English

Berezinskii-Kosterlitz-Thouless transition in Josephson junction arrays

Mesoscale and Nanoscale Physics 2016-08-16 v1 Statistical Mechanics

Abstract

The quantum XY model shows a Berezinskii-Kosterlitz-Thouless (BKT) transition between a phase with quasi long-range order and a disordered one, like the corresponding classical model. The effect of the quantum fluctuations is to weaken the transition and eventually to destroy it. However, in this respect the mechanism of disappearance of the transition is not yet clear. In this work we address the problem of the quenching of the BKT in the quantum XY model in the region of small temperature and high quantum coupling. In particular, we study the phase diagram of a 2D Josephson junction array, that is one of the best experimental realizations of a quantum XY model. A genuine BKT transition is found up to a threshold value gg^\star of the quantum coupling, beyond which no phase coherence is established. Slightly below gg^\star the phase stiffness shows a reentrant behavior at lowest temperatures, driven by strong nonlinear quantum fluctuations. Such a reentrance is removed if the dissipation effect of shunt resistors is included.

Keywords

Cite

@article{arxiv.cond-mat/0401030,
  title  = {Berezinskii-Kosterlitz-Thouless transition in Josephson junction arrays},
  author = {Luca Capriotti and Alessandro Cuccoli and Andrea Fubini and Valerio Tognetti and Ruggero Vaia},
  journal= {arXiv preprint arXiv:cond-mat/0401030},
  year   = {2016}
}

Comments

14 pages, Kluwer style. Proceeding of the EURESCO conference "Fundamental Problems of Mesoscopic Physics", Sept. 2003, Granada