Cavity Light-Matter Entanglement through Quantum Fluctuations

TL;DR

This paper explores how quantum fluctuations in a matter system enable entanglement with cavity light, which in turn can modify electronic properties and influence phase transitions in quantum materials.

Contribution

It demonstrates that quantum fluctuations are essential for light-matter entanglement in correlated systems, providing new insights into cavity control of quantum phases.

Findings

Quantum fluctuations enable light-matter entanglement.

Light-matter entanglement modifies electronic properties.

Implications for cavity-induced phase transitions.

Abstract

The hybridization between light and matter forms the basis to achieve cavity control over quantum materials. In this work we investigate a cavity coupled to an XXZ quantum chain of interacting spinless fermions by numerically exact solutions and perturbative analytical expansions. We find two important effects: (i) Specific quantum fluctuations of the matter system play a pivotal role in achieving entanglement between light and matter; and (ii) in turn, light-matter entanglement is the key ingredient to modify electronic properties by the cavity. We hypothesize that quantum fluctuations of those matter operators to which the cavity modes couple are a general prerequisite for light-matter entanglement in the groundstate. Implications of our findings for light-matter-entangled phases, cavity-modified phase transitions in correlated systems, and measurement of light-matter entanglement through Kubo response functions are discussed.