Coherent Magnetic Moment Reversal in Small Particles with Nuclear Spins

TL;DR

This paper introduces a discrete WKB method to analyze how nuclear spins influence quantum coherence in small magnetic particles, comparing results with numerical and instanton-based approaches.

Contribution

It develops a novel discrete WKB technique for calculating tunnel splittings in spin systems affected by nuclear spins.

Findings

WKB method effectively models nuclear spin effects on magnetic tunneling

Results align with numerical simulations and instanton approaches

Provides new insights into quantum coherence in magnetic nanoparticles

Abstract

A discrete WKB method is developed for calculating tunnel splittings in spin problems. The method is then applied to the issue of how nuclear spins affect the macroscopic quantum coherence of the total magnetic moment in small magnetic particles. The results are compared with numerical work, and with previous instanton based analytic approaches.