Goldstone Bosons in Josephson Junctions

TL;DR

This paper constructs a microscopic model of a Josephson junction to analyze the Goldstone bosons' normal coordinates and their dynamical spectrum, highlighting how the phase difference affects these properties.

Contribution

It provides an explicit microscopic derivation of Goldstone bosons in Josephson junctions and calculates their spectrum as a function of phase difference.

Findings

Normal coordinates of Goldstone bosons are constructed.

Dynamical spectrum depends explicitly on phase difference.

Phase dependence of Goldstone bosons is quantitatively characterized.

Abstract

For a microscopic model of a Josephson junction the normal coordinates of the two junction Goldstone bosons are constructed and their dynamical spectrum is computed. The explicit dependence on the phase difference of the two superconductors is calculated.