Engineering photon-mediated long-range spin interactions in Mott insulators

Fadler P, Schmidt KP, Li J, Eckstein M (2024)

Publication Type: Journal article

Publication year: 2024

Journal

Physical Review B American Physical Society

Book Volume: 109

Article Number: 085149

Journal Issue: 8

DOI: 10.1103/PhysRevB.109.085149

Abstract

We investigate the potential to induce long-range spin interactions in a Mott insulator via the quantum electromagnetic field of a cavity. The coupling between light and spins is inherently nonlinear, and occurs via multiphoton processes like Raman scattering and two-photon absorption and emission with electronically excited intermediate states. Based on this, two pathways are elucidated: (i) In the absence of external driving, long-range interactions are mediated by the exchange of at least two virtual cavity photons. We show that these vacuum-mediated interactions can surpass local Heisenberg interactions in mesoscopic setups such as sufficiently small split-ring resonators. (ii) In a laser-driven cavity, interactions can be tailored through a hybrid scheme involving both external laser photons and cavity photons. This offers a versatile pathway for Floquet engineering of long-range interactions in macroscopic systems. In general, the derivation of these interactions requires careful consideration: Notably, we demonstrate that a simple phenomenological approach, based on a spin-photon Hamiltonian that captures Raman and two-photon processes with effective matrix elements, can be used only if the cavity is resonantly driven. Outside of these narrow resonant regimes as well as for the undriven case, a fourth-order series expansion within the underlying electronic model is necessary, which we perform to obtain long-range four-spin interactions in the half-filled Hubbard model.

Authors with CRIS profile

Paul Fadler Lehrstuhl für Theoretische Physik Kai Phillip Schmidt Professur für Theoretische Physik

Involved external institutions

Paul Scherrer Institute (PSI) CH Switzerland (CH) Universität Hamburg (UHH) DE Germany (DE)

How to cite

APA:

Fadler, P., Schmidt, K.P., Li, J., & Eckstein, M. (2024). Engineering photon-mediated long-range spin interactions in Mott insulators. Physical Review B, 109(8). https://doi.org/10.1103/PhysRevB.109.085149

MLA:

Fadler, Paul, et al. "Engineering photon-mediated long-range spin interactions in Mott insulators." Physical Review B 109.8 (2024).

BibTeX: Download