Effective theory for matter in non-perturbative cavity QED

Román-Roche, Juan ; Zueco, David

Resumen: Starting from a general material system of N particles coupled to a cavity, we use a coherent-state path integral formulation to produce a effective theory for the material degrees of freedom. We tackle the effects of image charges, the A^2 term and a multimode arbitrary-geometry cavity. The resulting (non-local) action has the photonic degrees of freedom replaced by an effective position-dependent interaction between the particles. In the large-NN limit, we discuss how the theory can be cast into an effective Hamiltonian where the cavity induced interactions are made explicit. The theory is applicable, beyond cavity QED, to any system where bulk material is linearly coupled to a diagonalizable bosonic bath. We highlight the differences of the theory with other well-known methods and numerically study its finite-size scaling on the Dicke model. Finally, we showcase its descriptive power with three examples: photon condensation, the 2D free electron gas in a cavity and the modification of magnetic interactions between molecular spins; recovering, condensing and extending some recent results in the literature.

Idioma: Inglés

DOI: 10.21468/SciPostPhysLectNotes.50

Año: 2022

Publicado en: SciPost Physics Lecture Notes 50 (2022), [32 pp.]
ISSN: 2590-1990

Factor impacto CITESCORE: 9.1 - Physics and Astronomy (Q1)

Financiación: info:eu-repo/grantAgreement/ES/CSIC/PTI-001
Financiación: info:eu-repo/grantAgreement/ES/DGA/E09-17R-Q-MAD
Financiación: info:eu-repo/grantAgreement/EC/H2020/862893/EU/Molecular spin qudits offering new hope for quantum computing/FATMOLS
Financiación: info:eu-repo/grantAgreement/ES/MICINN-AEI/PID2020-115221GB-C41

Tipo y forma: Article (Published version)