The Weyl equation under an external electromagnetic field in the cosmic string space–time

Pramana ◽  
2019 ◽  
Vol 93 (1) ◽  
Author(s):  
M Hosseini ◽  
H Hassanabadi ◽  
S Hassanabadi
Keyword(s):  
Electromagnetic Field ◽  
Cosmic String ◽  
External Electromagnetic Field ◽  
Space Time ◽  
Weyl Equation

Scattering states of Dirac equation in the presence of cosmic string for Coulomb interaction

2015 ◽  
Vol 30 (21) ◽  
pp. 1550124 ◽  
Author(s):  
M. Hosseinpour ◽  
H. Hassanabadi
Keyword(s):  
Electromagnetic Field ◽  
Dirac Equation ◽  
Coulomb Interaction ◽  
Coulomb Potential ◽  
Cosmic String ◽  
Phase Shifts ◽  
Space Time ◽  
Radial Part ◽  
Scattering States ◽  
Scalar Potentials

We study the covariant Dirac equation in the space–time generated by a cosmic string in presence of vector and scalar potentials of electromagnetic field. We obtain the solution of the radial part of Dirac equation. We consider the scattering states under the Coulomb potential and obtain the phase shifts.

THE DYNAMICS OF OPEN STRINGS IN A BACKGROUND ELECTROMAGNETIC FIELD

1989 ◽  
Vol 04 (10) ◽  
pp. 2627-2652 ◽  
Author(s):  
V.V. NESTERENKO
Keyword(s):  
Electromagnetic Field ◽  
Electric Field ◽  
Quantum Dynamics ◽  
Dimensional Space ◽  
Open String ◽  
External Electromagnetic Field ◽  
Space Time ◽  
Bosonic String ◽  
Classical Level ◽  
Dimensional Space Time

The classical and quantum dynamics of an open bosonic string propagating in the D-dimensional space-time in the presence of a background electromagnetic field is investigated. An important point in this consideration is the use of the generalized light-like gauge. There are considered the two types of strings: the neutral strings with charges at their ends obeying the condition q1+q2=0 and the charged strings having a net charge q1+q2≠0. The consistency of the theory demands that the background electric field does not exceed its critical value. The distance between the mass levels of the neutral open string decreases (1−e2) times in comparison with the free string where e is the dimensionless strength of the electric field. The magnetic field does not affect this distance. It is shown that at a classical level, the squared mass of the neutral open string has a tachyonic contribution due to the motion of the string as a whole in transverse directions. The tachyonic term disappears if one considers, instead of M2, the string energy in a special reference frame where the projection of the total canonical momentum of the string onto the electric field vanishes. The contributions due to zero point fluctuations to the energy spectrum of the neutral string and to the Virasoro operators in the theory of charged string are found. It is shown that the constraint on the strength of an external electric field is absent when the open bosonic string is placed in an external electromagnetic field of a special configuration. In the case of four-dimensional space-time, it corresponds to the electric and magnetic fields which are equal and perpendicular to each other (isotropic configuration). The external electromagnetic field does not act on the fermionic variables of the spinning string.

The spin-zero Duffin-Kemmer-Petiau equation in a cosmic-string space-time with the Cornell interaction

2016 ◽  
Vol 31 (36) ◽  
pp. 1650191 ◽  
Author(s):  
M. de Montigny ◽  
M. Hosseinpour ◽  
H. Hassanabadi
Keyword(s):  
Gravitational Field ◽  
Coordinate System ◽  
Cosmic String ◽  
Topological Defects ◽  
Space Time ◽  
Dkp Equation

In this paper, we study the covariant Duffin-Kemmer-Petiau (DKP) equation in the cosmic-string space-time and consider the interaction of a DKP field with the gravitational field produced by topological defects in order to examine the influence of topology on this system. We solve the spin-zero DKP oscillator in the presence of the Cornell interaction with a rotating coordinate system in an exact analytical manner for nodeless and one-node states by proposing a proper ansatz solution.

