Dresden 2020 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 22: Quantum Dots, Quantum Wires, Point Contacts

TT 22.11: Talk

Tuesday, March 17, 2020, 12:15–12:30, HSZ 201

Perturbation theory for superconducting double quantum dot systems — •Vladislav Pokorný¹ and Martin Žonda² — ¹Institute of Physics, Czech Academy of Sciences, Na Slovance 2, Praha 8 CZ-182 21, Czech Republic — ²Institute of Physics, Albert Ludwig University of Freiburg, Hermann-Herder-Strasse 3, Freiburg DE-791 04, Germany

We present an approach based on the second order perturbation theory in the Coulomb interaction to calculate properties of double quantum dots coupled to superconducting BCS leads. We map the system on a generalized two-impurity Anderson model and using this perturbative method we evaluate several single-particle quantities such as the on-dot induced gap and generalized occupation numbers together with the Andreev in-gap spectra and compare them with numerically exact results from the Numerical Renormalization Group and Quantum Monte Carlo finding a good correspondence for not too strongly correlated regimes. This method can offer an efficient and reliable alternative to the heavy numerical tools in a wide parameter range.