Regensburg 2019 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 55: Superconductivity: Tunneling and Josephson Junctions

TT 55.7: Vortrag

Donnerstag, 4. April 2019, 10:45–11:00, H23

Quantum properties of a strongly driven Josephson junction — Jennifer Gosner, •Björn Kubala, and Joachim Ankerhold — Institute for Complex Quantum Systems and IQST, University of Ulm, 89069 Ulm, Germany

A Josephson junction embedded in a dissipative circuit can be externally driven to induce nonlinear dynamics of its phase. Classically, under sufficiently strong driving and weak damping, dynamic multi-stability emerges associated with dynamical bifurcations so that the often used modeling as a Duffing oscillator, which can exhibit bi-stability at the most, is insufficient. Here, corresponding quantum properties in this regime are analyzed by mapping the problem onto a highly-nonlinear quasi-energy operator in a rotating frame. This allows us to identify in detail parameter regions where simplifications such as the Duffing one are valid, to explore classical-quantum correspondences and to study how quantum fluctuations impact the effective junction parameters as well as the dynamics around higher amplitude classical fixed points.