Topology-Induced Spontaneous Non-reciprocal Pumping in Cold-Atom Systems with Loss

TL;DR

This paper demonstrates how topological properties combined with atom loss in a cold-atom system can induce spontaneous non-reciprocal pumping, revealing a new non-Hermitian phenomenon with potential applications in atomtronics.

Contribution

It introduces a cold-atom setup where topology and loss together enable non-reciprocal transport, acting as a switch for the non-Hermitian skin effect.

Findings

Non-reciprocal pumping occurs only with both loss and topological localization.

Asymmetric atomic population dynamics are observable at system edges.

The mechanism offers potential for non-reciprocal atomtronic devices.

Abstract

We propose a realistic cold-atom quantum setting where nontrivial energy-band topology induces non-reciprocal pumping. This is an intriguing non-Hermitian phenomenon that illustrates how topology, when assisted with atom loss, can act as a "switch" for non-Hermitian skin effect (NHSE), rather than as a passive property that is modified by the NHSE. In particular, we present a lattice shaking scenario to realize a two-dimensional cold-atom platform, where non-reciprocity is switched on only in the presence of both atom loss and topological localization due to time-reversal symmetry breaking. Such spontaneous non-reciprocal pumping is manifested by asymmetric dynamical evolution, detectable by atomic populations along the system edges. Our results may trigger possible applications in non-reciprocal atomtronics, where loss and topological mechanisms conspire to control atomic transport.