Quantum Dynamics Simulations of the Polariton Transport Process

Recent experiments have shown that the transport of excitons in organic semiconductors can be significantly enhanced through hybridization with confined photonic modes in a cavity, thereby forming molecular exciton-polaritons (EP). Dissipative mechanisms that affect the constituent states of EPs, such as exciton-phonon coupling and cavity loss, have been observed to diminish their effective velocities in experiments. To elucidate the impacts of these dissipative mechanisms on the transport characteristics of molecular EPs, we develop an efficient quantum dynamics simulation approach that allows us to directly simulate polariton transport dynamics under the collective coupling regime and beyond long-wavelength approximation. Our numerical results suggest a renormalization of the group velocities with stronger exciton-phonon coupling strengths and smaller Q-factor, in agreement with existing polariton transport experiments. Additionally, we observe the transition from ballistic to diffusive EP propagation, as well as the quality factor-dependent behavior of the transient mean square displacement, agreeing well with the recent experimental measurements.