SAMOP 2021 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 16: Quantum Optics
Q 16.6: Poster
Donnerstag, 23. September 2021, 16:30–18:30, P
Observation of a non-Hermitian phase transition and response dynamics in an optical quantum gas — •Aleksandr Sazhin1, Fahri Emre Özturk1, Göran Hellmann1, Jan Klaers2, Frank Vewinger1, Tim Lappe1, Johann Kroha1, Vladimir Gladilin3, Michiel Wouters3, Julian Schmitt1, and Martin Weitz1 — 1Universität Bonn — 2University of Twente — 3Universiteit Antwerpen
Quantum gases of light, such as photon or polariton condensates in optical microcavities, are collective quantum systems enabling a tailoring of dissipation from, for example, cavity loss. This gives access to new system states and phases, which would not be accessible otherwise. We experimentally demonstrate a non-Hermitian phase transition of a photon Bose-Einstein condensate to a dissipative phase characterized by a biexponential decay of the condensate's second-order coherence[1]. Although Bose-Einstein condensation is usually connected to lasing by a smooth crossover, the observed phase transition separates the biexponential phase from both lasing and an intermediate, oscillatory condensate regime. In more recent experiments, we study the response dynamics of the photon Bose-Einstein condensate to an external perturbation of the condensate photon number. Depending on the perturbation strength, we identify linear and nonlinear relaxation behavior, which we compare to the (intrinsic) second-order correlations. Our approach can be used to study a wide class of dissipative quantum phases in topological or lattice systems. [1]Oeztuerk et al., Science 372 (6537), 88 (2021)