Stuttgart 2012 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 29: Ultra-cold atoms, ions and BEC II
A 29.1: Vortrag
Donnerstag, 15. März 2012, 10:30–10:45, V47.02
Pomeranchuk effect and spin-gradient cooling of Bose-Bose mixtures in an optical lattice — •Yongqiang Li, Reza Bakhtiari, Liang He, and Walter Hofstetter — Institut für Theoretische Physik, Johann Wolfgang Goethe-Universität, 60438 Frankfurt/Main, Germany
We theoretically investigate finite-temperature thermodynamics and demagnetization cooling of two-component Bose-Bose mixtures in a cubic optical lattice, by using bosonic dynamical mean field theory (BDMFT). We calculate the finite-temperature phase diagram, and remarkably find that the system can be heated from the superfluid into the Mott insulator at low temperature, analogous to the Pomeranchuk effect in 3He. This provides a promising many-body cooling technique. We examine the entropy distribution in the trapped system and discuss its dependence on temperature and an applied magnetic field gradient. Our numerical simulations quantitatively validate the spin-gradient demagnetization cooling scheme proposed in recent experiments.