Continuous feedback on a quantum gas coupled to an optical cavity

Autor: Katrin Kroeger, Nishant Dogra, Rodrigo Rosa-Medina, Marcin Paluch, Francesco Ferri, Tobias Donner, Tilman Esslinger
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: New Journal of Physics, Vol 22, Iss 3, p 033020 (2020)
Druh dokumentu: article
ISSN: 1367-2630
DOI: 10.1088/1367-2630/ab73cc
Popis: We present an active feedback scheme acting continuously on the state of a quantum gas dispersively coupled to a high-finesse optical cavity. The quantum gas is subject to a transverse pump laser field inducing a self-organization phase transition, where the gas acquires a density modulation and photons are scattered into the resonator. Photons leaking from the cavity allow for a real-time and non-destructive readout of the system. We stabilize the mean intra-cavity photon number through a micro-processor controlled feedback architecture acting on the intensity of the transverse pump field. The feedback scheme can keep the mean intra-cavity photon number n _ph constant, in a range between n _ph = 0.17(4) and n _ph = 27.6(5), and for up to 4 s. Thus we can engage the stabilization in a regime where the system is very close to criticality as well as deep in the self-organized phase. The presented scheme allows us to approach the self-organization phase transition in a highly controlled manner and is a first step on the path towards the realization of many-body phases driven by tailored feedback mechanisms.
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