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Q: Fachverband Quantenoptik und Photonik

Q 10: Cavity QED

Q 10.7: Talk

Monday, March 11, 2024, 18:45–19:00, HS 1199

Position-resolved pseudomode description of open cavities — •Lucas Weitzel, Andreas Buchleitner, and Dominik Lentrodt — Physikalisches Institut, Albert-Ludwigs-Universität Freiburg

A wide-spread quantum optical method to describe light matter interaction consists in reducing the involved degrees of freedom to the absolute minimum, such as those of a two-level atom (strongly) coupled to an isolated mode of a cavity. All other degrees of freedom are thus screened away as an ``environment" which couples only weakly to the hybrid. Such separation is derived from first principles in many textbook scenarios, and allows an efficient description of the dynamics e.g. by Markovian Lindblad master equations. The system-environment separation becomes ever more difficult, though, as the number of strongly coupled degrees of freedom increases, e.g. for a two-level atom in a low-quality cavity where resonator modes may overlap or even drown in a continuum background. Given the mathematically well-controlled framework of Markovian Lindblad master equations, it is important to understand under which conditions the emerging dynamics can still be understood as resulting from an effective interaction of the atom with a set of broadened modes (pseudomodes), over a weakly coupled environment. To settle this question, we construct a fully analytical pseudomode representation of open cavities through ``reverse-engeneering" from the position-resolved atomic dynamics within the cavity. We discuss the versatility of our method and potential applications to more complex atomic (or molecular) targets.

Keywords: Resonance theory; Master equation; Quantum electrodynamics; Open quantum system