 matrix, and the Liouville equation satisfied by the Wigner function. this equivalent to the Dirac equation of changed fermion in QED. The equation is also equivalent to the Dirac equation in the Walecka model applied to the intermediate energy nuclear collision while the nucleon is coupled to the vector meson only (or taking mean field approximation for the scalar meson). Authors prove that the 2 x 2 Wigner function completely describes the quantum system just the same as the relativistic fermion wave function. All the information about the observables can be obtained with above Wigner function

An energy principle for two-dimensional collisionless relativistic plasmas

International Nuclear Information System (INIS)

Otto, A.; Schindler, K.

1984-01-01

Using relativistic Vlasov theory an energy principle for two-dimensional plasmas is derived, which provides a sufficient and necessary criterion for the stability of relativistic plasma equilibria. This energy principle includes charge separating effects since the exact Poisson equation was taken into consideration. Applying the variational principle to the case of the relativistic plane plasma sheet, the same marginal wave length is found as in the non-relativistic case. (author)

Importance of the single-particle continuum in BCS pairing with a pseudostate basis

Directory of Open Access Journals (Sweden)

Lay J. A.

2016-01-01

Full Text Available In a recent work [arXiv:1510.03185] the use of the Transformed Harmonic Oscillator (THO basis for the discretization of the singleparticle continuum into a Generalized Bardeen-Cooper-Schrieffer (BCS formalism was proposed for the description of weakly bound nuclei. We make use of the flexibility of this formalism to study the evolution of the pairing when the nucleus becomes more and more weakly bound. Specifically we focus on the evolution of the occupation of the different partial waves in 22O when the Fermi level approaches zero.

Relativistic neoclassical transport coefficients with momentum correction

International Nuclear Information System (INIS)

Marushchenko, I.; Azarenkov, N.A.

2016-01-01

The parallel momentum correction technique is generalized for relativistic approach. It is required for proper calculation of the parallel neoclassical flows and, in particular, for the bootstrap current at fusion temperatures. It is shown that the obtained system of linear algebraic equations for parallel fluxes can be solved directly without calculation of the distribution function if the relativistic mono-energetic transport coefficients are already known. The first relativistic correction terms for Braginskii matrix coefficients are calculated.

Penetration of relativistic heavy ions through matter

International Nuclear Information System (INIS)

Scheidenberger, C.; Geissel, H.

1997-07-01

New heavy-ion accelerators covering the relativistic and ultra-relativistic energy regime allow to study atomic collisions with bare and few-electron projectiles. High-resolution magnetic spectrometers are used for precise stopping-power and energy-loss straggling measurements. Refined theories beyond the Born approximation have been developed and are confirmed by experiments. This paper summarizes the large progress in the understanding of relativistic heavy-ion penetration through matter, which has been achieved in the last few years. (orig.)

Light Pollution in Québec: Progress Report

Science.gov (United States)

Dutil, Yvan

2005-08-01

Quebecers are among the worst light polluters in the world, producing 2 to 3 times more light than Americans or Europeans. Nevertheless, there is hope of losing this infamous title in the near future. Recently, there was a large increase in awareness both from the public and policy makers and action is now taken to preserve the dark sky elsewhere in Quebec. A Dark-Sky Preserve is now being put in place around Mont Mégantic Observatory. With a radius of 50 km, it will be will be, once completed, one of the largest in North America. In addition, the city of Sherbrooke is putting in place its own dark-sky policy to complement the protection provide by the preserve. These efforts are expected to stop the growth of light pollution at Mont Mégantic, which has doubled in the last 25 years. Even the cities of Montréal and Québec are taking action against the light pollution. This is a good example of how a few dedicated persons can change perceptions and fight efficiently against light pollution.

Relativistic Kinematics

OpenAIRE

Sahoo, Raghunath

2016-01-01

This lecture note covers Relativistic Kinematics, which is very useful for the beginners in the field of high-energy physics. A very practical approach has been taken, which answers "why and how" of the kinematics useful for students working in the related areas.

Relativistic klystrons

International Nuclear Information System (INIS)

Allen, M.A.; Azuma, O.; Callin, R.S.

1989-03-01

Experimental work is underway by a SLAC-LLNL-LBL collaboration to investigate the feasibility of using relativistic klystrons as a power source for future high gradient accelerators. Two different relativistic klystron configurations have been built and tested to date: a high grain multicavity klystron at 11.4 GHz and a low gain two cavity subharmonic buncher driven at 5.7 GHz. In both configurations power is extracted at 11.4 GHz. In order to understand the basic physics issues involved in extracting RF from a high power beam, we have used both a single resonant cavity and a multi-cell traveling wave structure for energy extraction. We have learned how to overcome our previously reported problem of high power RF pulse shortening, and have achieved peak RF power levels of 170 MW with the RF pulse of the same duration as the beam current pulse. 6 refs., 3 figs., 3 tabs

Chaos and maps in relativistic rynamical systems

Directory of Open Access Journals (Sweden)

L. P. Horwitz

2000-01-01

Full Text Available The basic work of Zaslavskii et al showed that the classical non-relativistic electromagnetically kicked oscillator can be cast into the form of an iterative map on the phase space; the resulting evolution contains a stochastic flow to unbounded energy. Subsequent studies have formulated the problem in terms of a relativistic charged particle in interaction with the electromagnetic field. We review the structure of the covariant Lorentz force used to study this problem. We show that the Lorentz force equation can be derived as well from the manifestly covariant mechanics of Stueckelberg in the presence of a standard Maxwell field, establishing a connection between these equations and mass shell constraints. We argue that these relativistic generalizations of the problem are intrinsically inaccurate due to an inconsistency in the structure of the relativistic Lorentz force, and show that a reformulation of the relativistic problem, permitting variations (classically in both the particle mass and the effective “mass” of the interacting electromagnetic field, provides a consistent system of classical equations for describing such processes.

A Primer to Relativistic MOND Theory

NARCIS (Netherlands)

Bekenstein, J.D..; Sanders, R.H.

2005-01-01

Abstract: We first review the nonrelativistic lagrangian theory as a framework for the MOND equation. Obstructions to a relativistic version of it are discussed leading up to TeVeS, a relativistic tensor-vector-scalar field theory which displays both MOND and Newtonian limits. The whys for its

Relativistic Quantum Transport in Graphene Systems

Science.gov (United States)

2015-07-09

dimensional Dirac material systems. 2 List of Publications 1. X. Ni, L. Huang, Y.-C. Lai, and L. M. Pecora, “Effect of chaos on relativistic quantum...development of relativistic quantum devices based on graphene or alternative two-dimensional Dirac material systems. In the project period, we studied

Relativistic astrophysics and theory of gravity

International Nuclear Information System (INIS)

Zel'dovich, Ya.B.

1982-01-01

A brief historical review of the development of astrophysical science in the State Astrophysical Institute named after Shternberg (SAISh) has been given in a popular form. The main directions of the SAISh astrophysical investigations have been presented: relativistic theory of gravity, relativistic astrophysics of interplanetary medium and cosmology

Purely in silico BCS classification: science based quality standards for the world's drugs.

Science.gov (United States)

Dahan, Arik; Wolk, Omri; Kim, Young Hoon; Ramachandran, Chandrasekharan; Crippen, Gordon M; Takagi, Toshihide; Bermejo, Marival; Amidon, Gordon L

2013-11-04

BCS classification is a vital tool in the development of both generic and innovative drug products. The purpose of this work was to provisionally classify the world's top selling oral drugs according to the BCS, using in silico methods. Three different in silico methods were examined: the well-established group contribution (CLogP) and atom contribution (ALogP) methods, and a new method based solely on the molecular formula and element contribution (KLogP). Metoprolol was used as the benchmark for the low/high permeability class boundary. Solubility was estimated in silico using a thermodynamic equation that relies on the partition coefficient and melting point. The validity of each method was affirmed by comparison to reference data and literature. We then used each method to provisionally classify the orally administered, IR drug products found in the WHO Model list of Essential Medicines, and the top-selling oral drug products in the United States (US), Great Britain (GB), Spain (ES), Israel (IL), Japan (JP), and South Korea (KR). A combined list of 363 drugs was compiled from the various lists, and 257 drugs were classified using the different in silico permeability methods and literature solubility data, as well as BDDCS classification. Lastly, we calculated the solubility values for 185 drugs from the combined set using in silico approach. Permeability classification with the different in silico methods was correct for 69-72.4% of the 29 reference drugs with known human jejunal permeability, and for 84.6-92.9% of the 14 FDA reference drugs in the set. The correlations (r(2)) between experimental log P values of 154 drugs and their CLogP, ALogP and KLogP were 0.97, 0.82 and 0.71, respectively. The different in silico permeability methods produced comparable results: 30-34% of the US, GB, ES and IL top selling drugs were class 1, 27-36.4% were class 2, 22-25.5% were class 3, and 5.46-14% were class 4 drugs, while ∼8% could not be classified. The WHO list

Making "Good" or "Critical" Citizens: From Social Justice to Financial Literacy in the Québec Education Program

Science.gov (United States)

Lefrançois, David; Ethier, Marc-André; Cambron-Prémont, Amélie

2017-01-01

Purpose: The Québec Ministry of Education has introduced--as of September 2017--a new mandatory course focusing on financial literacy and addressing such issues as credit scores, loans, taxes and budgets. This announcement has created intense educational debate on the "raison d'être" and content of the course. This article will summarise…

Québec's Childcare Universal Low Fees Policy 10 Years After: Effects, Costs and Benefits

OpenAIRE

Pierre Lefebvre; Philip Merrigan; Francis Roy-Desrosiers

2011-01-01

More than ten years ago the province of Québec implemented a universal early childhood education and care policy. This paper examines if the two objectives pursued, to increase mothers’ participation in the labour market (balance the needs of workplace and home) and to enhance child development and equality of opportunity for children, were reasonable meet. A non-experimental evaluation framework based on multiple pre- and post-treatment periods is used to estimate the policy effects. First, ...

Non-relativistic Bondi-Metzner-Sachs algebra

Science.gov (United States)

Batlle, Carles; Delmastro, Diego; Gomis, Joaquim

2017-09-01

We construct two possible candidates for non-relativistic bms4 algebra in four space-time dimensions by contracting the original relativistic bms4 algebra. bms4 algebra is infinite-dimensional and it contains the generators of the Poincaré algebra, together with the so-called super-translations. Similarly, the proposed nrbms4 algebras can be regarded as two infinite-dimensional extensions of the Bargmann algebra. We also study a canonical realization of one of these algebras in terms of the Fourier modes of a free Schrödinger field, mimicking the canonical realization of relativistic bms4 algebra using a free Klein-Gordon field.

Whispering gallery effect in relativistic optics

Science.gov (United States)

Abe, Y.; Law, K. F. F.; Korneev, Ph.; Fujioka, S.; Kojima, S.; Lee, S.-H.; Sakata, S.; Matsuo, K.; Oshima, A.; Morace, A.; Arikawa, Y.; Yogo, A.; Nakai, M.; Norimatsu, T.; d'Humières, E.; Santos, J. J.; Kondo, K.; Sunahara, A.; Gus'kov, S.; Tikhonchuk, V.

2018-03-01

relativistic laser pulse, confined in a cylindrical-like target, under specific conditions may perform multiple scattering along the internal target surface. This results in the confinement of the laser light, leading to a very efficient interaction. The demonstrated propagation of the laser pulse along the curved surface is just yet another example of the "whispering gallery" effect, although nonideal due to laser-plasma coupling. In the relativistic domain its important feature is a gradual intensity decrease, leading to changes in the interaction conditions. The proccess may pronounce itself in plenty of physical phenomena, including very efficient electron acceleration and generation of relativistic magnetized plasma structures.

Relativistic quantum mechanics and introduction to field theory

Energy Technology Data Exchange (ETDEWEB)

Yndurain, F.J. [Universidad Autonoma de Madrid (Spain). Dept. de Fisica Teorica

1996-12-01

The following topics were dealt with: relativistic transformations, the Lorentz group, Klein-Gordon equation, spinless particles, spin 1/2 particles, Dirac particle in a potential, massive spin 1 particles, massless spin 1 particles, relativistic collisions, S matrix, cross sections, decay rates, partial wave analysis, electromagnetic field quantization, interaction of radiation with matter, interactions in quantum field theory and relativistic interactions with classical sources.

Relativistic quantum mechanics and introduction to field theory

International Nuclear Information System (INIS)

Yndurain, F.J.

1996-01-01

The following topics were dealt with: relativistic transformations, the Lorentz group, Klein-Gordon equation, spinless particles, spin 1/2 particles, Dirac particle in a potential, massive spin 1 particles, massless spin 1 particles, relativistic collisions, S matrix, cross sections, decay rates, partial wave analysis, electromagnetic field quantization, interaction of radiation with matter, interactions in quantum field theory and relativistic interactions with classical sources

DMFC performance and methanol cross-over: Experimental analysis and model validation

Energy Technology Data Exchange (ETDEWEB)

Casalegno, A.; Marchesi, R. [Dipartimento di Energia, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

2008-10-15

A combined experimental and modelling approach is proposed to analyze methanol cross-over and its effect on DMFC performance. The experimental analysis is performed in order to allow an accurate investigation of methanol cross-over influence on DMFC performance, hence measurements were characterized in terms of uncertainty and reproducibility. The findings suggest that methanol cross-over is mainly determined by diffusion transport and affects cell performance partly via methanol electro-oxidation at the cathode. The modelling analysis is carried out to further investigate methanol cross-over phenomenon. A simple model evaluates the effectiveness of two proposed interpretations regarding methanol cross-over and its effects. The model is validated using the experimental data gathered. Both the experimental analysis and the proposed and validated model allow a substantial step forward in the understanding of the main phenomena associated with methanol cross-over. The findings confirm the possibility to reduce methanol cross-over by optimizing anode feeding. (author)

Effects of relativistic small radial component on atomic photoionization cross sections

International Nuclear Information System (INIS)

Liu Xiaobin; Xing Yongzhong; Sun Xiaowei

2008-01-01

The effects of relativistic small radial component on atomic photoionization cross sections have been studied within relativistic average self-consistent field theory. Relativistic effects are relatively unimportant for low photon energy, along with a review of high-energy photoionization the relativistic effects are quite important. The effects of relativistic small radial component on photoionization process should show breakdown when the nuclear finite-size effects is taken into account. The compression of wavefunction into the space near nucleus is so strong in highly charged ions that the electronic radius greatly decreases, and the effects of relativistic small radial component on photoionization cross sections turn to stronger than ordinary atoms. Since relativistic effects are extremely sensitive to the behavior of small radial component, the results are in good agreement with relativistic effects on photoionization cross section. (authors)

Extended precedence preservative crossover for job shop scheduling problems

Science.gov (United States)

Ong, Chung Sin; Moin, Noor Hasnah; Omar, Mohd

2013-04-01

Job shop scheduling problems (JSSP) is one of difficult combinatorial scheduling problems. A wide range of genetic algorithms based on the two parents crossover have been applied to solve the problem but multi parents (more than two parents) crossover in solving the JSSP is still lacking. This paper proposes the extended precedence preservative crossover (EPPX) which uses multi parents for recombination in the genetic algorithms. EPPX is a variation of the precedence preservative crossover (PPX) which is one of the crossovers that perform well to find the solutions for the JSSP. EPPX is based on a vector to determine the gene selected in recombination for the next generation. Legalization of children (offspring) can be eliminated due to the JSSP representation encoded by using permutation with repetition that guarantees the feasibility of chromosomes. The simulations are performed on a set of benchmarks from the literatures and the results are compared to ensure the sustainability of multi parents recombination in solving the JSSP.

Kohn's theorem in a superfluid Fermi gas with a Feshbach resonance

International Nuclear Information System (INIS)

Ohashi, Y.

