Photon condensation, Van Vleck paramagnetism, and chiral cavities

Open Access

Photon condensation, Van Vleck paramagnetism, and chiral cavities

Alberto Mercurio, Gian Marcello Andolina, Francesco M. D. Pellegrino, Omar Di Stefano, Pablo Jarillo-Herrero, Claudia Felser, Frank H. L. Koppens, Salvatore Savasta, and Marco Polini

Phys. Rev. Research 6, 013303 – Published 19 March 2024

Abstract

We introduce a gauge-invariant model of planar, square molecules coupled to a quantized spatially varying cavity electromagnetic vector potential $\hat{A} (r)$ . Specifically, we choose a temporally chiral cavity hosting a uniform magnetic field $\hat{B}$ , as this is the simplest instance in which a transverse spatially varying $\hat{A} (r)$ is at play. We show that when the molecules are in the Van Vleck paramagnetic regime, an equilibrium quantum phase transition to a photon condensate state occurs.

Received 23 March 2023
Revised 21 February 2024
Accepted 22 February 2024

DOI:https://doi.org/10.1103/PhysRevResearch.6.013303

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society

Physics Subject Headings (PhySH)

Paramagnetism Phase diagrams Polaritons

Molecules Photons

Atomic, Molecular & OpticalCondensed Matter, Materials & Applied Physics

Authors & Affiliations

Alberto Mercurio ^1,*, Gian Marcello Andolina ^2,*, Francesco M. D. Pellegrino ^3,4,5,*, Omar Di Stefano ¹, Pablo Jarillo-Herrero⁶, Claudia Felser⁷, Frank H. L. Koppens^2,8, Salvatore Savasta¹, and Marco Polini^9,10,2

¹Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università di Messina, I-98166 Messina, Italy
²ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona), Spain
³Dipartimento di Fisica e Astronomia “Ettore Majorana”, Università di Catania, Via S. Sofia 64, I-95123 Catania, Italy
⁴INFN, Sez. Catania, I-95123 Catania, Italy
⁵CNR-IMM, Via S. Sofia 64, I-95123 Catania, Italy
⁶Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
⁷Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, Dresden 01187, Germany
⁸ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig de Lluís Companys 23, 08010 Barcelona, Spain
⁹Dipartimento di Fisica dell'Università di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa, Italy
¹⁰Istituto Italiano di Tecnologia, Graphene Labs, Via Morego 30, I-16163 Genova, Italy