Efficiency of fermionic quantum distillation

TL;DR

This paper investigates quantum distillation in the Fermi--Hubbard model on a ladder, revealing new dynamical behaviors and proposing configurations for efficient atom separation in optical lattices.

Contribution

It extends the understanding of quantum distillation from chains to ladder geometries and analyzes additional dynamical effects affecting efficiency.

Findings

Quantum distillation occurs in ladder geometries, not just chains.

Density oscillations and defect self-trapping reduce distillation efficiency.

Certain initial product states enable faster, more efficient distillation.

Abstract

We present a time-dependent density-matrix renormalization group investigation of the quantum distillation process within the Fermi--Hubbard model on a quasi-1D ladder geometry. The term distillation refers to the dynamical, spatial separation of singlons and doublons in the sudden expansion of interacting particles in an optical lattice, i.e., the release of a cloud of atoms from a trapping potential. Remarkably, quantum distillation can lead to a contraction of the doublon cloud, resulting in an increased density of the doublons in the core region compared to the initial state. As a main result, we show that this phenomenon is not limited to chains that were previously studied. Interestingly, there are additional dynamical processes on the two-leg ladder such as density oscillations and selftrapping 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 behaviour. Initial product states are also considered, since in optical lattice experiments such states are often used as the initial setup. We propose configurations that lead to a fast and efficient quantum distillation.