Berlin 2018 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 75: Superconductivity: Mesoscopic Superconductivity and Quantum Circuits

TT 75.1: Talk

Wednesday, March 14, 2018, 17:00–17:15, H 2053

Reducing phase drift by injection locking a cavity mode driven by a Josephson junction — •Ciprian Padurariu, Björn Kubala, and Joachim Ankerhold — Institute for Complex Quantum Systems and IQST, Ulm University, 89069 Ulm, Germany

Circuit QED devices are highly tunable radiation emitters with high photon collection efficiency, leading as candidates for on-demand single photon sources, on-demand entangled photon pairs, and sensitive single photon detectors in the microwave spectrum [1]. The main hurdle on the way to full quantum control of the emitted radiation is phase drift due to electrical noises generated from outside, as well as from within, the device [2].

In quantum optics, a well known technique to reduce phase drift is injection locking to a low intensity, narrow bandwidth laser. We borrow this technique for circuit QED by locking the active mode to a small amplitude near-resonant microwave tone. We describe theoretically the quantum dynamics of injection locking and quantify the effectiveness of the phase drift reduction. When the microwave tone is off-resonant, we describe the phenomenon of frequency pulling, where the frequency of radiation emission is shifted towards that of the microwave tone.
M. Westig et al, Phys. Rev. Lett. 119, 137001 (2017).
S. Dambach et al, New J. Phys. 19, 023027 (2017).