Dephasing-induced mobility edges in quasicrystals

TL;DR

This paper demonstrates that pure dephasing can induce mobility edges in quasicrystals, creating a transition between localized and extended states, contrary to the common belief that dephasing destroys localization.

Contribution

It reveals that dephasing effects can generate mobility edges in quasicrystals, showing that decoherence can enhance localization rather than solely destroying it.

Findings

Dephasing can induce mobility edges in quasicrystals.

Localized states can have extremely long lifetimes under dephasing.

Decoherence can counterintuitively enhance localization in certain systems.

Abstract

Mobility edges (ME), separating Anderson-localized states from extended states, are known to arise in the single-particle energy spectrum of certain one-dimensional lattices with aperiodic order. Dephasing and decoherence effects are widely acknowledged to spoil Anderson localization and to enhance transport, suggesting that ME and localization are unlikely to be observable in the presence of dephasing. Here it is shown that, contrary to such a wisdom, ME can be created by pure dephasing effects in quasicrystals in which all states are delocalized under coherent dynamics. Since the lifetimes of localized states induced by dephasing effects can be extremely long, rather counter-intuitively decoherence can enhance localization of excitation in the lattice. The results are illustrated by considering photonic quantum walks in synthetic mesh lattices.