A versatile polarization method for particles with simple hyperfine structures

• Applicant: Dr. Chrysovalantis Kannis
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas ; Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 533904660

The study of atomic beams passing through a magnetic field, whose direction changes along the motion axis, gave rise to a new versatile polarization method. A sinusoidal longitudinal field produces a radial component, which is proportional to the gradient of the first. Such fields can be realized employing two opposing solenoid coils. The longitudinal field creates energy splittings between the hyperfine states and the radial field induces transitions between them. The hyperfine transitions can be described by absorption of photons, whose energy is equal to the energy splitting between the states. The energy of the photons depends on the relative motion between the particle beam and the magnetic field (for a given wavelength of the sinusoidal field) and the number of the photons increases with the increase of the magnetic field strength. Therefore, uneven transition rates are observed while ramping the magnetic field of the apparatus. As a result, it is feasible to achieve a high polarization degree by adjusting the magnetic field strength. In general, the produced polarization is higher for particles with simple hyperfine structures. However, it can also be applied to molecules in low rotational levels. The aim of the project is to experimentally verify this polarization technique for beams of simple atoms or ions, e.g., H, D, 3He+, etc., which are required for the investigation of polarized nuclear fusion. Furthermore, the applicability of the proposed method to molecular hydrogen isotopes and boron will be examined. The numerical simulations are developed by studying the spin dynamics in the rest frame of the particle beam, where the spatial variation of the magnetic field is transformed to time variation experienced by the particles, which move with a constant velocity. This suggests applying time-dependent magnetic pulses to particles at rest in order to polarize them. Consequently, solid samples will be investigated theoretically and the limits of the method will be determined.

• DFG Programme: WBP Position