Detailed discussion of a linear electric field frequency shift   (important for next generation) electric dipole moment searches) induced in   confined gases by a magnetic field gradient: Implications for electric dipole   moment experiments (II)
  The search for particle electric dipole moments represents a most promising way to search for physics beyond the standard model. A number of groups are planning a new generation of experiments using stored gases of various kinds. In order to achieve the target sensitivities it will be necessary to deal with the systematic error resulting from the interaction of the well-known E x v field with magnetic field gradients (often referred to as the geometric phase effect [9,10]). This interaction produces a frequency shift linear in the electric field, mimicking an edm. In this work we introduce an analytic model for the correlation function which determines the behavior of the frequency shift [11], and show in detail how it depends on the operating conditions of the experiment. We also propose a method to directly measure ths correlation function under the exact conditions of a given experiment. 
A.L. Barabanov, R. Golub, S.K. Lamoreaux