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The influence of a spherical boundary on the vacuum fluctuations of a massive scalar field is investigated in background of $(D+1)$-dimensional Milne universe, assuming that the field obeys Robin boundary condition on the sphere. The…

High Energy Physics - Theory · Physics 2020-04-24 A. A. Saharian , T. A. Petrosyan

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…

High Energy Physics - Theory · Physics 2022-01-12 S. Bellucci , W. Oliveira dos Santos , E. R. Bezerra de Mello , A. A. Saharian

We investigate the vacuum expectation values for the energy-momentum tensor of a massive scalar field with general curvature coupling and obeying the Robin boundary condition on a spherical shell in the $D+1$-dimensional global monopole…

High Energy Physics - Theory · Physics 2009-11-10 A. A. Saharian , M. R. Setare

We investigate vacuum expectation value of the energy-momentum tensor for a massive Dirac field in flat spacetime with a toroidal subspace of a general dimension. Quasiperiodicity conditions with arbitrary phases are imposed on the field…

High Energy Physics - Theory · Physics 2024-08-09 A. A. Saharian , R. M. Avagyan , G. H. Harutyunyan , G. H. Nikoghosyan

We study the fermionic condensate (FC) and the vacuum expectation value (VEV) of the energy-momentum tensor for a massive spinor field in the de Sitter (dS) spacetime including an ideal cosmic string. In addition, spatial dimension along…

High Energy Physics - Theory · Physics 2020-03-04 E. A. F. Bragança , E. R. Bezerra de Mello , A. Mohammadi

We calculate the Casimir energy of a massless scalar field in a cavity formed by nearby parallel plates orbiting a rotating spherical body surrounded by quintessence, investigating the influence of the gravitational field on that energy, at…

High Energy Physics - Theory · Physics 2016-12-21 V. B. Bezerra , M. S. Cunha , L. F. F. Freitas , C. R. Muniz

We present a rigorous, regularization independent local quantum field theoretic treatment of the Casimir effect for a quantum scalar field of mass $\mu\ne0$ which yields closed form expressions for the energy density and pressure. As an…

General Relativity and Quantum Cosmology · Physics 2015-05-13 G. Gazzola , M. C. Nemes , W. F. Wreszinski

Cosmic strings are the most popular topological defects arising from the spontaneous breaking of fundamental symmetries in the early Universe. They are the source of a number of interesting effects in cosmology and astrophysics. An…

General Relativity and Quantum Cosmology · Physics 2024-12-11 A. A. Saharian

In this paper we present a complete and detailed analysis of the calculation of both the Wightman function and the vacuum expectation value of the energy-momentum tensor that arise from quantum vacuum fluctuations of massive and massless…

High Energy Physics - Theory · Physics 2018-09-12 H. F. Mota , E. R. Bezerra de Mello , K. Bakke

We show that on the average, homogeneous and isotropic scalar field and on the average homogeneous and isotropic ensembles of classical and quantum gravitational waves generate the de Sitter expansion of the empty (with no matter)…

General Physics · Physics 2017-09-06 Leonid Marochnik

A finite, scheme-independent Casimir contribution to the stress-energy tensor arises naturally for quantum fields in universes with non-trivial spatial topology. We compute this Casimir stress-energy tensor contribution for a conformally…

We compute the expectations of the squares of the electric and magnetic fields in the vacuum region outside a half-space filled with a uniform dispersive dielectric. We find a positive energy density of the electromagnetic field which…

Quantum Physics · Physics 2009-11-07 V. Sopova , L. H. Ford

Casimir effect for massless minimally coupled scalar field is studied. An explicit answer for de Sitter spacetime is obtained and analized. Cosmological implications of the result are discussed.

High Energy Physics - Theory · Physics 2015-05-27 Philipp Burda

Over the last few years, low- and high-redshift observations set off tensions in the measurement of the present-day expansion rate $H_0$ and in the determination of the amplitude of the matter clustering in the late Universe (parameterized…

High Energy Physics - Theory · Physics 2024-06-11 Luis A. Anchordoqui , Ignatios Antoniadis , Dieter Lust

For scalar and electromagnetic fields we evaluate the vacuum expectation value of the energy-momentum tensor induced by a curved boundary in the Robertson--Walker spacetime with negative spatial curvature. In order to generate the vacuum…

High Energy Physics - Theory · Physics 2010-04-30 A. A. Saharian , M. R. Setare

We investigate the fermionic condensate and the vacuum expectation value of the energy-momentum tensor for a massive spinor field in the geometry of a straight cosmic string on background of de Sitter spacetime. By using the Abel-Plana…

High Energy Physics - Theory · Physics 2010-08-24 E. R. Bezerra de Mello , A. A. Saharian

The Casimir energy for scalar field of two parallel conductor in two dimensional domain wall background, with Dirichlet boundary conditions, is calculated by making use of general properties of renormalized stress tensor.We show that vacuum…

High Energy Physics - Theory · Physics 2009-10-31 M. R. Setare , A. H. Rezaeian

Two fundamental signatures of Quantum Mechanics are tunnelling and the Casimir effect. We examine the ground state energetic properties of a scalar field confined on a $D$-dimensional sphere, and subjected to these two effects. We focus on…

High Energy Physics - Theory · Physics 2024-09-02 Jean Alexandre , Drew Backhouse

Vacuum fluctuations and the Casimir effect are considered in a cosmological setting. It is suggested that the dark energy, which recent observations suggest make up 73% of our universe, is vacuum energy due to a causal boundary effect at…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Pawel O. Mazur , Emil Mottola

The vacuum energy density (Casimir energy) corresponding to a massless scalar quantum field living in different universes (mainly no-boundary ones), in several dimensions, is calculated. Hawking's zeta function regularization procedure…

High Energy Physics - Theory · Physics 2011-08-17 E. Elizalde