Report on 2112.05066v2

Abstract

Motivated by the interplay of Bethe Ansatz integrability and localization in a Richardson model of superconductivity, we consider a time-reversal symmetry breaking deformation of this model, known as a Russian Doll Model (RDM) by implementing diagonal on-site disorder.The localization and ergodicity-breaking properties of a single-particle spectrum are analyzed within a large-energy renormalization group (RG) over the momentum-space spectrum.Based on the above RG, we derive an effective Hamiltonian of the model, discover a fractal phase of non-ergodic delocalized states, with the fractal dimension different from the one of a paradigmatic Rosenzweig-Porter model, and explain it both in terms of the developed RG equations and matrix-inversion trick.

Locations

• arXiv (Cornell University) - PDF