Induced fermionic vacuum polarization in a de Sitter spacetime with a compactified cosmic string

Bragança, E. A. F.; Mello, E. R. Bezerra de; Mohammadi, Azadeh

doi:10.1103/physrevd.101.045019

Cited by 7 publications

(1 citation statement)

References 48 publications

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“…For example, they can affect the vacuum expectation values of the physical observables. An ideal cosmic string can induce vacuum polarization as well as bosonic and fermionic charge and current densities (see for example [16,17] and references therein). Not surprisingly, the scattering problem shall present rich features as well.…”

Section: Introductionmentioning

confidence: 99%

Scattering cross-section in gravitating cosmic string spacetimes

Silva

Mohammadi

2021

Class. Quantum Grav.

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We propose a modification of the partial wave approach to deal with the relativistic quantum scattering of bosonic and fermionic particles in a class of models concerning gravitating cosmic string spacetimes. These spacetimes are characterized by the Minkowski line element at the center of the vortex, non-vanishing curvature at a finite distance from the center but with a conical structure far from the core. We find the correction in the partial wave expansion and the phase shift. Consequently, we show the explicit form of the scattering amplitude and the correction to the differential cross-section for a massive scalar field. We also implement our formalism in a toy model mimicking this class of gravitating cosmic string spacetime. Moreover, we discuss the procedure to apply this formalism to a massive Dirac field.

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Section: Introductionmentioning

confidence: 99%

Scattering cross-section in gravitating cosmic string spacetimes

Silva

Mohammadi

2021

Class. Quantum Grav.

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Fermionic vacuum polarization around a cosmic string in compactified AdS spacetime

Bellucci

dos

Mello

et al. 2022

J. Cosmol. Astropart. Phys.

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We investigate topological effects of a cosmic string and compactification of a spatial dimension on the vacuum expectation value (VEV) of the energy-momentum tensor for a fermionic field in (4+1)-dimensional locally AdS spacetime. The contribution induced by the compactification is explicitly extracted by using the Abel-Plana summation formula. The mean energy-momentum tensor is diagonal and the vacuum stresses along the direction perpendicular to the AdS boundary and along the cosmic string are equal to the energy density. All the components are even periodic functions of the magnetic fluxes inside the string core and enclosed by compact dimension, with the period equal to the flux quantum. The vacuum energy density can be either positive or negative, depending on the values of the parameters and the distance from the string. The topological contributions in the VEV of the energy-momentum tensor vanish on the AdS boundary. Near the string the effects of compactification and gravitational field are weak and the leading term in the asymptotic expansion coincides with the corresponding VEV in (4+1)-dimensional Minkowski spacetime. At large distances, the decay of the cosmic string induced contribution in the vacuum energy-momentum tensor, as a function of the proper distance from the string, follows a power law. For a cosmic string in the Minkowski bulk and for massive fields the corresponding fall off is exponential. Within the framework of the AdS/CFT correspondence, the geometry for conformal field theory on the AdS boundary corresponds to the standard cosmic string in (3+1)-dimensional Minkowski spacetime compactified along its axis.

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