We present a simple microscopic model to show how fluctuating two--level systems in the Josephson junction tunnel barrier of thickness L can modify the potential energy of the barrier and produce critical current noise spectra. We find low frequency 1/f noise that goes as L5. Our values are in good agreement with recent experimental measurements of critical current noise in Al/AlOx/Al Josephson junctions. We also investigate the sensitivity of the noise on the nonuniformity of the tunnel barrier.
@article{arxiv.cond-mat/0612410,
title = {Microscopic Model of Critical Current Noise in Josephson Junctions},
author = {Magdalena Constantin and Clare C. Yu},
journal= {arXiv preprint arXiv:cond-mat/0612410},
year = {2007}
}