Speaker
Prof.
Gernot Alber
(University of Darmstadt, Germany)
Description
The dynamics of spontaneous photon emission and absorption by elementary two-level systems inside cavities of finite sizes is discussed. It is shown that the influence of boundaries of these cavities on spontaneous photon emission and absorption processes can be described in a convenient way with the help of semiclassical photon path representations over a wide range of wavelengths. Thereby, in the spirit of the Feynman path integral probability amplitudes of interest are represented as sums of contributions originating from all possible photon paths inside a cavity. Thereby also repeated reflections at the boundaries have to be taken into account. It is demonstrated that these semiclassical path representations are not only a convenient theoretical tool for describing these processes reliably but also for obtaining physical insight into the intricate interplay between the elementary quantum electrodynamical phenomena of photon emission and absorption and the photonic multimode dynamics in these cavities. As an example the spontaneous photon emission process of a two-level system located in the focus of a half-open cavity with a rotationally symmetric parabolic boundary is discussed in detail and the time evolutions of the two-level system and of the resulting photon wave packet are investigated [1]. In view of current activities aiming at the realization of qantum repeaters the quantum dynamics in such half-open cavities offers interesting perspectives for coupling an elementary material qubit to the electromagnetic radiation field efficiently.
References:
[1] G. Alber, J. Z. Bernad, M. Stobinska, L. L. Sanchez-Soto, G. Leuchs, ’QED with a parabolic mirror’, Phys. Rev. A 88, 023825 (2013).