2004-01-01

We investigate the dipole mode in a superfluid gas of Fermi atoms trapped in a harmonic potential. According to Kohn's theorem, the frequency of this collective mode is not affected by an interaction between the atoms and is always equal to the trap frequency. This remarkable property, however, does not necessarily hold in an approximate theory. We explicitly prove that the Hartree-Fock-Bogoliubov generalized random phase approximation (HFB-GRPA), including a coupling between fluctuations in the density and Cooper channels, is consistent with both Kohn's theorem as well as Goldstone's theorem. This proof can be immediately extended to the strong-coupling superfluid theory developed by Nozieres and Schmitt-Rink (NSR), where the effect of superfluid fluctuations is included within the Gaussian level. As a result, the NSR-GRPA formalism can be used to study collective modes in the BCS-BEC crossover region in a manner which is consistent with Kohn's theorem. We also include the effect of a Feshbach resonance and a condensate of the associated molecular bound states. A detailed discussion is given of the unusual nature of the Kohn mode eigenfunctions in a Fermi superfluid, in the presence and absence of a Feshbach resonance. When the molecular bosons feel a different trap frequency from the Fermi atoms, the dipole frequency is shown to depend on the strength of effective interaction associated with the Feshbach resonance

Systematic study of even-even nuclei with Hartree-Fock+BCS method using Skyrme SIII force

Energy Technology Data Exchange (ETDEWEB)

Tajima, Naoki; Takahara, Satoshi; Onishi, Naoki [Tokyo Univ. (Japan). Coll. of Arts and Sciences

1997-03-01

We have applied the Hartree-Fock+BCS method with Skyrme SIII force formulated in a three-dimensional Cartesian-mesh representation to even-even nuclei with 2 {<=} Z {<=} 114. We discuss the results concerning the atomic masses, the quadrupole (m=0, 2) and hexadecapole (m=0, 2, 4) deformations, the skin thicknesses, and the halo radii. We also discuss the energy difference between oblate and prolate solutions and the shape difference between protons and neutrons. (author)

The ionisation equation in a relativistic gas

International Nuclear Information System (INIS)

Kichenassamy, S.; Krikorian, R.A.

1983-01-01

By deriving the relativistic form of the ionisation equation for a perfect gas it is shown that the usual Saha equation is valid to 3% for temperatures below one hundred million Kelvin. Beyond 10 9 K, the regular Saha equation is seriously incorrect and a relativistic distribution function for electrons must be taken into account. Approximate forms are derived when only the electrons are relativistic (appropriate up to 10 12 K) and also for the ultrarelativistic case (temperatures greater than 10 15 K). (author)

Effectively semi-relativistic Hamiltonians of nonrelativistic form

International Nuclear Information System (INIS)

Lucha, W.; Schoeberl, F.F.; Moser, M.

1993-12-01

We construct effective Hamiltonians which despite their apparently nonrelativistic form incorporate relativistic effects by involving parameters which depend on the relevant momentum. For some potentials the corresponding energy eigenvalues may be determined analytically. Applied to two-particle bound states, it turns out that in this way a nonrelativistic treatment may indeed be able to simulate relativistic effects. Within the framework of hadron spectroscopy, this lucky circumstance may be an explanation for the sometimes extremely good predictions of nonrelativistic potential models even in relativistic regions. (authors)

Relativistic Astrophysics

International Nuclear Information System (INIS)

Font, J. A.

2015-01-01

The relativistic astrophysics is the field of astrophysics employing the theory of relativity Einstein as physical-mathematical model is to study the universe. This discipline analyzes astronomical contexts in which the laws of classical mechanics of Newton's law of gravitation are not valid. (Author)

Opioid Prescribing Practices and Training Needs of Québec Family Physicians for Chronic Noncancer Pain

Directory of Open Access Journals (Sweden)

Élise Roy

2017-01-01

Full Text Available Aim. To examine medical practices and training needs of Québec family physicians with respect to pain management and opioid prescription for chronic noncancer pain (CNCP. Methodology. An online survey was carried out in 2016. Results. Of 636 respondents (43.0% men; 54.3% ≥ 50 years old, 15.2% and 70.9% felt very or somewhat confident that they could properly prescribe opioids for CNCP. Concerns related to abuse (72.5% strongly/somewhat agree, dependence (73.2%, and lack of support (75.4% were the main barriers reported. Only 19.7% always/often screened their patients for risks of abuse and dependence using a screening tool. About two-thirds of participants (65.7% had recently (last five years taken part in continuing education programs on opioid use for CNCP and 73.4% on CNCP management. Patient evaluation and differential diagnoses of chronic pain syndromes were rated as a top priority for further training. Conclusions. This study provides insights into Québec family physicians’ concerns, practices, and needs with respect to the management of CNCP. Physicians’ difficulties around the application of strategies to mitigate the problem of opioid abuse and addiction are worrying. The need to better train physicians in the field of pain and addiction cannot be emphasized enough.

Relativistic description of directly interacting pions and nucleons

International Nuclear Information System (INIS)

Heller, L.

1976-01-01

The expected magnitudes of the leading relativistic effects on an off-energy-shell T matrix element are estimated using the Bakamjian--Thomas formulation of relativistic potential theory. For pion-nucleon scattering at medium energy, the two largest corrections are expected to result from the use of relativistic relative momenta rather than nonrelativistic values. The importance of additional terms depends upon the detailed behavior of the T matrix

Exotic open-flavor bcq¯q¯, bcs¯s¯ and qcq¯b¯, scs¯b¯ tetraquark states

Science.gov (United States)

Chen, Wei; Steele, T. G.; Zhu, Shi-Lin

2014-03-01

We study the exotic bcq¯q¯, bcs¯s¯ and qcq¯b¯, scs¯b¯ systems by constructing the corresponding tetraquark currents with JP=0+ and 1+. After investigating the two-point correlation functions and the spectral densities, we perform QCD sum rule analysis and extract the masses of these open-flavor tetraquark states. Our results indicate that the masses of both the scalar and axial vector tetraquark states are about 7.1-7.2 GeV for the bcq¯q¯ system and 7.2-7.3 GeV for the bcs¯s¯ system. For the qcq¯b¯ tetraquark states with JP=0+ and 1+, their masses are extracted to be around 7.1 GeV. The masses for the scalar and axial vector scs¯b¯ states are 7.1 and 6.9-7.1 GeV, respectively. The tetraquark states qcq¯b¯ and scs¯b¯ lie below the thresholds of D(*)B(*) and Ds(*)Bs(*) respectively, but they can decay into Bc plus a light meson. However, the tetraquark states bcq¯q¯ and bcs¯s¯ lie below the D(*)B¯(*) and Ds(*)B¯s(*) thresholds, suggesting dominantly weak decay mechanisms.

BCS superconductors: The out-of-equilibrium response to a laser pulse

Science.gov (United States)

Avella, Adolfo

2018-05-01

The dynamics of a 2D d-wave BCS superconductor driven out-of-equilibrium by a perpendicularly-impinging polarized laser pulse is analyzed on varying the laser pulse characteristics. The observed effects include: oscillations both in the amplitude and in the phase of the superconducting order parameter, suppression of the superconductivity, but also its enhancement with a strong dependence on all varying parameters and, in particular, on the polarization in plane of the applied vector potential and on the value of its frequency. This study opens up the possibility to distinguish very clearly the behavior of the nodal and anti-nodal non-thermal excitations and to tackle some of the puzzling results of the current experimental scenario in the field.

Relativistic and non-relativistic electronic molecular-structure calculations for dimers of 4p-, 5p-, and 6p-block elements.

Science.gov (United States)

Höfener, Sebastian; Ahlrichs, Reinhart; Knecht, Stefan; Visscher, Lucas

2012-12-07

We report results of non-relativistic and two-component relativistic single-reference coupled-cluster with single and double and perturbative triple excitations [CCSD(T)] treatments for the 4p-block dimers Ga(2) to Br(2) , the 5p-block dimers In(2) to I(2) , and their atoms. Extended basis sets up to pentuple zeta are employed and energies extrapolated to the complete basis-set limit. Relativistic and non-relativistic results for the dissociation energy D(e) are in close agreement with each other and previously published data, provided non-relativistic or scalar-relativistic results are corrected for spin-orbit contributions taken from the literature. An exception is Te(2) where theoretical results scatter by 0.085 eV. By virtue of this agreement it is unexpected that comparison with the experimental D(0) or D(e) dissociation energies (zero-point vibrational effects are negligible in this context) reveal errors larger than 0.1 eV for Ga(2), Ge(2), and Sb(2). Only relativistic treatments are presented for the 6p-block cases Tl(2) to At(2). Sufficient agreement with experimental data is found only for Pb(2) and Bi(2), the deviation of the computed and experimental D(0) values for Po(2) is again larger than 0.1 eV. Deviations of 0.1 eV between the computed and experimental D(0) values are a major reason for concern and call for additional investigations in both fields to clarify the situation. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lieu-de-mémoiriser hydro-québec comme symbole des représentations de la nature et de la technologie : esquisses de réponse et pistes de réflexion

Directory of Open Access Journals (Sweden)

Stéphane Savard

2007-09-01

Full Text Available Ce texte met en lumière l’importance des représentations symboliques de la nature et de la technologie –véhiculées par Hydro-Québec ou par le biais de cette société d’état – au sein de la mémoire collective québécoise ou, plus précisément, des usages du passé. Utilisant le concept de lieu de mémoire et débutant l’analyse à l’aide de quatre photographies significatives de l’histoire d’Hydro-Québec et du Québec des années 1960 et 1990, l’auteur montre que les représentations mémorielles, qui font d’Hydro-Québec un lieu de mémoire en ce qui concerne les rapports à la nature et à la technologie, ont changé entre ces deux périodes. Ainsi, Hydro-Québec et ses grandes réalisations représentent au crépuscule des années 1960 la conquête du Canadien français – qui deviendra le Québécois francophone – sur la nature et l’eau enfin domestiquées. Toutefois, vers le milieu des années 1990 et à la suite des catastrophes naturelles du déluge du Saguenay et de la Crise du verglas, l’entreprise publique devient l’instrument pour promouvoir des représentations centrées sur le respect de l’environnement et du développement durable. Quant au rapport à la technologie, la société d’État symbolise lors de la Révolution tranquille le fleuron d’un Québec francophone tourné vers la technologie, émancipé de son statut de porteur d’eau et entrant manifestement dans la « modernité »; image qui semble s’essouffler dans les années 1990 alors qu’Hydro-Québec et ses ouvrages ne sont plus perçus comme étant à la fine pointe de la technologie.

Relativistic ''potential model'' for N-particle systems

International Nuclear Information System (INIS)

Noyes, H.P.

1986-08-01

Neither quantum field theory nor S-Matrix theory have a well defined procedure for going over to an approximation that can be reliably used in non-relativistic models for nuclear physics. We meet the problem here by constructing a finite particle number relativistic scattering theory for (scalar) particles and mesons using integral equations of the Faddeev-Yakubovsky type. Restricted to N particles and one meson, we can go from the relativistic theory to a ''potential theory'' in the integral equation formulation by using boundary states which do not contain the meson asymptotically. The meson-particle input amplitudes contain a pole at the particle mass, and the particle-particle input amplitudes are null. This gives unique definition (numerically calculable) to the particle-particle off-shell amplitude, and hence to the covariant ''scattering potential'' (but not to the noninvariant concept of ''potential energy''). As we have commented before, if we take these scattering amplitudes as iput for relativistic Faddeev equations, the results are identical to those obtained from the same model starting from three particles and one meson. In this paper we explore how far we can extend this relativistic ''potential model'' to higher numbers of particles and mesons. 10 refs

Relativistic quantum chaos-An emergent interdisciplinary field.

Science.gov (United States)

Lai, Ying-Cheng; Xu, Hong-Ya; Huang, Liang; Grebogi, Celso

2018-05-01

Quantum chaos is referred to as the study of quantum manifestations or fingerprints of classical chaos. A vast majority of the studies were for nonrelativistic quantum systems described by the Schrödinger equation. Recent years have witnessed a rapid development of Dirac materials such as graphene and topological insulators, which are described by the Dirac equation in relativistic quantum mechanics. A new field has thus emerged: relativistic quantum chaos. This Tutorial aims to introduce this field to the scientific community. Topics covered include scarring, chaotic scattering and transport, chaos regularized resonant tunneling, superpersistent currents, and energy level statistics-all in the relativistic quantum regime. As Dirac materials have the potential to revolutionize solid-state electronic and spintronic devices, a good understanding of the interplay between chaos and relativistic quantum mechanics may lead to novel design principles and methodologies to enhance device performance.

Relativistic quantum chaos—An emergent interdisciplinary field

Science.gov (United States)

Lai, Ying-Cheng; Xu, Hong-Ya; Huang, Liang; Grebogi, Celso

2018-05-01

Quantum chaos is referred to as the study of quantum manifestations or fingerprints of classical chaos. A vast majority of the studies were for nonrelativistic quantum systems described by the Schrödinger equation. Recent years have witnessed a rapid development of Dirac materials such as graphene and topological insulators, which are described by the Dirac equation in relativistic quantum mechanics. A new field has thus emerged: relativistic quantum chaos. This Tutorial aims to introduce this field to the scientific community. Topics covered include scarring, chaotic scattering and transport, chaos regularized resonant tunneling, superpersistent currents, and energy level statistics—all in the relativistic quantum regime. As Dirac materials have the potential to revolutionize solid-state electronic and spintronic devices, a good understanding of the interplay between chaos and relativistic quantum mechanics may lead to novel design principles and methodologies to enhance device performance.

Relativistic Spacecraft Propelled by Directed Energy

Science.gov (United States)

Kulkarni, Neeraj; Lubin, Philip; Zhang, Qicheng

2018-04-01

Achieving relativistic flight to enable extrasolar exploration is one of the dreams of humanity and the long-term goal of our NASA Starlight program. We derive a relativistic solution for the motion of a spacecraft propelled by radiation pressure from a directed energy (DE) system. Depending on the system parameters, low-mass spacecraft can achieve relativistic speeds, thus enabling interstellar exploration. The diffraction of the DE system plays an important role and limits the maximum speed of the spacecraft. We consider “photon recycling” as a possible method to achieving higher speeds. We also discuss recent claims that our previous work on this topic is incorrect and show that these claims arise from an improper treatment of causality.

Spinning relativistic particles in external fields

International Nuclear Information System (INIS)

Pomeranskii, Andrei A; Sen'kov, Roman A; Khriplovich, Iosif B

2000-01-01

The motion of spinning relativistic particles in external electromagnetic and gravitational fields is considered. The self-consistent equations of motion are built with the noncovariant description of spin and with the usual, 'naive' definition of the coordinate of a relativistic particle. A simple derivation of the gravitational interaction of first order in spin is presented for a relativistic particle. The approach developed allows one to consider effects of higher order in spin. Concrete calculations are performed for the second order. The gravimagnetic moment is discussed, a special spin effect in general relativity. We also consider the contributions of the spin interactions of first and second order to the gravitational radiation of compact binary stars. (from the current literature)

The joy of six: how to control your crossovers.

Science.gov (United States)

Globus, Samuel T; Keeney, Scott

2012-03-30

Meiotic cells tightly regulate the number and distribution of crossovers to promote accurate chromosome segregation. Yokoo and colleagues uncover a metazoan-specific, cyclin-like protein that is crucial for crossover formation. They utilize this protein's unique properties to explore a remarkable example of biological numerology, whereby nearly every meiotic cell in C. elegans makes precisely six crossovers, one for each of its six chromosome pairs. Copyright © 2012 Elsevier Inc. All rights reserved.

Job Quality and Gender Inequality: Key Changes in Québec over the Last Decade

OpenAIRE

Diane-Gabrielle Tremblay; Luc Cloutier; Paul Bernard

2009-01-01

Using a new typology based on information available from the Labour Force Survey, the authors analyse how job quality evolved in Québec for both women and men over the last decade (1997-2007). Results show that family situation and educational attainment are two important factors in the determination of gender inequality in the labour market. The analysis emphasizes the very significant decline in gender differences with regard to job quality (from 23% to 35% according to groups), especially ...

New derivation of relativistic dissipative fluid dynamics

International Nuclear Information System (INIS)

Jaiswal, Amaresh; Bhalerao, Rajeev S.; Pal, Subrata

2012-01-01

Relativistic dissipative hydrodynamics has been quite successful in explaining the spectra and azimuthal anisotropy of particles produced in heavy-ion collisions at the RHIC and recently at the LHC. The first-order dissipative fluid dynamics or the relativistic Navier-Stokes (NS) theory involves parabolic differential equations and suffers from a causality and instability. The second-order or Israel-Stewart (IS) theory with its hyperbolic equations restores causality but may not guarantee stability. The correct formulation of relativistic viscous fluid dynamics is far from settled and is under intense investigation

Relativistic current sheets in electron-positron plasmas

International Nuclear Information System (INIS)

Zenitani, S.

