scholarly journals Induced vacuum energy-momentum tensor in the background of a(d−2)-brane in(d+1)-dimensional space-time

2003 ◽  
Vol 67 (8) ◽  
Author(s):  
Yurii A. Sitenko ◽  
Volodymyr M. Gorkavenko
Keyword(s):  
Vacuum Energy ◽  
Energy Momentum Tensor ◽  
Dimensional Space ◽  
Momentum Tensor ◽  
Space Time ◽  
Dimensional Space Time

scholarly journals Physical account of Weyl anomaly from Dirac Sea

2015 ◽  
Vol 30 (25) ◽  
pp. 1550147
Author(s):  
Yoshinobu Habara ◽  
Holger B. Nielsen ◽  
Masao Ninomiya
Keyword(s):  
Gravitational Field ◽  
Regularization Method ◽  
Energy Momentum Tensor ◽  
Dimensional Space ◽  
Momentum Tensor ◽  
Space Time ◽  
Two Dimensional ◽  
Dimensional Space Time ◽  
Dirac Sea ◽  
Mass Terms

We rederive in a physical manner the Weyl anomaly in two-dimensional space–time by considering the Dirac Sea. It is regularized by some bosonic extra species which are formally negatively counted. In fact, we calculate the trace of the energy–momentum tensor in the Dirac Sea in presence of background gravitational field. It has to be regularized, since the Dirac Sea is bottomless and thus causes divergence. The new regularization method consists in adding various massive bosonic species some of which are to be counted negative in the Dirac Sea. The mass terms in the Lagrangian of the regularization fields have a dependence on the background gravitational field.

scholarly journals Gravitational Theory Without the Cosmological Constant Problem

1997 ◽  
Vol 12 (32) ◽  
pp. 2421-2424 ◽  
Author(s):  
E. I. Guendelman ◽  
A. B. Kaganovich
Keyword(s):  
Cosmological Constant ◽  
Degrees Of Freedom ◽  
Vacuum Energy ◽  
Dimensional Space ◽  
Realistic Model ◽  
Gravitational Theory ◽  
Space Time ◽  
Higher Dimensional Space Time ◽  
Higher Dimensional ◽  
Dimensional Space Time

We develop a gravitational theory where the measure of integration in the action principle is not necessarily [Formula: see text] but it is determined dynamically through additional degrees of freedom. This theory is based on the demand that such measure respects the principle of "non-gravitating vacuum energy" which states that the Lagrangian density L can be changed to L + const. without affecting the dynamics. Formulating the theory in the first-order formalism we get as a consequence of the variational principle a constraint that enforces the vanishing of the cosmological constant. The most realistic model that implements these ideas is realized in a six or higher dimensional space–time. The compactification of extra dimensions into a sphere gives the possibility of generating scalar masses and potentials, gauge fields and fermionic masses. It turns out that the remaining four-dimensional space–time must have effective zero cosmological constant.

scholarly journals ON THE OCCURRENCE OF A POSITIVE VACUUM ENERGY IN A QUANTUM MODEL FOR SPACE–TIME

1999 ◽  
Vol 14 (31) ◽  
pp. 2169-2177
Author(s):  
GEORGE CHAPLINE
Keyword(s):  
Vacuum Energy ◽  
Dimensional Space ◽  
String Tension ◽  
Space Time ◽  
Accelerating Universe ◽  
Quantum Model ◽  
Observational Constraints ◽  
Discrete Form ◽  
Dimensional Space Time ◽  
New Type

It is shown that a previously proposed quantum model for four-dimensional space–time based on an SU (∞) generalization of anyonic superconductivity can be regarded as a discrete form of Polyakov's string theory. This suggests that in a Robertson–Walker universe there is a positive vacuum energy that is on the order of the string tension divided by square of the distance scale factor. This leads to a new type of cosmological model that, even though it resembles more an open universe than an accelerating universe, is apparently consistent with current observational constraints on cosmological models.

scholarly journals THE EFFECTIVE ENERGY-MOMENTUM TENSOR IN KALUZA–KLEIN GRAVITY WITH LARGE EXTRA DIMENSIONS AND OFF-DIAGONAL METRICS

2002 ◽  
Vol 11 (09) ◽  
pp. 1355-1380 ◽  
Author(s):  
J. PONCE DE LEON
Keyword(s):  
Energy Momentum Tensor ◽  
Dimensional Space ◽  
Large Extra Dimensions ◽  
Momentum Tensor ◽  
Space Time ◽  
Brane World ◽  
Splitting Technique ◽  
Klein Theory ◽  
Electromagnetic Tensor ◽  
Kaluza Klein

