scholarly journals Induced vacuum bosonic current in a compactified cosmic string spacetime

2016 ◽  
Vol 41 ◽  
pp. 1660117 ◽  
Author(s):  
E. A. F. Bragança ◽  
H. F. Santana Mota ◽  
E. R. Bezerra de Mello
Keyword(s):  
Magnetic Flux ◽  
Cosmic String ◽  
Wave Functions ◽  
Complete Set ◽  
Current Densities

We analyze the bosonic current densities induced by a magnetic flux running along an idealized cosmic string considering that the coordinate along its axis is compactified. We also consider the presence of a magnetic flux enclosed by the compactificatified axis. To develop this analysis, we calculate the complete set of normalized bosonic wave functions obeying a quasiperiodicity condition along the compactified dimension. We show that in this context only the azimuthal and axial currents take place.

scholarly journals Vacuum bosonic currents induced by a compactified cosmic string in dS background

2020 ◽  
Vol 29 (15) ◽  
pp. 2050103
Author(s):  
E. A. F. Bragança ◽  
E. R. Bezerra de Mello ◽  
A. Mohammadi
Keyword(s):  
Cosmic String ◽  
Axial Current ◽  
Wave Functions ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Fermionic Field ◽  
Sitter Spacetime ◽  
Compact Dimension ◽  
Complete Set ◽  
Current Densities

In this paper, we study the vacuum bosonic currents in the geometry of a compactified cosmic string in the background of the de Sitter spacetime. The currents are induced by magnetic fluxes, one running along the cosmic string and another one enclosed by the compact dimension. To develop the analysis, we obtain the complete set of normalized bosonic wave functions obeying a quasiperiodicity condition. In this context, we calculate the azimuthal and axial current densities and we show that these quantities are explicitly decomposed into two contributions: one originating from the geometry of a straight uncompactified cosmic string and the other induced by the compactification. We also compare the results with the literature in the case of a massive fermionic field in the same geometry.

Induced fermionic current by a magnetic flux in a cosmic string spacetime at finite temperature

2016 ◽  
Vol 31 (02n03) ◽  
pp. 1641021
Author(s):  
Eugênio R. Bezerra de Mello ◽  
Aram A. Saharian ◽  
Azadeh Mohammadi
Keyword(s):  
Magnetic Flux ◽  
Periodic Function ◽  
Cosmic String ◽  
Finite Temperature ◽  
Chemical Potential ◽  
Vacuum Expectation ◽  
Expectation Values ◽  
Quantum Flux ◽  
Current Densities ◽  
Azimuthal Current

Here we analyze the finite temperature expectation values of the charge and current densities for a massive fermionic quantum field with nonzero chemical potential [Formula: see text], induced by a magnetic flux running along the axis of an idealized cosmic string. These densities are decomposed into the vacuum expectation values and contributions coming from the particles and antiparticles. Specifically the charge density is an even periodic function of the magnetic flux with the period equal to the quantum flux and an odd function of the chemical potential. The only nonzero component of the current density corresponds to the azimuthal current and it is an odd periodic function of the magnetic flux and an even function of the chemical potential. Both analyzed are developed for the cases where [Formula: see text] is smaller than the mass of the field quanta [Formula: see text].

scholarly journals Induced fermionic current in AdS spacetime in the presence of a cosmic string and a compactified dimension

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
S. Bellucci ◽  
W. Oliveira dos Santos ◽  
E. R. Bezerra de Mello
Keyword(s):  
Magnetic Flux ◽  
Cosmic String ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Axial Current ◽  
De Sitter ◽  
Twisted Field ◽  
Compact Dimension ◽  
Ads Spacetime ◽  
Current Densities

AbstractIn this paper, we consider a massive charged fermionic quantum field and investigate the current densities induced by a magnetic flux running along the core of an idealized cosmic string in the background geometry of a 5-dimensional anti-de Sitter spacetime, assuming that an extra dimension is compactified. Along the compact dimension quasi-periodicity condition is imposed on the field with a general phase. Moreover, we admit the presence of a magnetic flux enclosed by the compactified axis. The latter gives rise to Ahanorov–Bohm-like effect on the vacuum expectation value of the currents. In this setup, only azimuthal and axial current densities take place. The former presents two contributions, with the first one due to the cosmic string in a 5-dimensional AdS spacetime without compact dimension, and the second one being induced by the compactification itself. The latter is an odd function of the magnetic flux along the cosmic string and an even function of the magnetic flux enclosed by the compactified axis with period equal to the quantum flux. As to the induced axial current, it is an even function of the magnetic flux along the string’s core and an odd function of the magnetic flux enclosed by the compactification perimeter. For untwisted and twisted field along compact dimension, the axial current vanishes. The massless field case is presented as well some asymptotic limits for the parameters of the model.

scholarly journals Self-Adjoint Extension Approach to Motion of Spin-1/2 Particle in the Presence of External Magnetic Fields in the Spinning Cosmic String Spacetime