2008-01-01

The current sheet structure with magnetic field reversal is one of the fundamental structure in space and astrophysical plasmas. It draws recent attention in high-energy astrophysical settings, where relativistic electron-positron plasmas are considered. In this talk we will review the recent progress of the physical processes in the relativistic current sheet. The kinetic stability of a single current sheet, the nonlinear behavior of these instabilities, and recent challenges on the multi current sheet systems are introduced. We will also introduce some problems of magnetic reconnection in these relativistic environments. (author)

Local density approximations for relativistic exchange energies

International Nuclear Information System (INIS)

MacDonald, A.H.

1986-01-01

The use of local density approximations to approximate exchange interactions in relativistic electron systems is reviewed. Particular attention is paid to the physical content of these exchange energies by discussing results for the uniform relativistic electron gas from a new point of view. Work on applying these local density approximations in atoms and solids is reviewed and it is concluded that good accuracy is usually possible provided self-interaction corrections are applied. The local density approximations necessary for spin-polarized relativistic systems are discussed and some new results are presented

Relativistic astrophysics

CERN Document Server

Price, R H

1993-01-01

Work reported in the workshop on relativistic astrophysics spanned a wide varicy of topics. Two specific areas seemed of particular interest. Much attention was focussed on gravitational wave sources, especially on the waveforms they produce, and progress was reported in theoretical and observational aspects of accretion disks.

Einstein Never Approved of Relativistic Mass

Science.gov (United States)

Hecht, Eugene

2009-01-01

During much of the 20th century it was widely believed that one of the significant insights of special relativity was "relativistic mass." Today there are two schools on that issue: the traditional view that embraces speed-dependent "relativistic mass," and the more modern position that rejects it, maintaining that there is only one mass and it's…

Crossover of burnout and engagement in work teams

NARCIS (Netherlands)

Bakker, A.B.; Van Emmerik, IJ.H.; Euwema, M.C.

2005-01-01

This study investigates the crossover of burnout and work engagement among 2,229 Royal Dutch constabulary officers, working in one of 85 teams. The authors hypothesized that both states may transfer from teams to individual team members. The results of multilevel analyses confirm this crossover

Polaron crossover in molecular solids

International Nuclear Information System (INIS)

Zoli, Marco; Das, A N

2004-01-01

An analytical variational method is applied to the molecular Holstein Hamiltonian in which the dispersive features of the dimension dependent phonon spectrum are taken into account by a force constant approach. The crossover between a large and a small size polaron is monitored, in one, two and three dimensions and for different values of the adiabatic parameter, through the behaviour of the effective mass as a function of the electron-phonon coupling. By increasing the strength of the intermolecular forces the crossover becomes smoother and occurs at higher e-ph couplings. These effects are more evident in three dimensions. We show that our modified Lang-Firsov method starts to capture the occurrence of a polaron self-trapping transition when the electron energies become of order of the phonon energies. The self-trapping event persists in the fully adiabatic regime. At the crossover we estimate polaron effective masses of order ∼ 5-40 times the bare band mass according to the dimensionality and the value of the adiabatic parameter. Modified Lang-Firsov polaron masses are substantially reduced in two and three dimensions. There is no self-trapping in the antiadiabatic regime

Lectures on relativistic quantum mechanics and path integration

International Nuclear Information System (INIS)

Gunn, J.M.F.

1989-02-01

The question posed is why bother with relativistic quantum mechanics? Three reasons are given: First that there are many experimental phenomena which cannot be explained in non-relativistic terms. Secondly it would be unsatisfactory if relativity and quantum mechanics could not be united. Thirdly, there are theoretical reasons why new effects can be expected at relativistic velocities. The objectives of the course are to set up relativistic analogues of the Schroedinger equation and to understand their consequences. In doing so there are some questions which are raised and discussed such as can a first order equation be used to describe spin 0 particles and a second order equation be used to describe spin 1/ 2 (author)

Relativistic and Non-Relativistic Electronic Molecular-Structure Calculations for Dimers of 4p-, 5p-, and 6p-Block Elements

NARCIS (Netherlands)

Hoefener, S.; Ahlrichs, R.; Knecht, S.; Visscher, L.

2012-01-01

We report results of non-relativistic and two-component relativistic single-reference coupled-cluster with single and double and perturbative triple excitations [CCSD(T)] treatments for the 4p-block dimers Ga

Symmetric low-voltage powering system for relativistic electronic devices

International Nuclear Information System (INIS)

Agafonov, A.V.; Lebedev, A.N.; Krastelev, E.G.

2005-01-01

A special driver for double-sided powering of relativistic magnetrons and several methods of localized electron flow forming in the interaction region of relativistic magnetrons are proposed and discussed. Two experimental installations are presented and discussed. One of them is designed for laboratory research and demonstration experiments at a rather low voltage. The other one is a prototype of a full-scale installation for an experimental research at relativistic levels of voltages on the microwave generation in the new integrated system consisting of a relativistic magnetron and symmetrical induction driver

Lagrangian formulation of a consistent relativistic guiding center theory

International Nuclear Information System (INIS)

Wimmel, H.K.

1983-02-01

A new relativistic guiding center mechanics is presented that conserves energy (in time-independent fields) and satisfies a Liouville's theorem. The theory reduces to Littlejohn's theory in the non-relativistic limit and agrees to leading orders in epsilon identical rsub(g)/L with the relativistic theory by Morozov and Solov'ev (which generally lacks a Liouville's theorem). The new theory is developed from an appropriate Lagrangian and is supplemented by a collisionless relativistic kinetic equation for the guiding centers. Moment equations for guiding center density and energy density are also derived. (orig.)

Relativistic gravitational instabilities

International Nuclear Information System (INIS)

Schutz, B.F.

1987-01-01

The purpose of these lectures is to review and explain what is known about the stability of relativistic stars and black holes, with particular emphases on two instabilities which are due entirely to relativistic effects. The first of these is the post-Newtonian pulsational instability discovered independently by Chandrasekhar (1964) and Fowler (1964). This effectively ruled out the then-popular supermassive star model for quasars, and it sets a limit to the central density of white dwarfs. The second instability was also discovered by Chandrasekhar (1970): the gravitational wave induced instability. This sets an upper bound on the rotation rate of neutron stars, which is near that of the millisecond pulsar PSR 1937+214, and which is beginning to constrain the equation of state of neutron matter. 111 references, 5 figures

The projective geometry of the spacetime yielded by relativistic positioning systems and relativistic location systems

OpenAIRE

Rubin , Jacques ,

2014-01-01

Version de travail de thèse d'habilitation à diriger des recherches; Preprint; Current positioning systems are not primary, relativistic systems. Nevertheless, genuine, relativistic and primary positioning systems have been proposed recently by Bahder, Coll et al. and Rovelli to remedy such prior defects. These new designs all have in common an equivariant conformal geometry featuring, as the most basic ingredient, the spacetime geometry. We show how this conformal aspect can be the four-dime...

Are stepparents always evil? Parental death, remarriage, and child survival in demographically saturated Krummhörn (1720-1859) and expanding Québec (1670-1750).

Science.gov (United States)

Willführ, Kai P; Gagnon, Alain

2013-01-01

Parental death precipitates a cascade of events leading to more or less detrimental exposures, from the sudden and dramatic interruption of parental care to cohabitation with stepparents and siblings in a recomposed family. This article compares the effect of early parental loss on child survival in the past in the Krummhörn region of East Frisia (Germany) and among the French Canadian settlers of the Saint Lawrence Valley (Québec, Canada). The Krummhörn region was characterized by a saturated habitat, while the opportunities for establishing a new family were virtually unlimited for the French Canadian settlers. Early parental loss had quite different consequences in these dissimilar environments. Event history analyses with time-varying specification of family structure are used on a sample of 7,077 boys and 6,906 girls born between 1720 and 1859 in the Krummhörn region and 31,490 boys and 33,109 girls whose parents married between 1670 and 1750 in Québec. Results indicate that in both populations, parental loss is associated with increased infant and child mortality. Maternal loss has a universal and consistent effect for both sexes, while the impact of paternal loss is less easy to establish and interpret. On the other hand, the effect of the remarriage of the surviving spouse is population-specific: the mother's remarriage has no effect in Krummhörn, while it is beneficial in Québec. In contrast, the father's remarriage in Krummhörn dramatically reduces the survival chances of the children born from his former marriage, while such an effect is not seen for Québec. These population-specific effects appear to be driven by the availability of resources and call into question the universality of the "Cinderella" effect.

Provisional in-silico biopharmaceutics classification (BCS) to guide oral drug product development.

Science.gov (United States)

Wolk, Omri; Agbaria, Riad; Dahan, Arik

2014-01-01

The main objective of this work was to investigate in-silico predictions of physicochemical properties, in order to guide oral drug development by provisional biopharmaceutics classification system (BCS). Four in-silico methods were used to estimate LogP: group contribution (CLogP) using two different software programs, atom contribution (ALogP), and element contribution (KLogP). The correlations (r(2)) of CLogP, ALogP and KLogP versus measured LogP data were 0.97, 0.82, and 0.71, respectively. The classification of drugs with reported intestinal permeability in humans was correct for 64.3%-72.4% of the 29 drugs on the dataset, and for 81.82%-90.91% of the 22 drugs that are passively absorbed using the different in-silico algorithms. Similar permeability classification was obtained with the various in-silico methods. The in-silico calculations, along with experimental melting points, were then incorporated into a thermodynamic equation for solubility estimations that largely matched the reference solubility values. It was revealed that the effect of melting point on the solubility is minor compared to the partition coefficient, and an average melting point (162.7 °C) could replace the experimental values, with similar results. The in-silico methods classified 20.76% (± 3.07%) as Class 1, 41.51% (± 3.32%) as Class 2, 30.49% (± 4.47%) as Class 3, and 6.27% (± 4.39%) as Class 4. In conclusion, in-silico methods can be used for BCS classification of drugs in early development, from merely their molecular formula and without foreknowledge of their chemical structure, which will allow for the improved selection, engineering, and developability of candidates. These in-silico methods could enhance success rates, reduce costs, and accelerate oral drug products development.

Relativistic transport theory for cosmic-rays

International Nuclear Information System (INIS)

Webb, G.M.

1985-01-01

Various aspects of the transport of cosmic-rays in a relativistically moving magnetized plasma supporting a spectrum of hydromagnetic waves that scatter the cosmic-rays are presented. A local Lorentz frame moving with the waves or turbulence scattering the cosmic-rays is used to specify the individual particle momentum. The comoving frame is in general a noninertial frame in which the observer's volume element is expanding and shearing, geometric energy change terms appear in the cosmic-ray transport equation which consist of the relativistic generalization of the adiabatic deceleration term and a further term involving the acceleration vector of the scatterers. A relativistic version of the pitch angle evolution equation, including the effects of adiabatic focussing, pitch angle scattering, and energy changes is presented

Gravitationally confined relativistic neutrinos

Science.gov (United States)

Vayenas, C. G.; Fokas, A. S.; Grigoriou, D.

2017-09-01

Combining special relativity, the equivalence principle, and Newton’s universal gravitational law with gravitational rather than rest masses, one finds that gravitational interactions between relativistic neutrinos with kinetic energies above 50 MeV are very strong and can lead to the formation of gravitationally confined composite structures with the mass and other properties of hadrons. One may model such structures by considering three neutrinos moving symmetrically on a circular orbit under the influence of their gravitational attraction, and by assuming quantization of their angular momentum, as in the Bohr model of the H atom. The model contains no adjustable parameters and its solution, using a neutrino rest mass of 0.05 eV/c2, leads to composite state radii close to 1 fm and composite state masses close to 1 GeV/c2. Similar models of relativistic rotating electron - neutrino pairs give a mass of 81 GeV/c2, close to that of W bosons. This novel mechanism of generating mass suggests that the Higgs mass generation mechanism can be modeled as a latent gravitational field which gets activated by relativistic neutrinos.

Relativistic corrections to molecular dynamic dipole polarizabilities

DEFF Research Database (Denmark)

Kirpekar, Sheela; Oddershede, Jens; Jensen, Hans Jørgen Aagaard

1995-01-01

obtained from the use of the Darwin and mass-velocity operators to first order are included at both levels of approximation. We find that correlation and relativistic contributions are not even approximately additive for the two molecules. The importance of the relativistic corrections is smallest...

From Lattice Boltzmann to hydrodynamics in dissipative relativistic fluids

Science.gov (United States)

Gabbana, Alessandro; Mendoza, Miller; Succi, Sauro; Tripiccione, Raffaele

2017-11-01

Relativistic fluid dynamics is currently applied to several fields of modern physics, covering many physical scales, from astrophysics, to atomic scales (e.g. in the study of effective 2D systems such as graphene) and further down to subnuclear scales (e.g. quark-gluon plasmas). This talk focuses on recent progress in the largely debated connection between kinetic transport coefficients and macroscopic hydrodynamic parameters in dissipative relativistic fluid dynamics. We use a new relativistic Lattice Boltzmann method (RLBM), able to handle from ultra-relativistic to almost non-relativistic flows, and obtain strong evidence that the Chapman-Enskog expansion provides the correct pathway from kinetic theory to hydrodynamics. This analysis confirms recently obtained theoretical results, which can be used to obtain accurate calibrations for RLBM methods applied to realistic physics systems in the relativistic regime. Using this calibration methodology, RLBM methods are able to deliver improved physical accuracy in the simulation of the physical systems described above. European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No. 642069.

Scalar Relativistic Study of the Structure of Rhodium Acetate

Directory of Open Access Journals (Sweden)

Emily E. Edwards

2004-01-01

Full Text Available Abstract: Rhodium acetate, related rhodium carboxylates, and rhodium amide complexes are powerful catalysts for carbene chemistry. They readily promote the decomposition of diazo compounds and transfer the resulting carbene to a variety of substrates. There have been several quantum chemistry studies of these compounds, particularly of the acetate. These have all used non-relativistic methods, and all have shown optimized Rh-Rh bond lengths significantly longer than the experimental value. In this study we have surveyed several scalar relativistic DFT methods using Gaussian, Slater, and numerical basis functions (in DGAUSS, ADF, and DMOL3. Several combinations of exchange-correlation functionals with relativistic and non-relativistic effective core potentials (ECP were investigated, as were non-relativistic and all electron scalar relativistic methods. The combination of the PW91 exchange and PW91 correlation functional with the Christiansen-Ermler ECP gave the best results: 2.3918 Å compared to the experimental value of 2.3855±0.0005 Å.

Holographic Aspects of a Relativistic Nonconformal Theory

Directory of Open Access Journals (Sweden)

Chanyong Park

2013-01-01

Full Text Available We study a general D-dimensional Schwarzschild-type black brane solution of the Einstein-dilaton theory and derive, by using the holographic renormalization, its thermodynamics consistent with the geometric results. Using the membrane paradigm, we calculate the several hydrodynamic transport coefficients and compare them with the results obtained by the Kubo formula, which shows the self-consistency of the gauge/gravity duality in the relativistic nonconformal theory. In order to understand more about the relativistic non-conformal theory, we further investigate the binding energy, drag force, and holographic entanglement entropy of the relativistic non-conformal theory.

On the physics of relativistic double layers

International Nuclear Information System (INIS)

Carlqvist, P.

1982-06-01

A model of a strong, time-independent, and relativistic double layer is studied. Besides double layers having the electric field parallel to the current the model also describes a certain type of oblique double layers. The 'Langmuir condition' (ratio of ion current density to electron current density) as well as an expression for the potential drop of the double layer are derived. Furthermore, the distribution of charged particles, electric field, and potential within the double layer are clarified and discussed. It is found that the properties of relativistic double layers differ substantially from the properties of corresponding non-relativistic double layers. (Author)

Two-dimensional approach to relativistic positioning systems

International Nuclear Information System (INIS)

Coll, Bartolome; Ferrando, Joan Josep; Morales, Juan Antonio

2006-01-01

A relativistic positioning system is a physical realization of a coordinate system consisting in four clocks in arbitrary motion broadcasting their proper times. The basic elements of the relativistic positioning systems are presented in the two-dimensional case. This simplified approach allows to explain and to analyze the properties and interest of these new systems. The positioning system defined by geodesic emitters in flat metric is developed in detail. The information that the data generated by a relativistic positioning system give on the space-time metric interval is analyzed, and the interest of these results in gravimetry is pointed out

Relativistic calculations of coalescing binary neutron stars

Indian Academy of Sciences (India)

We have designed and tested a new relativistic Lagrangian hydrodynamics code, which treats gravity in the conformally flat approximation to general relativity. We have tested the resulting code extensively, finding that it performs well for calculations of equilibrium single-star models, collapsing relativistic dust clouds, and ...

