Oct 16 – 20, 2016
Europe/Zurich timezone

Relaxation and Frequency shifts; a comparison between simulations and theory for the SNS nEDM experiment.

Oct 17, 2016, 12:20 PM
Oral Searches for permanent electric dipole moments Mo - 2


Dr Christopher Swank (Caltech)


The behavior of a spin undergoing Larmor precession in the presence of fluctuating fields is of interest to a variety of precision measurement experiments. The fluctuating fields cause frequency shifts and relaxation which according to Redfield theory are related to their power spectrum. Recently it was shown that scattering with energy exchange from an ensemble of scatterers in thermal equilibrium can be incorporated into the continuous time random walk to more accurately predict the behavior of dilute gases. It was found that the results in the 'thermalization' model for 1,2 and 3 dimensions are in perfect agreement contrary to the previously studied 'frozen' models. The results are compared to simulations of the SNS nEDM conditions where in the ballistic regime a strong deviation from Redfield theory is observed for mostly specular wall collisions. The Torrey equation can be solved exactly for purely specular case and the solution can be modified according to the average time between wall collisions of trajectories to allow for diffuse wall collisions. This allows accurate analytic predictions of the Monte Carlo simulations, and presumably the SNS nEDM experiment.

Primary author

Dr Christopher Swank (Caltech)

Presentation materials