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In this paper, we consider a charged massive fermionic quantum field in the idealized cosmic string spacetime and in the presence of a magnetic field confined in a cylindrical tube of finite radius. Three distinct configurations for the…

High Energy Physics - Theory · Physics 2017-02-22 M. S. Maior de Sousa , R. Freire Ribeiro , E. R. Bezerra de Mello

We propose an alternative scenario to cosmic inflation for producing the initial seeds of cosmic structures. The cosmological fluctuations are generated by thermal fluctuation of the energy density of the ideal string gas in three compact…

High Energy Physics - Theory · Physics 2007-05-23 Ali Nayeri

In this paper we investigate the vacuum polarization effects associated to a charged quantum massive scalar field on a $(D+1)$-dimensional anti-de Sitter background induced by a magnetic-flux-carrying cosmic string in the braneworld model…

High Energy Physics - Theory · Physics 2023-08-03 W. Oliveira dos Santos , E. R. Bezerra de Mello

This is a short review of string cosmology. We wish to connect string-scale physics as closely as possible to observables accessible to current or near-future experiments. Our possible best hope to do so is a description of inflation in…

High Energy Physics - Theory · Physics 2015-12-07 Alexander Westphal

Progress on string theory in curved spacetimes since 1992 are reviewed. After a short introduction on strings in Minkowski and curved spacetimes, we focus on strings in cosmological spacetimes. The classical behaviour of strings in FRW and…

High Energy Physics - Theory · Physics 2009-09-25 H. J. de Vega , N. Sánchez

We evaluate the Hadamard function and the vacuum expectation values (VEVs) of the field squared and energy-momentum tensor for a massless conformally coupled scalar field in $(D+1)$-dimensional de Sitter (dS) spacetime foliated by spatial…

High Energy Physics - Theory · Physics 2021-12-21 A. A. Saharian , T. A. Petrosyan , V. S. Torosyan

We show that stable local cosmic strings are a generic prediction of supersymmetric models where supersymmetry is broken at scales within a few orders of magnitude of the weak scale and is fed down to the observable sector by gauge…

High Energy Physics - Phenomenology · Physics 2009-10-30 Antonio Riotto

The responsibility of the electric field $E$ in the modification of the nature of the space is proved. We investigate the way the fundamental strings are related to supergravity background of D5-branes; i.e. once the endpoints of the…

High Energy Physics - Theory · Physics 2017-07-19 Jamila Douari

Superstring theory, models with extra dimensions and other SUSY models generically predict that the coupling constants are in fact vacuum expectation values of fields like the dilaton, moduli etc. Assuming some of these fields are light…

Astrophysics · Physics 2007-05-23 Lev Kofman

We evaluate the renormalized vacuum expectation values (VEVs) of electric and magnetic fields squared and the energy-momentum tensor for the electromagnetic field in the geometry of two parallel conducting plates on background of cosmic…

High Energy Physics - Theory · Physics 2012-09-06 E. R. Bezerra de Mello , A. A. Saharian , A. Kh. Grigoryan

Using the dS/QFT correspondence in the context of inflation allows for the study of interesting, otherwise inaccessible physics. In particular, by studying inflation via its dual field theory at the boundary of the de Sitter space, it may…

Cosmology and Nongalactic Astrophysics · Physics 2011-08-08 Mafalda Dias

We treat a model in which tensor perturbations of de~Sitter spacetime, represented as a spatially flat model, are modified by the effects of the vacuum fluctuations of a massless conformally invariant field, such as the electromagnetic…

General Relativity and Quantum Cosmology · Physics 2011-05-05 Jen-Tsung Hsiang , L. H. Ford , Da-Shin Lee , Hoi-Lai Yu

A model of a straight superconducting global cosmic string is examined in a setting wherein the string supports a charge/current pulse described by a travelling wave along the string. Linearized field equations are obtained for fluctuations…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. R. Morris

We show that if there is a realistic 4-d string, the dilaton and moduli supermultiplets will generically acquire a small mass O(m_{3/2}), providing the only vacuum-independent evidence of low-energy physics in string theory beyond the…

High Energy Physics - Phenomenology · Physics 2009-10-29 B. de Carlos , J. A. Casas , F. Quevedo , E. Roulet

We study cosmological correlators in de Sitter quantum gravity in the limit where $G_N \to 0$. This limit is distinct from a nongravitational QFT because the gravitational constraints still force states and observables to be de Sitter…

High Energy Physics - Theory · Physics 2025-07-23 Tuneer Chakraborty , Ashik H , Suvrat Raju

Two-point functions, mean-squared fluctuations, and the vacuum expectation value of the energy-momentum tensor operator are investigated for a massive scalar field with an arbitrary curvature coupling parameter, subject to a spherical…

High Energy Physics - Theory · Physics 2012-03-06 K. Milton , A. A. Saharian

We investigate the impact of Coleman-Weinberg inflation on the stochastic gravity wave background spectrum emitted by intermediate scale cosmic strings. The string network is partially inflated and re-enters the horizon at later times after…

High Energy Physics - Phenomenology · Physics 2021-11-17 George Lazarides , Rinku Maji , Qaisar Shafi

Using a simple analytic model based on seed superposition we obtain the spectrum of microwave background perturbations induced by cosmic strings on all angular scales larger than about 2 armin. We assume standard recombination in an…

Astrophysics · Physics 2011-05-10 Leandros Perivolaropoulos

The vacuum expectation values of the energy--momentum tensor and the fermionic condensate are analyzed for a massive spinor field obeying the MIT bag boundary condition on a cylindrical shell in the cosmic string spacetime. Both regions…

High Energy Physics - Theory · Physics 2008-12-18 E. R. Bezerra de Mello , V. B. Bezerra , A. A. Saharian , A. S. Tarloyan

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)…

High Energy Physics - Theory · Physics 2021-03-17 S. Bellucci , W. Oliveira dos Santos , E. R. Bezerra de Mello , A. A. Saharian