Regensburg 2025 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 35: Fluctuations, Noise and Other Transport Topics (joint session TT/DY)

DY 35.2: Vortrag

Donnerstag, 20. März 2025, 15:15–15:30, H31

Charge dissipation in Josephson systems and its impact on phase diffusion — •Johannes Hauff, Joachim Ankerhold, and Dominik Maile — Institut für komplexe Quantensysteme, Universität Ulm

We theoretically investigate the dynamics of the Josephson phase for different quantum circuits in the presence of dissipative couplings. Thereby, we study the environmental assisted quantum tunneling of the superconducting phase in a current-biased Josephson junction and consider Ohmic resistors inducing dissipation both in the phase and in the charge of the quantum circuit. We find that the charge dissipation leads to an enhancement of the quantum escape rate, which is strongly dependent on the shape of the potential. This effect appears already in the low Ohmic regime and also occurs in the presence of phase dissipation that favors localization [1]. Inserting realistic circuit parameters, we address the question of its experimental observability, the impact of temperature and discuss suitable parameter spaces for the observation of the enhanced rate. Furthermore, we show how the interplay of thermal and quantum fluctuations in such nonlinear systems can lead to an interesting stochastic cooling process. In this context, we also discuss the relevance of dissipative couplings for quantum annealing procedures.

[1] D. Maile et al., Phys. Rev. B 106, 045408 (2022)

Keywords: Open Quantum System; Josephson Systems; Dissipation; Diffusion; Quantum annealing