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In previous works, we studied the isotropisation of Bianchi class A models with a minimally coupled scalar field. In this paper, we extend these results to the case of a non minimally coupled one. We first make the calculations in the…

General Relativity and Quantum Cosmology · Physics 2009-09-01 Stephane Fay

A high temperature expansion is employed to map some complex anisotropic nonhermitian three and four dimensional Ising models with algebraic long range interactions into a solvable two dimensional variant. We also address the dimensional…

High Energy Physics - Theory · Physics 2007-05-23 Z. Nussinov

This paper generalizes two previously known techniques for generating minimally coupled Einstein-scalar field solutions in 4 dimensions; the Buchdahl and Fonarev transformations. By applying this solution generation technique, minimally…

General Relativity and Quantum Cosmology · Physics 2007-06-13 Kjell Tangen

Construction of optimal deformations is one of the long standing problems of computational mathematics. We consider the problem of computing quasi-isometric deformations with minimal possible quasi-isometry constant (global estimate for…

Computational Geometry · Computer Science 2022-01-31 Vladimir Garanzha , Igor Kaporin , Liudmila Kudryavtseva , François Protais , David Desobry , Dmitry Sokolov

We introduce a new geometric framework for the set of symmetric positive-definite (SPD) matrices, aimed to characterize deformations of SPD matrices by individual scaling of eigenvalues and rotation of eigenvectors of the SPD matrices. To…

Metric Geometry · Mathematics 2018-06-29 Sungkyu Jung , Armin Schwartzman , David Groisser

In this paper we accomplish the development of the fast rank-adaptive solver for tensor-structured symmetric positive definite linear systems in higher dimensions. In [arXiv:1301.6068] this problem is approached by alternating minimization…

Numerical Analysis · Mathematics 2014-10-07 Sergey V. Dolgov , Dmitry V. Savostyanov

In this work I develop a new framework for anisotropic hydrodynamics that generalizes the leading order of the hydrodynamic expansion to the full (3+1)-dimensional anisotropic massive case. Following previous works, my considerations are…

Nuclear Theory · Physics 2015-07-29 Leonardo Tinti

We present a new numerical code designed to solve the Einstein field equations for axisymmetric spacetimes. The long term goal of this project is to construct a code that will be capable of studying many problems of interest in axisymmetry,…

General Relativity and Quantum Cosmology · Physics 2009-11-10 M. W. Choptuik , E. W. Hirschmann , S. L. Liebling , F. Pretorius

We study the space-time geometry generated by coupling a free scalar field with a non-canonical kinetic term to General Relativity in $(2+1)$ dimensions. After identifying a family of scalar Lagrangians that yield exact analytical solutions…

General Relativity and Quantum Cosmology · Physics 2024-06-25 Roberto V. Maluf , Gerardo Mora-Pérez , Gonzalo J. Olmo , Diego Rubiera-Garcia

We consider a topological field theory derived from the Chern - Simons action in (2+1) dimensions with the I(ISO(2,1)) group,and we investigate in detail the canonical structure of this theory.Originally developed as a topological theory of…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Laurent Freidel , R. B. Mann , Eugeniu M. Popescu

We study the smallest intersecting and enclosing ball problems in Euclidean spaces for input objects that are compact and convex. They link and unify many problems in computational geometry and machine learning. We show that both problems…

Computational Geometry · Computer Science 2025-04-28 Jiaqi Zheng , Tiow-Seng Tan

We study anisotropic deformations of the spatially open homogeneous and isotropic cosmology in the ghost free massive gravity theory with flat reference metric. We find that if the initial perturbations are not too strong then the physical…

High Energy Physics - Theory · Physics 2017-05-03 Charles Mazuet , Shinji Mukohyama , Mikhail S. Volkov

We prove that the Einstein equations can be solved in a very general form for arbitrary spacetime dimensions and various types of vacuum and non-vacuum cases following a geometric method of anholonomic frame deformations for constructing…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Sergiu I. Vacaru

We prove that the minimally displaced set of a relatively irreducible automorphism of a free splitting, situated in a deformation space, is uniformly locally finite. The minimally displaced set coincides with the train track points for an…

Group Theory · Mathematics 2020-04-17 Stefano Francaviglia , Armando Martino , Dionysios Syrigos

We report a new family of solutions to Einstein-Maxwell-dilaton gravity in 2+1 dimensions and Einstein-Maxwell gravity with cylindrical symmetry in 3+1 dimensions. A set of static charged solutions in 2+1 dimensions are obtained by a…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Sharmanthie Fernando

The field equations for Einstein-Maxwell-dilaton gravity in $D$ dimensions are reduced to an effective one-dimensional system under the influence of exponential potentials. Various cases where exact solutions can be found are explored. With…

General Relativity and Quantum Cosmology · Physics 2017-05-10 Yen-Kheng Lim

The problem of covering a region of the plane with a fixed number of minimum-radius identical balls is studied in the present work. An explicit construction of bi-Lipschitz mappings is provided to model small perturbations of the union of…

Optimization and Control · Mathematics 2023-04-28 Ernesto G. Birgin , Antoine Laurain , Rafael Massambone , Arthur G. Santana

According to Ryu and Takayanagi, the entanglement entropy in conformal field theory (CFT) is related through the AdS/CFT correspondence to the area of a minimal surface in the bulk. We study this holographic geometrical method of…

High Energy Physics - Theory · Physics 2018-07-18 Pavel Krtous , Andrei Zelnikov

We obtain an exact solution for the Einstein's equations with cosmological constant coupled to a scalar, static particle in static, "spherically" symmetric background in 2+1 dimensions.

General Relativity and Quantum Cosmology · Physics 2009-11-11 Durmus Daghan , Ayse H. Bilge

In this work a static solution of Einstein-Cartan (EC) equations in 2+1 dimensional space-time is given by considering classical spin-1/2 field as external source for torsion of the space-time. Here, the torsion tensor is obtained from…

General Relativity and Quantum Cosmology · Physics 2008-07-29 M. Hortacsu , H. T. Ozcelik , N. Ozdemir