Witnessing nonequilibrium entanglement dynamics in a strongly correlated fermionic chain

TL;DR

This paper demonstrates that the quantum Fisher information can effectively detect multipartite entanglement dynamics in a strongly correlated fermionic chain driven out of equilibrium, with potential applications in light-driven quantum materials.

Contribution

It shows the applicability of the quantum Fisher information as an entanglement witness for nonequilibrium dynamics in a fermionic system, extending entanglement detection beyond equilibrium.

Findings

Quantum Fisher information witnesses entanglement near and far from equilibrium.

Entanglement signatures are robust against decoherence.

Implications for probing entanglement in light-driven quantum materials.

Abstract

Many-body entanglement in condensed matter systems can be diagnosed from equilibrium response functions through the use of entanglement witnesses and operator-specific quantum bounds. Here, we investigate the applicability of this approach for detecting entangled states in quantum systems driven out of equilibrium. We use a multipartite entanglement witness, the quantum Fisher information, to study the dynamics of a paradigmatic fermion chain undergoing a time-dependent change of the Coulomb interaction. Our results show that the quantum Fisher information is able to witness distinct signatures of multipartite entanglement both near and far from equilibrium that are robust against decoherence. We discuss implications of these findings for probing entanglement in light-driven quantum materials with time-resolved optical and x-ray scattering methods.