Symmetry-protected transport through a lattice with a local particle loss

TL;DR

This paper investigates how certain symmetries in a quantum lattice can protect particle transport from local losses, revealing conditions under which conductance remains unaffected despite dissipation.

Contribution

It demonstrates that spatial symmetry of eigenstates can protect transport in a lattice with local particle loss, a novel insight into dissipation-resistant quantum transport.

Findings

Transport can be unaffected by local loss at specific chemical potentials.

Symmetry of eigenstates underpins protected transport.

Density profile shows a drop at the lossy site at finite voltage.

Abstract

We study particle transport through a chain of coupled sites connected to free-fermion reservoirs at both ends, subjected to a local particle loss. The transport is characterized by calculating the conductance and particle density in the steady state using the Keldysh formalism for open quantum systems. Besides a reduction of conductance, we find that transport can remain (almost) unaffected by the loss for certain values of the chemical potential in the lattice. We show that this "protected" transport results from the spatial symmetry of single-particle eigenstates. At a finite voltage, the density profile develops a drop at the lossy site, connected to the onset of non-ballistic transport.