Stability of quantum many-body scars on PXP model

TL;DR

This paper studies the stability of quantum many-body scars in the PXP model, revealing that some scar signatures are highly sensitive to perturbations while others remain robust, with implications for quantum dynamics.

Contribution

It provides a detailed numerical analysis of how quantum many-body scars in the PXP model respond to perturbations, highlighting the differential robustness of various scar signatures.

Findings

Entanglement entropy of scars is highly sensitive to small perturbations.

Revival signatures of scars show remarkable robustness against disturbances.

Different disturbances can either sustain oscillations or accelerate thermalization.

Abstract

We investigate the stability of quantum many-body scars under perturbations, within the PXP model. We numerically compute the fidelity and average correlations to monitor the state evolution and to identify revivals. The results indicate that, on the one hand, the entanglement entropy of PXP scars exhibit great sensitivity, in the sense that their profile approaches the ones expected for thermal states already for very small perturbations. On the other hand, other scar signatures, such as the revivals of states having large overlap with scars, show remarkable robustness. Additionally, we examined the effects of minor disturbances on initial states that previously exhibited high overlap with scars and consistent revivals. Our analysis revealed that different types of disturbances can induce markedly different behaviors, such as partially "freezing" the chain, leading to sustained oscillations, or accelerating the process of thermalization.