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Josephson Coupling through a Quantum Dot

A. V. Rozhkov·D. P. Arovas·F. Guinea
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Abstract

We derive, via fourth order perturbation theory, an expression for the Josephson current through a gated interacting quantum dot. We analyze our expression for two different models of the superconductor-dot-superconductor (SDS) system. When the matrix elements connecting dot and leads are featureless constants, we compute the Josephson coupling J_c as a function of the gate voltage and Coulomb interaction. In the diffusive dot limit, we compute the probability distribution P(J_c) of Josephson couplings. In both cases, pi junction behavior (J_c < 0) is possible, and is not simply dependent on the parity of the dot occupancy.

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A. V. Rozhkov, D. P. Arovas, F. Guinea. 2000-11-12. Josephson Coupling through a Quantum Dot. https://doi.org/10.1103/physrevb.64.233301

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