500 research outputs found
Kinetics of the Phase Separation Transition in Cold-Atom Boson-Fermion Mixtures
We study the kinetics of the first order phase separation transition in
boson-fermion cold-atom mixtures. At sufficiently low temperatures such a
transition is driven by quantum fluctuations responsible for the formation of
critical nuclei of a stable phase. Based on a microscopic description of
interacting boson-fermion mixtures we derive an effective action for the
critical droplet and obtain an asymptotic expression for the nucleation rate in
the vicinity of the phase transition and near the spinodal instability of the
mixed phase. We also discuss effects of dissipation which play a dominant role
close to the transition point, and identify the regimes where quantum
nucleation can be experimentally observed in cold-atom systems.Comment: 4 pages 1 figure, typos correcte
Field-induced interaction of a pseudoscalar particle with photon in a magnetized plasma
The effective interaction of a pseudoscalar particle with photon in plasma
with the presence of a constant uniform magnetic field is investigated. It is
shown that under some physical conditions the effective coupling between
pseudoscalar particle and photon does not depend on medium parameters and
particles momentum. The probability of the familon decay into photon pair in a
strongly magnetized degenerate ultrarelativistic plasma is calculated.Comment: 10 pages, 2 figures. To be published in Modern Physics Letters
Propagation of axions in a strongly magnetized medium
The polarization operator of an axion in a degenerate gas of electrons
occupying the ground-state Landau level in a superstrong magnetic field G is investigated in a model with a
tree-level axion-electron coupling. It is shown that a dynamic axion mass,
which can fall within the allowed range of values , is generated under the conditions of strongly
magnetized neutron stars. As a result, the dispersion relation for axions is
appreciably different from that in a vacuum.Comment: RevTex, no figures, 13 pages, Revised version of the paper published
in J. Exp. Theor. Phys. {\bf 88}, 1 (1999
New bounds on the neutrino magnetic moment from the plasma induced neutrino chirality flip in a supernova
The neutrino chirality-flip process under the conditions of the supernova
core is investigated in detail with the plasma polarization effects in the
photon propagator taken into account, in a more consistent way than in earlier
publications. It is shown in part that the contribution of the proton fraction
of plasma is essential. New upper bounds on the neutrino magnetic moment are
obtained: mu_nu < (0.5 - 1.1) 10^{-12} mu_B from the limit on the supernova
core luminosity for nu_R emission, and mu_nu < (0.4 - 0.6) 10^{-12} mu_B from
the limit on the averaged time of the neutrino spin-flip. The best upper bound
on the neutrino magnetic moment from SN1987A is improved by the factor of 3 to
7.Comment: 19 pages, LaTeX, 7 EPS figures, submitted to Journal of Cosmology and
Astroparticle Physic
Actinic reticuloid: case report
This article is about the case of actinic reticuloid — the rare dermatosis which clinical presentation is similar to atopic dermatitis, T-cell lymphoma. Good treatment effect was obtained by long cycles (2 cycles for 3 months) of hydroxychloroquine and sun protective therapy included sunscreens SPF 50, nicotinic acid, sun-safe clothes which blocked ultraviolet radiation without any glucocorticosteroid drugs and cytostatic treatment
Large mixing angle oscillations as a probe of the deep solar interior
We re-examine the sensitivity of solar neutrino oscillations to noise in the
solar interior using the best current estimates of neutrino properties. Our
results show that the measurement of neutrino properties at KamLAND provides
new information about fluctuations in the solar environment on scales to which
standard helioseismic constraints are largely insensitive. We also show how the
determination of neutrino oscillation parameters from a combined fit of KamLAND
and solar data depends strongly on the magnitude of solar density fluctuations.
We argue that a resonance between helioseismic and Alfven waves might provide a
physical mechanism for generating these fluctuations and, if so,
neutrino-oscillation measurements could be used to constrain the size of
magnetic fields deep within the solar radiative zone.Comment: 13 pages, LaTeX file using AASLaTeX, 6 figures included. Improved
version including the new KamLAND data. To appear in APJ letter
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