Current responses and voltage fluctuations in Josephson-junction systems

TL;DR

This paper investigates the dynamic electrical responses of Josephson-junction systems, analyzing how their resistance and voltage fluctuations relate through the fluctuation-dissipation theorem in classical and quantum regimes.

Contribution

It introduces a generalized resistance concept for Josephson junctions and explores its relation to voltage fluctuations across classical and quantum regimes.

Findings

Generalized resistance relates to voltage fluctuations via fluctuation-dissipation theorem.

Voltage fluctuation power spectrum is connected to the system's dynamic response.

Implications for experimental measurements of Josephson junctions are discussed.

Abstract

We consider arrays of Josephson junctions as well as single junctions in both the classical and quantum-mechanical regimes, and examine the generalized (frequency-dependent) resistance, which describes the dynamic responses of such Josephson-junction systems to external currents. It is shown that the generalized resistance and the power spectrum of voltage fluctuations are related via the fluctuation-dissipation theorem. Implications of the obtained relations are also discussed in various experimental situations.