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Q: Fachverband Quantenoptik und Photonik
Q 2: Quantum Gases (Bosons) I
Q 2.2: Talk
Monday, March 14, 2022, 14:30–14:45, Q-H10
Observation of a dissipative time crystal — •Hans Keßler1, Phatthamon Kongkhambut1, Jim Skulte1, Ludwig Mathey1,2, Jayson G. Cosme3, and Andreas Hemmerich1,2 — 1Institut für Laser-Physik, Universität Hamburg — 2The Hamburg Center for Ultrafast Imaging — 3National 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 small field decay rate (κ/2π=4.5kHz), which is in the order of the recoil frequency (ωrec/2π=3.6kHz). This leads to a unique situation where cavity field evolves with the same timescale as the atomic distribution. If the system is pumped transversally with a steady state light field, red detuned with respect to the atomic resonance, the Hepp-Lieb superradiant phase transition of the open Dicke is realized. Starting in this self-ordered density wave 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 symmetrybroken states [1]. For a blue-detuned pump light with respect to the atomic resonance, we propose an experimental realization of limit cycles. Since the model describing the system is time-independent, the emergence of a limit cycle phase heralds the breaking of continuous time-translation symmetry [2]. References [1] H. Keßler et al., PRL 127, 043602 (2021). [2] H. Keßler et al., PRA 99, 053605 (2019).