Excitation transfer in disordered spin chains with long-range exchange interactions

TL;DR

This paper investigates how long-range disordered spin chains can transfer spin excitations efficiently, analyzing localization properties and comparing static and adiabatic transfer schemes to optimize excitation transfer.

Contribution

It introduces a method to identify suitable eigenstates for excitation transfer in disordered long-range spin chains and compares static and adiabatic transfer schemes for improved performance.

Findings

Localization length varies with disorder strength.

Adiabatic transfer outperforms static coupling in certain regimes.

Eigenstates with large localization length facilitate transfer.

Abstract

We examine spin excitation or polarization transfer via long-range interacting spin chains with diagonal and off-diagonal disorder. To this end, we determine the mean localization length of the single-excitation eigenstates of the chain for various strengths of the disorder. We then identify the energy eigenstates of the system with large localization length and sufficient support at the chain boundaries that are suitable to transfer an excitation between the sender and receiver spins connected to the opposite ends of the chain. We quantify the performance of two transfer schemes involving weak static couplings of the sender and receiver spins to the chain, and time-dependent couplings realizing stimulated adiabatic passage of the excitation via the intermediate eigenstates of the chain which exhibits improved performance.