Resumen: The spectrum and energy dynamics for a system that comprises a molecule interacting with a cavity photon is analyzed, taking into account the effect of both molecular vibrations and counter-rotating terms (CR) in the dipole Hamiltonian. The CR terms do not have a strong effect on the spectrum even for moderately large values of the exciton-photon interaction. However, it is shown that the polariton subspace is governed by an effective Quantum-Rabi Hamiltonian, where polaritons act as a two-level system and the phonons play the role of cavity photons. The effect of the CR terms is amplified in the dynamics: as the vibrations reduce the effective photon-exciton coupling, small Bloch-Siegert energy shifts can bring the system out of resonance. Idioma: Inglés DOI: 10.1515/nanoph-2019-0403 Año: 2020 Publicado en: Nanophotonics 9, 2 (2020), 277-281 ISSN: 2192-8606 Factor impacto JCR: 8.449 (2020) Categ. JCR: MATERIALS SCIENCE, MULTIDISCIPLINARY rank: 49 / 333 = 0.147 (2020) - Q1 - T1 Categ. JCR: NANOSCIENCE & NANOTECHNOLOGY rank: 25 / 106 = 0.236 (2020) - Q1 - T1 Categ. JCR: PHYSICS, APPLIED rank: 20 / 160 = 0.125 (2020) - Q1 - T1 Categ. JCR: OPTICS rank: 9 / 99 = 0.091 (2020) - Q1 - T1 Factor impacto SCIMAGO: 2.717 - Atomic and Molecular Physics, and Optics (Q1) - Electronic, Optical and Magnetic Materials (Q1) - Electrical and Electronic Engineering (Q1) - Biotechnology (Q1)