SELF-MAGNETIZATION IN ELECTROWEAK VACUUM AND IN VERY DENSE SYSTEMS

2011 ◽  
Vol 20 (supp02) ◽  
pp. 168-175
Author(s):  
HUGO PÉREZ ROJAS ◽  
ELIZABETH RODRÍGUEZ QUERTS
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
External Field ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
W Bosons ◽  
Large Density ◽  
Electron Positron ◽  
Vector Bosons ◽  
The Magnetic Field

For charged vector bosons (W bosons) of mass mw, magnetization diverges for B → Bcw, which suggests that if the magnetic field is large enough, it can be self-consistently maintained. For photons bearing an anomalous magnetic moment, having a sufficiently large density, their contribution to magnetization might become of the same order than the applied external field, leading also to self-magnetization. We discuss these models in connection to the case of radiation in equilibrium at high temperature (T ~ mc2) coexisting with hot magnetized electron-positron pairs.

scholarly journals Neutron anomalous magnetic moment in dense magnetized systems

2018 ◽  
Vol 27 (02) ◽  
pp. 1850011
Author(s):  
Zeinab Rezaei
Keyword(s):  
Magnetic Field ◽  
Equation Of State ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Nuclear Potential ◽  
Order Constraint ◽  
The Magnetic Field

In this work, we calculate the neutron anomalous magnetic moment (AMM) supposing that this value can depend on the density and magnetic field of the system. We employ the lowest-order constraint variation (LOCV) method and [Formula: see text] nuclear potential to calculate the medium dependency of the neutron AMM. It is confirmed that the neutron AMM increases by increasing the density, while it decreases as the magnetic field grows. The energy and equation of state for the system have also been investigated.

Specific features of penetration and trapping of a magnetic flux in film and bulk YBCO high-temperature superconductors

2018 ◽  
Vol 32 (31) ◽  
pp. 1850346
Author(s):  
Kh. R. Rostami
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Magnetic Flux ◽  
External Field ◽  
High Temperature Superconductors ◽  
Interaction Mechanism ◽  
Differential Method ◽  
Bulk Ybco ◽  
The Magnetic Field ◽  
Insight Into

An oscillatory differential method of local diagnostics of superconductors is applied to the analysis of the trapped magnetic flux and the effective demagnetization factor in YBCO samples. Regular steps over certain intervals of the external field are observed on the magnetic-field dependence of these parameters. It is demonstrated that, as the external field increases, crystallites in a sample are decomposed into sub- and nanocrystallites with a size much less than the penetration depth [Formula: see text] of the magnetic field. The first critical thermodynamic magnetic fields of sub- and nanocrystallites are determined. These results allow one to reveal the interaction mechanism between magnetic and crystalline microstructures of superconductors and provide a deeper insight into the physical processes that occur in high-temperature superconductors (HTSCs) in a magnetic field.

scholarly journals The Electrodynamics of Neutrinos in Dispersive Media

1990 ◽  
Vol 142 ◽  
pp. 35-38
Author(s):  
V.N. Oraevsky ◽  
V.B. Semikoz
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Charge Distribution ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Dispersive Media ◽  
Mean Square ◽  
Vector Bosons ◽  
Electromagnetic Characteristics ◽  
The Mean

Neutrinos interacting with the vacuum of vector bosons and leptons possess important vacuum electromagnetic characteristics: viz., the anomalous magnetic moment Δμvacν and the mean-square radius of charge distribution <r2>1/2. As a result, neutrinos, just like neutrons, may interact with an external magnetic field.

scholarly journals Neutrino Spin and Dispersion in Magnetized Medium

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
P. A. Eminov
Keyword(s):  
Magnetic Field ◽  
Real Time ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Energy Shift ◽  
Neutrino Energy ◽  
Imaginary Time ◽  
Superstrong Magnetic Field ◽  
Electron Positron ◽  
Free Case

