RQC Seminar

215th RQC Seminar

• Speaker

  Prof. Chen Ye-Hong
  ( Fuzhou University, Fujian, P. R. China )

• Date

  16:00-17:00 (4:00 p.m. - 5:00 p.m.), August 8, 2025 (Friday)

• Venue

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

• Title

  Nonlinear Effects and Criticality in the Quantum Rabi Model

• Inquiries

  rqc_info[at]ml.riken.jp

Abstract
The quantum Rabi model serves as a fundamental framework for studying light-matter interactions, with its ground state exhibiting diverse physical properties under varying parameter conditions. As the coupling strength increases, the system demonstrates progressively stronger nonlinear effects, such as multi-photon resonance. Notably, under appropriate conditions, when the coupling coefficient approaches a critical point, an abrupt change in photon number distribution occurs—a phenomenon known as the superradiant quantum phase transition. Recent research further reveals that such critical phenomena can significantly enhance performance in quantum sensing and precision measurement. However, these critical effects typically emerge in the ultrastrong or even deep-strong coupling regimes, which pose substantial experimental challenges with current technologies. Additionally, while criticality amplifies signals, it also enhances noise. Thus, a key question arises: Can this criticality improve the signal-to-noise ratio? Investigating the nonlinear effects and critical phenomena of the quantum Rabi model under realistic conditions—accounting for noise and dissipation—has become a central focus of our recent research.