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We have constructed gravity solutions by breaking the Lorentzian symmetry to its subgroup, which means there is Galilean symmetry but without the rotational and boost invariance. This solution shows anisotropic behavior along both the…

High Energy Physics - Theory · Physics 2010-10-26 Shesansu Pal

Bianchi attractors are near horizon geometries with homogeneous symmetries in the spatial directions. We construct supersymmetric Bianchi attractors in $\mathcal{N}=2, d=4,5$ gauged supergravity. In $d=4$ we consider gauged supergravity…

High Energy Physics - Theory · Physics 2017-09-27 Bidisha Chakrabarty , Karthik Inbasekar , Rickmoy Samanta

We analyze if Bianchi I, V, and IX models in the Induced Gravity (IG) theory can evolve to a Friedmann--Roberson--Walker (FRW) expansion due to the non--minimal coupling of gravity and the scalar field. The analytical results that we found…

General Relativity and Quantum Cosmology · Physics 2009-10-31 J. L. Cervantes-Cota , P. Ag. Chauvet

Anisotropies in the cosmic microwave background radiation due to gravity waves are investigated. An initial spectrum of gravity waves may have been induced during an epoch of inflation. We study the propagation of such a spectrum in a…

Astrophysics · Physics 2008-02-03 Ruth Durrer , Tina Kahniashvili

We focus on the initial state spatial anisotropies, originating at the thermalization stage, for central collisions in relativistic heavy-ion collisions. We propose that a plot of the root mean square values of the flow coefficients…

High Energy Physics - Phenomenology · Physics 2008-11-26 Ananta P. Mishra , Ranjita K. Mohapatra , P. S. Saumia , Ajit M. Srivastava

In this paper we study an anisotropic model generated from a particular Bianchi type-III metric, which is a generalization of G\"odel's metric and an exact solution of Einstein's field equations. We analyse type Ia supernova data, namely…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-02 R. S. Menezes , C. Pigozzo , S. Carneiro

In this paper, we adopt minimal gravitational decoupling scheme to extend a non-static spherically symmetric isotropic composition to anisotropic interior in…

General Relativity and Quantum Cosmology · Physics 2023-08-03 M. Sharif , Tayyab Naseer

The present matter density of the Universe, while highly inhomogeneous on small scales, displays approximate homogeneity on large scales. We propose that whereas it is justified to use the Friedmann-Lemaitre-Robertson-Walker (FLRW) line…

Astrophysics · Physics 2008-11-26 Aseem Paranjape , T. P. Singh

We investigate the cosmological implications of modified gravities induced by the quantum fluctuations of the gravitational metric. If the metric can be decomposed as the sum of the classical and of a fluctuating part, of quantum origin,…

General Relativity and Quantum Cosmology · Physics 2016-08-02 Xing Liu , Tiberiu Harko , Shi-Dong Liang

We generalize our previous theorem for FLRW spacetimes within the framework of generic metric gravity theories. In earlier work, we proved that, in the absence of matter fields, the field equations of any metric gravity theory constructed…

General Relativity and Quantum Cosmology · Physics 2026-03-31 Metin Gürses , Yaghoub Heydarzade

The cosmological principle asserts that the Universe is homogeneous and isotropic on large enough scales. However, alternative cosmological models can bring about anisotropies through local inhomogeneities, anisotropic evolution, or exotic…

A new method is proposed for modelling spherically symmetric inhomogeneities in the Universe. The inhomogeneities have finite size and are compensated, so they do not exert any measurable gravitational force beyond their boundary. The…

Astrophysics · Physics 2009-10-31 A. N. Lasenby , C. J. L. Doran , M. P. Hobson , Y. Dabrowski , A. D. Challinor

Assuming that the cosmological principle holds, Maartens, Ellis and Stoeger (MES) recently constructed a detailed scheme linking anisotropies in the cosmic background radiation (CMB) with anisotropies and inhomogeneities in the large scale…

Astrophysics · Physics 2008-12-01 William Stoeger , Marcelo Araujo , Tim Gebbie

We construct a cosmological model from the inception of the Friedmann-Lem\^aitre-Robertson-Walker metric into the field equations of the f(R,L_m) gravity theory, with R being the Ricci scalar and L_m being the matter lagrangian density. The…

General Relativity and Quantum Cosmology · Physics 2024-03-21 B. S. Gonçalves , P. H. R. S. Moraes , B. Mishra

We present an anisotropic cosmological model based on a new exact solution of Einstein equations. The matter content consists of an anisotropic scalar field minimally coupled to gravity and of two isotropic perfect fluids that represent…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Saulo Carneiro , Guillermo A. Mena Marugan

The dynamics of the tilted axisymmetric Bianchi IX cosmological models are explored allowing energy flux in the source fluid. The Einstein equations and the continuity equation are presented treating the equation of state $w$ and the tilt…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-30 Peter Sundell , Tomi Koivisto

The behaviour of the wave function of the Universe under the barrier for anisotropic cosmological Bianchi type IX model with account of influence of the scalar field is explored. In view of known difficulties with interpretation of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 V. N. Folomeev , V. Ts. Gurovich , I. V. Tokareva

We explore the Hubble tension within an anisotropic cosmological framework by revisiting the Bianchi type-I model introduced in Le Delliou et al. 2020. Motivated by ongoing debates surrounding back-reaction effects and observed anomalies in…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-23 Maksym Deliyergiyev , Morgan Le Delliou , Antonino Del Popolo

Although the new era of high precision cosmology of the cosmic microwave background (CMB) radiation improves our knowledge to understand the infant as well as the presentday Universe, it also leads us to question the main assumption of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Esra Russell , Can Battal Kilinc , Oktay K. Pashaev

We revisit the stochastic effects in the model of anisotropic inflation containing a $U(1)$ gauge field. We obtain the Langevin equations for the inflaton and gauge fields perturbations and solve them analytically. We show that if the…

General Relativity and Quantum Cosmology · Physics 2020-02-05 Alireza Talebian , Amin Nassiri-Rad , Hassan Firouzjahi