Spin g Factors and Neutrino Magnetic Moment of Elementary Fermions

The spin magnetic moments and spin g factors (gs = -2) of electron, muon and tau are explained based on the electric charges (EC) and lepton charges (LC) in terms of the three-dimensional quantized space model. The spin g factors of electron, muon and tau are gs = -2 which is the sum of the EC g factor (gEC = -1) and the LC g factor (gLC = -1). The spin g factor (gs = -2) of the electron is predicted by the Dirac’s equation. The orbit g factors of electron, muon and tau are gL = gEC = -1 from the EC g factor (gEC = -1) without the contribution of the LC g factor (gLC = -1). The spin g factors of the elementary fermions are calculated from the equation of gs = gEC + gLC + gCC where gEC = EC/|EC|, gLC = LC/|LC| and gCC = CC/|CC|. For example, the spin g factors of the neutrinos and dark matters are gs = -1. The spin g factors of the u and d quarks are gs = 0 and gs = -2, respectively. The g factor problem of neutrinos with the non-zero LC charges are solved by the LC Coulomb force of Fc(LC) ≈0. It is, for the first time, proposed that the binary motion (fluctuations) of the mEC and mLC masses for the electron, muon and tau leptons make the anomalous g factor. This binary motion could be originated from the virtual particle processes including the photons. Also, the weak force (beta) decay is closely related to the binary motion of the mEC and mLC for the electron, muon and tau leptons.

Valley-filling instability and critical magnetic field for interaction-enhanced Zeeman response in doped WSe2 monolayers

Carrier-doped transition metal dichalcogenide (TMD) monolayers are of great interest in valleytronics due to the large Zeeman response (g-factors) in these spin-valley-locked materials, arising from many-body interactions. We develop an ab initio approach based on many-body perturbation theory to compute the interaction-enhanced g-factors in carrier-doped materials. We show that the g-factors of doped WSe2 monolayers are enhanced by screened-exchange interactions resulting from magnetic-field-induced changes in band occupancies. Our interaction-enhanced g-factors g* agree well with experiment. Unlike traditional valleytronic materials such as silicon, the enhancement in g-factor vanishes beyond a critical magnetic field Bc achievable in standard laboratories. We identify ranges of g* for which this change in g-factor at Bc leads to a valley-filling instability and Landau level alignment, which is important for the study of quantum phase transitions in doped TMDs. We further demonstrate how to tune the g-factors and optimize the valley-polarization for the valley Hall effect.