A Mean-Field Treatment of Vacuum Fluctuations in Strong Light-Matter Coupling

Abstract

Mean-field mixed quantum--classical dynamics could provide a much-needed means to inexpensively model quantum electrodynamical phenomena, by describing the optical field and its vacuum fluctuations classically. However, this approach is known to suffer from an unphysical transfer of energy out of the vacuum fluctuations when the light--matter coupling becomes strong. We highlight this issue for the case of an atom in an optical cavity, and resolve it by introducing an additional set of classical coordinates to specifically represent vacuum fluctuations whose light--matter interaction is scaled by the instantaneous ground-state population of the atom. This not only rigorously prevents the aforementioned unphysical energy transfer, but is also shown to yield a radically improved accuracy in terms of the atomic population and the optical field dynamics, generating results in excellent agreement with full quantum calculations. As such, the resulting method emerges as an attractive solution for the affordable modeling of strong light--matter coupling phenomena involving macroscopic numbers of optical modes.

6 pages with 3 figures

References in corpus (6)

• Quantum theory of collective strong coupling of molecular vibrations with a microcavity mode
• Molecular polaritonics: Chemical Dynamics under strong Light-Matter Coupling
• Theoretical Challenges in Polaritonic Chemistry
• Capturing Vacuum Fluctuations and Photon Correlations in Cavity Quantum Electrodynamics with Multi-Trajectory Ehrenfest Dynamics
• Benchmarking Semiclassical and Perturbative Methods for Real-time Simulations of Cavity-Bound Emission and Interference
• A theoretical perspective on molecular polaritonics

Cited by in corpus (6)

• Revealing Ultrafast Phonon Mediated Inter-Valley Scattering through Transient Absorption and High Harmonic Spectroscopies
• Ehrenfest Modeling of Cavity Vacuum Fluctuations and How to Achieve Emission from a Three-Level Atom
• Focused Sampling for Low-Cost and Accurate Ehrenfest Modeling of Cavity Quantum Electrodynamics
• Mixed Quantum-Classical Dynamics Yields Anharmonic Rabi Oscillations
• Excitation density controlled regimes of collective light--matter dynamics
• Linear and nonlinear vibrational excitation driven by molecular polaritons