Prominent quantum many-body scars in a truncated Schwinger model

TL;DR

This paper demonstrates the existence and prominence of quantum many-body scars in a truncated Schwinger model, providing insights into their persistence and relevance to quantum simulation experiments.

Contribution

It shows that quantum many-body scars are more prominent in a truncated Schwinger model than in spin-$S$ quantum link models, with evidence of their persistence in the limit $S oinity.

Findings

Quantum many-body scars exist in the truncated Schwinger model.

Scarring persists in the limit $S oinity$ in the truncated model.

The truncated model is experimentally relevant and offers insights into lattice gauge theories.

Abstract

The high level of control and precision achievable in current synthetic quantum matter setups has enabled first attempts at quantum-simulating various intriguing phenomena in condensed matter physics, including those probing thermalization or its absence in closed quantum systems. In a recent work [Desaules \textit{et al.} [arXiv:2203.08830], we have shown that quantum many-body scars -- special low-entropy eigenstates that weakly break ergodicity in nonintegrable systems -- arise in spin-$S$ quantum link models that converge to $(1+1)-$D lattice quantum electrodynamics (Schwinger model) in the Kogut--Susskind limit $S\to\infty$. In this work, we further demonstrate that quantum many-body scars exist in a truncated version of the Schwinger model, and are qualitatively more prominent than their counterparts in spin-$S$ quantum link models. We illustrate this by, among other things, performing a finite-$S$ scaling analysis that strongly suggests that scarring persists in the truncated Schwinger model in the limit $S\to\infty$. Although it does not asymptotically converge to the Schwinger model, the truncated formulation is relevant to synthetic quantum matter experiments, and also provides fundamental insight into the nature of quantum many-body scars, their connection to lattice gauge theories, and the thermalization dynamics of the latter. Our conclusions can be readily tested in current cold-atom setups.