Vladislav Pokorný

Perturbation theory for an Anderson quantum dot asymmetrically attached to two superconducting leads

Self-consistent perturbation expansion up to the second order in the interaction strength is used to study a single-level quantum dot with local Coulomb repulsion attached asymmetrically to two generally different superconducting leads. At zero temperature and wide range of other parameters the spin-symmetric version of the expansion yields excellent results for the position of the

Josephson-phase-controlled interplay between correlation effects and electron pairing in a three-terminal nanostructure

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Thermodynamically consistant description of criticality in models of correlated electrons

impurity quantum phase transition boundary and Josephson current together with the energy of Andreev bound states in the

Mean-field approximation for thermodynamic and spectral functions of correlated electrons: Strong coupling and arbitrary band filling

0

Silver Makes Better Electrical Contacts to Thiol‐Terminated Silanes than Gold

-phase as confirmed by numerical calculations using the Numerical Renormalisation Group method. We analytically prove that the method is charge-conserving as well as thermodynamically consistent. Explicit formulas for the position of the

Quantum transport in strongly disordered crystals: Electrical conductivity with large negative vertex corrections

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Correlation effects in superconducting quantum dot systems

phase boundary are presented for the Hartree-Fock approximation as well as for its variant called Generalized Atomic Limit. It is shown that the Generalized Atomic Limit can be used as a quick estimate for the position of the phase boundary at half-filling in a broad range of parameters. We apply our second order perturbation method to the interpretation of the existing experimental data on the phase boundary with very satisfactory outcome suggesting that the so far employed heavy numerical tools such as Numerical Renormalization Group and/or Quantum Monte Carlo are not necessary in a class of generic situations and can be safely replaced by a perturbative approach.

Spin-symmetric solution of an interacting quantum dot attached to superconducting leads: Andreev states and the 0-π transition

We study the subgap spectrum of the interacting single-level quantum dot coupled between two superconducting reservoirs, forming the Josephson-type circuit, and additionally hybridized with a metallic normal lead. This system allows for the phase-tunable interplay between the correlation effects and the proximity-induced electron pairing resulting in the singlet-doublet (0-

Conductivity of the disordered Anderson model

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Practical Guide to Quantum Phase Transitions in Superconducting Quantum Dots

) crossover and the phase-dependent Kondo effect. We investigate the spectral function, induced local pairing, Josephson supercurrent, and Andreev conductance in a wide range of system parameters by the numerically exact Numerical Renormalization Group and Quantum Monte Carlo calculations along with perturbative treatments in terms of the Coulomb repulsion and the hybridization term. Our results address especially the correlation effects reflected in dependencies of various quantities on the local Coulomb interaction strength as well as on the coupling to the normal lead. We quantitatively establish the phase-dependent Kondo temperature