On the critical point of an interacting two-dimensional trapped Bose gas
Department of Physics, Okayama University, 700-8530, Okayama, Japan
Revised: 14 January 2009
Published online: 25 March 2009
We consider a quantized vortex excitation in a two-dimensional, harmonically trapped Bose gas and derive an equation for the Berezinskii-Kosterlitz-Thouless transition temperature based on a simple free-energy argument. We relate the critical phase-space density at the transition to the ratio between the entropy gain and the corresponding cost in energy of creating a free vortex excitation in the system.
PACS: 03.75.Lm – Tunneling, Josephson effect, Bose-Einstein condensates in periodic potentials, solitons, vortices, and topological excitations / 05.30.Jp – Boson systems / 67.85.De – Dynamic properties of condensates; excitations, and superfluid flow
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009