Ultrafast exciton–polaron dynamics in moiré superlattices

Abstract

We develop a fully computational framework to simulate exciton–polaron–polariton formation in moiré superlattices under strong light–matter coupling. The model combines parametrized moiré potentials with analytical cavity representations and non-Hermitian quantum propagation to capture hybridization between moiré-confined excitons and cavity photons. The present model uses a reduced first-harmonic parametrization of the moiré potential and omits atomic-scale reconstruction and material-specific microscopic details. Even so, it captures the leading energy modulation and provides qualitative polariton dynamics predictions relevant to current experiments. The calculated detuning–coupling map reveals the onset of strong coupling near g_X ≈ 0.035 eV, yielding a transient Rabi splitting of ħΩ_R ≈ 6 meV that collapses within 0.3 ps due to carrier-induced dephasing. Time-resolved spectra show ultrafast conversion from neutral excitons to exciton–polarons with formation and depletion times of τ_AP ≈ 0.24 ps and τ_X0 ≈ 0.27 ps, respectively. Principal component and Bayesian analyses quantitatively recover the optimal coupling (g_X ≈ 0.034 eV) and cavity resonance (E_C ≈ 1.72 eV), consistent with reported Rabi splittings in twisted TMD nanocavity systems. This work provides a predictive computational platform for understanding correlated exciton–photon phenomena in two-dimensional moiré quantum materials.