Dresden 2009 – wissenschaftliches Programm
DY 12.47: Poster
Dienstag, 24. März 2009, 14:30–16:30, P1A
Bose condensation for attractive interaction? — •Michael Männel1, Pavel Lipavský2,3, Klaus Morawetz4,5, and Michael Schreiber1 — 1Institute of Physics, Chemnitz University of Technology, 09107 Chemnitz, Germany — 2Institute of Physics, Academy of Sciences, Cukrovarnická 10, 16253 Prague 6, Czech Republic — 3Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 12116 Prague 2, Czech Republic — 4Research-Center Dresden-Rossendorf, Bautzner Landstr. 128, 01328 Dresden, Germany — 5International Center of Condensed Matter Physics, University of Brasilia, 70904-970, Brasilia-DF, Brazil
We investigate a Bose gas with finite range interaction using a scheme to eliminate successive collisions as well as a single-channel T-matrix approximation. For attractive interaction we find a Evans-Rashid transition from a quasi-ideal Bose gas to a BCS like phase with a gaped dispersion. The gap decreases with increasing density. At another critical point the gap vanishes, the dispersion becomes linear for small momenta and a Bose condensate appears. It is well known, that a Bose gas with contact interaction and a negative scattering length becomes instable and undergoes a gas-liquid or gas-solid transition. Looking for this instability we also calculate the pressure for the three phases.