Witnessing Light-Driven Entanglement using Time-Resolved Resonant Inelastic X-Ray Scattering

TL;DR

This paper proposes a method to measure and control entanglement in quantum materials using time-resolved resonant inelastic X-ray scattering, enabling the observation of light-enhanced entanglement dynamics.

Contribution

It introduces a systematic approach to quantify time-dependent entanglement in quantum materials through spectroscopic observables, extending entanglement detection to nonequilibrium states.

Findings

Demonstrates light-enhanced entanglement near phase boundaries

Benchmarks the approach using a Hubbard model

Predicts dynamical entanglement phenomena in quantum materials

Abstract

Characterizing and controlling entanglement in quantum materials is crucial for the development of next-generation quantum technologies. However, defining a quantifiable figure of merit for entanglement in macroscopic solids is theoretically and experimentally challenging. At equilibrium the presence of entanglement can be diagnosed by extracting entanglement witnesses from spectroscopic observables and a nonequilibrium extension of this method could lead to the discovery of novel dynamical phenomena. Here, we propose a systematic approach to quantify the time-dependent quantum Fisher information and entanglement depth of transient states of quantum materials with time-resolved resonant inelastic x-ray scattering. Using a quarter-filled extended Hubbard model as an example, we benchmark the efficiency of this approach and predict a light-enhanced many-body entanglement due to the proximity to a phase boundary. Our work sets the stage for experimentally witnessing and controlling entanglement in light-driven quantum materials via ultrafast spectroscopic measurements.