Quantum toroidal moments of an elliptic toroidal helix in a constant   magnetic field
  An effective one-dimensional Schr\"odinger equation for a spinless particle constrained to motion near a toroidal helix immersed in an arbitrarily oriented constant magnetic field is developed. The dependence of the induced toroidal moments on the magnetic flux through the helix is presented. The magnitude of the moments depend strongly on the component of the field normal to the toroidal plane. A strong dependence on coil eccentricity is also indicated. It is also shown that field-curvature coupling potential terms are necessary to preserve the Hermiticity of the minimal prescription Hamiltonian. 
J. Williamson and M. Encinosa
quant-ph