Phase-dependent magnetoconductance fluctuations in a chaotic Josephson junction

Abstract

Motivated by recent experiments by Den Hartog et al., we present a random-matrix theory for the magnetoconductance fluctuations of a chaotic quantum dot which is coupled by point contacts to two superconductors and one or two normal metals. There are aperiodic conductance fluctuations as a function of the magnetic field through the quantum dot and $2\pi$-periodic fluctuations as a function of the phase difference $\varphi$ of the superconductors. If the coupling to the superconductors is weak compared to the coupling to the normal metals, the $\varphi$-dependence of the conductance is harmonic, as observed in the experiment. In the opposite regime, the conductance becomes a random $2\pi$-periodic function of $\varphi$, in agreement with the theory of Altshuler and Spivak. The theoretical method employs an extension of the circular ensemble which can describe the magnetic field dependence of the scattering matrix.

4 pages, RevTeX, 3 figures

References in corpus (1)

• Crossover of magnetoconductance autocorrelation for a ballistic chaotic quantum dot

Cited by in corpus (11)

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• Controlling the Sign of Magnetoconductance in Andreev Quantum Dots
• Phase-coherent heat circulators with normal- or superconducting contacts
• Charge fluctuations in open chaotic cavities
• Superconducting Proximity Effect and Universal Conductance Fluctuations
• Effects of Andreev reflection on the conductance of quantum-chaotic dots