Exact new mobility edges
Yongjian Wang, Qi Zhou
TL;DR
This work establishes two exact new mobility edges in physically realistic quasiperiodic models by analyzing singular Jacobi operators on the strip. It presents Type II ME (critical versus localized) for a mosaic-type singular Jacobi operator and Type III ME (critical versus extended) for a tailored long-range operator, using a unifying strip-operator framework and Aubry duality. key tools include explicit Lyapunov exponent formulas, Thouless theory, the IDS–rotation-number relation, Jitomirskaya–Last inequalities, and nonperturbative localization techniques. The results illuminate how singularity and duality drive coexistence and transitions among localized, critical, and extended spectral types, with potential experimental relevance for mosaic-like and related systems.
Abstract
Mobility edges (ME), defined as critical energies that separate the extended states from the localized states, are a significant topic in quantum physics. In this paper, we demonstrate the existence of two exact new mobility edges for two physically realistic models: the first, referred to as Type II ME, represents the critical energy that separates the critical states from localized states; the second, referred to as Type III ME, marks the critical energy that separate the critical states from extended states. The proof is based on spectral analysis of singular Jacobi operator on the strip.
