# Cavity-QED-controlled two-dimensional Moiré excitons without twisting

## TL;DR

The paper shows how light can be used to control excitons in materials, mimicking the effects of Moiré patterns without physically twisting layers.

## Contribution

The study introduces a non-perturbative quantum electro-dynamical framework for cavity-controlled excitons without material twisting.

## Key findings

- Structured optical cavities can emulate Moiré physics through optical confinement of excitons.
- Cavity vacuum fluctuations induce long-range interactions that modify exciton masses and optical properties.
- Non-perturbative methods are essential to capture cavity-mediated exciton-exciton interactions.

## Abstract

We propose an all-optical Moiré-like exciton confinement by means of spatially periodic optical cavities. Such periodic photonic structures can control the material properties by coupling the matter excitations to the confined photons and their quantum fluctuations. We develop a low energy non-perturbative quantum electro-dynamical description of strongly coupled excitons and photons at finite momentum transfer. We find that in the classical limit of a laser driven cavity the induced optical confinement directly emulates Moiré physics. In a dark cavity instead, the sole presence of quantum fluctuations of light generates a sizable renormalization of the excitonic bands and effective mass. We attribute these effects to long-range cavity-mediated exciton-exciton interactions which can only be captured in a non-perturbative treatment. With these findings we propose spatially structured cavities as a promising avenue for cavity material engineering.

The authors show that structured optically driven cavities can recreate Moiré-like exciton localization and that cavity vacuum fluctuations induce long-range exciton interactions, modifying exciton masses and optical properties without twisting.