Dynamically generated anomalous magnetic moment in massless QED

In this paper we investigate the non-perturbative generation of an anomalous magnetic moment for massless fermions in the presence of an external magnetic field. In the context of massless QED in a magnetic field, we prove that the phenomenon of magnetic catalysis of chiral symmetry breaking, which has been associated in the literature with dynamical mass generation, is also responsible for the generation of a dynamical anomalous magnetic moment. As a consequence, the degenerate energy of electrons in Landau levels higher than zero exhibits Zeeman splitting. We explicitly report the splitting for the first Landau level and find the non-perturbative Lande g-factor and Bohr magneton. We anticipate that a dynamically generated anomalous magnetic moment will be a universal feature of theories with magnetic catalysis. Our findings can be important for condensed planar systems as graphene, as well as for highly magnetized dense systems as those forming the core of compact stars.     

Radiation of a relativistic magneton. I

A derivation is given of the field intensities created in vacuum by a neutral, arbitrarily moving point particle possessing a proper magnetic moment. For brevity this particle is called a magneton. The field of the magneton is represented as the superposition of a convective field and a radiation field. It is shown that the radiation field possesses the characteristic properties of the field of an electromagnetic plane wave — orthogonality and transversality.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 12–16, May, 1978.The authors wish to thank Professor V. G. Bagrov for his interest in the work and for valuable remarks.     

Valley-contrasting physics in graphene: magnetic moment and topological transport

We investigate physical properties that can be used to distinguish the valley degree of freedom in systems where inversion symmetry is broken, using graphene systems as examples. We show that the pseudospin associated with the valley index of carriers has an intrinsic magnetic moment, in close analogy with the Bohr magneton for the electron spin. There is also a valley dependent Berry phase effect that can result in a valley contrasting Hall transport, with carriers in different valleys turning into opposite directions transverse to an in-plane electric field. These effects can be used to generate and detect valley polarization by magnetic and electric means, forming the basis for the valley-based electronics applications.     

170 nm nuclear magnetic resonance imaging using magnetic resonance force microscopy

We demonstrate one-dimensional nuclear magnetic resonance imaging of the semiconductor GaAs with 170 nm slice separation and resolve two regions of reduced nuclear spin polarization density separated by only 500 nm. This was achieved by force detection of the magnetic resonance, magnetic resonance force microscopy (MRFM), in combination with optical pumping to increase the nuclear spin polarization. Optical pumping of the GaAs created spin polarization up to 12 times larger than the thermal nuclear spin polarization at 5K and 4T. The experiment was sensitive to sample volumes of 50 microm(3) containing approximately 4 x 10(11)71 Ga/Hz. These results demonstrate the ability of force-detected magnetic resonance to apply magnetic resonance imaging to semiconductor devices and other nanostructures.     

A new measurement of the magnetic moment of the neutron

The magnetic moment of the neutron has been measured with a factor of one hundred improvement in accuracy. In terms of the Bohr magneton and proton magnetic moment, respectively, the result is μ_n/μ_B= ?1.041 875 79 (26) × 10^?3, μ_n/μ_p = ?0.684 979 45 (17).     

Paramagnetic state NMR and susceptibility measurements in cobalt based Heusler alloys

Susceptibility of Co₂TAl (T Ti, Zr and Hf) and ⁵⁹Co and ²⁷Al Knight shifts have been measured down to the magnetic ordering temperature of these itinerant ferromagnets. The effective hyperfine fields per Bohr magneton at Co and Al nuclear sites have been derived and for Co these are in very good agreement with the spin echo results in ferromagnetic state of these alloys. The effective fields at Al site are small which is the reason that no spin echo signal due to Al could be observed. The sign of the field at Al site is accounted for in terms of an RKKY model of conduction electron polarization with appropriate preasymptotic correction.     

Energy values for the H+2 ion in superstrong magnetic fields using the adiabatic approximation

Energy values, equilibrium internuclear separations, and zero-point energies of nuclear vibrations parallel to the magnetic field are calculated for the lowest states of the H⁺₂ ion in magnetic fields B?10⁶ T (characteristic of neutron stars) using numerical wave functions that are products of Landau states and arbitrary z-dependent functions, thus improving on previous estimates of variational or LCAO type, which have been obtained in the high-field regime.     

Effects of magnetic monopoles on nuclear wave functions and possible catalysis of nuclear beta decay and spontaneous fission

Mixing effects in nuclear wave functions by the strong magnetic field of a magnetic monopole are estimated. A monopole at a distance of 10 fm from a deuteron mixes the single and triplet spin levels with a strength comparable to the deuteron binding energy. Forbidden nuclear beta decay transitions can be enhanced bymixing nuclear wave functions with other states for which the beta decay transition is less inhibited. Particularly suitable candidates have nearby excited states connected by magnetic dipole transitions to the ground state. Magnetic mixing can also strongly enhance spontaneous fission.     

Ionization of helium atoms under the effect of the antineutrino magnetic moment

Differential cross sections for inelastic antineutrino interaction with a helium atom are calculated. It is shown that, in the energy-transfer range extending up to 1 keV, the cross sections in question are considerably enhanced in the electromagnetic-interaction channel in relation to the cross sections for elastic scattering on a free electron. Absolute cross-section values are of interest in searches for the antineutrino magnetic moment, provided that its value in Bohr magneton units falls within the range (10^?13?10^?12)_µB.