31894
2009
2009
eng
article
1
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Casimir energy of a BEC : from moderate interactions to the ideal gas
Considering the Casimir effect due to phononic excitations of a weakly interacting dilute Bose-Einstein condensate ( BEC), we derive a renormalized expression for the zero-temperature Casimir energy E-C of a BEC confined to a parallel plate geometry with periodic boundary conditions. Our expression is formally equivalent to the free energy of a bosonic field at finite temperature, with a nontrivial density of modes that we compute analytically. As a function of the interaction strength, E-C smoothly describes the transition from the weakly interacting Bogoliubov regime to the non- interacting ideal BEC. For the weakly interacting case, E-C reduces to leading order to the Casimir energy due to zero- point fluctuations of massless phonon modes. In the limit of an ideal Bose gas, our result correctly describes the Casimir energy going to zero.
http://iopscience.iop.org/1751-8121/
10.1088/1751-8113/42/4/045401
1751-8113
allegro:1991-2014
10108243
Journal of physics A. - ISSN 1751-8113. - 42 (2009), 4, Art. 045401
Jürgen Schiefele
Carsten Henkel
Institut für Physik und Astronomie
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