Second Quantization Approach to Many-Body Dispersion Interactions Yields Insights Into Chemical and Biological Systems- Raw Data and Molecular Structures

The many-body dispersion (MBD) framework is a successful approach for modeling the long-rangeelectronic correlation energy and optical response of systems with thousands of atoms. Inspired byfield theory, here we develop a second-quantized MBD formalism (SQ-MBD) that recasts a system of atomic quantum Drude oscillators in a Fock-space representation. SQ-MBD provides: (i)tools for projecting observables (interaction energy, transition multipoles, polarizability tensors) oncoarse-grained representations of the atomistic system ranging from single atoms to large structural motifs, (ii) a quantum-information framework to analyze correlations and (non)separabilityamong fragments in a given molecular complex, and (iii) a path toward the applicability of theMBD framework to molecular complexes with millions of atoms. The SQ-MBD approach offersconceptual insights into quantum fluctuations in molecular systems and enables direct coupling ofcollective plasmon-like MBD degrees of freedom with arbitrary environments, providing a tractablecomputational framework to treat dispersion interactions and polarization response in intricate systems