138 research outputs found
The chiral magnetic effect in hydrodynamical approach
In quark-gluon plasma nonzero chirality can be induced by the chiral anomaly.
When a magnetic field is applied to a system with nonzero chirality an
electromagnetic current is induced along the magnetic field. This phenomenon is
called the chiral magnetic effect. In this paper appearance of the chiral
magnetic effect in hydrodynamical approximation is shown. We consider a
hydrodynamical model for chiral liquid with two independent currents of left
and right handed particles in the presence of the chiral anomaly.Comment: 4 page
Radiation of electrons in Weibel-generated fields: a general case
Weibel instability turns out to be the a ubiquitous phenomenon in High-Energy
Density environments, ranging from astrophysical sources, e.g., gamma-ray
bursts, to laboratory experiments involving laser-produced plasmas.
Relativistic particles (electrons) radiate in the Weibel-produced magnetic
fields in the Jitter regime. Conventionally, in this regime, the particle
deflections are considered to be smaller than the relativistic beaming angle of
1/ ( being the Lorentz factor of an emitting particle) and the
particle distribution is assumed to be isotropic. This is a relatively
idealized situation as far as lab experiments are concerned. We relax the
assumption of the isotropy of radiating particle distribution and present the
extension of the jitter theory amenable for comparisons with experimental data.Comment: Proceedings of International Conference on HEDP/HEDLA-0
Entropy paradox in strongly correlated Fermi systems
A system of interacting, identical fermions described by standard Landau
Fermi-liquid (FL) theory can experience a rearrangement of its Fermi surface if
the correlations grow sufficiently strong, as occurs at a quantum critical
point where the effective mass diverges. As yet, this phenomenon defies full
understanding, but salient aspects of the non-Fermi-liquid (NFL) behavior
observed beyond the quantum critical point are still accessible within the
general framework of the Landau quasiparticle picture. Self-consistent
solutions of the coupled Landau equations for the quasiparticle momentum
distribution and quasiparticle energy spectrum are shown
to exist in two distinct classes, depending on coupling strength and on whether
the quasiparticle interaction is regular or singular at zero momentum transfer.
One class of solutions maintains the idempotency condition of
standard FL theory at zero temperature while adding pockets to the Fermi
surface. The other solutions are characterized by a swelling of the Fermi
surface and a flattening of the spectrum over a range of momenta
in which the quasiparticle occupancies lie between 0 and 1 even at T=0. The
latter, non-idempotent solution is revealed by analysis of a Poincar\'e mapping
associated with the fundamental Landau equation connecting and
and validated by solution of a variational condition that yields
the symmetry-preserving ground state. Paradoxically, this extraordinary
solution carries the burden of a large temperature-dependent excess entropy
down to very low temperatures, threatening violation of the Nernst Theorem. It
is argued that certain low-temperature phase transitions offer effective
mechanisms for shedding the entropy excess. Available measurements in
heavy-fermion compounds provide concrete support for such a scenario.Comment: 34 pages, 6 figure
The Ginzburg-Landau theory in application
A numerical approach to Ginzburg-Landau (GL) theory is demonstrated and we
review its applications to several examples of current interest in the research
on superconductivity. This analysis also shows the applicability of the
two-dimensional approach to thin superconductors and the re-defined effective
GL parameter kappa. For two-gap superconductors, the conveniently written GL
equations directly show that the magnetic behavior of the sample depends not
just on the GL parameter of two bands, but also on the ratio of respective
coherence lengths.Comment: To be published in Physica C, VORTEX VI Conference Proceeding
Fundamental solution method applied to time evolution of two energy level systems: exact and adiabatic limit results
A method of fundamental solutions has been used to investigate transitions in
two energy level systems with no level crossing in a real time. Compact
formulas for transition probabilities have been found in their exact form as
well as in their adiabatic limit. No interference effects resulting from many
level complex crossings as announced by Joye, Mileti and Pfister (Phys. Rev.
