Transition from the Bose-Einstein condensate to the Berezinskii-Kosterlitz-Thouless phase

Tapio Simula, M Lee, D Hutchinson

Research output: Contribution to journalLetterResearchpeer-review

23 Citations (Scopus)


We obtain a phase diagram for a trapped two-dimensional ultracold Bose gas. We find a critical temperature above which the free energy of a state with a pair of vortices of opposite circulation is lower than that for a vortex-free Bose-Einstein condensed ground state. We identify three distinct phases which are, in order of increasing temperature, a phase coherent Bose-Einstein condensate, a vortex pair plasma with a fluctuating condensate phase, and a thermal Bose gas. The existence of the vortex pair phase could be verified using current experimental set-ups.
Original languageEnglish
Pages (from-to)395 - 403
Number of pages9
JournalPhilosophical Magazine Letters
Issue number8
Publication statusPublished - 2005
Externally publishedYes

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