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Q: Fachverband Quantenoptik und Photonik

Q 22: Poster II

Q 22.9: Poster

Tuesday, March 7, 2023, 16:30–19:00, Empore Lichthof

Dynamical light-matter phases in an atom-cavity platform — •Phatthamon Kongkhambut¹, Hans Keßler¹, Jim Skulte¹, Ludwig Mathey¹, Jayson G. Cosme², and Andreas Hemmerich¹ — ¹Institut für Laser-Physik, Universität Hamburg — ²National Institute of Physics, University of the Philippines

We are experimentally exploring the light-matter interaction of a Bose-Einstein condensate (BEC) with a single light mode of an ultra-high finesse optical cavity. The key feature of our cavity is the very small field decay rate (κ/2π = 3.5 kHz), which is in the order of the recoil frequency (ω_rec/2π = 3.6 kHz). This leads to a unique situation where cavity field evolves with the same time scale as the atomic density distribution. Pumping the system with a steady state light field, red detuned with respect to the atomic resonance, the Dicke model is implemented including the self-organisation phase transition. Starting in the self-ordered superradinat phase and modulating the amplitude of the pump field, we observe a dissipative discrete time crystal, whose signature is a robust subharmonic oscillation between two symmetry-broken states [1]. Modulation of the phase of the pump field give rise to an incommensurate time crystalline behaviour [2]. For a blue-detuned pump light with respect to the atomic resonance, we observe limit cycles. Since the used pump protocol is time-independent, the emergence of a limit cycle phase heralds the breaking of continuous time-translation symmetry[3]. [1] H. Keßler et al., PRL 127, 043602 (2021), [2] P. Kongkhambut et al., PRL 127, 253601 (2021), [3] P. Kongkhambut et al., Science 377, 6606 (2022).