Universe ◽  
2020 ◽  
Vol 6 (11) ◽  
pp. 203
Author(s):  
Márcio M. Cunha ◽  
Edilberto O. Silva
Keyword(s):  
Energy Spectrum ◽  
Dirac Equation ◽  
Magnetic Fields ◽  
Cosmic String ◽  
Relativistic Quantum ◽  
Wave Functions ◽  
The Self ◽  
Extension Method ◽  
Adjoint Extension ◽  
Quantum Motion

In this work, we study the relativistic quantum motion of an electron in the presence of external magnetic fields in the spinning cosmic string spacetime. The approach takes into account the terms that explicitly depend on the particle spin in the Dirac equation. The inclusion of the spin element in the solution of the problem reveals that the energy spectrum is modified. We determine the energies and wave functions using the self-adjoint extension method. The technique used is based on boundary conditions allowed by the system. We investigate the profiles of the energies found. We also investigate some particular cases for the energies and compare them with the results in the literature.

scholarly journals VACUUM POLARIZATION OF A CHARGED MASSLESS FERMIONIC FIELD BY A MAGNETIC FLUX IN THE COSMIC STRING SPACETIME

2004 ◽  
Vol 13 (04) ◽  
pp. 607-624 ◽  
Author(s):  
J. SPINELLY ◽  
E. R. BEZERRA DE MELLO
Keyword(s):  
Magnetic Flux ◽  
Cosmic String ◽  
Energy Momentum Tensor ◽  
Finite Thickness ◽  
Momentum Tensor ◽  
Homogeneous Field ◽  
Physical Systems ◽  
Left Handed ◽  
Spinor Fields ◽  
Fermionic Fields

We calculate the vacuum averages of the energy–momentum tensor associated with a massless left-handed spinor fields due to magnetic fluxes on idealized cosmic string spacetime. In this analysis three distinct configurations of magnetic fields are considered: (i) a homogeneous field inside the tube, (ii) a magnetic field proportional to 1/r, and (iii) a cylindrical shell with δ-function. In these three cases the axis of the infinitely long tubes of radius R coincides with the cosmic string. In order to proceed with these calculations we explicitly obtain the Euclidean Feynman propagators associated with these physical systems. As we shall see, these propagators possess two distinct parts. The first are the standard ones, i.e. corresponding to the spinor Green's functions associated with the massless fermionic fields on the idealized cosmic string spacetime with a magnetic flux running through the line singularity. The second parts are new, they are due to the finite thickness of the radius of the tubes. As we shall see these extra parts provide relevant contributions to the vacuum averages of the energy–momentum tensor.

On the theory of elastic collisions between electrons and hydrogen atoms

1960 ◽  
Vol 254 (1277) ◽  
pp. 259-272 ◽  
Keyword(s):  
Wave Function ◽  
Hydrogen Atom ◽  
Boundary Conditions ◽  
Continuous Spectrum ◽  
Ground State ◽  
Wave Functions ◽  
Hydrogen Atoms ◽  
Complete Set ◽  
Exchange Scattering ◽  
Conditions At Infinity

A hydrogen atom in the ground state scatters an electron with kinetic energy too small for inelastic collisions to occur. The wave function Ψ(r 1 ; r 2 ) of the system has boundary conditions at infinity which must be chosen to allow correctly for the possibilities of both direct and exchange scattering. The expansion Ψ = Σ ψ,(r 1 )F y (r 2 ) of the total wave function in y terms of a complete set of hydrogen atom wave functions ψ y (r 1 ) includes an integration over the continuous spectrum. It is si own that the integrand contains a singularity. The explicit form of this singularity and its connexion with the boundary conditions are examined in detail. The symmetrized functions Y* may be represented by expansions of the form Σ {ψ y (r 1 ) G y ±(r 2 ) ±ψ y (r 2 ) y G y ±(r 1 )}, where the integrand in the continuous spectrum does not involve singularities. Finally, it is shown that because all the states ψ y of the hydrogen atom are included in the expansion, the equation satisfied by F 1 , the coefficient of the ground state, contains a polarization potential which behaves like — a/2 r 4 for large r and is independent of the velocity of the incident electron.

AHARONOV–BOHM EFFECT FOR BOUND STATES IN KALUZA–KLEIN THEORY

2000 ◽  
Vol 15 (04) ◽  
pp. 253-258 ◽  
Author(s):  
CLÁUDIO FURTADO ◽  
V. B. BEZERRA ◽  
FERNANDO MORAES
Keyword(s):  
Cosmic String ◽  
Bound States ◽  
Scalar Particle ◽  
Wave Functions ◽  
Energy Spectra ◽  
Global Features ◽  
Klein Theory ◽  
Bohm Effect ◽  
Aharonov Bohm ◽  
Kaluza Klein

Using Kaluza-Klein theory we study the quantum mechanics of a scalar particle in the background of a chiral cosmic string and of a magnetic cosmic string. We show that the wave functions and the energy spectra associated with the particle depend on the global features of those space–times. These dependences represent the analogs of the well-known Aharonov–Bohm effect. This effect appears as the sum of two contributions, one of gravitational origin and the other of electromagnetic origin.

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