Cavity Spectroscopy for Strongly Correlated Systems

TL;DR

This paper introduces a novel all-optical framework for probing strongly correlated materials embedded in optical cavities by measuring emitted photons, enabling access to their static and dynamic properties.

Contribution

It develops a general theoretical framework linking photon and matter observables in cavity-embedded systems, allowing direct measurement of complex quantum properties.

Findings

Demonstrates how to measure entanglement phase transitions via cavity photons

Shows access to dynamical spin correlations through photon correlation functions

Provides a universal method for probing static and dynamic properties of quantum materials

Abstract

Embedding materials in optical cavities has emerged as an intriguing perspective for controlling quantum materials, but a key challenge lies in measuring properties of the embedded matter. Here, we propose a framework for probing strongly correlated cavity-embedded materials through direct measurements of cavity photons. We derive general relations between photon and matter observables inside the cavity, and show how these can be measured via the emitted photons. As an example, we demonstrate how the entanglement phase transition of an embedded H$_2$ molecule can be accessed by measuring the cavity photon occupation, and showcase how dynamical spin correlation functions can be accessed by measuring dynamical photon correlation functions. Our framework provides an all-optical method to measure static and dynamic properties of cavity-embedded materials.