Effect of a high-frequency magnetic field on the resonant behavior displayed by a spin-$1/2$ particle under the influence of a rotating magnetic field

TL;DR

This paper explores how a high-frequency magnetic field influences the resonant behavior of a spin-1/2 particle in a rotating magnetic field, comparing analytical methods with numerical solutions to determine the most accurate approach.

Contribution

It introduces and compares averaging and multiple scale analytical methods for analyzing the system, demonstrating the superiority of the multiple scale method in capturing the true dynamics.

Findings

Multiple scale method provides better understanding of system dynamics.

Averaging method incorrectly predicts destruction of resonance.

Numerical solutions confirm the resonance persists despite high-frequency fields.

Abstract

In this paper, we investigate the role of a high-frequency magnetic field in the resonant behavior displayed by a spin-$1/2$ particle under the influence of a rotating magnetic field. We propose two alternative methods for analyzing the system dynamics, namely, the averaging method and the multiple scale method. The analytical results achieved by applying these two methods are compared with those obtained from the numerical solution of the Schr\"odinger equation. This comparison leads to the conclusion that the multiple scale method provides a better understanding of the system dynamics than the averaging method. In particular, the averaging method predicts the complete destruction of the resonant behavior by an appropriate choice of the parameter values of the high-frequency magnetic field. This conclusion is disproved both by the numerical results, and also by the results obtained from the multiple scale method.