scholarly journals Casimir energy–momentum tensor for a brane in de Sitter spacetime

2004 ◽  
Vol 584 (3-4) ◽  
pp. 306-314 ◽  
Author(s):  
A.A. Saharian ◽  
M.R. Setare
Keyword(s):  
Energy Momentum Tensor ◽  
Casimir Energy ◽  
Momentum Tensor ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Sitter Spacetime

scholarly journals CASIMIR EFFECT IN DE SITTER SPACETIME

2011 ◽  
Vol 03 ◽  
pp. 215-226 ◽  
Author(s):  
A. A. SAHARIAN
Keyword(s):  
Energy Momentum Tensor ◽  
Coupling Parameter ◽  
Momentum Tensor ◽  
Curvature Radius ◽  
De Sitter Spacetime ◽  
Parallel Plates ◽  
De Sitter ◽  
Casimir Forces ◽  
Massive Scalar Field ◽  
Sitter Spacetime

The vacuum expectation value of the energy-momentum tensor and the Casimir forces are investigated for a massive scalar field with an arbitrary curvature coupling parameter in the geometry of two parallel plates, on the background of de Sitter spacetime. The field is prepared in the Bunch–Davies vacuum state and is constrained to satisfy Robin boundary conditions on the plates. The vacuum energy-momentum tensor is non-diagonal, with the off-diagonal component corresponding to the energy flux along the direction normal to the plates. It is shown that the curvature of the background spacetime decisively influences the behavior of the Casimir forces at separations larger than the curvature radius of de Sitter spacetime. In dependence of the curvature coupling parameter and the mass of the field, two different regimes are realized, which exhibit monotonic or oscillatory behavior of the forces. The decay of the Casimir force at large plate separation is shown to be power-law, with independence of the value of the field mass.

scholarly journals CASIMIR EFFECT IN DE SITTER SPACETIME

2011 ◽  
Vol 26 (22) ◽  
pp. 3833-3844 ◽  
Author(s):  
A. A. SAHARIAN
Keyword(s):  
Energy Momentum Tensor ◽  
Coupling Parameter ◽  
Momentum Tensor ◽  
Curvature Radius ◽  
De Sitter Spacetime ◽  
Parallel Plates ◽  
De Sitter ◽  
Casimir Forces ◽  
Massive Scalar Field ◽  
Sitter Spacetime

The vacuum expectation value of the energy-momentum tensor and the Casimir forces are investigated for a massive scalar field with an arbitrary curvature coupling parameter in the geometry of two parallel plates, on the background of de Sitter spacetime. The field is prepared in the Bunch–Davies vacuum state and is constrained to satisfy Robin boundary conditions on the plates. The vacuum energy-momentum tensor is non-diagonal, with the off-diagonal component corresponding to the energy flux along the direction normal to the plates. It is shown that the curvature of the background space-time decisively influences the behavior of the Casimir forces at separations larger than the curvature radius of de Sitter spacetime. In dependence of the curvature coupling parameter and the mass of the field, two different regimes are realized, which exhibit monotonic or oscillatory behavior of the forces. The decay of the Casimir force at large plate separation is shown to be power-law, with independence of the value of the field mass.

Casimir effect in spacetimes with cosmological constant

2016 ◽  
Vol 25 (09) ◽  
pp. 1641017
Author(s):  
C. H. G. Bessa ◽  
V. B. Bezerra ◽  
J. C. J. Silva
Keyword(s):  
Gravitational Field ◽  
Energy Density ◽  
Cosmological Constant ◽  
Casimir Effect ◽  
Casimir Energy ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Sitter Spacetime

In this work, we study the influence of the gravitational field induced by the presence of a cosmological constant [Formula: see text] on the Casimir energy density. We consider two metrics with the presence of the [Formula: see text]-term, namely de Sitter and Schwarzschild-de Sitter (SdS). In the former case, we consider a conformal de Sitter spacetime and in the last one, a weak gravitational SdS spacetime.

scholarly journals Unimodular vs nilpotent superfield approach to pure dS supergravity

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Sukruti Bansal ◽  
Silvia Nagy ◽  
Antonio Padilla ◽  
Ivonne Zavala
Keyword(s):  
String Theory ◽  
General Framework ◽  
Recent Progress ◽  
High Energy ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
New Approach ◽  
Sitter Spacetime ◽  
Novel Approach ◽  
De Sitter Vacua

Abstract Recent progress in understanding de Sitter spacetime in supergravity and string theory has led to the development of a four dimensional supergravity with spontaneously broken supersymmetry allowing for de Sitter vacua, also called de Sitter supergravity. One approach makes use of constrained (nilpotent) superfields, while an alternative one couples supergravity to a locally supersymmetric generalization of the Volkov-Akulov goldstino action. These two approaches have been shown to give rise to the same 4D action. A novel approach to de Sitter vacua in supergravity involves the generalisation of unimodular gravity to supergravity using a super-Stückelberg mechanism. In this paper, we make a connection between this new approach and the previous two which are in the context of nilpotent superfields and the goldstino brane. We show that upon appropriate field redefinitions, the 4D actions match up to the cubic order in the fields. This points at the possible existence of a more general framework to obtain de Sitter spacetimes from high-energy theories.

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