RQC Seminar

201st RQC Seminar

• Speaker

  Dr. Roberto Stassi
  ( University of Messina, Italy )

• Date

  16:00-17:00 (4:00 p.m. - 5:00 p.m.), May 22, 2025 (Thursday)

• Venue

  Hybrid(ZOOM・ Wako Main Research 3F 345-347 Seminar Room / 研究本館3階 セミナー室 (345-347) (C01))

• Title

  Dicke Model with Atom-Atom and Longitudinal Interactions : Asymmetric Spectra and Light-Matter Decoupli

• Inquiries

  norilab_rqc_assist[at]ml.riken.jp

Abstract
The Dicke model describes the interaction between a collection of N two-level systems (atoms or qubits) and a single mode of a quantized electromagnetic field (light) within a cavity or resonator. This seminar examines an extended Dicke Hamiltonian that incorporates both atom-atom and longitudinal atom interactions when the system is in the ultrastrong coupling regime. Considering flux qubits, the energy spectrum exhibits a strong dependence on the sign of the applied bias flux, leading to a pronounced asymmetry in its energy level structure. The asymmetry originates from a decoupling of the longitudinal interaction that depends on the sign of the bias flux. Moreover, it will be shown that the atom-atom direct coupling and the one mediated by the cavity are competitive interactions that reduce the dressing.