Quantum Many-Body Scars beyond the PXP model in Rydberg simulators

TL;DR

This paper demonstrates the existence of quantum many-body scars in a broader class of models beyond the PXP model, revealing new types of non-thermal eigenstates with potential experimental realizations in Rydberg atom systems.

Contribution

The study extends the concept of QMBS beyond the PXP model to include models with longer-range constraints and diverse periodicities, identifying multiple scar families with different algebraic structures.

Findings

QMBS exist in models beyond PXP with longer-range interactions

Multiple QMBS families rely on different approximate su(2) algebras

Observation of QMBS requires weakly entangled initial states

Abstract

Persistent revivals recently observed in Rydberg atom simulators have challenged our understanding of thermalization and attracted much interest to the concept of quantum many-body scars (QMBSs). QMBSs are non-thermal highly excited eigenstates that coexist with typical eigenstates in the spectrum of many-body Hamiltonians, and have since been reported in multiple theoretical models, including the so-called PXP model, approximately realized by Rydberg simulators. At the same time, questions of how common QMBSs are and in what models they are physically realized remain open. In this Letter, we demonstrate that QMBSs exist in a broader family of models that includes and generalizes PXP to longer-range constraints and states with different periodicity. We show that in each model, multiple QMBS families can be found. Each of them relies on a different approximate $\mathfrak{su}(2)$ algebra, leading to oscillatory dynamics in all cases. However, in contrast to the PXP model, their observation requires launching dynamics from weakly entangled initial states rather than from a product state. QMBSs reported here may be experimentally probed using Rydberg atom simulator in the regime of longer-range Rydberg blockades.