Explore a lecture on the second-quantization of many-body dispersion formalism and its application to modeling million-atom systems in arbitrary environments. Delve into the importance of dispersive van der Waals and Casimir interactions in accurately describing physical, chemical, and biological systems. Learn about the many-body dispersion (MBD) formalism and its limitations when analyzing collective normal modes in large systems. Discover a quantum field theoretical approach based on second quantization formalism that addresses these challenges, offering higher computational efficiency, easier application of quantum information tools, and a framework for describing MBD mode interactions with the surrounding environment. Gain insights into how this approach can be applied to large systems such as realistic biomolecular complexes, potentially revolutionizing our understanding of complex molecular interactions.