Orthogonal Quantum Many-body Scars

TL;DR

This paper introduces a minimal model with orthogonal quantum many-body scars that exhibit persistent oscillations despite rapid entanglement growth, offering new insights into quantum ergodicity and non-equilibrium dynamics.

Contribution

It constructs a novel minimal model combining kinetic constraints and fractionalized orthogonal metals to realize orthogonal quantum many-body scars with infinite lifetime.

Findings

Persistent oscillations coexist with volume-law entanglement.

Adding kinetic constraints induces quantum scars in a fractionalized metal.

The model reveals a complex link between ergodicity and entanglement growth.

Abstract

Quantum many-body scars have been put forward as counterexamples to the Eigenstate Thermalization Hypothesis. These atypical states are observed in a range of correlated models as long-lived oscillations of local observables in quench experiments starting from selected initial states. The long-time memory is a manifestation of quantum non-ergodicity generally linked to a sub-extensive generation of entanglement entropy, the latter of which is widely used as a diagnostic for identifying quantum many-body scars numerically as low entanglement outliers. Here we show that, by adding kinetic constraints to a fractionalized orthogonal metal, we can construct a minimal model with orthogonal quantum many-body scars leading to persistent oscillations with infinite lifetime coexisting with rapid volume-law entanglement generation. Our example provides new insights into the link between quantum ergodicity and many-body entanglement while opening new avenues for exotic non-equilibrium dynamics in strongly correlated multi-component quantum systems.