# Stationary Charge Imbalance Effect in System of Coupled Josephson Junction

## TL;DR

This paper studies how stationary charge imbalance affects coupled Josephson junctions, revealing impacts on Josephson frequency, voltage characteristics, and Shapiro steps through theoretical and experimental analysis.

## Contribution

It introduces a detailed analysis of stationary charge imbalance effects in coupled Josephson junctions, including theoretical and experimental insights into their influence on junction dynamics.

## Key findings

- Charge imbalance decreases Josephson frequency.
- Nonuniform switching to Shapiro steps occurs due to frequency difference.
- Charge imbalance causes slope in Shapiro steps.

## Abstract

We investigate stationary charge imbalance effect in the system of coupled overdamped Josephson junctions. We show that coupling between junction and nonzero stationary charge imbalance in the resistive state bring to a decrease of the Josephson frequency in the Josephson junctions of the stack. The formed difference in Josephson frequency leads to the nonuniform switch to the Shapiro step regime in the presence of external electromagnetic radiation and appearance of kinks of voltage on the IV-characteristics of the stack. We also show that stationary charge imbalance brings to the slope of the Shapiro step due to the difference of the charge imbalance potential on the edges of the step. The theoretical and experimental results for voltage bias coupled Josephson junctions have been compared with the current bias case.