We consider a version of Kaluza–Klein theory where the cylinder condition is not imposed. The metric is allowed to have explicit dependence on the "extra" coordinate(s). This is the usual scenario in brane-world and space-time-matter theories. We extend the usual discussion by considering five-dimensional metrics with off-diagonal terms. We replace the condition of cylindricity by the requirement that physics in four-dimensional space-time should remain invariant under changes of coordinates in the five-dimensional bulk. This invariance does not eliminate physical effects from the extra dimension but separates them from spurious geometrical ones. We use the appropriate splitting technique to construct the most general induced energy-momentum tensor, compatible with the required invariance. It generalizes all previous results in the literature. In addition, we find two four-vectors, [Formula: see text] and [Formula: see text], induced by off-diagonal metrics, that separately satisfy the usual equation of continuity in 4D. These vectors appear as source-terms in equations that closely resemble the ones of electromagnetism. These are Maxwell-like equations for an antisymmetric tensor [Formula: see text] that generalizes the usual electromagnetic one. This generalization is not an assumption, but follows naturally from the dimensional reduction. Thus, if[Formula: see text] could be identified with the electromagnetic tensor, then the theory would predict the existence of classical magnetic charge and current. The splitting formalism used allows us to construct 4D physical quantities from five-dimensional ones, in a way that is independent from how we choose our space-time coordinates from those of the bulk.

Vacuum energy for 3+1 dimensional space‐time with compact hyperbolic spatial part

1992 ◽  
Vol 33 (9) ◽  
pp. 3108-3111 ◽  
Author(s):  
Andrei A. Bytsenko ◽  
Guido Cognola ◽  
Luciano Vanzo
Keyword(s):  
Vacuum Energy ◽  
Dimensional Space ◽  
Space Time ◽  
Spatial Part ◽  
Dimensional Space Time

scholarly journals The fate of the trace anomaly in a finite formulation of field theory

2021 ◽  
Author(s):  
Jean-François Mathiot
Keyword(s):  
Field Theory ◽  
Energy Momentum Tensor ◽  
Dimensional Space ◽  
Momentum Tensor ◽  
Quantum Corrections ◽  
Regularization Scheme ◽  
Trace Anomaly ◽  
Dimensional Space Time ◽  
Canonical Dimension ◽  
Anomalous Contribution

Within the framework of the recently proposed Taylor–Lagrange regularization scheme which leads to finite elementary amplitudes in four-dimensional space–time with no additional dimensionful scales — we show that the trace of the energy–momentum tensor does not show any anomalous contribution even though quantum corrections are considered. Moreover, since the only renormalization we can think of within this scheme is a finite renormalization of the bare parameters to give the physical ones, the canonical dimension of quantum fields is also preserved by the use of this regularization scheme.

Topology knots and hierarchy problem

2019 ◽  
Author(s):  
Vitaly Kuyukov
Keyword(s):  
Quantum Theory ◽  
String Theory ◽  
Quantum Gravity ◽  
Dimensional Space ◽  
Space Time ◽  
Elementary Particles ◽  
Hierarchy Problem ◽  
Topological Quantum ◽  
Dimensional Space Time ◽  
New Formula

Many approaches to quantum gravity consider the revision of the space-time geometry and the structure of elementary particles. One of the main candidates is string theory. It is possible that this theory will be able to describe the problem of hierarchy, provided that there is an appropriate Calabi-Yau geometry. In this paper we will proceed from the traditional view on the structure of elementary particles in the usual four-dimensional space-time. The only condition is that quarks and leptons should have a common emerging structure. When a new formula for the mass of the hierarchy is obtained, this structure arises from topological quantum theory and a suitable choice of dimensional units.

CASIMIR EFFECT FOR THE ROBIN SURFACES IN STATIC ROBERTSON–WALKER SPACE–TIME

2011 ◽  
Vol 20 (02) ◽  
pp. 161-168 ◽  
Author(s):  
MOHAMMAD R. SETARE ◽  
M. DEHGHANI
Keyword(s):  
Scalar Field ◽  
Energy Momentum Tensor ◽  
Casimir Effect ◽  
Vacuum Expectation ◽  
Robin Boundary Condition ◽  
Momentum Tensor ◽  
Space Time ◽  
Conformally Invariant ◽  
Time Space ◽  
Robin Boundary

We investigate the energy–momentum tensor for a massless conformally coupled scalar field in the region between two curved surfaces in k = -1 static Robertson–Walker space–time. We assume that the scalar field satisfies the Robin boundary condition on the surfaces. Robertson–Walker space–time space is conformally related to Rindler space; as a result we can obtain vacuum expectation values of the energy–momentum tensor for a conformally invariant field in Robertson–Walker space–time space from the corresponding Rindler counterpart by the conformal transformation.

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