Classification of phase transitions of finite Bose-Einstein condensates in power law traps by Fisher zeros

Oliver Muelken   Phone: +49-(0)441-798-3467   Fax: +49-(0)441-798-3201
Peter Borrmann   Phone: +49-(0)441-798-3362   Fax: +49-(0)441-798-3201
Jens Harting   Phone: +49-(0)441-798-3467   Fax: +49-(0)441-798-3201
Heinrich Stamerjohanns   Phone: +49-(0)441-798-3467   Fax: +49-(0)441-798-3201

Small systems group   University of Oldenburg, Germany


Date: 20000620

Article: published in Phys. Rev. A 64, 013611 (2001)

Bose-Einstein condensation, Fisher zeros, complex temperature, phase transitions, small systems.

We present a detailed description of a classification scheme for phase
transitions in finite systems based on the distribution of Fisher zeros of the
canonical partition function in the complex temperature plane.  We apply this
scheme to finite Bose-systems in power law traps within a semi-analytic
approach with a continuous one-particle density of states $\Omega(E)\sim
E^{d-1}$ for different values of $d$ and to a three dimensional harmonically
confined ideal Bose-gas with discrete energy levels. Our results indicate that
the order of the Bose-Einstein condensation phase transition sensitively
depends on the confining potential.

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Upload by Oliver Muelken on June 20th 2000