Deep processes in non-relativistic confining potentials

International Nuclear Information System (INIS)

Fishbane, P.M.; Grisaru, M.T.

1978-01-01

The authors study deep inelastic and hard scattering processes for non-relativistic particles confined in deep potentials. The mechanisms by which the effects of confinement disappear and the particles scatter as if free are useful in understanding the analogous results for a relativistic field theory. (Auth.)

Isolating relativistic effects in large-scale structure

Science.gov (United States)

Bonvin, Camille

2014-12-01

We present a fully relativistic calculation of the observed galaxy number counts in the linear regime. We show that besides the density fluctuations and redshift-space distortions, various relativistic effects contribute to observations at large scales. These effects all have the same physical origin: they result from the fact that our coordinate system, namely the galaxy redshift and the incoming photons’ direction, is distorted by inhomogeneities in our Universe. We then discuss the impact of the relativistic effects on the angular power spectrum and on the two-point correlation function in configuration space. We show that the latter is very well adapted to isolate the relativistic effects since it naturally makes use of the symmetries of the different contributions. In particular, we discuss how the Doppler effect and the gravitational redshift distortions can be isolated by looking for a dipole in the cross-correlation function between a bright and a faint population of galaxies.

Quantification and Sequencing of Crossover Recombinant Molecules from Arabidopsis Pollen DNA.

Science.gov (United States)

Choi, Kyuha; Yelina, Nataliya E; Serra, Heïdi; Henderson, Ian R

2017-01-01

During meiosis, homologous chromosomes undergo recombination, which can result in formation of reciprocal crossover molecules. Crossover frequency is highly variable across the genome, typically occurring in narrow hotspots, which has a significant effect on patterns of genetic diversity. Here we describe methods to measure crossover frequency in plants at the hotspot scale (bp-kb), using allele-specific PCR amplification from genomic DNA extracted from the pollen of F 1 heterozygous plants. We describe (1) titration methods that allow amplification, quantification and sequencing of single crossover molecules, (2) quantitative PCR methods to more rapidly measure crossover frequency, and (3) application of high-throughput sequencing for study of crossover distributions within hotspots. We provide detailed descriptions of key steps including pollen DNA extraction, prior identification of hotspot locations, allele-specific oligonucleotide design, and sequence analysis approaches. Together, these methods allow the rate and recombination topology of plant hotspots to be robustly measured and compared between varied genetic backgrounds and environmental conditions.

Report of seminar on relativistic approach to nuclear reaction and nuclear structure

International Nuclear Information System (INIS)

1986-05-01

A seminar on 'Relativistic Approach to Nuclear Reaction and Nuclear Structure' was held in 1985 at Osaka University. This booklet includes twenty-four reports given at the seminar, which deal with: Conventional Nonrelativistic Description of Nuclear Matter and Nuclear Spin-Orbit Interactions; Relativistic Approach to Nuclear Structure; Atomic and Molecular Structure Calculations; Electromagnetic Interaction in Nucleus and Relativistic Effect; Nuclear Magnetic Moment in the Relativistic Mean Field Theory, Effective Mass and Particle-Vibration Coupling in the Relativistic σ-ω Model; Gauge Invariance in Relativistic Many-Body Theory; Relativistic Description of Nucleon-Nucleon Interaction in Review; σ-Particle in NN Interaction; Nuclear Optical Potentials Based on the Brueckner-Hartree-Fock Approach; Elastic Backscattering and Optical Potential; Description of Intermediate-Energy Nuclear Reactions; Dirac Phenomenology at E(p) = 65 MeV; Relativistic Impulse Approximation; Reaction Studies with Intermediate Energy Deuterons at SATURNE; Folding Model for Intermediate-Energy Deutron Scattering; Folding Model for Polarized Deutron Scattering at 700 MeV; Dirac Approach Problems and a Different Viewpoint; Relativistic Approach and EMC Effect; Quasielastic Electron Scattering; Response Function of Quasielastic Electron Scattering; Relativistic Hartree Response Function for Quasielastic Electron Scattering on 12 C and 40 Ca; Backflow-, Retardation- and Relativistic Effects on the Longitudinal Response Function of Nuclear Matter; Pion-Photoproduction in the σ-ω Model. (Nogami, K.)

Electromagnetic interactions in relativistic infinite component wave equations

International Nuclear Information System (INIS)

Gerry, C.C.

1979-01-01

The electromagnetic interactions of a composite system described by relativistic infinite-component wave equations are considered. The noncompact group SO(4,2) is taken as the dynamical group of the systems, and its unitary irreducible representations, which are infinite dimensional, are used to find the energy spectra and to specify the states of the systems. First the interaction mechanism is examined in the nonrelativistic SO(4,2) formulation of the hydrogen atom as a heuristic guide. A way of making a minimal relativistic generalization of the minimal ineractions in the nonrelativistic equation for the hydrogen atom is proposed. In order to calculate the effects of the relativistic minimal interactions, a covariant perturbation theory suitable for infinite-component wave equations, which is an algebraic and relativistic version of the Rayleigh-Schroedinger perturbation theory, is developed. The electric and magnetic polarizabilities for the ground state of the hydrogen atom are calculated. The results have the correct nonrelativistic limits. Next, the relativistic cross section of photon absorption by the atom is evaluated. A relativistic expression for the cross section of light scattering corresponding to the seagull diagram is derived. The Born amplitude is combusted and the role of spacelike solutions is discussed. Finally, internal electromagnetic interactions that give rise to the fine structure splittings, the Lamb shifts and the hyperfine splittings are considered. The spin effects are introduced by extending the dynamical group

Is a Relativistic Thermodynamics possible?; Es posible una Termodinamica Relativista?

Energy Technology Data Exchange (ETDEWEB)

Guemez, J.

2010-07-01

A brief historical review the literature on developing the concept of Thermodynamics Relativistic. We analyze two examples of application of the Galilean and Relativistic Thermodynamics discussed under what circumstances could build a relativistic Thermodynamics Lorentz covariant with physical sense. (Author) 19 refs.

Study of the O-mode in a relativistic degenerate electron plasma

Science.gov (United States)

Azra, Kalsoom; Ali, Muddasir; Hussain, Azhar

2017-03-01

Using the linearized relativistic Vlasov-Maxwell equations, a generalized expression for the plasma conductivity tensor is derived. The dispersion relation for the O-mode in a relativistic degenerate electron plasma is investigated by employing the Fermi-Dirac distribution function. The propagation characteristics of the O-mode (cut offs, resonances, propagation regimes, harmonic structure) are examined by using specific values of the density and the magnetic field that correspond to different relativistic dense environments. Further, it is observed that due to the relativistic effects the cut off and the resonance points are shifted to low frequency values, as a result the propagation regime is reduced. The dispersion relations for the non-relativistic and the ultra-relativistic limits are also presented.

Skating crossovers on a motorized flywheel: a preliminary experimental design to test effect on speed and on crossovers.

Science.gov (United States)

Smith, Aynsley M; Krause, David A; Stuart, Michael J; Montelpare, William J; Sorenson, Matthew C; Link, Andrew A; Gaz, Daniel V; Twardowski, Casey P; Larson, Dirk R; Stuart, Michael B

2013-12-01

Ice hockey requires frequent skater crossovers to execute turns. Our investigation aimed to determine the effectiveness of training crossovers on a motorized, polyethylene high-resistance flywheel. We hypothesized that high school hockey players training on the flywheel would perform as well as their peers training on ice. Participants were 23 male high-school hockey players (age 15-19 years). The study used an experimental prospective design to compare players who trained for 9 sessions on the 22-foot flywheel with players who trained for 9 sessions on a similarly sized on-ice circle. Both groups were compared with control subjects who were randomly selected from the same participant pool as those training on ice. All players were tested before and after their 3-week training regimens, and control subjects were asked to not practice crossovers between testing. Group 1 trained in a hockey training facility housing the flywheel, and group 2 trained in the ice hockey arena where testing occurred. Primary outcome measures tested in both directions were: (a) speed (time in seconds) required to skate crossovers for 3 laps of a marked face-off circle, (b) cadence of skating crossovers on the similarly sized circles, and (c) a repeat interval speed test, which measures anaerobic power. No significant changes were found between groups in on-ice testing before and after training. Among the group 1 players, 7 of 8 believed they benefited from flywheel training. Group 2 players, who trained on ice, did not improve performance significantly over group 1 players. Despite the fact that no significant on-ice changes in performance were observed in objective measures, players who trained on the flywheel subjectively reported that the flywheel is an effective cost-effective alternative to training on ice. This is a relevant finding when placed in context with limited availability of on-ice training.

Relativistic Calculations for Be-like Iron

International Nuclear Information System (INIS)

Yang Jianhui; Zhang Jianping; Li Ping; Li Huili

2008-01-01

Relativistic configuration interaction calculations for the states of 1s 2 2s 2 , 1s 2 2s3l (l = s,p,d) and 1s 2 2p3l (l = s,p,d) configurations of iron are carried out using relativistic configuration interaction (RCI) and multi-configuration Dirac-Fock (MCDF) method in the active interaction approach. In the present calculation, a large-scale configuration expansion was used in describing the target states. These results are extensively compared with other available calculative and experimental and observed values, the corresponding present results are in good agreement with experimental and observed values, and some differences are found with other available calculative values. Because more relativistic effects are considered than before, the present results should be more accurate and reliable

Relativistic dynamical reduction models and nonlocality

International Nuclear Information System (INIS)

Ghirardi, G.C.; Grassi, R.

1990-09-01

We discuss some features of continuous dynamical models yielding state vector reduction and we briefly sketch some recent attempts to get a relativistic generalization of them. Within the relativistic context we analyze in detail the local an nonlocal features of the reduction mechanism and we investigate critically the possibility of attributing objective properties to individual systems in the micro and macroscopic cases. At the nonrelativistic level, two physically equivalent versions of continuous reduction mechanisms have been presented. However, only one of them can be taken as a starting point for the above considered relativistic generalization. By resorting to counterfactual arguments we show that the reason for this lies in the fact that the stochasticity involved in the two approaches has different conceptual implications. (author). 7 refs, 4 figs

Interference-mediated synaptonemal complex formation with embedded crossover designation

Science.gov (United States)

Zhang, Liangran; Espagne, Eric; de Muyt, Arnaud; Zickler, Denise; Kleckner, Nancy E.

2014-01-01

Biological systems exhibit complex patterns at length scales ranging from the molecular to the organismic. Along chromosomes, events often occur stochastically at different positions in different nuclei but nonetheless tend to be relatively evenly spaced. Examples include replication origin firings, formation of chromatin loops along chromosome axes and, during meiosis, localization of crossover recombination sites (“crossover interference”). We present evidence in the fungus Sordaria macrospora that crossover interference is part of a broader pattern that includes synaptonemal complex (SC) nucleation. This pattern comprises relatively evenly spaced SC nucleation sites, among which a subset are crossover sites that show a classical interference distribution. This pattern ensures that SC forms regularly along the entire length of the chromosome as required for the maintenance of homolog pairing while concomitantly having crossover interactions locally embedded within the SC structure as required for both DNA recombination and structural events of chiasma formation. This pattern can be explained by a threshold-based designation and spreading interference process. This model can be generalized to give diverse types of related and/or partially overlapping patterns, in two or more dimensions, for any type of object. PMID:25380597

Recent progresses in relativistic beam-plasma instability theory

Directory of Open Access Journals (Sweden)

A. Bret

2010-11-01

Full Text Available Beam-plasma instabilities are a key physical process in many astrophysical phenomena. Within the fireball model of Gamma ray bursts, they first mediate a relativistic collisionless shock before they produce upstream the turbulence needed for the Fermi acceleration process. While non-relativistic systems are usually governed by flow-aligned unstable modes, relativistic ones are likely to be dominated by normally or even obliquely propagating waves. After reviewing the basis of the theory, results related to the relativistic kinetic regime of the poorly-known oblique unstable modes will be presented. Relevant systems besides the well-known electron beam-plasma interaction are presented, and it is shown how the concept of modes hierarchy yields a criterion to assess the proton to electron mass ratio in Particle in cell simulations.

Individual and crossover effects of stress on adjustment in medical student marriages.

Science.gov (United States)

Katz, J; Monnier, J; Libet, J; Shaw, D; Beach, S R

2000-07-01

High-stress individuals may benefit from social support, although their support providers may be adversely affected via stress crossover effects. Individual and crossover effects of perceived stress within medical student marriages (n = 30) were investigated. Perceived spousal support was positively associated with individuals' own marital and emotional adjustment, attenuating stress effects. With regard to crossover effects, medical students' perceived stress was significantly associated with their spouses' emotional adjustment. Further, medical students' own emotional adjustment fully mediated this crossover effect. Results suggest that the contagion of negative affect may serve as a key mechanism through which stress crossover effects operate in marriage.

Quantum Monte Carlo studies of superfluid Fermi gases

International Nuclear Information System (INIS)

Chang, S.Y.; Pandharipande, V.R.; Carlson, J.; Schmidt, K.E.

2004-01-01

We report results of quantum Monte Carlo calculations of the ground state of dilute Fermi gases with attractive short-range two-body interactions. The strength of the interaction is varied to study different pairing regimes which are characterized by the product of the s-wave scattering length and the Fermi wave vector, ak F . We report results for the ground-state energy, the pairing gap Δ, and the quasiparticle spectrum. In the weak-coupling regime, 1/ak F FG . When a>0, the interaction is strong enough to form bound molecules with energy E mol . For 1/ak F > or approx. 0.5, we find that weakly interacting composite bosons are formed in the superfluid gas with Δ and gas energy per particle approaching E mol /2. In this region, we seem to have Bose-Einstein condensation (BEC) of molecules. The behavior of the energy and the gap in the BCS-to-BEC transition region, -0.5 F <0.5, is discussed

Rayleigh-Brillouin spectrum in special relativistic hydrodynamics

International Nuclear Information System (INIS)

Garcia-Perciante, A. L.; Garcia-Colin, L. S.; Sandoval-Villalbazo, A.

2009-01-01

In this paper we calculate the Rayleigh-Brillouin spectrum for a relativistic simple fluid according to three different versions available for a relativistic approach to nonequilibrium thermodynamics. An outcome of these calculations is that Eckart's version predicts that such spectrum does not exist. This provides an argument to question its validity. The remaining two results, which differ one from another, do provide a finite form for such spectrum. This raises the rather intriguing question as to which of the two theories is a better candidate to be taken as a possible version of relativistic nonequilibrium thermodynamics. The answer will clearly require deeper examination of this problem.

Frontiers in relativistic celestial mechanics

CERN Document Server

2014-01-01

Relativistic celestial mechanics – investigating the motion celestial bodies under the influence of general relativity – is a major tool of modern experimental gravitational physics. With a wide range of prominent authors from the field, this two-volume series consists of reviews on a multitude of advanced topics in the area of relativistic celestial mechanics – starting from more classical topics such as the regime of asymptotically-flat spacetime, light propagation and celestial ephemerides, but also including its role in cosmology and alternative theories of gravity as well as modern experiments in this area.

Chiral quark model with relativistic kinematics

International Nuclear Information System (INIS)

Garcilazo, H.; Valcarce, A.

2003-01-01

The nonstrange baryon spectrum is studied within a three-body model that incorporates relativistic kinematics. We found that the combined effect of relativistic kinematics together with the pion exchange between quarks is able to reverse the order of the first positive- and negative-parity nucleon excited states as observed experimentally. Including the chiral partner of the pion (the σ meson) leads to an overall good description of the spectrum

Chiral quark model with relativistic kinematics

OpenAIRE

Garcilazo, H.; Valcarce, A.

2003-01-01

The non-strange baryon spectrum is studied within a three-body model that incorporates relativistic kinematics. We found that the combined effect of relativistic kinematics together with the pion exchange between quarks is able to reverse the order of the first positive- and negative-parity nucleon excited states as observed experimentally. Including the chiral partner of the pion (the $\\sigma$ meson) leads to an overall good description of the spectrum.

Acoustic geometry for general relativistic barotropic irrotational fluid flow

International Nuclear Information System (INIS)

Visser, Matt; Molina-ParIs, Carmen

2010-01-01

'Acoustic spacetimes', in which techniques of differential geometry are used to investigate sound propagation in moving fluids, have attracted considerable attention over the last few decades. Most of the models currently considered in the literature are based on non-relativistic barotropic irrotational fluids, defined in a flat Newtonian background. The extension, first to special relativistic barotropic fluid flow and then to general relativistic barotropic fluid flow in an arbitrary background, is less straightforward than it might at first appear. In this paper, we provide a pedagogical and simple derivation of the general relativistic 'acoustic spacetime' in an arbitrary (d+1)-dimensional curved-space background.

