Seminarium "Coherence-Correlations-Complexity" (KFT, PWr)

Quantum distillation: how to make cold atoms cold

dr Jacek Herbrych

University of Tennessee, Knoxville, USA oraz Oak Ridge National Laboratory, Oak Ridge, USA

In my presentation, I will focus on one aspect of transient nonequilibrium mass transport, namely the quantum distillation in a system of interacting fermions. Quantum distillation is the dynamical spatial separation of the lattice gas into one portion that carries predominantly interaction energy and another one that carries mostly kinetic energy. Such phenomenon was proposed as a possible cooling mechanism for, both, bosons and fermions. Dynamical filtering leads to the formation of low entropy (and therefore low temperature) regions consisting of doubly occupied sites. 

I present a numerical investigation of the quantum distillation process within one- and quasi-one-dimensional lattice geometries. As a main result, we show that this phenomenon is not limited to the chains that were previously studied. Interestingly, there are additional dynamical processes on the two-leg ladder such as density oscillations and self-trapping of defects that lead to a less efficient distillation process. An investigation of the time evolution starting from product states provides an explanation for this behavior. Initial product states are also considered, since in optical lattice experiments such states are often used as the initial setup. I propose configurations that lead to a fast and efficient quantum distillation.