The full energy shift of a massive Dirac neutrino in magnetized electron-positron plasma was investigated using the Matsubara imaginary time and real time formalisms. The neutrino dispersion in the magnetized medium was analyzed as a function of the neutrino spin and mass. It was shown that in a superstrong magnetic field the CP-symmetric plasma contribution to the neutrino energy greatly exceeds the analogous correction in the field-free case. The contribution of plasma to the anomalous magnetic moment of a neutrino was obtained.

scholarly journals MAGNETIC FIELDS IN QUANTUM DEGENERATE SYSTEMS AND IN VACUUM

2007 ◽  
Vol 16 (02n03) ◽  
pp. 165-173 ◽  
Author(s):  
H. PÉREZ ROJAS ◽  
E. RODRÍGUEZ QUERTS
Keyword(s):  
Magnetic Moment ◽  
W Bosons ◽  
Einstein Condensate ◽  
Electron Mass ◽  
State Behavior ◽  
Bose Einstein Condensate ◽  
Electron Positron ◽  
Vector Bosons ◽  
Neutral Vector ◽  
Bose Einstein

We consider self-magnetization of charged and neutral vector bosons bearing a magnetic moment in a gas and in vacuum. For charged vector bosons (W bosons) a divergence of the magnetization in both the medium and the electroweak vacuum occurs for the critical field [Formula: see text]. For B > Bwc the system is unstable. This behavior suggests the occurrence of a phase transition at B = Bc, where the field is self-consistently maintained. This mechanism actually prevents B from reaching the critical value Bc. For virtual neutral vector bosons bearing an anomalous magnetic moment, the ground state behavior for [Formula: see text] have a similar behavior. The magnetization in the medium is associated to a Bose–Einstein condensate and we conjecture a similar condensate occurs also in the case of vacuum. The model is applied to virtual electron-positron pairs bosonization in a magnetic field [Formula: see text], where me is the electron mass. This would lead also to vacuum self-magnetization in QED, where in both cases the symmetry breaking is due to a condensate of quasi-massless particles.

scholarly journals Condensation of Neutral Vector Bosons with Magnetic Moment

2017 ◽  
Vol 45 ◽  
pp. 1760047 ◽  
Author(s):  
Gretel Quintero Angulo ◽  
Aurora Pérez Martínez ◽  
Hugo Pérez Rojas
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Moment ◽  
Magnetic Field Intensity ◽  
Rest Mass ◽  
Critical Value ◽  
Equation Of Motion ◽  
Vector Bosons ◽  
Neutral Vector ◽  
The Magnetic Field

We study the equation of motion of neutral vector bosons bearing a magnetic moment (MM). The effective rest mass of vector bosons is a decreasing function of the magnetic field intensity. Consequently a diffuse condensation of the bosons appears below a critical value of the field. For typical values of densities and magnetic fields the magnetization is positive and the neutral boson system can maintain a magnetic field self-consistently. A discussion of the relevance in astrophysics is presented.

The activation energy U(T,B) in high temperature superconductor

2020 ◽  
Vol 92 (2) ◽  
pp. 20601
Author(s):  
Abdelaziz Labrag ◽  
Mustapha Bghour ◽  
Ahmed Abou El Hassan ◽  
Habiba El Hamidi ◽  
Ahmed Taoufik ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Activation Energy ◽  
Phase Diagram ◽  
High Temperature ◽  
Apparent Activation Energy ◽  
High Temperature Superconductor ◽  
Flux Flow ◽  
Resistivity Measurements ◽  
Vortex Phase ◽  
The Magnetic Field

It is reported in this paper on the thermally assisted flux flow in epitaxial YBa2Cu3O7-δ deposited by Laser ablation method on the SrTiO3 substrate. The resistivity measurements ρ (T, B) of the sample under various values of the magnetic field up to 14T in directions B∥ab-plane and B∥c-axis with a dc weak transport current density were investigated in order to determine the activation energy and then understand the vortex dynamic phenomena and therefore deduce the vortex phase diagram of this material. The apparent activation energy U0 (B) calculated using an Arrhenius relation. The measured results of the resistivity were then adjusted to the modified thermally assisted flux flow model in order to account for the temperature-field dependence of the activation energy U (T, B). The obtained values from the thermally assisted activation energy, exhibit a behavior similar to the one showed with the Arrhenius model, albeit larger than the apparent activation energy with ∼1.5 order on magnitude for both cases of the magnetic field directions. The vortex glass model was also used to obtain the vortex-glass transition temperature from the linear fitting of [d ln ρ/dT ] −1 plots. In the course of this work thanks to the resistivity measurements the upper critical magnetic field Hc2 (T), the irreversibility line Hirr (T) and the crossover field HCrossOver (T) were located. These three parameters allowed us to establish a phase diagram of the studied material where limits of each vortex phase are sketched in order to optimize its applicability as a practical high temperature superconductor used for diverse purposes.