What's Mine Is Yours: The Crossover of Day-Specific Self-Esteem

Science.gov (United States)

Neff, Angela; Sonnentag, Sabine; Niessen, Cornelia; Unger, Dana

2012-01-01

This diary study examines the daily crossover of self-esteem within working couples. By integrating self-esteem research into the crossover framework, we hypothesized that the day-specific self-esteem experienced by one partner after work crosses over to the other partner. Furthermore, we proposed that this daily crossover process is moderated by…

Bose–Einstein condensation of anti-kaons and neutron star twins

Indian Academy of Sciences (India)

We investigate the role of Bose–Einstein condensation (BEC) of anti-kaons on the equation of state (EoS) and other properties of compact stars. In the framework of relativistic mean field model we determine the EoS for -stable hyperon matter and compare it to the situation when anti-kaons condense in the system.

Non-relativistic spinning particle in a Newton-Cartan background

Science.gov (United States)

Barducci, Andrea; Casalbuoni, Roberto; Gomis, Joaquim

2018-01-01

We construct the action of a non-relativistic spinning particle moving in a general torsionless Newton-Cartan background. The particle does not follow the geodesic equations, instead the motion is governed by the non-relativistic analog of Papapetrou equation. The spinning particle is described in terms of Grassmann variables. In the flat case the action is invariant under the non-relativistic analog of space-time vector supersymmetry.

Fully relativistic free-electron laser in a completely filled waveguide

International Nuclear Information System (INIS)

Farokhi, B.; Abdykian, A.

2005-01-01

An analysis of the azimuthally symmetrical, high frequency eigenmodes of a cylindrical metallic waveguide completely filled with a relativistic magnetized plasma is presented. A relativistic nonlinear wave equation is derived in a form which includes the coupling of EH and HE modes due to the finite axial magnetic field. Relativistic equations that permit calculation of the dispersion curves for four families of electromagnetic and electrostatic modes are derived. Numerical analysis is conducted to study the relativistic dispersion curves of various modes as a function of axial magnetic field B 0 . This treatment is shown that the dispersion curves dependent to γ in low frequency which is ignored in previous work. It is found that in drawn figures shown difference between relativistic and non-relativistic cases. The former each figure is treated for two orbit groups. This study is benefiting to facilities the development of devices for generation of high-power electromagnetic radiation, charged particle acceleration, and other applications of plasma waveguide. (author)

High-pressure water electrolysis: Electrochemical mitigation of product gas crossover

International Nuclear Information System (INIS)

Schalenbach, Maximilian; Stolten, Detlef

2015-01-01

Highlights: • New technique to reduce gas crossover during water electrolysis • Increase of the efficiency of pressurized water electrolysis • Prevention of safety hazards due to explosive gas mixtures caused by crossover • Experimental realization for a polymer electrolyte membrane electrolyzer • Discussion of electrochemical crossover mitigation for alkaline water electrolysis - Abstract: Hydrogen produced by water electrolysis can be used as an energy carrier storing electricity generated from renewables. During water electrolysis hydrogen can be evolved under pressure at isothermal conditions, enabling highly efficient compression. However, the permeation of hydrogen through the electrolyte increases with operating pressure and leads to efficiency loss and safety hazards. In this study, we report on an innovative concept, where the hydrogen crossover is electrochemically mitigated by an additional electrode between the anode and the cathode of the electrolysis cell. Experimentally, the technique was applied to a proton exchange membrane water electrolyzer operated at a hydrogen pressure that was fifty times larger than the oxygen pressure. Therewith, the hydrogen crossover was reduced and the current efficiency during partial load operation was increased. The concept is also discussed for water electrolysis that is operated at balanced pressures, where the crossover of hydrogen and oxygen is mitigated using two additional electrodes

Relativistic modeling capabilities in PERSEUS extended MHD simulation code for HED plasmas

Energy Technology Data Exchange (ETDEWEB)

Hamlin, Nathaniel D., E-mail: nh322@cornell.edu [438 Rhodes Hall, Cornell University, Ithaca, NY, 14853 (United States); Seyler, Charles E., E-mail: ces7@cornell.edu [Cornell University, Ithaca, NY, 14853 (United States)

2014-12-15

We discuss the incorporation of relativistic modeling capabilities into the PERSEUS extended MHD simulation code for high-energy-density (HED) plasmas, and present the latest hybrid X-pinch simulation results. The use of fully relativistic equations enables the model to remain self-consistent in simulations of such relativistic phenomena as X-pinches and laser-plasma interactions. By suitable formulation of the relativistic generalized Ohm’s law as an evolution equation, we have reduced the recovery of primitive variables, a major technical challenge in relativistic codes, to a straightforward algebraic computation. Our code recovers expected results in the non-relativistic limit, and reveals new physics in the modeling of electron beam acceleration following an X-pinch. Through the use of a relaxation scheme, relativistic PERSEUS is able to handle nine orders of magnitude in density variation, making it the first fluid code, to our knowledge, that can simulate relativistic HED plasmas.

RELATIVISTIC DOPPLER BEAMING AND MISALIGNMENTS IN AGN JETS

International Nuclear Information System (INIS)

Singal, Ashok K.

2016-01-01

Radio maps of active galactic nuclei often show linear features, called jets, on both parsec and kiloparsec scales. These jets supposedly possess relativistic motion and are oriented close to the line of sight of the observer, and accordingly the relativistic Doppler beaming makes them look much brighter than they really are in their respective rest frames. The flux boosting due to the relativistic beaming is a very sensitive function of the jet orientation angle, as seen by the observer. Sometimes, large bends are seen in these jets, with misalignments being 90° or more, which might imply a change in the orientation angle that should cause a large change in the relativistic beaming factor. Hence, if relativistic beaming does play an important role in these jets such large bends should usually show high contrast in the brightness of the jets before and after the bend. It needs to be kept in mind that sometimes a small intrinsic change in the jet angle might appear as a much larger misalignment due to the effects of geometrical projection, especially when seen close to the line of sight. What really matters are the initial and final orientation angles of the jet with respect to the observer’s line of sight. Taking the geometrical projection effects properly into account, we calculate the consequences of the presumed relativistic beaming and demonstrate that there ought to be large brightness ratios in jets before and after the observed misalignments.

Relativistic Doppler Beaming and Misalignments in AGN Jets

Science.gov (United States)

Singal, Ashok K.

2016-08-01

Radio maps of active galactic nuclei often show linear features, called jets, on both parsec and kiloparsec scales. These jets supposedly possess relativistic motion and are oriented close to the line of sight of the observer, and accordingly the relativistic Doppler beaming makes them look much brighter than they really are in their respective rest frames. The flux boosting due to the relativistic beaming is a very sensitive function of the jet orientation angle, as seen by the observer. Sometimes, large bends are seen in these jets, with misalignments being 90° or more, which might imply a change in the orientation angle that should cause a large change in the relativistic beaming factor. Hence, if relativistic beaming does play an important role in these jets such large bends should usually show high contrast in the brightness of the jets before and after the bend. It needs to be kept in mind that sometimes a small intrinsic change in the jet angle might appear as a much larger misalignment due to the effects of geometrical projection, especially when seen close to the line of sight. What really matters are the initial and final orientation angles of the jet with respect to the observer’s line of sight. Taking the geometrical projection effects properly into account, we calculate the consequences of the presumed relativistic beaming and demonstrate that there ought to be large brightness ratios in jets before and after the observed misalignments.

Relativistic Polarizable Embedding

DEFF Research Database (Denmark)

Hedegård, Erik Donovan; Bast, Radovan; Kongsted, Jacob

2017-01-01

Most chemistry, including chemistry where relativistic effects are important, occurs in an environment, and in many cases, this environment has a significant effect on the chemistry. In nonrelativistic quantum chemistry, a lot of progress has been achieved with respect to including environments s...

A new perspective on relativistic transformation for Maxwell's equations of electrodynamics

International Nuclear Information System (INIS)

Huang, Y.-S.

2009-01-01

A new scheme for relativistic transformation of the electromagnetic fields is formulated through relativistic transformation in the wavevector space, instead of the space-time space. Maxwell's equations of electrodynamics are shown to be form-invariant among inertial frames in accordance with this new scheme of relativistic transformation. This new perspective on relativistic transformation not only fulfills the principle of relativity, but is also compatible with quantum theory.

Thermal BEC Black Holes

Directory of Open Access Journals (Sweden)

Roberto Casadio

2015-10-01

Full Text Available We review some features of Bose–Einstein condensate (BEC models of black holes obtained by means of the horizon wave function formalism. We consider the Klein–Gordon equation for a toy graviton field coupled to a static matter current in a spherically-symmetric setup. The classical field reproduces the Newtonian potential generated by the matter source, while the corresponding quantum state is given by a coherent superposition of scalar modes with a continuous occupation number. An attractive self-interaction is needed for bound states to form, the case in which one finds that (approximately one mode is allowed, and the system of N bosons can be self-confined in a volume of the size of the Schwarzschild radius. The horizon wave function formalism is then used to show that the radius of such a system corresponds to a proper horizon. The uncertainty in the size of the horizon is related to the typical energy of Hawking modes: it decreases with the increasing of the black hole mass (larger number of gravitons, resulting in agreement with the semiclassical calculations and which does not hold for a single very massive particle. The spectrum of these systems has two components: a discrete ground state of energy m (the bosons forming the black hole and a continuous spectrum with energy ω > m (representing the Hawking radiation and modeled with a Planckian distribution at the expected Hawking temperature. Assuming the main effect of the internal scatterings is the Hawking radiation, the N-particle state can be collectively described by a single-particle wave-function given by a superposition of a total ground state with energy M = Nm and Entropy 2015, 17 6894 a Planckian distribution for E > M at the same Hawking temperature. This can be used to compute the partition function and to find the usual area law for the entropy, with a logarithmic correction related to the Hawking component. The backreaction of modes with ω > m is also shown to reduce

Relativistic laser channeling in plasmas for fast ignition

Science.gov (United States)

Lei, A. L.; Pukhov, A.; Kodama, R.; Yabuuchi, T.; Adumi, K.; Endo, K.; Freeman, R. R.; Habara, H.; Kitagawa, Y.; Kondo, K.; Kumar, G. R.; Matsuoka, T.; Mima, K.; Nagatomo, H.; Norimatsu, T.; Shorokhov, O.; Snavely, R.; Yang, X. Q.; Zheng, J.; Tanaka, K. A.

2007-12-01

We report an experimental observation suggesting plasma channel formation by focusing a relativistic laser pulse into a long-scale-length preformed plasma. The channel direction coincides with the laser axis. Laser light transmittance measurement indicates laser channeling into the high-density plasma with relativistic self-focusing. A three-dimensional particle-in-cell simulation reproduces the plasma channel and reveals that the collimated hot-electron beam is generated along the laser axis in the laser channeling. These findings hold the promising possibility of fast heating a dense fuel plasma with a relativistic laser pulse.

Modelling of the PROTO-II crossover network

International Nuclear Information System (INIS)

Proulx, G.A.; Lackner, H.; Spence, P.; Wright, T.P.

1985-01-01

In order to drive a double ring, symmetrically fed bremsstrahlung diode, the PROTO II accelerator was redesigned. The radially converging triplate water line was reconfigured to drive two radial converging triplate lines in parallel. The four output lines were connected to the two input lines via an electrically enclosed tubular crossover network. Low-voltage Time Domain Reflectrometry (TDR) experiments were conducted on a full scale water immersed model of one section of the crossover network as an aid in this design. A lumped element analysis of the power flow through the network was inadequate in explaining the observed wave transmission and reflection characteristics. A more detailed analysis was performed with a circuit code in which we considered both localized lump-element and transmission line features of the crossover network. Experimental results of the model tests are given and compared with the circuit simulations. 7 figs

On the convexity of relativistic hydrodynamics

International Nuclear Information System (INIS)

Ibáñez, José M; Martí, José M; Cordero-Carrión, Isabel; Miralles, Juan A

2013-01-01

The relativistic hydrodynamic system of equations for a perfect fluid obeying a causal equation of state is hyperbolic (Anile 1989 Relativistic Fluids and Magneto-Fluids (Cambridge: Cambridge University Press)). In this report, we derive the conditions for this system to be convex in terms of the fundamental derivative of the equation of state (Menikoff and Plohr1989 Rev. Mod. Phys. 61 75). The classical limit is recovered. Communicated by L Rezzolla (note)

Limits and signatures of relativistic spaceflight

Science.gov (United States)

Yurtsever, Ulvi; Wilkinson, Steven

2018-01-01

While special relativity imposes an absolute speed limit at the speed of light, our Universe is not empty Minkowski spacetime. The constituents that fill the interstellar/intergalactic vacuum, including the cosmic microwave background photons, impose a lower speed limit on any object travelling at relativistic velocities. Scattering of cosmic microwave photons from an ultra-relativistic object may create radiation with a characteristic signature allowing the detection of such objects at large distances.

Angular analyses in relativistic quantum mechanics; Analyses angulaires en mecanique quantique relativiste

Energy Technology Data Exchange (ETDEWEB)

Moussa, P [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

1968-06-01

This work describes the angular analysis of reactions between particles with spin in a fully relativistic fashion. One particle states are introduced, following Wigner's method, as representations of the inhomogeneous Lorentz group. In order to perform the angular analyses, the reduction of the product of two representations of the inhomogeneous Lorentz group is studied. Clebsch-Gordan coefficients are computed for the following couplings: l-s coupling, helicity coupling, multipolar coupling, and symmetric coupling for more than two particles. Massless and massive particles are handled simultaneously. On the way we construct spinorial amplitudes and free fields; we recall how to establish convergence theorems for angular expansions from analyticity hypothesis. Finally we substitute these hypotheses to the idea of 'potential radius', which gives at low energy the usual 'centrifugal barrier' factors. The presence of such factors had never been deduced from hypotheses compatible with relativistic invariance. (author) [French] On decrit un formalisme permettant de tenir compte de l'invariance relativiste, dans l'analyse angulaire des amplitudes de reaction entre particules de spin quelconque. Suivant Wigner, les etats a une particule sont introduits a l'aide des representations du groupe de Lorentz inhomogene. Pour effectuer les analyses angulaires, on etudie la reduction du produit de deux representations du groupe de Lorentz inhomogene. Les coefficients de Clebsch-Gordan correspondants sont calcules dans les couplages suivants: couplage l-s couplage d'helicite, couplage multipolaire, couplage symetrique pour plus de deux particules. Les particules de masse nulle et de masse non nulle sont traitees simultanement. Au passage, on introduit les amplitudes spinorielles et on construit les champs libres, on rappelle comment des hypotheses d'analyticite permettent d'etablir des theoremes de convergence pour les developpements angulaires. Enfin on fournit un substitut a la

Gravitation relativiste

CERN Document Server

Hakim, Rémi

1994-01-01

Il existe à l'heure actuelle un certain nombre de théories relativistes de la gravitation compatibles avec l'expérience et l'observation. Toutefois, la relativité générale d'Einstein fut historiquement la première à fournir des résultats théoriques corrects en accord précis avec les faits.

Relativistic klystron

International Nuclear Information System (INIS)

Marks, R.

1985-09-01

Theoretical analysis is presented of a relativisic klystron; i.e. a high-relativistic bunched electron beam which is sent through a succession of tuned cavities and has its energy replenished by periodic induction accelerator units. Parameters are given for a full-size device and for an experimental device using the FEL at the ETA; namely the ELF Facility. 6 refs., 2 figs

Viscous photons in relativistic heavy ion collisions

International Nuclear Information System (INIS)

Dion, Maxime; Paquet, Jean-Francois; Young, Clint; Jeon, Sangyong; Gale, Charles; Schenke, Bjoern

2011-01-01

Theoretical studies of the production of real thermal photons in relativistic heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) are performed. The space-time evolution of the colliding system is modelled using music, a 3+1D relativistic hydrodynamic simulation, using both its ideal and viscous versions. The inclusive spectrum and its azimuthal angular anisotropy are studied separately, and the relative contributions of the different photon sources are highlighted. It is shown that the photon v 2 coefficient is especially sensitive to the details of the microscopic dynamics like the equation of state, the ratio of shear viscosity over entropy density, η/s, and to the morphology of the initial state.

Quasi-relativistic fermions and dynamical flavour oscillations

CERN Document Server

Alexandre, Jean; Mavromatos, Nick E.

