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Irreducible bilinear tensorial concomitants of an arbitrary complex antisymmetric valence-2 tensor are derived in four-dimensional spacetime. In addition these bilinear concomitants are symmetric (or antisymmetric), self-dual (or…

Mathematical Physics · Physics 2007-05-23 T. D. Carozzi , J. E. S. Bergman

We introduce the concept of singular values for the Riemann curvature tensor, a central mathematical tool in Einstein's theory of general relativity. We study the properties related to the singular values, and investigate five typical cases…

Differential Geometry · Mathematics 2018-07-24 Xiaokai He , Hua Xiang

Several approaches to quantum gravity (including the model of superplastic vacuum; Diakonov tetrads emerging as the bilinear combinations of the fermionis fields; $BF$-theories of gravity; and effective acoustic metric) suggest that in…

General Relativity and Quantum Cosmology · Physics 2023-01-18 G. E. Volovik

Scalar perturbations of Friedmann-Lemaitre cosmologies can be analyzed in a variety of ways using Einstein's field equations, the Ricci and Bianchi identities, or the conservation equations for the stress-energy tensor, and possibly…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Claes Uggla , John Wainwright

Einstein-Hilbert action with a determinantal invariant has been considered. The obtained field equation contains the \texttt{inverse Ricci tensor}, $\Re_{\alpha\beta}$. The linearized solution of invariant has been examined, and constant…

General Relativity and Quantum Cosmology · Physics 2016-02-16 Nurettin Pirinccioglu

We discuss two scenarios of emergent gravity. In one of them the quantum vacuum is considered as superplastic crystal, and the effective gravity describes the dynamical elastic deformations of this crystal. In the other one the…

General Relativity and Quantum Cosmology · Physics 2021-06-16 G. E. Volovik

A model of relativistic extended particle is considered with the help of generalization of space-time inter-val. Ten additional dimensions are connected with six rotational and four deformational degrees of freedom. An obtained…

High Energy Physics - Theory · Physics 2007-05-23 A. N. Tarakanov

We present a Lorentzian version of three-dimensional noncommutative Einstein-AdS gravity by making use of the Chern-Simons formulation of pure gravity in 2+1 dimensions. The deformed action contains a real, symmetric metric and a real,…

High Energy Physics - Theory · Physics 2009-11-07 S. Cacciatori , D. Klemm , L. Martucci , D. Zanon

Starting with a field theoretic approach in Minkowski space, the gravitational energy momentum tensor is derived from the Einstein equations in a straightforward manner. This allows to present them as {\it acceleration tensor} = const.…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Theo M. Nieuwenhuizen

The Gauss-Bonnet curvature of order $2k$ is a generalization to higher dimensions of the Gauss-Bonnet integrand in dimension $2k$, as the usual scalar curvature generalizes the two dimensional Gauss-Bonnet integrand. In this paper, we…

Differential Geometry · Mathematics 2007-05-23 Mohammed-Larbi Labbi

We examine the question of scale versus conformal invariance on maximally symmetric curved backgrounds and study general 2-derivative conformally invariant free theories of vectors and tensors. For spacetime dimension $D>4$, these conformal…

High Energy Physics - Theory · Physics 2024-08-15 Kara Farnsworth , Kurt Hinterbichler , Ondrej Hulik

Dimensional analysis provides many simple and useful tools for various situations in science. The objective of this paper is to investigate its relations to functions, i.e., the dimensions for functions that yield physical quantities and…

General Physics · Physics 2017-12-05 Shinji Tanimoto

Intrinsic dimension and differential entropy estimators are studied in this paper, including their systematic bias. A pragmatic approach for joint estimation and bias correction of these two fundamental measures is proposed. Shared steps on…

Machine Learning · Statistics 2020-05-01 Jugurta Montalvão , Jânio Canuto , Luiz Miranda

The present paper continues the work of the authors [arXiv:1306.6887 [gr-qc]]. Here, we study generally covariant metric-torsion theories of gravity presented more concretely, setting that their Lagrangians are \emph{manifestly} generally…

General Relativity and Quantum Cosmology · Physics 2014-01-14 Robert R. Lompay , Alexander N. Petrov

We study a noncommutative deformation of general relativity where the gravitational field is described by a matrix-valued symmetric two-tensor field. The equations of motion are derived in the framework of this new theory by varying a…

General Relativity and Quantum Cosmology · Physics 2011-02-17 Guglielmo Fucci , Ivan G. Avramidi

Information about intrinsic dimension is crucial to perform dimensionality reduction, compress information, design efficient algorithms, and do statistical adaptation. In this paper we propose an estimator for the intrinsic dimension of a…

Machine Learning · Statistics 2017-11-09 Paulo Serra , Michel Mandjes

We construct polynomial conformal invariants, the vanishing of which is necessary and sufficient for an $n$-dimensional suitably generic (pseudo-)Riemannian manifold to be conformal to an Einstein manifold. We also construct invariants…

Differential Geometry · Mathematics 2007-05-23 A. Rod Gover , Pawel Nurowski

The equations of motion for a self-interacting self-dual tensor in six dimensions are extracted from the equations describing the M-theory five-brane. These equations are presented in a self-contained, six-dimensional Lorentz-covariant…

High Energy Physics - Theory · Physics 2009-10-30 P. S. Howe , E. Sezgin , P. C. West

It is developed a Riemannian reformulation of classical statistical mechanics for systems in thermodynamic equilibrium, which arises as a natural extension of Ruppeiner geometry of thermodynamics. The present proposal leads to interpret…

Statistical Mechanics · Physics 2010-11-19 L Velazquez

Determinants of the second-rank tensors stand useful in forming generally invariant terms as in the case of the volume element of the gravitational actions. Here, we extend the action of the matter fields by an arbitrary function $f(D)$ of…

General Relativity and Quantum Cosmology · Physics 2023-01-04 Hemza Azri , Salah Nasri