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Title

Finite-temperature excitations of a trapped Bose-Fermi mixture

Author(s)

Liu, Xia-Ji;  Hu, Hui

Abstract

We present a detailed study of the low-lying collective excitations of a spherically trapped Bose-Fermi mixture at finite temperature in the collisionless regime. The excitation frequencies of the condensate are calculated self-consistently using the static Hartree-Fock-Bogoliubov theory within the Popov approximation. The frequency shifts and damping rates due to the coupled dynamics of the condensate, noncondensate, and degenerate Fermi gas are also taken into account by means of the random-phase approximation and linear-response theory. In our treatment, the dipole excitation remains close to the bare trapping frequency for all temperatures considered, and thus is consistent with the generalized Kohn theorem. We discuss in some detail the behavior of monopole and quadrupole excitations as a function of the Bose-Fermi coupling. At nonzero temperatures we find that, as the mixture moves towards spatial separation with increasing Bose-Fermi coupling, the damping rate of the monopole (quadrupole) excitation increases (decreases). This provides us a useful signature to identify the phase transition of spatial separation.

Publication type

Journal article

Source

Physical Review A: Atomic, Molecular, and Optical Physics, Vol. 68, no. 3 (Sep 2003), article no. 033613

Publication year

2003

FOR Code(s)

0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics;  0204 Condensed Matter Physics;  0205 Optical Physics

Keyword(s)

Approximation theory;  Atomic physics;  BEC;  Bose-Einstein condensation;  Bose-Fermi mixtures;  Differential equations;  Fermi level;  Finite-temperature excitation;  Hamiltonians;  Hartree-Fock-Bogoliubov theory;  Integral equations;  Lithium;  Mathematical transformations;  Matrix algebra;  Potassium;  Random-phase approximation;  Rubidium;  Sodium;  Statistical methods;  Trapped Bose-Fermi mixture

Publisher

American Physical Society

ISSN

1050-2947

Publisher URL

http://dx.doi.org/10.1103/PhysRevA.68.033613

Copyright

Copyright © 2003 The American Physical Society. The accepted manuscript of the paper is reproduced here for noncommerical purposes only in accordance with the copyright policy of the publisher.

Full text

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