Entangled photon pair excitation and time-frequency-filtered multidimensional photon correlation spectroscopy as a probe for dissipative exciton kinetics.

In quantum aggregates, delocalized exciton states across energy manifolds interact with phonon modes, making state-resolved spectroscopic monitoring of dynamics challenging. We propose a scheme that combines photon-entanglement-enhanced narrowband excitation of two-exciton states with time-frequency-filtered two-photon coincidence counting, which allows high-resolution probing of dissipative two-exciton dynamics spread across multiple spectral and temporal windows. We demonstrate that entangled photon pairs can be used to prepare narrowband two-exciton population distributions, circumventing transport in the mediating one-exciton manifold, and the redistributed two-exciton population can be monitored using time-frequency-filtered two-photon coincidence counting. Numerical simulations for a light-harvesting aggregate highlight the ability of this protocol to suppress or amplify specific pathways under a realistic scenario. Combining entangled photonic sources with multidimensional photon correlation techniques enables promising applications in spectroscopy and sensing.