Düsseldorf 2007 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 12: Quantengase (Unordnung)

Q 12.2: Talk

Monday, March 19, 2007, 16:45–17:00, 6J

Mean-Field Phase Diagram of Disordered Bosons in a Lattice at Non-Zero Temperature — Konstantin Krutitsky, •Axel Pelster, and Robert Graham — Fachbereich Physik, Universität Duisburg-Essen, Lotharstraße 1, 47048 Duisburg, Germany

Bosons in a periodic lattice with on-site disorder at low but non-zero temperature are considered within a mean-field theory [1]. The criteria used for the definition of the superfluid, Mott insulator and Bose glass are analysed. Since the compressibility does never vanish at non-zero temperature, it cannot be used as a general criterion. We show that the phases are unambiguously distinguished by the superfluid density and the density of states of the low-energy exitations. The phase diagram of the system is calculated. It is shown that even a tiny temperature leads to a significant shift of the boundary between the Bose glass and superfluid.

[1] K.V. Krutitsky, A.Pelster, and R.Graham, New J.Phys. 8, 187 (2006)