scholarly journals PALATINI FORMALISM OF FIVE-DIMENSIONAL KALUZA–KLEIN THEORY

2005 ◽  
Vol 20 (05) ◽  
pp. 345-353 ◽  
Author(s):  
YOU DING ◽  
YONGGE MA ◽  
MUXIN HAN ◽  
JIANBING SHAO

The Einstein field equations can be derived in n dimensions (n>2) by the variations of the Palatini action. The Killing reduction of five-dimensional Palatini action is studied on the assumption that pentads and Lorentz connections are preserved by the Killing vector field. A Palatini formalism of four-dimensional action for gravity coupled to a vector field and a scalar field is obtained, which gives exactly the same field equations in Kaluza–Klein theory.

2020 ◽  
Vol 35 (36) ◽  
pp. 2030020
Author(s):  
Chris Vuille

In this paper I introduce tensor multinomials, an algebra that is dense in the space of nonlinear smooth differential operators, and use a subalgebra to create an extension of Einstein’s theory of general relativity. In a mathematical sense this extension falls between Einstein’s original theory of general relativity in four dimensions and the Kaluza–Klein theory in five dimensions. The theory has elements in common with both the original Kaluza–Klein and Brans–Dicke, but emphasizes a new and different underlying mathematical structure. Despite there being only four physical dimensions, the use of tensor multinomials naturally leads to expanded operators that can incorporate other fields. The equivalent Ricci tensor of this geometry is robust and yields vacuum general relativity and electromagnetism, as well as a Klein–Gordon-like quantum scalar field. The formalism permits a time-dependent cosmological function, which is the source for the scalar field. I develop and discuss several candidate Lagrangians. Trial solutions of the most natural field equations include a singularity-free dark energy dust cosmology.


2010 ◽  
Vol 25 (19) ◽  
pp. 1635-1646 ◽  
Author(s):  
F. DARABI

In the framework of Kaluza–Klein theory, we investigate a (4+1)-dimensional universe consisting of a (4+1)-dimensional Robertson–Walker type metric coupled with a (4+1)-dimensional energy–momentum tensor. The matter part consists of an energy density together with a pressure subject to 4D part of the (4+1)-dimensional energy–momentum tensor. The dark part consists of just a dark pressure [Formula: see text], corresponding to the extra-dimension endowed by a scalar field, with no element of dark energy. It is shown that the reduced Einstein field equations are free of 4D pressure and are just affected by an effective pressure produced by the 4D energy density and dark pressure. It is then proposed that the expansion of the universe may be controlled by the equation of state in higher dimension rather than four dimensions. This may account for the current acceleration at the beginning or in the middle of matter dominant era.


2017 ◽  
Vol 5 (2) ◽  
pp. 73-78
Author(s):  
Jay Prakash Singh ◽  

In this paper author present an investigation of some differential geometric properties of Para-Sasakian manifolds. Condition for a vector field to be Killing vector field in Para-Sasakian manifold is obtained. Mathematics Subject Classification (2010). 53B20, 53C15.


2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Guido Festuccia ◽  
Anastasios Gorantis ◽  
Antonio Pittelli ◽  
Konstantina Polydorou ◽  
Lorenzo Ruggeri

Abstract We construct a large class of gauge theories with extended supersymmetry on four-dimensional manifolds with a Killing vector field and isolated fixed points. We extend previous results limited to super Yang-Mills theory to general $$ \mathcal{N} $$ N = 2 gauge theories including hypermultiplets. We present a general framework encompassing equivariant Donaldson-Witten theory and Pestun’s theory on S4 as two particular cases. This is achieved by expressing fields in cohomological variables, whose features are dictated by supersymmetry and require a generalized notion of self-duality for two-forms and of chirality for spinors. Finally, we implement localization techniques to compute the exact partition function of the cohomological theories we built up and write the explicit result for manifolds with diverse topologies.


1996 ◽  
Vol 93 (1) ◽  
pp. 157-170 ◽  
Author(s):  
J. Monterde ◽  
O. A. Sánchez-Valenzuela

2016 ◽  
Vol 25 (02) ◽  
pp. 1650022 ◽  
Author(s):  
I. G. Contopoulos ◽  
F. P. Esposito ◽  
K. Kleidis ◽  
D. B. Papadopoulos ◽  
L. Witten

Exact solutions to the Einstein field equations may be generated from already existing ones (seed solutions), that admit at least one Killing vector. In this framework, a space of potentials is introduced. By the use of symmetries in this space, the set of potentials associated to a known solution is transformed into a new set, either by continuous transformations or by discrete transformations. In view of this method, and upon consideration of continuous transformations, we arrive at some exact, stationary axisymmetric solutions to the Einstein field equations in vacuum, that may be of geometrical or/and physical interest.


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