Quantum mechanics of spin transfer in coupled electron-spin chains

TL;DR

This paper develops a fully quantum mechanical model of spin transfer in coupled electron-spin chains, advancing the understanding of spin dynamics beyond semi-classical descriptions by incorporating quantum entanglement and density matrix formalism.

Contribution

It introduces a novel quantum approach to spin transfer in spin chains, moving beyond semi-classical models and accounting for quantum entanglement effects.

Findings

Demonstrates quantum evolution of individual spins due to spin transfer

Highlights the role of entanglement in spin dynamics

Provides a formalism for quantum spin transfer in chains

Abstract

The manner in which spin-polarized electrons interact with a magnetized thin film is currently described by a semi-classical approach. This in turn provides our present understanding of the spin transfer, or spin torque phenomenon. However, spin is an intrinsically quantum mechanical quantity. Here, we make the first strides towards a fully quantum mechanical description of spin transfer through spin currents interacting with a Heisenberg-coupled spin chain. Because of quantum entanglement, this requires a formalism based on the density matrix approach. Our description illustrates how individual spins in the chain time-evolve as a result of spin transfer.