Quantum distillation: dynamical generation of low-entropy states of strongly correlated fermions in an optical lattice

TL;DR

This paper investigates how strongly interacting fermions in an optical lattice can undergo quantum distillation during expansion, leading to low-entropy, nearly insulating states that could be useful for cooling in quantum simulations.

Contribution

It introduces the concept of quantum distillation during fermion expansion, showing how doublons cluster to form low-entropy states in optical lattices.

Findings

Doublons group together during expansion under strong interactions.

The resulting state is a metastable low-entropy band insulator.

Potential application in cooling two-component Fermi gases.

Abstract

Correlations between particles can lead to subtle and sometimes counterintuitive phenomena. We analyze one such case, occurring during the sudden expansion of fermions in a lattice when the initial state has a strong admixture of double occupancies. We promote the notion of quantum distillation: during the expansion, and in the presence of strongly repulsive interactions, doublons group together, forming a nearly ideal band insulator, which is metastable with a low entropy. We propose that this effect could be used for cooling purposes in experiments with two-component Fermi gases.