Speaker: Johannes Knörzer
Affiliation: ETH
Date: Thursday, 15 June 2023 at 12:00
Location: Seminar Room, Serrano 121 (CFMAC)
The ultra-strong coupling regime in light-matter interactions requires non-perturbative methods, for example, to calculate the radiation emitted from an atom. In this talk, I will discuss how star-to-chain transformations may be utilised for such tasks, when combined with methods based on matrix product or Gaussian states, respectively. Being well known in the study of open quantum systems, we demonstrate that the approach allows us to also treat field observables – both in vacuum states and thermal states of the field. As applications, here I consider giant atoms in the ultra-strong coupling regime [1], and the emission from a uniformly accelerated emitter in the Unruh effect [2].
[1] D. D. Noachtar, JK, R. H. Jonsson, “Nonperturbative treatment of giant atoms using chain transformations”, PRA 106, 013702 (2022).
[2] R. H. Jonsson, JK, “Chain-mapping methods for relativistic light-matter interactions”, in preparation (2023).