Theoretical seminar | 21 October 2020

University of the Basque Country, San Sebastian, Spain; Ikerbasque, Basque Foundation for Science, Bilbao, Spain; Donostia International Physics Center, San Sebastian, Spain
Quantum electrodynamical density functional theory: First principle approach to cavity QED

In this talk I present Quantum Electrodynamical (Time Dependent) Density Functional Theory (QED-DFT) – a recently proposed ab initio approach to the theory of atomic, molecular, and condensed matter systems strongly interacting with quantum electromagnetic field. I start from a general physical picture and a formal statement of the many-body problem for non-relativistic electrons strongly coupled to photon modes of a microcavity. Then I discuss basic QED-DFT mapping theorems and possible approximation strategies. In particular I will introduce generalization of the concept of optimized effective potential that makes a connection of QED-DFT to the many-body perturbation theory. Finally, I will discuss first test applications of this approach and its connection to the theory of quantum dissipative systems.