Spinor Green function in higher-dimensional cosmic string space-time in the presence of magnetic flux

Spinelly, J.; Mello, E. R. Bezerra de

doi:10.1088/1126-6708/2008/09/005

Cited by 35 publications

(30 citation statements)

References 51 publications

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“…Now, by taking into account the expression for the vacuum expectation value of the current density from [17], the total current density is expressed as 11) where the prime on the sign of the summation over n means that the term n = 0 should be taken with the coefficient 1/2. This term corresponds to the vacuum expectation value of the current density, j φ 0 .…”

Section: Azimuthal Currentmentioning

confidence: 99%

Finite temperature fermionic charge and current densities induced by a cosmic string with magnetic flux

Mohammadi

Mello

Saharian

2015

J. Phys. A: Math. Theor.

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We investigate the finite temperature expectation values of the charge and current densities for a massive fermionic field with nonzero chemical potential, µ, in the geometry of a straight cosmic string with a magnetic flux running along its axis. These densities are decomposed into the vacuum expectation values and contributions coming from the particles and antiparticles. 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. The latter is an odd periodic function of the magnetic flux and an even function of the chemical potential. At high temperatures, the parts in the charge density and azimuthal current induced by the planar angle deficit and magnetic flux are exponentially small. The asymptotic behavior at low temperatures crucially depends whether the value |µ| is larger or smaller than the mass of the field quanta, m. For |µ| < m the charge density and the contributions into the azimuthal current coming from the particles and antiparticles are exponentially suppressed at low temperatures. In the case |µ| > m, the charge and current densities receive two contributions coming from the vacuum expectation values and from particles or antiparticles (depending on the sign of chemical potential). At large distances from the string the latter exhibits a damping oscillatory behavior with the amplitude inversely proportional to the square of the distance.

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Section: Azimuthal Currentmentioning

confidence: 99%

Finite temperature fermionic charge and current densities induced by a cosmic string with magnetic flux

Mohammadi

Mello

Saharian

2015

J. Phys. A: Math. Theor.

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“…Explicit calculations for vacuum expectation values of the energy-momentum tensor associated with various fields in the vicinity of a string have been done in [11]- [25]. Moreover, considering the presence of a magnetic flux running along the cosmic strings, there appear additional contributions to the corresponding vacuum polarization effects associated with charged fields [26]- [30]. 1 The presence of a magnetic flux along the cosmic string induces vacuum current densities, as well.…”

Section: Introductionmentioning

confidence: 99%

Fermionic current induced by magnetic flux in compactified cosmic string spacetime

Mello

Saharian

2013

Eur. Phys. J. C

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In this paper, we investigate the fermionic current densities induced by a magnetic flux running along the idealized cosmic string in a four-dimensional spacetime, admitting that the coordinate along the string's axis is compactified. In order to develop this investigation we construct the complete set of fermionic mode functions obeying a general quasiperiodicity condition along the compactified dimension. The vacuum expectation value of the azimuthal current density is decomposed into two parts. The first one corresponds to the uncompactified cosmic string geometry and the second one is the correction induced by the compactification. For the first part we provide a closed expression which includes various special cases previously discussed in the literature. The second part is an odd periodic function of the magnetic flux along the string axis with the period equal to the flux quantum and it is an even function of the magnetic flux enclosed by the string axis. The compactification of the cosmic string axis in combination with the quasiperiodicity condition leads to the nonzero axial current density. The latter is an even periodic function of the magnetic flux along the string axis and an odd periodic function of the magnetic flux enclosed by the string axis. The axial current density vanishes for untwisted and twisted fields in the absence of the magnetic flux enclosed by the string axis. The asymptotic behavior of the vacuum fermionic current is investigated near the string and at large distances from it. In particular, the topological part of the azimuthal current and the axial current are finite on the string's axis.

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“…This paper is organized as follows: In Section 2 we briefly present some important results obtained in [42], associated with fermionic propagators in an arbitrary (1 + d)−dimensional cosmic string space-time, with d ≥ 2, in the presence of a magnetic flux. Although the main objective is to investigate induced currents in a higher-dimensional spaces, the formalism obtained allows us to develop similar analysis for a three-dimensional spacetime, as well.…”

Section: Introductionmentioning

confidence: 99%

Induced fermionic current densities by magnetic flux in higher dimensional cosmic string spacetime

Mello¹

2010

Class. Quantum Grav.

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In this paper we analyse the vacuum fluctuations of quantum fermionic current densities, j A (x) , induced by a magnetic flux running along the core of the conical space produced by the presence of cosmic string, in a (1 + d)−dimensional bulk, for 2 ≤ d ≤ 5. In order to develop this investigation we construct an expression for the fermionic propagator, which can be applied for those different dimensions of the spacetime. Two specific analysis for the induced current densities are presented: (i) for massless fields in three and four dimensions, and (ii) for massive fields in all dimensions considered. In the latter specific values for the parameters which codify the presence of the cosmic string and the fractional part of the ratio of the magnetic flux by the quantum one are considered. Although being a very special situation and somewhat unnatural, the corresponding analysis of induced fermionic current densities under this circumstance may shed light on the qualitative behavior of these quantities in a more general situation.

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Spinor Green function in higher-dimensional cosmic string space-time in the presence of magnetic flux

Cited by 35 publications

References 51 publications

Finite temperature fermionic charge and current densities induced by a cosmic string with magnetic flux

Finite temperature fermionic charge and current densities induced by a cosmic string with magnetic flux

Fermionic current induced by magnetic flux in compactified cosmic string spacetime

Induced fermionic current densities by magnetic flux in higher dimensional cosmic string spacetime

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