Efficient quantum information probes of non-equilibrium quantum criticality

TL;DR

This paper introduces the single-particle affinity as an accessible quantum information measure to detect and analyze non-equilibrium quantum phase transitions, including potentially unknown phases, overcoming limitations of traditional methods.

Contribution

It demonstrates that the single-particle affinity can identify non-equilibrium phase transitions and discover new phases in quantum many-body systems.

Findings

Single-particle affinity signals known non-equilibrium phase transitions.

Potential to detect previously unknown quantum phases.

Applicable beyond Landau's paradigm in quantum criticality.

Abstract

Quantum information-based approaches, in particular the fidelity, have been flexible probes for phase boundaries of quantum matter. A major hurdle to a more widespread application of fidelity and other quantum information measures to strongly correlated quantum materials is the inaccessibility of the fidelity susceptibility to most state-of-the-art numerical methods. This is particularly apparent away from equilibrium where, at present, no general critical theory is available and many standard techniques fail. Motivated by the usefulness of quantum information based measures we show that a widely accessible quantity, the single-particle affinity, is able to serve as a versatile instrument to identify phase transitions beyond Landau's paradigm. We demonstrate that it not only is able to signal previously identified non-equilibrium phase transitions but also has the potential to detect hitherto unknown phases in models of quantum matter far from equilibrium.