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Related papers: Casimir energy and a cosmological bounce

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The contribution, E, of hyperbolic elements to the scalar Casimir energy on a compact quotient of the upper half hyperbolic plane is computed for a propagation operator conformal in three dimensions. Due to the proliferation of prime closed…

High Energy Physics - Theory · Physics 2024-02-07 J. S. Dowker

We consider the possibility to produce a bouncing universe in the framework of scalar-tensor gravity models in which the scalar field potential may be negative, and even unbounded from below. We find a set of viable solutions with nonzero…

General Relativity and Quantum Cosmology · Physics 2015-07-15 B. Boisseau , H. Giacomini , D. Polarski , A. A. Starobinsky

The renormalized mean value of the corresponding components of the Energy-Momentum tensor for massive scalar fields coupled to an arbitrary gravitational field configuration having cylindrical symmetry are analytically evaluated using the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Owen Pavel Fernandez Piedra , Alejandro Cabo Montes de Oca

The discussion of vacuum energy is currently a subject of great theoretical importance, specially concerning the cosmological constant problem in General Relativity. From Quantum Field Theory, it is stated that vacuum states subject to…

High Energy Physics - Theory · Physics 2020-02-07 A. P. C. M. Lima , G. Alencar , C. R. Muniz , R. R. Landim

Cosmological models with inflation and those with bounce have their own strengths and weaknesses. Here we construct a model in which a phase of bounce is followed by a viable inflationary phase. This incorporates several advantages of both…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-02 Manjeet Kaur , Debottam Nandi , Debajyoti Choudhury , T. R. Seshadri

The Paper actually concerns a toy model, not physical Casimir cavities made of conducting plates, but the results are taken implicitly to apply in general. We question on general physical grounds one basic assumption and the results of a…

General Relativity and Quantum Cosmology · Physics 2017-07-25 Massimo Cerdonio , Carlo Rovelli

Motivated by the recent works of Refs. \cite{R1, R2} where a model of inflation has been suggested with non-minimally coupled massive vector fields, we generalize their work to the study of the bouncing solution. So we consider a massive…

High Energy Physics - Theory · Physics 2015-05-18 J. Sadeghi , M. R. Setare , A. R. Amani , S. M. Noorbakhsh

The cosmological evolution of free massless vector or tensor (but not gauge) fields minimally coupled to gravity is analyzed. It is shown that there are some unstable solutions for these fields in De Sitter background. The back reaction of…

Astrophysics · Physics 2009-12-30 A. D. Dolgov

A global approach with cut-off exponential functions previously proposed is used to obtain the Casimir energy of a massless scalar field in the presence of a spherical shell. The proposed method makes the use of two regulators, one of them…

High Energy Physics - Theory · Physics 2011-03-22 M. S. R. Miltão , Franz A. Farias

In this paper, we extend previous results on the quantum vacuum or Casimir energy, for a noninteracting rotating system and for an interacting nonrotating system, to the case where both rotation and interactions are present. Concretely, we…

High Energy Physics - Theory · Physics 2023-02-02 Antonino Flachi , Matthew Edmonds

We construct nonsingular cyclic cosmologies that respect the null energy condition, have a large hierarchy between the minimum and maximum size of the universe, and are stable under linearized fluctuations. The models are supported by a…

High Energy Physics - Theory · Physics 2015-06-19 Peter W. Graham , Bart Horn , Surjeet Rajendran , Gonzalo Torroba

There appears to be three, perhaps related, ways of approaching the nature of vacuum energy . The first is to say that it is just the lowest energy state of a given, usually quantum, system. The second is to equate vacuum energy with the…

High Energy Physics - Theory · Physics 2007-05-23 Mark D. Roberts

We examine non-singular bounce cosmology within the framework of a phantom scalar field coupled to the Gauss-Bonnet term in both non-viscous and bulk-viscous cases. Using the scale factor ansatz…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-07 Khandro K. Chokyi , Surajit Chattopadhyay

Vacuum expectation values of the energy-momentum tensor and the Casimir forces are evaluated for scalar and electromagnetic fields in the geometry of two curved boundaries on background of the Robertson-Walker spacetime with negative…

High Energy Physics - Theory · Physics 2010-11-12 A. A. Saharian , M. R. Setare

We compute the one-loop Casimir energy of gravity and matter fields, obeying various boundary conditions, in 5-dimensional S^1/Z_2 and 6-dimensional T^2/Z_k orbifolds. We discuss the role of the Casimir energy in possible radius…

High Energy Physics - Phenomenology · Physics 2010-05-28 Eduardo Ponton , Erich Poppitz

The vacuum expectation value of the stress energy tensor for a massive scalar field with arbitrary coupling in flat spaces with non-trivial topology is discussed. We calculate the Casimir energy in these spaces employing the recently…

General Relativity and Quantum Cosmology · Physics 2007-05-23 N. Ahmadi , M. Nouri-Zonoz

We explore a family of generalised scalar-tensor theories that exhibit self-tuning to low scale anti de Sitter vacua, even in the presence of a large cosmological constant. We are able to examine the linearised fluctuations about these…

General Relativity and Quantum Cosmology · Physics 2022-03-09 Edmund J. Copeland , Sukhraj Ghataore , Florian Niedermann , Antonio Padilla

The lowest radiative correction to the Casimir energy density between two parallel plates is calculated using effective field theory. Since the correlators of the electromagnetic field diverge near the plates, the regularized energy density…

Quantum Physics · Physics 2009-10-30 Xinwei Kong , Finn Ravndal

The Casimir energy is evaluated for massless scalar fields under Dirichlet or Neumann boundary conditions, and for the electromagnetic field with perfect conductor boundary conditions on one and two infinite parallel plates moving by…

High Energy Physics - Theory · Physics 2009-11-10 A. A. Saharian , R. S. Davtyan , A. H. Yeranyan

The Casimir interaction energy due to the vacuum fluctuations of a massive vector field between two perfectly conducting concentric spherical bodies is computed. The TE contribution to the Casimir interaction energy is a direct…

Quantum Physics · Physics 2015-05-20 L. P. Teo
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