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

Additional Organisation(s)

FAU Profilzentrum Licht.Materie.Quantentechnologien (FAU LMQ) Sonderforschungsbereich/Transregio 306/1: Quantenkooperativität von Licht und Materie - QuCoLiMa

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).

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