Recent experiments demonstrated the possibilities of modifying ground-state chemical reaction rates by placing an ensemble of molecules in an optical microcavity. A strong collective, resonant coupling between the cavity mode and molecular vibrations forms vibration-polaritons. This regime is commonly referred to as Vibrational Strong Coupling (VSC), and typically operates in the absence of any light source (“in the dark”). VSC causes reaction rate constant modifications, exhibits phase-transition type of behavior for equilibrium constant modifications, and the effect starts only when the collective Rabi splitting surpasses a threshold. Existing theoretical work often focuses on the single excitation pictures, centered around the idea of vibrational polaritons and dark states. We found that due to the many-body nature of VSC, most of the VSC effects could be potentially explained by forming a macroscopic condensation of Bogoliubov quasiparticles, commonly referred to as Bogolon. We theoretically demonstrate that by surpassing a critical Rabi splitting, the VSC system starts to macroscopically occupy one Bogolon condensate state, which we believe is the common explanation for VSC-induced effects.
Mondal et al. (Wed,) studied this question.