{\bf A44} 4280 (1991)) have been detected in either case. It is argued that
these results of this work are incorrect. However, some effects of Berry's
phases are confirmed.Comment: LaTeX2e, 23 pages, 8 EPS figures. Style correcte
Visual tool for estimating the fractal dimension of images
This work presents a new Visual Basic 6.0 application for estimating the
fractal dimension of images, based on an optimized version of the box-counting
algorithm. Following the attempt to separate the real information from noise,
we considered also the family of all band-pass filters with the same band-width
(specified as parameter). The fractal dimension can be thus represented as a
function of the pixel color code. The program was used for the study of
paintings cracks, as an additional tool which can help the critic to decide if
an artistic work is original or not. In its second version, the application was
extended for working also with csv files and three-dimensional images.Comment: A new version was accepted to Computer Physics Communications
doi:10.1016/j.cpc.2009.12.00
Supersymmetric Model of a 2D Long-Range Bose Liquid
The model Hamiltonian of a two-dimensional Bose liquid (proposed earlier by
Kane, Kivelson, Lee and Zhang as the Hamiltonian which has Jastrow-type
wavefunctions as the ground-state solution), is shown to possess
nonrelativistic supersymmetry. For the special value of the coupling constant
the quantum mechanics described by this Hamiltonian is shown to be
equivalent to the dynamics of (complex) eigenvalues of random Gaussian ensemble
of normal complex matrices. For general , an exact relation between the
equal-time current-current and density-density correlation functions is
obtained, and used to derive an asymptotically exact (at low wavevectors q)
spectrum of single-particle excitations beyond the superfluid ground-state
(realized at low 's). The ground-state at very large is shown
to be of ``Quantum Hexatic" type, possessing long-range orientational order and
quasi-long-range translational order but with zero shear modulus. Possible
scenaria of the ground-state phase transitions as function of are
discussed.Comment: Revtex; 12 pages, 1 Postscript figur
The influence of strong magnetic field on photon-neutrino reactions
The two-photon two-neutrino interaction induced by magnetic field is
investigated. In particular the processes and
are studied in the presence of strong magnetic
field. An effective Lagrangian and partial amplitudes of the processes are
presented. Neutrino emissivities due to the reactions and are calculated taking into
account of the photon dispersion and large radiative corrections. A comparison
of the results obtained with previous estimations and another inducing
mechanisms of the processes under consideration is made.Comment: 16 pages, LATEX, 3 EPS figures, based on the talk presented at XXXI
ITEP Winter School of Physics, Moscow, Russia, February 18 - 26, 200
On Fields with Finite Information Density
The existence of a natural ultraviolet cutoff at the Planck scale is widely
expected. In a previous Letter, it has been proposed to model this cutoff as an
information density bound by utilizing suitably generalized methods from the
mathematical theory of communication. Here, we prove the mathematical
conjectures that were made in this Letter.Comment: 31 pages, to appear in Phys.Rev.
Adiabatic following criterion, estimation of the nonadiabatic excitation fraction and quantum jumps
An accurate theory describing adiabatic following of the dark, nonabsorbing
state in the three-level system is developed. An analytical solution for the
wave function of the particle experiencing Raman excitation is found as an
expansion in terms of the time varying nonadiabatic perturbation parameter. The
solution can be presented as a sum of adiabatic and nonadiabatic parts. Both
are estimated quantitatively. It is shown that the limiting value to which the
amplitude of the nonadiabatic part tends is equal to the Fourier component of
the nonadiabatic perturbation parameter taken at the Rabi frequency of the
Raman excitation. The time scale of the variation of both parts is found. While
the adiabatic part of the solution varies slowly and follows the change of the
nonadiabatic perturbation parameter, the nonadiabatic part appears almost
instantly, revealing a jumpwise transition between the dark and bright states.
This jump happens when the nonadiabatic perturbation parameter takes its
maximum value.Comment: 33 pages, 8 figures, submitted to PRA on 28 Oct. 200
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