2014-01-01

We introduce new Lorentz-symmetry violating kinematics for a four-fermion interaction model, where dynamical mass generation is allowed, irrespectively of the strength of the coupling. In addition, these kinematics lead to a quasi-relativistic dispersion relation, in the sense that it is relativistic in both the infrared and the ultraviolet, but not in an intermediate regime, characterized by the mass $M$. For two fermions, we show that a flavour-mixing mass matrix is generated dynamically, and the Lorentz symmetric limit $M\\to\\infty$ leads to two free relativistic fermions, with flavour oscillations. This model, valid for either Dirac or Majorana fermions, can describe any set of phenomenological values for the eigen masses and the mixing angle.

Regional-Dependent Intestinal Permeability and BCS Classification: Elucidation of pH-Related Complexity in Rats Using Pseudoephedrine

OpenAIRE

Fairstein, Moran; Swissa, Rotem; Dahan, Arik

2013-01-01

Based on its lower Log P value relative to metoprolol, a marker for the low/high-permeability (Peff) class boundary, pseudoephedrine was provisionally classified as BCS low-permeability compound. On the other hand, following oral administration, pseudoephedrine fraction dose absorbed (Fabs) and systemic bioavailability approaches 100%. This represents a challenge to the generally recognized Peff–Fabs correlation. The purpose of this study was to elucidate the underlying mechanisms behind the ...

Analysis of multi-step transitions in spin crossover nanochains

Energy Technology Data Exchange (ETDEWEB)

Chiruta, Daniel [GEMaC, Université de Versailles Saint-Quentin-en-Yvelines, CNRS-UVSQ (UMR 8635), 78035 Versailles Cedex (France); LISV, Université de Versailles Saint-Quentin-en-Yvelines, 78140 Velizy (France); Faculty of Electrical Engineering and Computer Science, Stefan cel Mare University, Suceava 720229 (Romania); Linares, Jorge, E-mail: jorge.linares@uvsq.fr [GEMaC, Université de Versailles Saint-Quentin-en-Yvelines, CNRS-UVSQ (UMR 8635), 78035 Versailles Cedex (France); Garcia, Yann, E-mail: yann.garcia@uclouvain.be [Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Molecules, Solids and Reactivity (IMCN/MOST), Place Louis Pasteur, 1, 1348 Louvain-la-Neuve (Belgium); Dimian, Mihai [Faculty of Electrical Engineering and Computer Science, Stefan cel Mare University, Suceava 720229 (Romania); Dahoo, Pierre Richard [LATMOS, Université de Versailles-Saint-Quentin-en-Yvelines, CNRS-UPMC-UVSQ (UMR 8190), 78280 Guyancourt (France)

2014-02-01

The temperature driven phase transition occurring in spin crossover nanochains has been studied by an Ising-like model considering both short-range and long-range interactions. Various types of spin crossover profiles have been described in this framework, including a novel three-step transition identified in a nanosystem with eight molecules, which is modeled for the first time. A special interest has been also given to stepwise transitions accompanied by two hysteresis loops. The edge and size effects on spin crossover behavior have been investigated in order to get a deeper insight of the underlying mechanisms involved in these unusual spin transitions.

Pressure and Temperature Sensors Using Two Spin Crossover Materials

Science.gov (United States)

Jureschi, Catalin-Maricel; Linares, Jorge; Boulmaali, Ayoub; Dahoo, Pierre Richard; Rotaru, Aurelian; Garcia, Yann

2016-01-01

The possibility of a new design concept for dual spin crossover based sensors for concomitant detection of both temperature and pressure is presented. It is conjectured from numerical results obtained by mean field approximation applied to a Ising-like model that using two different spin crossover compounds containing switching molecules with weak elastic interactions it is possible to simultaneously measure P and T. When the interaction parameters are optimized, the spin transition is gradual and for each spin crossover compounds, both temperature and pressure values being identified from their optical densities. This concept offers great perspectives for smart sensing devices. PMID:26848663

Pressure and Temperature Sensors Using Two Spin Crossover Materials.

Science.gov (United States)

Jureschi, Catalin-Maricel; Linares, Jorge; Boulmaali, Ayoub; Dahoo, Pierre Richard; Rotaru, Aurelian; Garcia, Yann

2016-02-02

The possibility of a new design concept for dual spin crossover based sensors for concomitant detection of both temperature and pressure is presented. It is conjectured from numerical results obtained by mean field approximation applied to a Ising-like model that using two different spin crossover compounds containing switching molecules with weak elastic interactions it is possible to simultaneously measure P and T. When the interaction parameters are optimized, the spin transition is gradual and for each spin crossover compounds, both temperature and pressure values being identified from their optical densities. This concept offers great perspectives for smart sensing devices.

Pressure and Temperature Sensors Using Two Spin Crossover Materials

Directory of Open Access Journals (Sweden)

Catalin-Maricel Jureschi

2016-02-01

Full Text Available The possibility of a new design concept for dual spin crossover based sensors for concomitant detection of both temperature and pressure is presented. It is conjectured from numerical results obtained by mean field approximation applied to a Ising-like model that using two different spin crossover compounds containing switching molecules with weak elastic interactions it is possible to simultaneously measure P and T. When the interaction parameters are optimized, the spin transition is gradual and for each spin crossover compounds, both temperature and pressure values being identified from their optical densities. This concept offers great perspectives for smart sensing devices.

On the relativistic extended Thomas-Fermi method

International Nuclear Information System (INIS)

Centelles, M.; Vinas, X.; Barranco, M.; Schuck, P.

1990-01-01

We have derived the semiclassical relativistic energy functional for a set of fermions moving in the mean field arising from scalar and vector fields, including up to ℎ 2 corrective terms. The method is applied to a relativistic harmonic oscillator model for which the semiclassical result can be compared with the exact solution of the Dirac equation. (orig.)

On the relativistic extended Thomas-Fermi method

International Nuclear Information System (INIS)

Centelles, M.; Vinas, X.; Barranco, M.; Schuck, P.

1990-01-01

We have derived the semiclassical relativistic energy functional for a set of fermions moving in the mean field arising from scalar and vector fields, including up to ℎ 2 corrective terms. The method is applied to a relativistic harmonic oscillator model for which the semiclassical result can be compared with the exact solution of the Dirac equation

Low-momentum-transfer nonrelativistic limit of the relativistic impulse approximation expression for Compton-scattering doubly differential cross sections and characterization of their relativistic contributions

International Nuclear Information System (INIS)

LaJohn, L. A.

2010-01-01

The nonrelativistic (nr) impulse approximation (NRIA) expression for Compton-scattering doubly differential cross sections (DDCS) for inelastic photon scattering is recovered from the corresponding relativistic expression (RIA) of Ribberfors [Phys. Rev. B 12, 2067 (1975)] in the limit of low momentum transfer (q→0), valid even at relativistic incident photon energies ω 1 >m provided that the average initial momentum of the ejected electron i > is not too high, that is, i > b 1 >m using nr expressions when θ is small. For example, a 1% accuracy can be obtained when ω 1 =1 MeV if θ 1 increases into the MeV range, the maximum θ at which an accurate Compton peak can be obtained from nr expressions approaches closer to zero, because the θ at which the relativistic shift of CP to higher energy is greatest, which starts at 180 deg. when ω 1 min ,ρ rel ) (where p min is the relativistic version of the z component of the momentum of the initial electron and ρ rel is the relativistic charge density) and K(p min ) on p min . This characterization approach was used as a guide for making the nr QED S-matrix expression for the Compton peak kinematically relativistic. Such modified nr expressions can be more readily applied to large systems than the fully relativistic version.

Relativistic Coulomb excitation

International Nuclear Information System (INIS)

Winther, A.; Alder, K.

1979-01-01

Coulomb excitation of both target and projectile in relativistic heavy ion collisions is evaluated including the lowest order correction for the deviation from a straight line trajectory. Explicit results for differential and total cross sections are given in the form of tables and figures. (Auth.)

Genetic relationships between body condition score and reproduction traits in Canadian Holstein and Ayrshire first-parity cows.

Science.gov (United States)

Bastin, C; Loker, S; Gengler, N; Sewalem, A; Miglior, F

2010-05-01

The objective of this study was to investigate the genetic relationship between body condition score (BCS) and reproduction traits for first-parity Canadian Ayrshire and Holstein cows. Body condition scores were collected by field staff several times over the lactation in herds from Québec, and reproduction records (including both fertility and calving traits) were extracted from the official database used for the Canadian genetic evaluation of those herds. For each breed, six 2-trait animal models were run; they included random regressions that allowed the estimation of genetic correlations between BCS over the lactation and reproduction traits that are measured as a single lactation record. Analyses were undertaken on data from 108 Ayrshire herds and 342 Holstein herds. Average daily heritabilities of BCS were close to 0.13 for both breeds; these relatively low estimates might be explained by the high variability among herds and BCS evaluators. Genetic correlations between BCS and interval fertility traits (days from calving to first service, days from first service to conception, and days open) were negative and ranged between -0.77 and -0.58 for Ayrshire and between -0.31 and -0.03 for Holstein. Genetic correlations between BCS and 56-d nonreturn rate at first insemination were positive and moderate. The trends of these genetic correlations over the lactation suggest that a genetically low BCS in early lactation would increase the number of days that the primiparous cow was not pregnant and would decrease the chances of the primiparous cow to conceive at first service. Genetic correlations between BCS and calving traits were generally the strongest at calving and decreased with increasing days in milk. The correlation between BCS at calving and maternal calving ease was 0.21 for Holstein and 0.31 for Ayrshire and emphasized the relationship between fat cows around calving and dystocia. Genetic correlations between calving traits and BCS during the subsequent

Radiative electron capture studied in relativistic heavy-ion atom collisions

International Nuclear Information System (INIS)

Stoehlker, T.; Kozhuharov, C.; Mokler, P.H.; Warczak, A.; Bosch, F.; Geissel, H.; Moshammer, R.; Scheidenberger, C.; Eichler, J.; Shirai, T.; Stachura, Z.; Rymuza, P.

1994-08-01

The process of Radiative Electron Capture (REC) in relativistic collisions of high-Z ions with low-Z gaseous and solid targets is studied experimentally and theoretically. The observed X-ray spectra are analysed with respect to photon angular distributions as well as to total K-REC cross sections. The experimental results for angle-differential cross sections are well-reproduced by exact relativistic calculations which yield significant deviations from standard sin 2 θ distributions. Total cross sections for K-REC are shown to follow a simple scaling rule obtained from exact relativistic calculations as well as from a non-relativistic dipole approximation. The agreement between these different theoretical approaches must be regarded as fortuitous, but it lends support to the use of the non-relativistic approach for practical purposes. (orig.)

Canonical analysis of non-relativistic particle and superparticle

Energy Technology Data Exchange (ETDEWEB)

Kluson, Josef [Masaryk University, Department of Theoretical Physics and Astrophysics, Faculty of Science, Brno (Czech Republic)

2018-02-15

We perform canonical analysis of non-relativistic particle in Newton-Cartan Background. Then we extend this analysis to the case of non-relativistic superparticle in the same background. We determine constraints structure of this theory and find generator of κ-symmetry. (orig.)

Methods in relativistic nuclear physics

International Nuclear Information System (INIS)

Danos, M.; Gillet, V.; Cauvin, M.

1984-01-01

This book is intended to provide the methods and tools for performing actual calculations for finite many-body systems of bound relativistic constituent particles. The aim is to cover thoroughly the methodological aspects of the relativistic many-body problem for bound states while avoiding the presentation of specific models. The many examples contained in the later part of the work are meant to give concrete illustrations of how to actually apply the methods which are given in the first part. The basic framework of the approach is the lagrangian field theory solved in the time-independent Schroedinger picture. (Auth.)

Fundamental problem in the relativistic approach to atomic structure theory

International Nuclear Information System (INIS)

Kagawa, Takashi

1987-01-01

It is known that the relativistic atomic structure theory contains a serious fundamental problem, so-called the Brown-Ravenhall (BR) problem or variational collapse. This problem arises from the fact that the energy spectrum of the relativistic Hamiltonian for many-electron systems is not bounded from below because the negative-energy solutions as well as the positive-energy ones are obtained from the relativistic equation. This report outlines two methods to avoid the BR problem in the relativistic calculation, that is, the projection operator method and the general variation method. The former method is described first. The use of a modified Hamiltonian containing a projection operator which projects the positive-energy solutions in the relativistic wave equation has been proposed to remove the BR difficulty. The problem in the use of the projection operator method is that the projection operator for the system cannot be determined uniquely. The final part of this report outlines the general variation method. This method can be applied to any system, such as relativistic ones whose Hamiltonian is not bounded from below. (Nogami, K.)

Relativistic particle in a box: Klein-Gordon versus Dirac equations

Science.gov (United States)

Alberto, Pedro; Das, Saurya; Vagenas, Elias C.

2018-03-01

The problem of a particle in a box is probably the simplest problem in quantum mechanics which allows for significant insight into the nature of quantum systems and thus is a cornerstone in the teaching of quantum mechanics. In relativistic quantum mechanics this problem allows also to highlight the implications of special relativity for quantum physics, namely the effect that spin has on the quantised energy spectra. To illustrate this point, we solve the problem of a spin zero relativistic particle in a one- and three-dimensional box using the Klein-Gordon equation in the Feshbach-Villars formalism. We compare the solutions and the energy spectra obtained with the corresponding ones from the Dirac equation for a spin one-half relativistic particle. We note the similarities and differences, in particular the spin effects in the relativistic energy spectrum. As expected, the non-relativistic limit is the same for both kinds of particles, since, for a particle in a box, the spin contribution to the energy is a relativistic effect.

Gastrointestinal Behavior of Weakly Acidic BCS Class II Drugs in Man--Case Study of Diclofenac Potassium.

Science.gov (United States)

Van Den Abeele, Jens; Brouwers, Joachim; Mattheus, Ruben; Tack, Jan; Augustijns, Patrick

2016-02-01

This study aimed to investigate the gastrointestinal supersaturation and precipitation behavior of a weakly acidic Biopharmaceutics Classification System (BCS) Class II drug in healthy volunteers. For this purpose, a tablet containing 50 mg diclofenac potassium (Cataflam(®)) was predissolved in 240 mL of water and this solution was subsequently orally administered to five healthy volunteers under fasted and fed state conditions with or without concomitant use of a proton-pump inhibitor (PPI) (40 mg esomeprazole, Nexiam(®)). Subsequently, total diclofenac content and dissolved intraluminal drug concentrations as well as drug thermodynamic solubility were determined in gastrointestinal aspirates. In all volunteers, gastric supersaturation resulted in precipitation of diclofenac in the stomach. The extent of precipitation correlated well with gastric pH (r = - 0.78). pH dependency of precipitation was corroborated by the absence of precipitate in the stomach after coadministration of a meal and/or a PPI. Diclofenac was found to be fully dissolved in the duodenum in all test conditions. It can be concluded that substantial pH-dependent gastric precipitation of a weakly acidic BCS Class II drug administered as a solution occurs in humans. With regard to its implications for intestinal absorption, results suggest the instantaneous redissolution of gastric drug precipitate upon transfer to the duodenum. Copyright © 2016. Published by Elsevier Inc.

Relativistic simulation of the Vlasov equation for plasma expansion into vacuum

Directory of Open Access Journals (Sweden)

H Abbasi

2012-12-01

Full Text Available   In this study, relativistic Vlasov simulation of plasma for expansion of collisionless plasma for into vacuum is presented. The model is based on 1+1 dimensional phase space and electrostatic approximation. For this purpose, the electron dynamics is studied by the relativistic Vlasov equation. Regardless of the ions temperature, fluid equations are used for their dynamics. The initial electrons distribution function is the relativistic Maxwellian. The results show that due to the electrons relativistic temperature, the process of the plasma expansion takes place faster, the resulting electric field is stronger and the ions are accelerated to higher velocities, in comparison to the non-relativistic case.

Relativistic thermodynamics and kinetic theory, with applications to cosmology

International Nuclear Information System (INIS)

Stewart, J.M.

1973-01-01

The discussion of relativistic thermodynamics and kinetic theory with applications to cosmology also covers the fundamentals and nonequilibrium relativistic kinetic theory and applications to cosmology and astrophysics. (U.S.)

Observational and theoretical aspects of relativistic astrophysics and cosmology

International Nuclear Information System (INIS)

Sanz, J.L.; Goicoechea, L.J.

