Phase controlled metal-insulator transition in multi-leg quasiperiodic optical lattices

TL;DR

This paper investigates how phase control in multi-leg quasiperiodic optical lattices can induce a re-entrant metal-insulator transition, revealing the spectral and transport properties of cold atom systems with tunable parameters.

Contribution

It introduces a phase-controlled model of multi-leg ladder networks with quasiperiodic modulation, demonstrating the possibility of re-entrant metal-insulator transitions.

Findings

Phase difference controls spectral measures and transport.

Re-entrant metal-insulator transition observed.

Numerical analysis confirms spectral and transmission properties.

Abstract

A tight-binding model of a multi-leg ladder network with a continuous quasiperiodic modulation in both the site potential and the inter-arm hopping integral is considered. The model mimics optical lattices where ultra-cold fermionic or bosonic atoms are trapped in double well potentials. It is observed that, the relative phase difference between the on-site potential and the inter-arm hopping integral, which can be controlled by the tuning of the interfering laser beams trapping the cold atoms, can result in a mixed spectrum of one or more absolutely continuous subband(s) and point like spectral measures. This opens up the possibility of a re-entrant metal-insulator transition. The subtle role played by the relative phase difference mentioned above is revealed, and we corroborate it numerically by working out the multi-channel electronic transmission for finite two-, and three-leg ladder networks. The extension of the calculation beyond the two-leg case is trivial, and is discussed in the work.