Cavity induced many-body localization

TL;DR

This paper investigates how strong coupling in cavity quantum electrodynamics can induce many-body localization in a spinless electronic Hubbard chain, challenging the expectation that electron-photon interactions delocalize fermionic excitations.

Contribution

It introduces a high-frequency expansion method and numerical analysis demonstrating that cavity coupling can promote localization even with quantum photon fluctuations.

Findings

Localization persists at low photon numbers (~2 photons).

Electron-photon interactions can favor localization contrary to expectations.

Numerical evidence supports many-body localization in the studied system.

Abstract

In this manuscript, we explore the feasibility of achieving many-body localization in the context of cavity quantum electrodynamics at strong coupling. Working with a spinless electronic Hubbard chain sitting coupled to a single-mode cavity, we show that the global coupling between electrons and photons -- which generally would be expected to delocalize the fermionic excitations -- can instead favor the appearance of localization. This is supported by a novel high-frequency expansion that correctly accounts for electron-photon interaction at strong coupling, as well as numerical calculations in both single particle and many-bod regimes. We find evidence that many-body localization may survive strong quantum fluctuations of the photon number by exploring energy dependence, seeing signatures of localization down to photon numbers as small as $n\sim2$.