NonEquilibrium MOlecular processes in the ultrastrong coupling regime

The manipulation of the electromagnetic environment of molecular systems provides a way to control their properties and dynamics. Specifically, under strong coupling conditions, the formation of hybrid light-matter states delocalized over a large number of molecules has been shown to change the rate of chemical reactions and modify diverse transport phenomena. Despite considerable theoretical and experimental efforts, the ultimate physical mechanism responsible for these effects is not well-understood, mainly because of the complexity of these systems. Molecules present multiple internal degrees of freedom, which makes their theoretical description unmanageable when dealing with macroscopically large ensemble sizes. Besides, the phenomenology when entering the ultrastrong coupling regime is largely unexplored, where new theoretical challenges come into play. The objective of this action is to provide the missing theoretical and computational frameworks to study the dynamics of realistic molecular systems ultrastrongly coupled to a complex electromagnetic environment. Starting from the full multimode cavity QED Hamiltonian, we will first derive the effective model for such physical settings including effects that have been missed so far but are nonetheless important to address the observed (as well as the accessible) phenomenology. Then, we will apply many-body numerical techniques from quantum optics to describe the dynamics of strongly-driven, ultrastrongly-coupled systems. With these tools at hand, we will study nonequilibrium effects in these platforms, specifically energy transport and driven-dissipative phase transitions. The outcomes of this project will thus bring us closer to the definite understanding of the phenomena afforded by molecular strong coupling, and allow us to reliably predict nonequilibrium effects relying on molecular ultrastrong light-matter coupling.