1,798 research outputs found
Three-Body Losses in Trapped Bose-Einstein Condensed Gases
A time-dependent Kohn-Sham (KS)-like equation for N bosons in a trap is
generalized for the case of inelastic collisions. We derive adiabatic equations
which are used to calculate the nonlinear dynamics of the Bose-Einstein
condensate (BEC) and non-mean field corrections due to the three-body
recombination. We find that the calculated corrections are about 13 times
larger for 3D trapped dilute bose gases and about 7 times larger for 1D trapped
weakly interacting bose gases when compared with the corresponding corrections
for the ground state energy and for the collective frequencies.Comment: 11 pages, 2 figure
Cold Bose Gases near Feshbach Resonances
The lowest order constrained variational method [Phys. Rev. Lett. 88, 210403
(2002)] has been generalized for a dilute (in the sense that the range of
interatomic potential is small compared with inter-particle spacing) uniform
gas of bosons near the Feshbach resonance using the multi-channel zero-range
potential model. The method has been applied to Na (F=1, m_F=1) atoms near the
G Feshbach resonance. It is shown that at high densities, there are
significant differences between our results for the real part of energy per
particle and the one-channel zero-range potential approximation. We point out
the possibility of stabilization of the uniform con densate for the case of
negative scattering length.Comment: Revised version of cond-mat/0212196. Added Eqs. (21,22) and
references for section
Hydrodynamic Modes in a Trapped Strongly Interacting Fermi Gases of Atoms
The zero-temperature properties of a dilute two-component Fermi gas in the
BCS-BEC crossover are investigated. On the basis of a generalization of the
variational Schwinger method, we construct approximate semi-analytical formulae
for collective frequencies of the radial and the axial breathing modes of the
Fermi gas under harmonic confinement in the framework of the hydrodynamic
theory. It is shown that the method gives nearly exact solutions.Comment: 11 page
Dynamics of the Free Surface of a Conducting Liquid in a Near-Critical Electric Field
Near-critical behavior of the free surface of an ideally conducting liquid in
an external electric field is considered. Based on an analysis of three-wave
processes using the method of integral estimations, sufficient criteria for
hard instability of a planar surface are formulated. It is shown that the
higher-order nonlinearities do not saturate the instability, for which reason
the growth of disturbances has an explosive character.Comment: 19 page
Calculation of shear viscosity using Green-Kubo relations within a parton cascade
The shear viscosity of a gluon gas is calculated using the Green-Kubo
relation. Time correlations of the energy-momentum tensor in thermal
equilibrium are extracted from microscopic simulations using a parton cascade
solving various Boltzmann collision processes. We find that the pQCD based
gluon bremsstrahlung described by Gunion-Bertsch processes significantly lowers
the shear viscosity by a factor of 3-8 compared to elastic scatterings. The
shear viscosity scales with the coupling as 1/(alpha_s^2\log(1/alpha_s)). For a
constant coupling constant the shear viscosity to entropy density ratio has no
dependence on temperature. Replacing the pQCD-based collision angle
distribution of binary scatterings by an isotropic form decreases the shear
viscosity by a factor of 3.Comment: 17 pages, 5 figure
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