Ab initio few-mode theories for quantum potential scattering problems
14:00 - 15:30
Max-Planck-Institut für Kernphysik, Heidelberg
CFEL (Bldg. 99)
Seminar Room IV, O1.111
The concept of a single mode of the electromagnetic field interacting with matter has been a paradigm in the field of light-matter interactions. For example, the single mode Jaynes-Cummings model and its many generalizations have been indispensable tools in studying the quantum dynamics of various systems. In particular in cavity and circuit QED, where strong light-matter coupling is routinely achieved in experiment, such models have been tremendously successful .
however, various experimental platforms have emerged where multi-mode
effects and the openness of the system constitute an essential part of
the physics [1,2,3], and where the applicability of few-mode models has
been debated. In this talk, we will present "ab initio few-mode theory"
, where these factors are treated systematically and which allows to
include new physics into Jaynes-Cummings type models without abandoning
their conceptual and computational simplicity.
We will outline some
implications, in particular for the new field of X-ray cavity QED. From a
practical perspective, our method connects the extensive toolbox of
few-mode models to ab initio theory. From a more general perspective, it
constitutes a non-perturbative expansion scheme that allows to extract
the relevant degrees of freedom of quantized scattering problems . As
such, it may find applications in a broader context ranging from
transport theory to open quantum dynamics.
 A. Frisk Kockum et al.,
Nat. Rev. Phys. 1, 19–40 (2019)
 G. Hackenbroich et al., Phys. Rev.
Lett. 89, 083902 (2002)
 S. Rotter and S. Gigan, Rev. Mod. Phys. 89,
 D. Lentrodt and J. Evers, submitted, arXiv:1812.08556