Vacuum expectation values of the energy-momentum tensor of quantized fields on manifolds of different topology and geometry. IV

1981 ◽  
Vol 24 (2) ◽  
pp. 171-174 ◽  
Author(s):  
S. G. Mamaev ◽  
N. N. Trunov
Keyword(s):  
Energy Momentum Tensor ◽  
Vacuum Expectation ◽  
Momentum Tensor ◽  
Expectation Values ◽  
Quantized Fields

scholarly journals VACUUM POLARIZATION IN A COSMIC STRING SPACETIME INDUCED BY FLAT BOUNDARY

2011 ◽  
Vol 03 ◽  
pp. 434-445
Author(s):  
EUGÊNIO R. BEZERRA DE MELLO ◽  
ARAM A. SAHARIAN
Keyword(s):  
Cosmic String ◽  
Vacuum Polarization ◽  
Energy Momentum Tensor ◽  
Neumann Boundary ◽  
Vacuum Expectation ◽  
Momentum Tensor ◽  
Massive Scalar ◽  
Expectation Values ◽  
Massive Scalar Field ◽  
Higher Dimensional

In this paper we analyze the vacuum expectation values of the field squared and the energy-momentum tensor associated to a massive scalar field in a higher dimensional cosmic string spacetime, obeying Dirichlet or Neumann boundary conditions on the surface orthogonal to the string.

scholarly journals Quantum Effects in the Spacetime of a Magnetic Flux Cosmic String

2003 ◽  
Vol 18 (12) ◽  
pp. 2093-2098 ◽  
Author(s):  
M. E. X. Guimarães ◽  
A. L. N. Oliveira
Keyword(s):  
Scalar Field ◽  
Magnetic Flux ◽  
Cosmic String ◽  
Energy Momentum Tensor ◽  
Vacuum Expectation ◽  
Momentum Tensor ◽  
Expectation Values ◽  
Charged Scalar ◽  
Average Value ◽  
Charged Scalar Field

In this work we compute the vacuum expectation values of the energy-momentum tensor and the average value of a massive, charged scalar field in the presence of a magnetic flux cosmic string for both zero- and finite-temperature cases.

scholarly journals CASIMIR DENSITIES FOR A MASSIVE FERMIONIC QUANTUM FIELD IN A GLOBAL MONOPOLE BACKGROUND WITH SPHERICAL BOUNDARY

2005 ◽  
Vol 20 (11) ◽  
pp. 2380-2387 ◽  
Author(s):  
A. A. SAHARIAN ◽  
E. R. BEZERRA DE MELLO
Keyword(s):  
Energy Momentum Tensor ◽  
Solid Angle ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Momentum Tensor ◽  
Global Monopole ◽  
Expectation Values ◽  
Fermionic Field ◽  
Sphere Center ◽  
Spherical Boundary

We investigate the vacuum expectation value of the energy-momentum tensor associated with a massive fermionic field obeying the MIT bag boundary condition on a spherical shell in the global monopole spacetime. The asymptotic behavior of the vacuum densities is investigated near the sphere center and surface, and at large distances from the sphere. In the limit of strong gravitational field corresponding to small values of the parameter describing the solid angle deficit in global monopole geometry, the sphere-induced expectation values are exponentially suppressed.

The effect of backreaction on inflationary Brans–Dicke cosmology

2016 ◽  
Vol 25 (10) ◽  
pp. 1650097 ◽  
Author(s):  
M. Sahraee ◽  
M. R. Setare
Keyword(s):  
Energy Momentum Tensor ◽  
Equations Of Motion ◽  
Dimensional Regularization ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Momentum Tensor ◽  
Expectation Values ◽  
Quantum Energy ◽  
Expectation Value ◽  
Dimensional Spacetime

In this paper, we study the effect of the quantum backreaction on Brans–Dicke cosmology in inflation era. We consider an inflaton field in the [Formula: see text]-dimensional spacetime in the framework of Brans–Dicke model. We use a new notation for the Brans–Dicke field in terms of the dilaton field. Then we obtain the vacuum expectation value of the full energy–momentum tensor using WKB approximation of the mode functions which satisfy the equations of motion. The obtained vacuum expectation values of energy–momentum tensor are divergent. In order to renormalize it, we introduce a constant cut-off [Formula: see text]. The vacuum expectation value of energy–momentum tensor is separated to the UV and IR parts by using [Formula: see text] cut-off. Then, we use the dimensional regularization method to eliminate divergences by introducing a counterterm action. Also, we calculate the IR contribution of the vacuum expectation value of energy–momentum tensor. Thus, we obtain a physically finite result for the quantum energy–momentum tensor. Finally, we find the effect of backreaction on scale factor.

scholarly journals VACUUM POLARIZATION IN THE SPACE–TIME OF A SCALAR–TENSOR COSMIC STRING

2001 ◽  
Vol 16 (24) ◽  
pp. 1565-1571 ◽  
Author(s):  
V. B. BEZERRA ◽  
R. M. TEIXEIRA FILHO ◽  
G. GREBOT ◽  
M. E. X. GUIMARÃES
Keyword(s):  
Cosmic String ◽  
Polarization Effect ◽  
Vacuum Polarization ◽  
Energy Momentum Tensor ◽  
Vacuum Expectation ◽  
Momentum Tensor ◽  
Space Time ◽  
Scalar Tensor Theory ◽  
Expectation Values ◽  
Tensor Theory

We study the vacuum polarization effect in the space–time generated by a magnetic flux cosmic string in the framework of a scalar–tensor theory of gravity. The vacuum expectation values of the energy–momentum tensor of a conformally coupled scalar field are calculated and the dilaton's contribution to the vacuum polarization effect is shown.

scholarly journals CASIMIR EFFECT IN BACKGROUND OF STATIC DOMAIN WALL

2001 ◽  
Vol 16 (08) ◽  
pp. 1463-1469 ◽  
Author(s):  
M. R. SETARE ◽  
A. SAHARIAN
Keyword(s):  
Domain Wall ◽  
Boundary Conditions ◽  
Energy Momentum Tensor ◽  
Casimir Effect ◽  
Vacuum Expectation ◽  
Momentum Tensor ◽  
Dirichlet Boundary Conditions ◽  
Expectation Values ◽  
Plate Geometry ◽  
Gravitational Background

In this paper we investigate the vacuum expectation values of energy–momentum tensor for conformally coupled scalar field in the standard parallel plate geometry with Dirichlet boundary conditions and in the background of planar domain wall case. First we calculate the vacuum expectation values of energy–momentum tensor by using the mode sums, then we show that corresponding properties can be obtained by using the conformal properties of the problem. The vacuum expectation values of energy–momentum tensor contain two terms which come from the boundary conditions and the the gravitational background. In the Minkowskian limit our results agree with those obtained in Ref. 3.

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