Integrability vs Quantum Thermalization

TL;DR

This paper challenges the common assumption that non-integrability guarantees quantum thermalization, showing through the driven Rabi model that systems can be non-integrable yet fail to thermalize, questioning standard definitions of quantum integrability.

Contribution

It demonstrates that the driven Rabi model, classified as non-integrable, does not thermalize, highlighting issues with current definitions of quantum integrability.

Findings

Non-integrable driven Rabi model does not thermalize.

Standard definitions of quantum integrability are inadequate.

Care is needed when linking non-integrability to thermalization.

Abstract

Non-integrability is often taken as a prerequisite for quantum thermalization. Still, a generally accepted definition of quantum integrability is lacking. With the basis in the driven Rabi model we discuss this careless usage of the term "integrability" in connection to quantum thermalization. The model would be classified as non-integrable according to the most commonly used definitions, for example, the only preserved quantity is the total energy. Despite this fact, a thorough analysis conjectures that the system will not thermalize. Thus, our findings suggest first of all (i) that care should be paid when linking non-integrability with thermalization, and secondly (ii) that the standardly used definitions for quantum integrability are unsatisfactory.