Limits on weak magnetic confinement of neutral atoms

TL;DR

This paper derives fundamental limits on the strength of magnetic confinement for neutral atoms, showing that the magnetic field curvature imposes a lower bound on achievable trapping strength, especially in low-dimensional configurations.

Contribution

It establishes a theoretical lower bound on magnetic field curvature necessary for trapping neutral atoms, highlighting fundamental constraints on magnetic confinement.

Findings

Magnetic field curvature must exceed a specific threshold for effective trapping.

Limits are tighter for one- or two-dimensional magnetic potentials.

Conjecture that curvature must be at least twice the minimum for such potentials.

Abstract

It is shown that when a magnetic field is used to support neutral atoms against the gravitational force mg, the total curvature of the field magnitude B must be larger than m^2 g^2/(2 \mu^2 B), where mu is the magnetic moment of the atoms. This limits the minimum confinement strength obtainable for a trapped atomic gas. It is also conjectured that the curvature must be larger than twice this value for a magnetic potential that varies in only one or two dimensions, such as an atomic waveguide.