Magnetic Moments of Electrons and Positrons

Author(s):  
David E. Newman ◽  
Eric Sweetman ◽  
Ralph S. Conti ◽  
Arthur Rich
1987 ◽  
Vol 187 (1-2) ◽  
pp. 172-174 ◽  
Author(s):  
I.B. Vasserman ◽  
P.V. Vorobyov ◽  
E.S. Gluskin ◽  
P.M. Ivanov ◽  
G.Ya. Kezerashvili ◽  
...  

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1703
Author(s):  
Yunhua Ding ◽  
Teague D. Olewiler ◽  
Mohammad Farhan Rawnak

An overview of recent progress on testing Lorentz and CPT symmetry using Penning traps is presented. The theory of quantum electrodynamics with Lorentz-violating operators of mass dimensions up to six is summarized. Dominant shifts in the cyclotron and anomaly frequencies of the confined particles and antiparticles due to Lorentz and CPT violation are derived. Existing results of the comparisons of charge-to-mass ratios and magnetic moments involving protons, antiprotons, electrons, and positrons are used to constrain various coefficients for Lorentz violation.


2018 ◽  
Vol 33 (26) ◽  
pp. 1850154 ◽  
Author(s):  
Maxim Dvornikov

We study the possibility of the existence of the electric current, formed by massive electrons and positrons, flowing along an external magnetic field. The charged fermions are supposed to have nonzero anomalous magnetic moments and electroweakly interact with background matter. The expression for the current is obtained on the basis of the exact solution of the Dirac equation in the corresponding external fields. We demonstrate that, in the state of equilibrium, such a current is vanishing for any characteristics of the electron–positron plasma as well as the external fields. Our results are compared with the recent findings of other authors.


2016 ◽  
Vol 12 (3) ◽  
pp. 4307-4321 ◽  
Author(s):  
Ahmed Hassan Ibrahim ◽  
Yehia Abbas

The physical properties of ferrites are verysensitive to microstructure, which in turn critically dependson the manufacturing process.Nanocrystalline Lithium Stannoferrite system Li0.5+0.5XFe2.5-1.5XSnXO4,X= (0, 0.2, 0.4, 0.6, 0.8 and 1.0) fine particles were successfully prepared by double sintering ceramic technique at pre-sintering temperature of 500oC for 3 h andthepre-sintered material was crushed and sintered finally in air at 1000oC.The structural and microstructural evolutions of the nanophase have been studied using X-ray powder diffraction (XRD) and the Rietveld method.The refinement results showed that the nanocrystalline ferrite has a two phases of ordered and disordered phases for polymorphous lithium Stannoferrite.The particle size of as obtained samples were found to be ~20 nm through TEM that increases up to ~ 85 nmand isdependent on the annealing temperature. TEM micrograph reveals that the grains of sample are spherical in shape. (TEM) analysis confirmed the X-ray results.The particle size of stannic substituted lithium ferrite fine particle obtained from the XRD using Scherrer equation.Magneticmeasurements obtained from lake shore’s vibrating sample magnetometer (VSM), saturation magnetization ofordered LiFe5O8 was found to be (57.829 emu/g) which was lower than disordered LiFe5O8(62.848 emu/g).Theinterplay between superexchange interactions of Fe3+ ions at A and B sublattices gives rise to ferrimagnetic ordering of magnetic moments,with a high Curie-Weiss temperature (TCW ~ 900 K).


2008 ◽  
Vol 33 (4) ◽  
pp. 351-356
Author(s):  
Rachid Abdia ◽  
Ablehamid El Kaaouachi ◽  
Abdelhakim Nafidi ◽  
Gérard Biskupski ◽  
Jamal Hemine

2008 ◽  
Vol 59 (7) ◽  
Author(s):  
Madalina Angelusiu ◽  
Maria Negoiu ◽  
Stefania-Felicia Barbuceanu ◽  
Tudor Rosu

The paper presents the synthesis and characterization of Cu(II), Co(II), Ni(II), Cd(II), Zn(II) and Hg(II) complexes with N1-[4-(4-bromo-phenylsulfonyl)-benzoyl]-N4-(4-methoxyphenyl)-thiosemicarbazide. The new compounds were characterized by IR, EPR, electronic spectroscopy, magnetic moments, thermo-gravimetric analysis and elemental analysis.


Author(s):  
M. M. Glazov

The discussion of the electron spin decoherence and relaxation phenomena via the hyperfine interaction with host lattice spins is presented here. The spin relaxation processes processes limit the conservation time of spin states as well as the response time of the spin system to external perturbations. The central spin model, where the spin of charge carrier interacts with the bath of nuclear spins, is formulated. We also present different methods to calculate the spin dynamics within this model. Simple but physically transparent semiclassical treatment where the nuclear spins are considered as largely static classical magnetic moments is followed by more advanced quantum mechanical approach where the feedback of electron spin dynamics on the nuclei is taken into account. The chapter concludes with an overview of experimental data and its comparison with model calculations.


Author(s):  
M. M. Glazov

The transfer of nonequilibrium spin polarization between the electron and nuclear subsystems is studied in detail. Usually, a thermal orientation of nuclei in magnetic field is negligible due to their small magnetic moments, but if electron spins are optically oriented, efficient nuclear spin polarization can occur. The microscopic approach to the dynamical nuclear polarization effect based on the kinetic equation method, along with a phenomenological but very powerful description of dynamical nuclear polarization in terms of the nuclear spin temperature concept is given. In this way, one can account for the interaction between neighbouring nuclei without solving a complex many-body problem. The hyperfine interaction also induces the feedback of polarized nuclei on the electron spin system giving rise to a number of nonlinear effects: bistability of nuclear spin polarization and anomalous Hanle effect, dragging and locking of optical resonances in quantum dots. Theory is illustrated by experimental data on dynamical nuclear polarization.


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