Quantum and thermal fluctuations in the dynamics of a resistively and capacitively shunted Josephson junction

Year: 2021

Authors: Furutani K., Salasnich L.

Autors Affiliation: Dipartimento di Fisica e Astronomia “Galileo Galilei”, Università, di Padova, via Marzolo 8, Padova, 35131, Italy; Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Padova, via Marzolo 8, Padova, 35131, Italy; CNR-INO, via Nello Carrara, Sesto Fiorentino, 1-50019, Italy

Abstract: We theoretically investigate the phase and voltage correlation dynamics, which includes both the deterministic contribution and stochastic fluctuations, under a current noise generated by a resistor including thermal and quantum fluctuations in a resistively and capacitively shunted Josephson junction. An external current is found to shift and intensify the deterministic contributions in phase and voltage. In addition to effects of external current, we observe the relaxation of autocorrelation functions of phase and voltage, which includes the variances due to the current noise, to finite values in the long-time limit. In particular, we find that the asymptotic correlations depend on the resistance as a consequence of quantum effects. We also find an earlier decay of coherence at a higher temperature in which thermal fluctuations dominate over quantum ones. These theoretical predictions can be tested in the next future experiments. (c) 2021 American Physical Society


Volume: 104 (1)      Pages from: 014519-1  to: 014519-8

More Information: K.F. is supported by a Ph.D. fellowship of the Fondazione Cassa di Risparmio di Padova e Rovigo. This work is partially supported by the BIRD project “Time-dependent density functional theory of quantum atomic mixtures” in the University of Padova.
KeyWords: phase-diagram; noise; agitation
DOI: 10.1103/PhysRevB.104.014519