Probing Collective Quantum Dynamics in Solid-State Molecular Systems

Solid-state molecular systems are emerging as powerful platforms for quantum simulation and sensing. Their rich spatial organization—characterized by molecular disorder and domain formation—combined with strong dipolar interactions, enables the study of quantum transport and collective phenomena at the nanoscale. Understanding these effects requires new theoretical tools capable of connecting microscopic molecular dynamics with experimentally accessible observables.

We develop a comprehensive theoretical framework to describe how a molecular substrate modifies the emission of a near-field probe, such as in vibrational coupling nanocrystallography (VCNC) using atomic force microscopy (AFM). In this setting, coupling between molecular vibrations gives rise to collective vibrational excitons, whose spectral features reveal information about local molecular order and intermolecular interactions. Our theory captures both weak- and strong-excitation regimes, predicting signatures such as interaction-induced frequency shifts  in agreement with experimental observations. It also opens a path  for the near term exploration of collective quantum correlations of molecular vibrations in solids.