We investigate quasiparticle states driven by the proximity effect in the quantum dot(s) coupled to superconducting samples. For the single quantum impurity, we show that its subgap spectrum consists of either the magnetically unpolarized (Andreev) or polarized (Yu–Shiba–Rusinov) bound states appearing at energies which depend on the hybridization strength with a superconductor. We also analyze the molecular bound states of the double quantum dot attached in series to a superconductor and weakly coupled to a metallic lead on the opposite side. For this setup, we show that a magnetic field is detrimental to the on-dot pairings, in much the same way as spinful impurities are pair-breakers for the Cooper pairs in conventional bulk superconductors. Finally, we address the issue of triplet pairing induced by the spin–orbit interactions in superconducting nanostructures. Abstract Published by the Jagiellonian University 2026 authors
Domański et al. (Fri,) studied this question.