Energy Rectification in Quantum Graded Spin Chains: Analysis of the XXZ Model

TL;DR

This paper investigates energy rectification in quantum graded XXZ spin chains, demonstrating that energy transport asymmetry occurs across various structures, extending classical rectification phenomena to quantum systems.

Contribution

It provides the first analysis of energy rectification in quantum graded XXZ chains, showing its ubiquity even under homogeneous magnetic fields.

Findings

Energy rectification occurs in various graded XXZ chains.

Rectification persists even with homogeneous magnetic fields.

Results suggest extension to larger quantum systems.

Abstract

In this work, with focus on the energy transport properties in quantum, low dimensional, graded materials, we address the investigation of the energy (and spin) current in XXZ open chains with graded inner structures and driven out of equilibrium by magnetization pumping applied at the ends. We study several types of graded structures in different situations in order to show a ubiquitous occurrence of energy rectification, even for the system under a homogeneous magnetic field. Due to technical difficulties, we carry out the computation for small chains, but we present arguments which indicate the extension of some results to larger systems. Recalling the generic existence of energy rectification in classical, graded materials, which are described by anharmonic chains of oscillators, and recalling also the anharmonicity of these XXZ models, which involve quartic terms in more transparent representation in terms of fermionic creation and annihilation operators, we may say that our results extend the ubiquity of energy rectification occurrence in classical graded materials to the case of quantum systems.