Qualitative features of the mean-field BCS-like theory of superconductivity in a strongly disordered system of fermions with short-range attraction are discussed. Specifically, I consider two versions of the effective bosonic low-energy theory for the electron pairs: with the infinite range, and with the nearest neighbor hoping between localized states. In the first case the superconducting gap...

Abstract Prozorov and Bud’ko (On the analysis of tin-inside- H 3 S Mössbauer experiment, 2022) recently analyzed nuclear resonant scattering (NRS) experiment that reportedly demonstrated magnetic field exclusion in sulfur hydride under pressure (Science 351, 1303, 2016), concluded is consistent with expected behavior a type II superconductor. Here I point out their shows reported NRS measuremen...

A serious obstacle impeding the application of lowand hightemperature superconductor devices is the presence of trapped magnetic flux: flux lines or vortices can be induced by fields as small as the Earth’s magnetic field. Once present, vortices dissipate energy and generate internal noise, limiting the operation of numerous superconducting devices. Methods used to overcome this difficulty incl...

Qualitative features of the mean-field theory of superconductivity in a strongly disordered system of fermions with short-range attraction are discussed. In this limit the effective theory at low energies is entirely bosonic, and I consider both the artificial infiniterange limit and the more realistic case of ”nearest-neighbor” hopping of bosons between the localized states. In the infinite-ra...

We report the observation of negative quasiparticle dynamic resistance on the DC I-V curves of superconductor-insulator-superconductor tunnel junctions. This negative resistance appears on the first few photon assisted tunneling steps below 2A/e when our tin-tin oxide-tin tunnel junctions are pumped with a 36 GHz microwave current source. We present a simple analytical model which shows that la...