Quantum Vacuum Effects in Braneworlds on AdS Bulk

Saharian, A. A.

doi:10.3390/universe6100181

Cited by 9 publications

(8 citation statements)

References 106 publications

(202 reference statements)

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“…The vacuum fluctuations of quantum fields along those dimensions are quantized and, as a consequence, contributions in the vacuum expectation values (VEVs) of physical observables appear that depend on the geometrical characteristics of the compactification. The effects of compactification on the properties of the quantum vacuum in locally AdS spacetime have been considered previously (for a recent review see [19]). The vacuum energy, the Casimir forces and the radion stabilization in braneworld models with compact dimensions were discussed in [20]- [24].…”

Section: Introductionmentioning

confidence: 99%

Topological effects in fermion condensate induced by cosmic string and compactification on AdS bulk

Bellucci,

Santos,

de Mello

et al. 2021

Preprint

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We investigate the fermion condensate (FC) for a massive spinor field on background of the 5-dimensional locally anti-de Sitter (AdS) spacetime with a compact dimension and in the presence of a cosmic string carrying a magnetic flux. The FC is decomposed into two contributions. The first one corresponds to the geometry without compactification and the second one is induced by the compactification. Depending on the values of the parameters, the total FC can be either positive or negative. As a limiting case, the expression for the FC on locally Minkowski spacetime is derived. It vanishes for a massless fermion field and the nonzero FC on the AdS bulk in the massless case is an effect induced by gravitation. This shows that the gravitational field may essentially influence the parameters space for phase transitions. For a massive field the FC diverges on the string as the inverse cube of the proper distance from the string. In the case of a massless field, depending on the magnetic flux along the string and planar angle deficit, the limiting value of the FC on the string can be either finite or infinite. At large distances, the decay of the FC as a function of the distance from the string is power law for both cases of massive and massless fields. For a cosmic string on the Minkowski bulk and for a massive field the decay is exponential. The topological part in the FC vanishes on the AdS boundary. We show that the FCs coincide for the fields realizing two inequivalent irreducible representations of the Clifford algebra. In the special case of the zero planar angle deficit, the results presented in this paper describe Aharonov-Bohm-type effects induced by magnetic fluxes in curved spacetime.

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Section: Introductionmentioning

confidence: 99%

Topological effects in fermion condensate induced by cosmic string and compactification on AdS bulk

Bellucci,

Santos,

de Mello

et al. 2021

Preprint

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show abstract

“…For the field corresponding to M = −iγ (3) we get the boundary condition (5.3). The FC and the VEV of the energy-momentum tensor in the RSII model with a topological defect (for quantum effects in higher-dimensional generalizations of RSII model see [30] and references therein) are expressed by the formulas given above for respective boundary conditions taking w 0 = a and with an additional coefficient 1/2. The latter is related to the fact that in Z 2symmetric braneworld model the integral over y in the normalization condition for the fermionic modes goes over the region −∞ < y < +∞ instead of the region y ∈ [y 0 = 0, ∞) in our consideration above for the R-region.…”

Section: Vevs For the Second Representation And Applications In Rsii ...mentioning

confidence: 99%

Cosmic string and brane induced effects on the fermionic vacuum in AdS spacetime

Bellucci,

Santos,

de Mello

et al. 2022

Preprint

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We investigate the combined effects of a magnetic flux-carrying cosmic string and a brane on the fermionic condensate (FC) and on the vacuum expectation value (VEV) of the energymomentum tensor for a massive charged fermionic field in background of 5-dimensional anti-de Sitter (AdS) spacetime. The brane is parallel to the AdS boundary and it divides the space into two regions with distinct properties of the fermionic vacuum. For two types of boundary conditions on the field operator and for the fields realizing two inequivalent representations of the Clifford algebra, the brane-induced contributions in VEVs are explicitly separated. The VEVs are even periodic functions of the magnetic flux, confined in the core, with the period of flux quantum. Near the horizon the FC and the vacuum energy-momentum tensor are dominated by the branefree contribution, whereas the brane-induced part dominates in the region near the brane. Both the contributions vanish on the AdS boundary. At large distances from the cosmic string, the topological contributions in the VEVs, as functions of the proper distance, exhibit an inverse power-law decrease in the region between the brane and AdS horizon and an exponential decrease in the region between the brane and AdS boundary. We show that the FC and the vacuum energy density can be either positive or negative, depending on the distance from the brane. Applications are discussed in fermionic models invariant under the charge conjugation and parity transformation and also in Z 2 -symmetric braneworld models. By the limiting transition we derive the expressions of the FC and the vacuum energy-momentum tensor for a cosmic string on 5-dimensional Minkowski bulk in the presence of a boundary perpendicular to the string.

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“…The results given above can be directly applied for the investigation of the cosmic string induced effects in background of the Randall-Sundrum model with a single brane (RSII model) [69,70] (for quantum effects in higher-dimensional generalizations of RSII model see [71] and references therein). In the presence of cosmic string perpendicular to the brane, the corresponding background geometry contains two copies of the R-region that are identified by the Z 2 -symmetry with respect to the brane located at y = 0 (or at w = w 0 = a in terms of the coordinate w).…”

Section: Applications To Randall-sundrum Modelmentioning

confidence: 99%

Vacuum fermionic currents in braneworld models on AdS bulk with a cosmic string

Bellucci

dos

Mello

et al. 2021

J. High Energ. Phys.

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We investigate the effects of a brane and magnetic-flux-carrying cosmic string on the vacuum expectation value (VEV) of the current density for a charged fermionic field in the background geometry of (4+1)-dimensional anti-de Sitter (AdS) spacetime. The brane is parallel to the AdS boundary and the cosmic string is orthogonal to the brane. Two types of boundary conditions are considered on the brane that include the MIT bag boundary condition and the boundary conditions in Z2-symmetric braneworld models. The brane divides the space into two regions with different properties of the vacuum state. The only nonzero component of the current density is along the azimuthal direction and in both the regions the corresponding VEV is decomposed into the brane- free and brane-induced contributions. The latter vanishes on the string and near the string the total current is dominated by the brane-free part. At large distances from the string and in the region between the brane and AdS horizon the decay of the brane-induced current density, as a function of the proper distance, is power-law for both massless and massive fields. For a massive field this behavior is essentially different from that in the Minkowski bulk. In the region between the brane and AdS boundary the large-distance decay of the current density is exponential. Depending on the boundary condition on the brane, the brane-induced contribution is dominant or subdominant in the total current density at large distances from the string. By using the results for fields realizing two inequivalent irreducible representations of the Clifford algebra, the vacuum current density is investigated in C - and P -symmetric fermionic models. Applications are given for a cosmic string in the Randall-Sundrum-type braneworld model with a single brane.

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Quantum Vacuum Effects in Braneworlds on AdS Bulk

Cited by 9 publications

References 106 publications

Topological effects in fermion condensate induced by cosmic string and compactification on AdS bulk

Topological effects in fermion condensate induced by cosmic string and compactification on AdS bulk

Cosmic string and brane induced effects on the fermionic vacuum in AdS spacetime

Vacuum fermionic currents in braneworld models on AdS bulk with a cosmic string

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