1985-01-01

The studies of relativistic astrophysics and cosmology in these proceedings include primordial nucleosynthesis, nonluminous matter, star and galaxy evolution, cosmic microwave background, and general relativistic models of the universe

Relativistic stars in vector-tensor theories

Science.gov (United States)

Kase, Ryotaro; Minamitsuji, Masato; Tsujikawa, Shinji

2018-04-01

We study relativistic star solutions in second-order generalized Proca theories characterized by a U (1 )-breaking vector field with derivative couplings. In the models with cubic and quartic derivative coupling, the mass and radius of stars become larger than those in general relativity for negative derivative coupling constants. This phenomenon is mostly attributed to the increase of star radius induced by a slower decrease of the matter pressure compared to general relativity. There is a tendency that the relativistic star with a smaller mass is not gravitationally bound for a low central density and hence is dynamically unstable, but that with a larger mass is gravitationally bound. On the other hand, we show that the intrinsic vector-mode couplings give rise to general relativistic solutions with a trivial field profile, so the mass and radius are not modified from those in general relativity.

Cross-Over Clinical Trials?

Directory of Open Access Journals (Sweden)

Latif Gachkar

2017-01-01

Full Text Available Abstract Cross-Over Clinical Trials in comparison with Parallel groups clinical trials have some advantages such as control of confounding variables, small sample size, and short time to implement the research project. But this type of research has few essential limitations that discusses in this monogram.

Relativistic Wigner functions

Directory of Open Access Journals (Sweden)

Bialynicki-Birula Iwo

2014-01-01

Full Text Available Original definition of the Wigner function can be extended in a natural manner to relativistic domain in the framework of quantum field theory. Three such generalizations are described. They cover the cases of the Dirac particles, the photon, and the full electromagnetic field.

Single-crossover recombination in discrete time.

Science.gov (United States)

von Wangenheim, Ute; Baake, Ellen; Baake, Michael

2010-05-01

Modelling the process of recombination leads to a large coupled nonlinear dynamical system. Here, we consider a particular case of recombination in discrete time, allowing only for single crossovers. While the analogous dynamics in continuous time admits a closed solution (Baake and Baake in Can J Math 55:3-41, 2003), this no longer works for discrete time. A more general model (i.e. without the restriction to single crossovers) has been studied before (Bennett in Ann Hum Genet 18:311-317, 1954; Dawson in Theor Popul Biol 58:1-20, 2000; Linear Algebra Appl 348:115-137, 2002) and was solved algorithmically by means of Haldane linearisation. Using the special formalism introduced by Baake and Baake (Can J Math 55:3-41, 2003), we obtain further insight into the single-crossover dynamics and the particular difficulties that arise in discrete time. We then transform the equations to a solvable system in a two-step procedure: linearisation followed by diagonalisation. Still, the coefficients of the second step must be determined in a recursive manner, but once this is done for a given system, they allow for an explicit solution valid for all times.

Mixed precipitation occurrences over southern Québec, Canada, under warmer climate conditions using a regional climate model

Science.gov (United States)

Matte, Dominic; Thériault, Julie M.; Laprise, René

2018-05-01

Winter weather events with temperatures near 0°C are often associated with freezing rain. They can have major impacts on the society by causing power outages and disruptions to the transportation networks. Despite the catastrophic consequences of freezing rain, very few studies have investigated how their occurrences could evolve under climate change. This study aims to investigate the change of freezing rain and ice pellets over southern Québec using regional climate modeling at high resolution. The fifth-generation Canadian Regional Climate Model with climate scenario RCP 8.5 at 0.11° grid mesh was used. The precipitation types such as freezing rain, ice pellets or their combination are diagnosed using five methods (Cantin and Bachand, Bourgouin, Ramer, Czys and, Baldwin). The occurrences of the diagnosed precipitation types for the recent past (1980-2009) are found to be comparable to observations. The projections for the future scenario (2070-2099) suggested a general decrease in the occurrences of mixed precipitation over southern Québec from October to April. This is mainly due to a decrease in long-duration events (≥6 h ). Overall, this study contributes to better understand how the distribution of freezing rain and ice pellets might change in the future using high-resolution regional climate model.

Relativistic centrifugal instability

Science.gov (United States)

Gourgouliatos, Konstantinos N.; Komissarov, Serguei S.

2018-03-01

Near the central engine, many astrophysical jets are expected to rotate about their axis. Further out they are expected to go through the processes of reconfinement and recollimation. In both these cases, the flow streams along a concave surface and hence, it is subject to the centrifugal force. It is well known that such flows may experience the centrifugal instability (CFI), to which there are many laboratory examples. The recent computer simulations of relativistic jets from active galactic nuclei undergoing the process of reconfinement show that in such jets CFI may dominate over the Kelvin-Helmholtz instability associated with velocity shear (Gourgouliatos & Komissarov). In this letter, we generalize the Rayleigh criterion for CFI in rotating fluids to relativistic flows using a heuristic analysis. We also present the results of computer simulations which support our analytic criterion for the case of an interface separating two uniformly rotating cylindrical flows. We discuss the difference between CFI and the Rayleigh-Taylor instability in flows with curved streamlines.

Studying extremely peripheral collisions of relativistic heavy ions

International Nuclear Information System (INIS)

Fatyga, M.

1990-01-01

Relativistic heavy ion facilities have been proposed (and in some cases constructed) with an intent to search for a new state of matter, a quark gluon plasma. As with all tools in the experimental physics, one should always search for ways in which relativistic heavy ions can be used to study physical phenomena beyond this original goal. New possibilities for a study of higher order photonuclear excitations in extremely peripheral collisions of relativistic heavy ions are discussed in this contribution. Data on the electromagnetic and nuclear fragmentation of a 14.6Gev/nucleon 28 Si projectile are presented

Crecimiento económico, desarrollo sustentable y turismo: Una aproximación del posicionamiento de Baja California Sur (BCS en el Barómetro de Sustentabilidad

Directory of Open Access Journals (Sweden)

Reyna Ibáñez Pérez

2011-01-01

Full Text Available Uno de los mayores anhelos de toda sociedad es alcanzar un nivel económico elevado; otro es el de tener la oportunidad de disfrutar eternamente de los servicios proporcionados por la madre naturaleza. Sin embargo, las tendencias indican que se experimenta un deterioro importante en el ambiente, a la par, de una elevada concentración de pobreza. Esto, aunado a la dependencia que algunas entidades y países han desarrollado en relación a actividades -como la turística- se ha convertido en una de las preocupaciones centrales de los gobiernos, el establecer mediciones para determinar si las pautas de crecimiento y desarrollo, van acorde con el cuidado del ambiente y el bienestar de las personas. Por ello, dentro de este artículo se analizan la evolución del crecimiento económico y posicionamiento de Baja California Sur (BCS -un estado con importante actividad turística- en el Barómetro de Sustentabilidad. En la introducción, se aprecia la evolución del concepto de crecimiento y desarrollo, para continuar con la caracterización de la zona de estudio. Posteriormente, se detalla la metodología empleada. Enseguida, se estudia la situación actual del sector turístico en BCS y la evolución del crecimiento y desarrollo económico. En el análisis de resultados, se describen los factores que ubican a BCS en un nivel Medio de sustentabilidad. Finalmente, se presentan algunas reflexiones en relación a los retos que en materia de turismo, crecimiento económico, desarrollo sustentable afronta BCS.

Neutron relativistic phenomenological and microscopic optical potential

International Nuclear Information System (INIS)

Shen Qing-biao; Feng Da-chun; Zhuo Yi-zhong

1991-01-01

In this paper, both the phenomenological and microscopic neutron relativistic optical potentials are presented. The global neutron relativistic phenomenological optical potential (RPOP) based on the available experimental data for various nuclei ranging from C to U with incident energies E n =20--1000 MeV has been obtained through an automatic search of the best parameters by computer. Then the nucleon relativistic microscopic optical potential (RMOP) is studied by utilizing the effective Lagrangian based on the popular Walecka model. Through comparison between the theoretical results and experimental data we shed some insight into both the RMOP and RPOP. Further improvement concerning how to combine the phenomenological potential with the microscopic one in order to reduce the number of free parameters appearing in the RPOP is suggested

A relativistic, meson exchange model of pion-nucleon scattering

International Nuclear Information System (INIS)

Pearces, B.C.; Jennings, B.K.

1990-06-01

A relativistic meson exchange approach to the pion-nucleon interaction is developed using a three-dimensional relativistic two-body propagator, and the results using different propagators are compared. The relativistic approach is able to describe low energy scattering up to 400 MeV above threshold, while preserving the soft pion theorems. The different propagators give similar results, as the form factors necessary to get a fit suppress much of the multiple scattering. (Author) (24 refs., 4 tabs., 6 figs.)

On the dispersion characteristics of extraordinary mode in a relativistic fully degenerate electron plasma

Science.gov (United States)

Noureen, S.; Abbas, G.; Sarfraz, M.

2018-01-01

The study of relativistic degenerate plasmas is important in many astrophysical and laboratory environments. Using linearized relativistic Vlasov-Maxwell equations, a generalized expression for the plasma conductivity tensor is derived. Employing Fermi-Dirac distribution at zero temperature, the dispersion relation of the extraordinary mode in a relativistic degenerate electron plasma is investigated. The propagation characteristics are examined in different relativistic density ranges. The shifting of cutoff points due to relativistic effects is observed analytically and graphically. Non-relativistic and ultra-relativistic limiting cases are also presented.

Analytic study of 1D diffusive relativistic shock acceleration

Energy Technology Data Exchange (ETDEWEB)

Keshet, Uri, E-mail: ukeshet@bgu.ac.il [Physics Department, Ben-Gurion University of the Negev, POB 653, Be' er-Sheva 84105 (Israel)

2017-10-01

Diffusive shock acceleration (DSA) by relativistic shocks is thought to generate the dN / dE ∝ E{sup −p} spectra of charged particles in various astronomical relativistic flows. We show that for test particles in one dimension (1D), p {sup −1}=1−ln[γ{sub d}(1+β{sub d})]/ln[γ{sub u}(1+β{sub u})], where β{sub u}(β{sub d}) is the upstream (downstream) normalized velocity, and γ is the respective Lorentz factor. This analytically captures the main properties of relativistic DSA in higher dimensions, with no assumptions on the diffusion mechanism. Unlike 2D and 3D, here the spectrum is sensitive to the equation of state even in the ultra-relativistic limit, and (for a J(üttner-Synge equation of state) noticeably hardens with increasing 1<γ{sub u}<57, before logarithmically converging back to p (γ{sub u→∞})=2. The 1D spectrum is sensitive to drifts, but only in the downstream, and not in the ultra-relativistic limit.

50 CFR 660.320 - Open access fishery-crossover provisions.

Science.gov (United States)

2010-10-01

... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Open access fishery-crossover provisions... West Coast Groundfish-Open Access Fisheries § 660.320 Open access fishery—crossover provisions. (a) Operating in both limited entry and open access fisheries. See provisions at § 660.60, subpart C. (b...

Relativistic classical limit of quantum theory

International Nuclear Information System (INIS)

Shin, G.R.; Rafelski, J.

1993-01-01

We study the classical limit of the equal-time relativistic quantum transport theory. We discuss in qualitative terms the need to fold first the Wigner function with a coarse-graining function. Only then does the singularity at ℎ→0 seem to be manageable. In the limit ℎ→0, we obtain the relativistic Vlasov equations for the particle and the antiparticle sector of the Fock space. Similarly, we address the evolution equations of the spin and the magnetic-moment density

Relativistic and Non-Relativistic Electronic Molecular-Structure Calculations for Dimers of 4p-, 5p-, and 6p-Block Elements

DEFF Research Database (Denmark)

Hofener, S.; Ahlrichs, R.; Knecht, S.

2012-01-01

We report results of non-relativistic and two-component relativistic single-reference coupled-cluster with single and double and perturbative triple excitations [CCSD(T)] treatments for the 4p-block dimers Ga2 to Br2, the 5p-block dimers In2 to I2, and their atoms. Extended basis sets up...

Pion production in relativistic collisions of nuclear drops

International Nuclear Information System (INIS)

Alonso, C.T.; Wilson, J.R.; McAbee, T.L.; Zingman, J.A.

1988-09-01

In a continuation of the long-standing effort of the nuclear physics community to model atomic nuclei as droplets of a specialized nuclear fluid, we have developed a hydrodynamic model for simulating the collisions of heavy nuclei at relativistic speeds. Our model couples ideal relativistic hydrodynamics with a new Monte Carlo treatment of dynamic pion production and tracking. The collective flow for low-energy (200 MeV/N) collisions predicted by this model compares favorably with results from earlier hydrodynamic calculations which used quite different numerical techniques. Our pion predictions at these lower energies appear to differ, however, from the experimental data on pion multiplicities. In this case of ultra-relativistic (200 GeV/N) collisions, our hydrodynamic model has produced baryonic matter distributions which are in reasonable agreement with recent experimental data. These results may shed some light on the sensitivity of relativistic collision data to the nuclear equation of state. 20 refs., 12 figs

A Link between Meiotic Prophase Progression and CrossoverControl

Energy Technology Data Exchange (ETDEWEB)

Carlton, Peter M.; Farruggio, Alfonso P.; Dernburg, Abby F.

2005-07-06

During meiosis, most organisms ensure that homologous chromosomes undergo at least one exchange of DNA, or crossover, to link chromosomes together and accomplish proper segregation. How each chromosome receives a minimum of one crossover is unknown. During early meiosis in Caenorhabditis elegans and many other species, chromosomes adopt a polarized organization within the nucleus, which normally disappears upon completion of homolog synapsis. Mutations that impair synapsis even between a single pair of chromosomes in C. elegans delay this nuclear reorganization. We quantified this delay by developing a classification scheme for discrete stages of meiosis. Immunofluorescence localization of RAD-51 protein revealed that delayed meiotic cells also contained persistent recombination intermediates. Through genetic analysis, we found that this cytological delay in meiotic progression requires double-strand breaks and the function of the crossover-promoting heteroduplex HIM-14 (Msh4) and MSH-5. Failure of X chromosome synapsis also resulted in impaired crossover control on autosomes, which may result from greater numbers and persistence of recombination intermediates in the delayed nuclei. We conclude that maturation of recombination events on chromosomes promotes meiotic progression, and is coupled to the regulation of crossover number and placement. Our results have broad implications for the interpretation of meiotic mutants, as we have shown that asynapsis of a single chromosome pair can exert global effects on meiotic progression and recombination frequency.

Hybrid Genetic Algorithm with Multiparents Crossover for Job Shop Scheduling Problems

Directory of Open Access Journals (Sweden)

Noor Hasnah Moin

2015-01-01

Full Text Available The job shop scheduling problem (JSSP is one of the well-known hard combinatorial scheduling problems. This paper proposes a hybrid genetic algorithm with multiparents crossover for JSSP. The multiparents crossover operator known as extended precedence preservative crossover (EPPX is able to recombine more than two parents to generate a single new offspring distinguished from common crossover operators that recombine only two parents. This algorithm also embeds a schedule generation procedure to generate full-active schedule that satisfies precedence constraints in order to reduce the search space. Once a schedule is obtained, a neighborhood search is applied to exploit the search space for better solutions and to enhance the GA. This hybrid genetic algorithm is simulated on a set of benchmarks from the literatures and the results are compared with other approaches to ensure the sustainability of this algorithm in solving JSSP. The results suggest that the implementation of multiparents crossover produces competitive results.

Relativistic beaming and quasar statistics

International Nuclear Information System (INIS)

Orr, M.J.L.; Browne, I.W.A.

1982-01-01

The statistical predictions of a unified scheme for the radio emission from quasars are explored. This scheme attributes the observed differences between flat- and steep-spectrum quasars to projection and the effects of relativistic beaming of the emission from the nuclear components. We use a simple quasar model consisting of a compact relativistically beamed core with spectral index zero and unbeamed lobes, spectral index - 1, to predict the proportion of flat-spectrum sources in flux-limited samples selected at different frequencies. In our model this fraction depends on the core Lorentz factor, γ and we find that a value of approximately 5 gives satisfactory agreement with observation. In a similar way the model is used to construct the expected number/flux density counts for flat-spectrum quasars from the observed steep-spectrum counts. Again, good agreement with the observations is obtained if the average core Lorentz factor is about 5. Independent estimates of γ from observations of superluminal motion in quasars are of the same order of magnitude. We conclude that the statistical properties of quasars are entirely consistent with the predictions of simple relativistic-beam models. (author)

Relativistic studies in actinides

International Nuclear Information System (INIS)

Weinberger, P.; Gonis, A.

