Localization in one dimensional lattices with non-nearest-neighbor hopping: Generalized Anderson and Aubry-Andr\'e models

TL;DR

This paper investigates quantum localization in one-dimensional lattices with extended hopping terms, generalizing the Aubry-André and Anderson models, and identifies conditions for localization transitions and mobility edges.

Contribution

It introduces a class of self dual models with analytically determined localization boundaries and explores the effects of various non-nearest-neighbor hopping decays on localization.

Findings

Self dual models have analytically solvable localization boundaries.

Mobility edges can be approximated in non-dual models with fast decay hopping.

Power-law decay hopping exhibits a critical exponent for mobility edges.

Abstract

We study the quantum localization phenomena of noninteracting particles in one-dimensional lattices based on tight-binding models with various forms of hopping terms beyond the nearest neighbor, which are generalizations of the famous Aubry-Andr\'e and noninteracting Anderson model. For the case with deterministic disordered potential induced by a secondary incommensurate lattice (i.e. the Aubry-Andr\'e model), we identify a class of self dual models, for which the boundary between localized and extended eigenstates are determined analytically by employing a generalized Aubry-Andr\'e transformation. We also numerically investigate the localization properties of non-dual models with next-nearest-neighbor hopping, Gaussian, and power-law decay hopping terms. We find that even for these non-dual models, the numerically obtained mobility edges can be well approximated by the analytically obtained condition for localization transition in the self dual models, as long as the decay of the hopping rate with respect to distance is sufficiently fast. For the disordered potential with genuinely random character, we examine scenarios with next-nearest-neighbor hopping, exponential, Gaussian, and power-law decay hopping terms numerically. We find that the higher order hopping terms can remove the symmetry in the localization length about the energy band center compared to the Anderson model. Furthermore, our results demonstrate that for the power-law decay case, there exists a critical exponent below which mobility edges can be found. Our theoretical results could, in principle, be directly tested in shallow atomic optical lattice systems enabling non-nearest-neighbor hopping.