Josephson current anomalies driven by fluctuation imbalance in superconducting junctions
Phys. Rev. B 113, 195201 – Published 1 May, 2026
DOI: https://doi.org/10.1103/b1jl-6d4m
Abstract
We investigate fluctuation-dominated physics in a superconductor–insulator–superconductor Josephson junction modeled by a Bogoliubov–de Gennes Hamiltonian. The resulting free-energy functional, expanded in powers of the fluctuations, depends explicitly on the imbalance between the absolute values of the fluctuations in the two electrodes. By solving a Ginzburg-Landau equation for this imbalance field, we determine its spatial configuration and the corresponding Josephson current. Going beyond the harmonic approximation for the effective potential reveals the emergence of a regime characterized by singular behavior of the Josephson current.
