Time dependent spin-dressing using a $^3$He atomic beam

TL;DR

This study experimentally investigates spin precession in a dressed $^3$He atomic beam, validating the spin-dressing Hamiltonian beyond traditional limits and exploring effects of magnetic misalignment for precision measurements like neutron EDM searches.

Contribution

The paper provides high-precision measurements of spin-dressing effects in $^3$He, extending the understanding of the Hamiltonian's validity and analyzing magnetic misalignment impacts for advanced magnetic resonance techniques.

Findings

Validated spin-dressing Hamiltonian beyond the small Larmor frequency limit.

Quantified effects of magnetic field misalignment on spin precession.

Discussed modulation of dressing fields for improved control in precision measurements.

Abstract

We have performed high precision experimental measurements of spin precession using a dressed $^3$He atomic beam. Spin-dressing uses an oscillating magnetic field detuned to high frequency which is orthogonal to a static magnetic field to effectively change the gyromagnetic ratio of a spin. We verify the validity of the spin-dressing Hamiltonian in regions beyond the limiting solution in which the Larmor frequency is much smaller than the frequency of the dressing field. We also evaluate the effect of magnetic field misalignment, e.g. if the oscillating magnetic field is not orthogonal to the static magnetic field. Modulation of the dressing field parameters is also discussed, with a focus on whether such a modulation can be approximated merely as a time dependent, dressed gyromagnetic ratio. Furthermore, we discuss implications for a proposed search for the neutron electric dipole moment, which would employ spin-dressing to make the effective $^3$He and neutron magnetic moments equal.