Regensburg 2022 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 15: Nano- and Optomechanics
TT 15.4: Vortrag
Dienstag, 6. September 2022, 12:00–12:15, H23
Josephson optomechanics — •Surangana Sen Gupta1, Bjoern Kubala1,2, Ciprian Padurariu1, and Joachim Ankerhold1 — 1ICQ and IQST, Ulm University, Germany — 2Institute of Quantum Technologies, German Aerospace Center (DLR), Ulm, Germany
Optomechanical phenomena can be investigated in the microwave regime using a circuit-QED setup combining superconducting microwave cavities and a mechanical degree of freedom. In conventional optomechanics the cavity is usually driven to a coherent state by a laser. In contrast, in circuit optomechanics, the cavity can be driven by inelastic tunneling in a Josephson junction, which provides a large inherent non-linearity and leads to complex quantum states of light [1]. Here, we theoretically investigate a superconducting cavity with a single mode ω0 coupled to a mechanical resonator. The cavity is driven by a dc-biased Josephson junction at 2eVdc=pℏω0 where each Cooper pair excites p=1,2,3 photons.
(i) We characterise signatures of the mechanics in the emission spectrum for squeezed light (p=2) and for the p=3 case, which is challenging for optical cavities, but easily realised in our microwave cavities. The inherent nonlinearity not only allows efficient driving at p ≥ 2, but can also drastically change the spectrum at p=1, where for stronger driving Mollow-like features arise. (ii) We calculate heating and cooling rates for the mechanical degree of freedom and find in the non-linear regime enhanced and non-monotonous rates.
[1] G. C. Ménard et al., Phys. Rev. X 12, 021006 (2022).