Trapping neutral particles endowed with a magnetic moment by an electromagnetic wave carrying orbital angular momentum: Semiclassical theory

TL;DR

This paper develops a semiclassical theory describing how neutral particles with magnetic moments can be trapped using electromagnetic waves with orbital angular momentum, providing insights into their motion and trapping mechanisms.

Contribution

It derives coupled nonlinear equations from quantum mechanics and analyzes particle trapping in complex electromagnetic fields, advancing understanding of neutral particle manipulation.

Findings

Transverse trapping achieved with running waves.

Longitudinal trapping possible with standing waves.

Analytic and numerical solutions elucidate particle dynamics.

Abstract

The motion of a neutral atom endowed with a magnetic moment interacting with the magnetic field is determined from the Ehrenfest-like equations of motion. These equations for the average values of the translational and spin degrees of freedom are derived from the Schr\"odinger-Pauli wave equation and they form a set of nine coupled nonlinear evolution equations. The numerical and analytic solutions of these equations are obtained for the combination of the rotating magnetic field of a wave carrying orbital angular momentum and a static magnetic field. The running wave traps the atom only in the transverse direction while the standing wave traps the atom also in the direction of the beam.