Many-Body Exciton Interactions, Coherence, and Transport in Perovskite Quantum Dots

Realizing robust many-body exciton interactions, coherence, and long-range exciton transport is central to technologies ranging from quantum information science (QIS) to light-emitting devices and solar cells. Colloidal quantum dots (QDs) offer scalable fabrication and spectral tunability, yet performance is suppressed by inhomogeneous broadening, defects, and fast dephasing. Lead-halide perovskite QDs, exhibiting large transition dipole moments, high radiative efficiencies, and slow low-temperature dephasing, enable strong light-matter coupling and long-range dipolar exciton-exciton interactions. This review focuses on the origins and consequences of many-body exciton physics in perovskite QDs, including dipole-mediated interactions and cooperative radiative phenomena. We discuss how exciton fine structure, inter-QD electronic coupling, and exciton-phonon interactions govern coherence and the role of disorder. We then examine exciton transport in QD solids, emphasizing the crossover from coherent motion enabled by delocalized excitonic wave functions to dephasing-driven incoherent hopping. Finally, we survey routes toward scalable many-body states through nanophotonic integration.