Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 98: Poster Session: Superconductivity

TT 98.21: Poster

Donnerstag, 15. März 2018, 15:00–19:00, Poster B

Properties of self-consistent random matrices: Case study for the superconductor-insulator transition — •Matthias Stosiek and Ferdinand Evers — Institute of Theoretical Physics, University of Regensburg, Germany

Our general interest is in the properties of ensembles of random Hamiltonians that satisfy a self-consistency property. Such ensembles typically appear in mean-field treatments of interacting systems. The example we here consider is the Superconductor-Insulator Transition (SIT) where the superconducting gap is calculated self-consistently in the presence of short-range disorder. Our focus is on disordered films with conventional s-wave pairing that we study numerically employing the negative-U Hubbard model within the standard Bogoliubov-deGennes approximation. The general question that we would like to address here concerns the auto-correlation function of the pairing amplitude: How does it decay in real space and in what way does it change across the SIT?

These correlations are typically neglected in analytical theories. Our research might have significant impact on the understanding of the SIT, if the correlations turn out sufficiently long-ranged, so that they influence properties of the critical point.

We present preliminary data that indicates the existence of very long ranged (power-law) correlations that may indeed change the critical behavior in a significant way.