We show that the macroscopic magnetic and electronic properties of strongly correlated electron systems can be manipulated by coupling them to a cavity mode. As a paradigmatic example we consider the Fermi-Hubbard model and find that the electron-cavity coupling enhances the magnetic interaction between the electron spins in the ground-state manifold. At half filling this effect can be observed by a change in the magnetic susceptibility. At less than half filling, the cavity introduces a next-nearest neighbour hopping and mediates a long-range electron-electron interaction between distant sites. We study the ground state properties with Tensor Network methods and find that the cavity coupling can induce a new phase characterized by a momentum-space pairing effect for electrons.
@article{arxiv.1806.06752,
title = {Manipulating quantum materials with quantum light},
author = {Martin Kiffner and Jonathan Coulthard and Frank Schlawin and Arzhang Ardavan and Dieter Jaksch},
journal= {arXiv preprint arXiv:1806.06752},
year = {2019}
}