Electric-dipole-moment searches: Reexamination of frequency shifts for particles in traps

摘要

In experiments searching for a nonzero electric dipole moment of trapped particles, frequency shifts correlatednwith an applied electric field can be interpreted as a false signal. One such effect, referred to as the geometricnphase effect, is known to occur in a magnetic field that is nonperfectly homogeneous. The increase in sensitivitynof experiments demands improved theoretical description of this effect. In the case of fast particles, like atoms atnroom temperature and low pressure, the validity of established theories was limited to a cylindrical confinementncell in a uniform gradient with cylindrical symmetry.We develop a more general theory valid for an arbitrary shapenof the magnetic field as well as for arbitrary geometry of the confinement cell. Our improved theory is especiallynrelevant for experiments measuring the neutron electric dipole moment with an atomic comagnetometer. In thisncontext, we have reproduced and extended earlier numerical studies of the geometric phase effect induced bynlocalized magnetic impurities.