Robust Finite-Temperature Many-Body Scarring on a Quantum Computer

TL;DR

This study demonstrates that quantum many-body scars exhibit unexpected robustness at finite temperatures in the PXP model, with implications for quantum information processing and understanding thermalization in quantum systems.

Contribution

We experimentally show the finite-temperature robustness of quantum many-body scars in the PXP model using a quantum computer, highlighting differences with other scar models.

Findings

Quantum many-body scars are robust at finite temperatures in the PXP model.

Other scar models lack this robustness and decay quickly with temperature.

The algebraic structure of scar models influences their thermal resilience.

Abstract

Mechanisms for suppressing thermalization in disorder-free many-body systems, such as Hilbert space fragmentation and quantum many-body scars, have recently attracted much interest in foundations of quantum statistical physics and potential quantum information processing applications. However, their sensitivity to realistic effects such as finite temperature remains largely unexplored. Here, we have utilized IBM's Kolkata quantum processor to demonstrate an unexpected robustness of quantum many-body scars at finite temperatures when the system is prepared in a thermal Gibbs ensemble. We identify such robustness in the PXP model, which describes quantum many-body scars in experimental systems of Rydberg atom arrays and ultracold atoms in tilted Bose--Hubbard optical lattices. By contrast, other theoretical models which host exact quantum many-body scars are found to lack such robustness, and their scarring properties quickly decay with temperature. Our study sheds light on the important differences between scarred models in terms of their algebraic structures, which impacts their resilience to finite temperature.