Density profile of a strictly two-dimensional Bose gas at finite temperature

Abstract

We study a Bose-condensed gas at finite temperature, in which the particles of the condensate and of the thermal cloud are constrained to move in a plane under radial harmonic confinement and interact via strictly two-dimensional collisions. The coupling parameters are obtained from a calculation of the many-body T-matrix and decreases as temperature increases through a dependence on the chemical potential and on the occupancy of excited states. We discuss the consequences on the condensate fraction and on the density profiles of the condensed and thermal components as functions of temperature, within a simplified form of the two-fluid model.

Temperature dependence of the energy of a vortex in a two-dimensional Bose gas

“…This is appropriate to a situation in which the s-wave scattering length starts to exceed the vertical confinement length. Previous work has established that the dimensionality of the scattering collisions strongly affects the equilibrium density profiles [10,11] and the process of free expansion of a BEC containing a vortex [12]. A similar study of the density profiles of a rotating BEC in 3D geometry at finite temperature has been carried out by Mizushima et al [13], who also determined the location of various dynamical instabilities within the Bogoliubov-Popov theory.…”

“…In Eq. ( 2) we have omitted a term due to thermal excitations [11], which is negligible in the temperature range of present interest (T ≤ 0.5T c , with T c the critical temperature).…”

Yukawa bosons in two-dimensional harmonic confinement

“…This can be done by taking a contact potential gδ(|r − r ′ |) in Eq. ( 11), where g = 4π 2 /m log |2 2 /(mµa 2 )| is the coupling parameter for the two-dimensional BEC [17,18,19] incorporating the s-wave scattering legth a. We assumed a negligible exchange correlation between the atoms (V xc = 0) and would like to stress here that the condensate density is approximated to the total density n GP (r) at absolute zero temperature (neglecting quantum fluctuation).…”

Feshbach resonances in a strictly two-dimensional atomic Bose gas

“…Equation ( 9) is our main result. The non-resonant first term has been calculated from the two-body T-matrix for a binary collision occurring at low momenta and energy in the presence of a condensate, which fixes the energy of each colliding atom at the chemical potential [29,30]. The resonant second term can be tuned by exploiting the dependence of the energy denominator on external parameters and in particular on the strength of the applied magnetic field.…”