Dissipation-Stabilized Quantum Revivals in a Non-Hermitian Lattice Gauge Theory

TL;DR

This paper introduces a non-Hermitian lattice gauge theory variant of the PXP model, showing that non-Hermiticity can enhance quantum revivals and the stability of many-body scars, contrary to typical suppression expectations.

Contribution

It presents a non-Hermitian PXP model where oscillations are enhanced, and provides a similarity transformation linking it to the standard PXP model, revealing new effects of non-Hermiticity.

Findings

Enhanced quantum revivals in the non-Hermitian model.

Similarity transformation maps the model to the standard PXP.

Non-Hermiticity can stabilize coherent many-body modes.

Abstract

With the advent of quantum simulation experiments of lattice gauge theories (LGTs), an open question is the effect of non-Hermiticity on their rich physics. The well-known PXP model, a U$(1)$ LGT with a two-level electric field in one spatial dimension, has become a paradigm of exotic physics in and out of equilibrium. Here, we introduce a non-Hermitian version in which the spin-flip rate differs between the two spin directions. While the naive expectation is that non-Hermiticity might suppress coherent phenomena such as quantum many-body scars, we find that when the facilitating direction of the spin is disfavored, the oscillations are instead \emph{enhanced}, decaying much slower than in the PXP limit. We demonstrate that this can be understood through a similarity transformation that maps our model to the standard PXP model, revealing that the oscillations are enhanced versions of the PXP scars. Our work provides an analytically tractable and conceptually simple example where non-Hermiticity enhances the stability of dynamically non-trivial coherent many-body modes.