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DY: Fachverband Dynamik und Statistische Physik
DY 11: Superfluidity and Bose-Einstein condensation
DY 11.4: Talk
Tuesday, March 27, 2007, 10:30–10:45, H2
Phase diagram for interacting Bose systems — •Michael Maennel1, Klaus Morawetz1,2, and Michael Schreiber1 — 1Institute of Physics, Chemnitz University of Technology, 09107 Chemnitz, Germany — 2Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str. 38, 01187 Dresden, Germany
We propose a new form of the inversion method in terms of selfenergy expansion to access the phase diagram of the Bose-Einstein transition. The dependence of the critical temperature on the interaction parameter is calculated. This is discussed with the help of a new condition for Bose-Einstein condensation in interacting systems which follows from the pole of the T-matrix the same way as from the divergence of the medium-dependent scattering length. A conserving many-body approximation consisting of screened ladder diagrams is proposed which describes the MC data more appropriate. The specific results are that a non-selfconsistent T-matrix leads to a linear coefficient in leading order of 4.7, the selfconsistent T-matrix due to the effective mass to a coefficient of 1.3 and the screened ladder approximation to 2.3 close to the Monte Carlo data.