scholarly journals PSEUDOCLASSICAL MODEL OF SPINNING PARTICLE WITH ANOMALOUS MAGNETIC MOMENTUM

1993 ◽  
Vol 08 (05) ◽  
pp. 463-468 ◽  
Author(s):  
D.M. GITMAN ◽  
A.V. SAA
Keyword(s):  
Electromagnetic Field ◽  
External Electromagnetic Field ◽  
Invariant Form ◽  
Pauli Equation ◽  
Spinning Particle ◽  
Dirac Quantization

A generalization of the pseudoclassical action of a spinning particle in the presence of an anomalous magnetic momentum is given. The action is written in reparametrization and supergauge invariant form. The Dirac quantization, based on the Hamiltonian analyzes of the model, leads to the Dirac-Pauli equation for a particle with an anomalous magnetic momentum in an external electromagnetic field. Due to the structure of first class constraints in that case, the Dirac quantization demands for consistency to take into account an operator’s ordering problem.

Electrospun Sodium-Cobalt Oxide Ceramic Nanofiber and the Electromagnetic Responses

2017 ◽  
Author(s):  
Arturo G. Bautista ◽  
Juan A. Aguado ◽  
Yong X. Gan
Keyword(s):  
Electromagnetic Field ◽  
Cobalt Oxide ◽  
External Electromagnetic Field ◽  
Dielectric Behavior ◽  
Ceramic Fiber ◽  
Oxide Ceramic ◽  
Hyperthermia Treatment ◽  
Electromagnetic Responses ◽  
Sodium Cobalt Oxide ◽  
Heating Behavior

In this work, a sodium-cobalt oxide (NaxCo2O4) ceramic composite nanofiber was manufactured through electrospinning. The response of the fiber to external electromagnetic field was characterized to observe the heat generation in the fiber. In addition, we also measured the current passing through the fiber under the polarization of DC potential. It is found that the fiber has intensive heating behavior when it is exposed to the electromagnetic field. The temperature increases more than 5 degrees in Celsius scale only after 5 s exposure. The current – potential curve of the fiber reveals its dielectric behavior. It is concluded that this ceramic fiber has the potential to be used for hyperthermia treatment in biomedical engineering or for energy conversions.

scholarly journals Spinning cosmic strings in conformal gravity

2020 ◽  
Vol 35 (05) ◽  
pp. 2050024
Author(s):  
Reinoud Jan slagter ◽  
Christopher Levi Duston
Keyword(s):  
Cosmic String ◽  
Energy Condition ◽  
Space Time ◽  
Special Choice ◽  
Mass Relation ◽  
Conformal Gravity ◽  
Field Equations ◽  
Closed Timelike Curves ◽  
The Core ◽  
Kerr Space

We investigate the space–time of a spinning cosmic string in conformal invariant gravity, where the interior consists of a gauged scalar field. We find exact solutions of the exterior of a stationary spinning cosmic string, where we write the metric as [Formula: see text], with [Formula: see text] a dilaton field which contains all the scale dependences. The “unphysical” metric [Formula: see text] is related to the [Formula: see text]-dimensional Kerr space–time. The equation for the angular momentum [Formula: see text] decouples, for the vacuum situation as well as for global strings, from the other field equations and delivers a kind of spin-mass relation. For the most realistic solution, [Formula: see text] falls off as [Formula: see text] and [Formula: see text] close to the core. The space–time is Ricci flat. The formation of closed timelike curves can be pushed to space infinity for suitable values of the parameters and the violation of the weak energy condition can be avoided. For the interior, a numerical solution is found. This solution can easily be matched at the boundary on the exterior exact solution by special choice of the parameters of the string. This example shows the power of conformal invariance to bridge the gap between general relativity and quantum field theory.

The Electromagnetic Field in Quantized Space-Time

1947 ◽  
Vol 72 (1) ◽  
pp. 68-71 ◽  
Author(s):  
Hartland S. Snyder
Keyword(s):  
Electromagnetic Field ◽  
Space Time
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