Quantum Many-Body Scars and Weak Breaking of Ergodicity

TL;DR

This paper reviews the phenomenon of quantum many-body scars, a form of weak ergodicity breaking observed in Rydberg atom systems, exploring their theoretical basis, connections to semiclassical quantization, and potential applications in quantum technology.

Contribution

It provides a comprehensive pedagogical overview of quantum many-body scars, linking them to semiclassical methods and discussing their implications for quantum dynamics and technology.

Findings

Identification of quantum many-body scars as non-thermal eigenstates

Connection between scars and semiclassical quantization techniques

Potential applications in quantum information processing

Abstract

Recent discovery of persistent revivals in quantum simulators based on Rydberg atoms have pointed to the existence of a new type of dynamical behavior that challenged the conventional paradigms of integrability and thermalization. This novel collective effect has been named quantum many-body scars by analogy with weak ergodicity breaking of a single particle inside a stadium billiard. In this overview, we provide a pedagogical introduction to quantum many-body scars and highlight the newly emerged connections with the semiclassical quantization of many-body systems. We discuss the relation between scars and more general routes towards weak violations of ergodicity due to "embedded" algebras and non-thermal eigenstates, and highlight possible applications of scars in quantum technology.