scholarly journals Interpolation of externally-caused magnetic fields over large sparse arrays using Spherical Elementary Current Systems

2010 ◽  
Vol 28 (9) ◽  
pp. 1795-1805 ◽  
Author(s):  
S. A. McLay ◽  
C. D. Beggan
Keyword(s):  
Magnetic Field ◽  
External Field ◽  
Current System ◽  
Electrical Current ◽  
Ionospheric Currents ◽  
Large Area ◽  
Physically Based ◽  
Subsurface Current ◽  
Current Systems ◽  
The Magnetic Field

Abstract. A physically-based technique for interpolating external magnetic field disturbances across large spatial areas can be achieved with the Spherical Elementary Current System (SECS) method using data from ground-based magnetic observatories. The SECS method represents complex electrical current systems as a simple set of equivalent currents placed at a specific height in the ionosphere. The magnetic field recorded at observatories can be used to invert for the electrical currents, which can subsequently be employed to interpolate or extrapolate the magnetic field across a large area. We show that, in addition to the ionospheric currents, inverting for induced subsurface current systems can result in strong improvements to the estimate of the interpolated magnetic field. We investigate the application of the SECS method at mid- to high geomagnetic latitudes using a series of observatory networks to test the performance of the external field interpolation over large distances. We demonstrate that relatively few observatories are required to produce an estimate that is better than either assuming no external field change or interpolation using latitudinal weighting of data from two other observatories.

scholarly journals Magnetic dominance of axion electrodynamics: photon capture effect and anisotropy of Coulomb potential

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
S. Villalba-Chávez ◽  
A. E. Shabad ◽  
C. Müller
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Strong Magnetic Field ◽  
Coulomb Potential ◽  
Heat Radiation ◽  
Radiation Mechanism ◽  
Electron Positron ◽  
Coulomb Singularity ◽  
Relativistic Hydrogen ◽  
The Magnetic Field

AbstractFor magnetic fields larger than the characteristic scale linked to axion-electrodynamics, quantum vacuum fluctuations due to axion-like fields can dominate over those associated with the electron-positron fields. This conjecture is explored by investigating both the axion-modified photon capture by a strong magnetic field and the Coulomb potential of a static pointlike charge. We show that in magnetic fields characteristic of neutron stars $$\sim 10^{13}$$ ∼ 10 13 –$$10^{15}\;\mathrm{G}$$ 10 15 G , the capture of gamma photons prior to the production of a pair can prevent the existence of an electron-positron plasma, essential for explaining the pulsar radiation mechanism. This incompatibility is used to limit the axion parameter space. Our bounds improve existing outcomes in the region of mass $$m\sim 10^{-10}$$ m ∼ 10 - 10 –$$10^{-5}\;{\mathrm{eV}}$$ 10 - 5 eV . The effect of capture, known in QED as relating to gamma-quanta, is extended in axion electrodynamics to include X-ray photons with the result that a specially polarized part of the heat radiation from the surface is canalized along the magnetic field. Besides, we find that in the regime in which the dominance takes place, the running QED coupling depends on the field strength and the modified Coulomb potential is of Yukawa-type in the direction perpendicular to the magnetic field at distances much smaller than the axion Compton wavelength, while along the field it follows approximately the Coulomb law at any length scale. Despite the Coulomb singularity manifested in the latter case, we argue that the ground-state energy of a non-relativistic hydrogen atom placed in a strong magnetic field turns out to be bounded due to the nonrenormalizable feature of axion-electrodynamics.

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