1987-01-01

In this review the theoretical background is given for a relativistic description for actinide systems. A short introduction is given of the density functional theory which forms the basis for a fully relativistic single-particle theory. A section on the Dirac Hamiltonian is followed by a brief summary on group theoretical concepts. Single site scattering is presented such that formal extensions to the case of the presence of an internal (external) magnetic field and/or anisotropic scattering are evident. Multiple scattering is discussed such that it can readily be applied also to the problem of dislocations. In connection with the problem of selfconsistency particular attention is drawn to the use of complex energies. Finally the various theoretical aspects discussed are illustrated through the results of numerical calculations. 101 refs.; 37 figs.; 5 tabs

The structure and process of workers' compensation systems and the role of doctors: A comparison of Ontario and Québec.

Science.gov (United States)

Lippel, Katherine; Eakin, Joan M; Holness, D Linn; Howse, Dana

2016-12-01

This study sought to identify impacts of compensation system characteristics on doctors in Québec and Ontario. (i) Legal analysis; (ii) Qualitative methods applied to documentation and individual and group interviews with doctors (34) and other system participants (31); and (iii) Inter-jurisdictional transdisciplinary analysis involving cross-disciplinary comparative and integrative analysis of policy contexts, qualitative data, and the relationship between the two. In both jurisdictions the compensation board controlled decisions on work-relatedness and doctors perceived the bureaucratic process negatively. Gatekeeping roles differed between jurisdictions both in initial adjudication and in dispute processes. Québec legislation gives greater weight to the opinion of the treating physician. These differences affected doctors' experiences. Policy-makers should contextualize the sources of the "evidence" they rely on from intervention research because findings may reflect a system rather than an intervention effect. Researchers should consider policy contexts to both adequately design a study and interpret their results. Am. J. Ind. Med. 59:1070-1086, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Relativistic supersymmetric quantum mechanics based on Klein-Gordon equation

International Nuclear Information System (INIS)

Znojil, Miloslav

2004-01-01

Witten's the non-relativistic formalism of supersymmetric quantum mechanics was based on a factorization and partnership between Schroedinger equations. We show how it accommodates a transition to the partnership between relativistic Klein-Gordon equations

Ionization of hydrogen by a relativistic heavy projectile

International Nuclear Information System (INIS)

Hofstetter, S.; Hofmann, C.; Soff, G.

1991-10-01

Using a relativistic analogue of the classical trajectory Monte-Carlo method we investigate the influence of the magnetic field of a relativistic heavy projectile on the ionization cross section of hydrogen. In particular we focus our attention on the angular and energy distribution of the emitted delta electrons. (orig.)

Particle Acceleration and Radiative Losses at Relativistic Shocks

Science.gov (United States)

Dempsey, P.; Duffy, P.

A semi-analytic approach to the relativistic transport equation with isotropic diffusion and consistent radiative losses is presented. It is based on the eigenvalue method first introduced in Kirk & Schneider [5]and Heavens & Drury [3]. We demonstrate the pitch-angle dependence of the cut-off in relativistic shocks.

Causal dissipation for the relativistic dynamics of ideal gases.

Science.gov (United States)

Freistühler, Heinrich; Temple, Blake

2017-05-01

We derive a general class of relativistic dissipation tensors by requiring that, combined with the relativistic Euler equations, they form a second-order system of partial differential equations which is symmetric hyperbolic in a second-order sense when written in the natural Godunov variables that make the Euler equations symmetric hyperbolic in the first-order sense. We show that this class contains a unique element representing a causal formulation of relativistic dissipative fluid dynamics which (i) is equivalent to the classical descriptions by Eckart and Landau to first order in the coefficients of viscosity and heat conduction and (ii) has its signal speeds bounded sharply by the speed of light. Based on these properties, we propose this system as a natural candidate for the relativistic counterpart of the classical Navier-Stokes equations.

SPECIAL RELATIVISTIC HYDRODYNAMICS WITH GRAVITATION

Energy Technology Data Exchange (ETDEWEB)

Hwang, Jai-chan [Department of Astronomy and Atmospheric Sciences, Kyungpook National University, Daegu (Korea, Republic of); Noh, Hyerim [Korea Astronomy and Space Science Institute, Daejon (Korea, Republic of)

2016-12-20

Special relativistic hydrodynamics with weak gravity has hitherto been unknown in the literature. Whether such an asymmetric combination is possible has been unclear. Here, the hydrodynamic equations with Poisson-type gravity, considering fully relativistic velocity and pressure under the weak gravity and the action-at-a-distance limit, are consistently derived from Einstein’s theory of general relativity. An analysis is made in the maximal slicing, where the Poisson’s equation becomes much simpler than our previous study in the zero-shear gauge. Also presented is the hydrodynamic equations in the first post-Newtonian approximation, now under the general hypersurface condition. Our formulation includes the anisotropic stress.

Pivotal issues on relativistic electrons in ITER

Science.gov (United States)

Boozer, Allen H.

2018-03-01

The transfer of the plasma current from thermal to relativistic electrons is a threat to ITER achieving its mission. This danger is significantly greater in the nuclear than in the non-nuclear phase of ITER operations. Two issues are pivotal. The first is the extent and duration of magnetic surface breaking in conjunction with the thermal quenches. The second is the exponential sensitivity of the current transfer to three quantities: (1) the poloidal flux change required to e-fold the number of relativistic electrons, (2) the time τa after the beginning of the thermal quench before the accelerating electric field exceeds the Connor-Hastie field for runaway, and (3) the duration of the period τ_op in which magnetic surfaces remain open. Adequate knowledge does not exist to devise a reliable strategy for the protection of ITER. Uncertainties are sufficiently large that a transfer of neither a negligible nor the full plasma current to relativistic electrons can be ruled out during the non-nuclear phase of ITER. Tritium decay can provide a sufficiently strong seed for a dangerous relativistic-electron current even if τa and τ_op are sufficiently long to avoid relativistic electrons during non-nuclear operations. The breakup of magnetic surfaces that is associated with thermal quenches occurs on a time scale associated with fast magnetic reconnection, which means reconnection at an Alfvénic rather than a resistive rate. Alfvénic reconnection is well beyond the capabilities of existing computational tools for tokamaks, but its effects can be studied using its property of conserving magnetic helicity. Although the dangers to ITER from relativistic electrons have been known for twenty years, the critical issues have not been defined with sufficient precision to formulate an effective research program. Studies are particularly needed on plasma behavior in existing tokamaks during thermal quenches, behavior which could be clarified using methods developed here.

The spatial regulation of meiotic recombination hotspots: are all DSB hotspots crossover hotspots?

Science.gov (United States)

Serrentino, Maria-Elisabetta; Borde, Valérie

2012-07-15

A key step for the success of meiosis is programmed homologous recombination, during which crossovers, or exchange of chromosome arms, take place. Crossovers increase genetic diversity but their main function is to ensure accurate chromosome segregation. Defects in crossover number and position produce aneuploidies that represent the main cause of miscarriages and chromosomal abnormalities such as Down's syndrome. Recombination is initiated by the formation of programmed double strand breaks (DSBs), which occur preferentially at places called DSB hotspots. Among all DSBs generated, only a small fraction is repaired by crossover, the other being repaired by other homologous recombination pathways. Crossover maps have been generated in a number of organisms, defining crossover hotspots. With the availability of genome-wide maps of DSBs as well as the ability to measure genetically the repair outcome at several hotspots, it is becoming more and more clear that not all DSB hotspots behave the same for crossover formation, suggesting that chromosomal features distinguish different types of hotspots. Copyright © 2012. Published by Elsevier Inc.

Selectivity of the nucleon-induced deuteron breakup and relativistic effects

OpenAIRE

Witała, H.; Golak, J.; Skibiński, R.

2006-01-01

Theoretical predictions for the nucleon induced deuteron breakup process based on solutions of the three-nucleon Faddeev equation including such relativistic features as the relativistic kinematics and boost effects are presented. Large changes of the breakup cross section in some complete configurations are found at higher energies. The predicted relativistic effects, which are mostly of dynamical origin, seem to be supported by existing data.

On the time delay between ultra-relativistic particles

Energy Technology Data Exchange (ETDEWEB)

Fleury, Pierre, E-mail: pierre.fleury@uct.ac.za [Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701, Cape Town (South Africa); Department of Physics, University of the Western Cape, Robert Sobukwe Road, Bellville 7535 (South Africa)

2016-09-10

The time delay between the receptions of ultra-relativistic particles emitted simultaneously is a useful observable for both fundamental physics and cosmology. The expression of the delay when the particles travel through an arbitrary spacetime has been derived recently by Fanizza et al., using a particular coordinate system and self-consistent assumptions. The present article shows that this formula enjoys a simple physical interpretation: the relative velocity between two ultra-relativistic particles is constant. This result reveals an interesting kinematical property of general relativity, namely that the tidal forces experienced by ultra-relativistic particles in the direction of their motion are much smaller than those experienced orthogonally to their motion.

On the time delay between ultra-relativistic particles

International Nuclear Information System (INIS)

Fleury, Pierre

2016-01-01

The time delay between the receptions of ultra-relativistic particles emitted simultaneously is a useful observable for both fundamental physics and cosmology. The expression of the delay when the particles travel through an arbitrary spacetime has been derived recently by Fanizza et al., using a particular coordinate system and self-consistent assumptions. The present article shows that this formula enjoys a simple physical interpretation: the relative velocity between two ultra-relativistic particles is constant. This result reveals an interesting kinematical property of general relativity, namely that the tidal forces experienced by ultra-relativistic particles in the direction of their motion are much smaller than those experienced orthogonally to their motion.

Relativistic spin precession in the double pulsar.

Science.gov (United States)

Breton, Rene P; Kaspi, Victoria M; Kramer, Michael; McLaughlin, Maura A; Lyutikov, Maxim; Ransom, Scott M; Stairs, Ingrid H; Ferdman, Robert D; Camilo, Fernando; Possenti, Andrea

2008-07-04

The double pulsar PSR J0737-3039A/B consists of two neutron stars in a highly relativistic orbit that displays a roughly 30-second eclipse when pulsar A passes behind pulsar B. Describing this eclipse of pulsar A as due to absorption occurring in the magnetosphere of pulsar B, we successfully used a simple geometric model to characterize the observed changing eclipse morphology and to measure the relativistic precession of pulsar B's spin axis around the total orbital angular momentum. This provides a test of general relativity and alternative theories of gravity in the strong-field regime. Our measured relativistic spin precession rate of 4.77 degrees (-0 degrees .65)(+0 degrees .66) per year (68% confidence level) is consistent with that predicted by general relativity within an uncertainty of 13%.

Modeling terrestrial gamma ray flashes produced by relativistic feedback discharges

Science.gov (United States)

Liu, Ningyu; Dwyer, Joseph R.

2013-05-01

This paper reports a modeling study of terrestrial gamma ray flashes (TGFs) produced by relativistic feedback discharges. Terrestrial gamma ray flashes are intense energetic radiation originating from the Earth's atmosphere that has been observed by spacecraft. They are produced by bremsstrahlung interactions of energetic electrons, known as runaway electrons, with air atoms. An efficient physical mechanism for producing large fluxes of the runaway electrons to make the TGFs is the relativistic feedback discharge, where seed runaway electrons are generated by positrons and X-rays, products of the discharge itself. Once the relativistic feedback discharge becomes self-sustaining, an exponentially increasing number of relativistic electron avalanches propagate through the same high-field region inside the thundercloud until the electric field is partially discharged by the ionization created by the discharge. The modeling results indicate that the durations of the TGF pulses produced by the relativistic feedback discharge vary from tens of microseconds to several milliseconds, encompassing all durations of the TGFs observed so far. In addition, when a sufficiently large potential difference is available in thunderclouds, a self-propagating discharge known as the relativistic feedback streamer can be formed, which propagates like a conventional positive streamer. For the relativistic feedback streamer, the positive feedback mechanism of runaway electron production by the positrons and X-rays plays a similar role as the photoionization for the conventional positive streamer. The simulation results of the relativistic feedback streamer show that a sequence of TGF pulses with varying durations can be produced by the streamer. The relativistic streamer may initially propagate with a pulsed manner and turn into a continuous propagation mode at a later stage. Milliseconds long TGF pulses can be produced by the feedback streamer during its continuous propagation. However

Travel agents and the prevention of health problems among travelers in Québec.

Science.gov (United States)

Provost, Sylvie; Gaulin, Colette; Piquet-Gauthier, Blandine; Emmanuelli, Julien; Venne, Sylvie; Dion, Réjean; Grenier, Jean-Luc; Dessau, Jean-Claude; Dubuc, Martine

2002-01-01

Among the factors influencing travelers to seek preventive health advice before departure, the travel agent's recommendation plays an important role. The objective of our study was to document the practices and needs of travel agents in Québec (Canada) in relation to the prevention of health problems among travelers. In June 2000, a cross-sectional descriptive survey was carried out among travel agents from all travel agencies in Québec. One agent per agency was asked to answer our questions. Data were collected using a 32-item telephone questionnaire. Altogether, 708 travel agents from the 948 agencies contacted answered our questionnaire (participation rate: 75%). Most respondents (81%) believed that the travel agent has a role to play in the prevention of health problems among travelers, especially to recommend that travelers consult a travel clinic before departure. Although over 80% of the agents interviewed mentioned recommending a visit to a travel clinic before an organized tour to Thailand or a backpacking trip in Mexico, less than half said they make the same recommendation for a stay in a seaside resort in Mexico. The majority of respondents were acquainted with the services offered in travel health clinics, and these clinics were the source of travel health information most often mentioned by travel agents. However, nearly 60% of the agents questioned had never personally consulted a travel clinic. When asked about the best way to receive information about travelers' health, more than 40% of respondents favoured receiving information newsletters from public health departments regularly whereas 28% preferred the Internet. Despite the limits of this study, our results should help the public health network better target its interventions aimed to inform travel agents on prevention of health problems among travelers.

Contribution to the theory of ultracold highly polarized Fermi gases

International Nuclear Information System (INIS)

Giraud, Sebastien

2010-01-01

This thesis deals with the N+1 body problem in highly polarized Fermi gases. This is the situation where a single atom of one spin species is immersed in a Fermi sea of atoms of the other species. The first part uses a Hamiltonian approach based on a general expansion for the wave function of the system with any number of particle-hole pairs. We show that the constructed series of successive approximations converges very rapidly and thus we get an essentially exact solution for the energy and the effective mass of the polaron. In one dimension, for two particular cases, this problem can be solved analytically. The excellent agreement with our series of approximations provides a further check of the reliability of this expansion. Finally, we consider more specifically various limiting cases, as well as the effect of the mass ratio between the two spin species. In the second part, we use the Feynman diagrams formalism to describe both the polaron and the bound state. For the polaron, we develop a theory which is equivalent to the Hamiltonian approach. For the bound state, we get again a series of successive approximations whose fast convergence is perfectly understood. Therefore, this approach provides an essentially exact solution to the problem along the whole BEC-BCS crossover. Finally, by comparing the energies of the two quasi-particles, we study the position of the polaron to bound state transition. (author)

Non-relativistic supersymmetry

International Nuclear Information System (INIS)

Clark, T.E.; Love, S.T.

1984-01-01

The most general one- and two-body hamiltonian invariant under galilean supersymmetry is constructed in superspace. The corresponding Feynman rules are given for the superfield Green functions. As demonstrated by a simple example, it is straightforward to construct models in which the supersymmetry is spontaneously broken by the non-relativistic vacuum. (orig.)

The Relativistic Rocket

Science.gov (United States)

Antippa, Adel F.

2009-01-01

We solve the problem of the relativistic rocket by making use of the relation between Lorentzian and Galilean velocities, as well as the laws of superposition of successive collinear Lorentz boosts in the limit of infinitesimal boosts. The solution is conceptually simple, and technically straightforward, and provides an example of a powerful…

Relativistic klystron research at SLAC and LLNL

International Nuclear Information System (INIS)

Allen, M.A.; Callin, R.S.; Deruyter, H.

1988-06-01

We are developing relativistic klystrons as a power source for high gradient accelerator applications such as large linear electron-positron colliders and compact accelerators. We have attained 200 MW peak power at 11.4 GHz from a relativistic klystron, and 140 MV/m longitudinal gradient in a short 11.4 GHz accelerator section. We report here briefly on our experiments so far. 5 refs., 1 fig., 1 tab