Regensburg 2019 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 35: HL Poster II

HL 35.34: Poster

Wednesday, April 3, 2019, 17:30–20:00, Poster E

Non-Markovian quantum feedback control of driven few-level quantum systems — Leon Droenner, •Kisa Barkemeyer, Andreas Knorr, and Alexander Carmele — Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany

Motivated by classical Pyragas control and its impressive successes in laser physics and self-organizing nonlinear systems [1], the concept of non-invasive, coherent feedback is investigated in the quantum regime. In case of a pulsed excitation, a few-level system fundamentally acts as a single-photon source when excited with a π-pulse, while for a 2 π-pulse two-photon emission is more likely to occur [2]. Employing feedback, we observe a qualitatively different reaction of single- and two-photon events to the feedback-induced coupling strength. The delay-dependent phase of the feedback signal results either in the enhancement or the suppression of single-photon events, whereas two-photon events become more probable [3]. Furthermore, we discuss how the delay-dependent phase shapes the photon-statistics and how this phase can be addressed externally.

[1] E. Schöll, S. H. Klapp, and P. Hövel (Eds.), Control of Self-Organizing Nonlinear Systems (Springer, 2016).

[2] K. A. Fischer, L. Hanschke, J. Wierzbowski, T. Simmet, C. Dory, J. J. Finley, J. Vučković, and K. Müller, Nature Physics 13, 649 (2017).

[3] L. Droenner, N. L. Naumann, A. Knorr, and A. Carmele, arXiv:1801.03342v2 (2018).