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Motivated by the recent suggestions that very massive pulsar (PSR J0952-0607) and very light compact object (HESS J1731-347) exist, in this article, we revisit the possibility of such objects being strange stars instead of the standard…

High Energy Astrophysical Phenomena · Physics 2023-09-06 H. C. Das , Luiz L. Lopes

A class of nonstationary spacetimes is obtained by means of a conformal transformation of the Schwarzschild metric, where the conformal factor $a(t)$ is an arbitrary function of the time coordinate only. We investigate several situations…

General Relativity and Quantum Cosmology · Physics 2017-05-05 Marina M. C. Mello , Alan Maciel , Vilson T. Zanchin

Experimental measurements of contact forces are limited to spheres and disks in three and two dimensions, making the evaluation of the shape effect and universality of force distributions and the comparison between experiments and theories…

Soft Condensed Matter · Physics 2021-10-22 Yinqiao Wang , Jin Shang , Yujie Wang , Jie Zhang

A new time-dependent, scale-independent parameter, \varpi, is employed in a phenomenological model of the deviation from General Relativity in which the Newtonian and longitudinal gravitational potentials slip apart on cosmological scales…

Astrophysics · Physics 2008-11-26 Scott F. Daniel , Robert R. Caldwell , Asantha Cooray , Alessandro Melchiorri

A description of mesoscopic fluctuations of the pairing gap in finite-sized quantum systems based on periodic orbit theory is presented. The size of the fluctuations are found to depend on quite general properties. We distinguish between…

Nuclear Theory · Physics 2011-04-11 S. Åberg , H. Olofsson , P. Leboeuf

Spatial non-locality of space-fractional viscoelastic equations of motion is studied. Relaxation effects are accounted for by replacing second-order time derivatives by lower-order fractional derivatives and their generalizations. It is…

Mathematical Physics · Physics 2015-06-03 Andrzej Hanyga , Malgorzata Seredynska

A powerful result in theoretical cosmology states that a subset of anisotropic Bianchi models can be seen as the homogeneous limit of (standard) linear cosmological perturbations. Such models are precisely those leading to Friedmann…

General Relativity and Quantum Cosmology · Physics 2025-06-03 Thiago S. Pereira , Cyril Pitrou

In this work we study the influence of isotropic and anisotropic fluids on the spherically symmetric warp metric. We evaluate the energy conditions and the influence of including a cosmological constant type term. We find that, considering…

General Relativity and Quantum Cosmology · Physics 2023-05-09 Gabriel Abellán , Nelson Bolívar , Ivaylo Vasilev

We analyze the possibility of global anisotropy of the universe. We consider an altered Friedmann Lemaitre Robertson Walker metric in which there are different scale factors along the three different axes of space. We construct the…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-06 Mark P. Hertzberg , Abraham Loeb

This paper is devoted to study the effects of electromagnetic on the collapse and expansion of anisotropic gravitating source. For this purpose, we have evaluated the generating solutions of Einstein-Maxwell field equations with spherically…

General Relativity and Quantum Cosmology · Physics 2015-06-18 G. Abbas

We evaluate the modifications to the cosmic microwave background anisotropy spectrum that result from a semiclassical expansion of the Wheeler-DeWitt equation. Recently, such an investigation in the case of a real scalar field coupled to…

General Relativity and Quantum Cosmology · Physics 2015-06-15 Donato Bini , Giampiero Esposito , Claus Kiefer , Manuel Kraemer , Francesco Pessina

In this exposition, we seek solutions of the Einstein-Maxwell field equations in the presence of a massive scalar field cast in the Brans-Dicke (BD) formalism which describes charged anisotropic strange stars. The interior spacetime is…

General Relativity and Quantum Cosmology · Physics 2020-12-08 S. K. Maurya , Ksh. Newton Singh , M. Govender , Abdelghani Errehymy

We investigate the dominant physical effects of superhorizon fluctuations in a flat FLRW universe, focusing on whether the combined evolution of scalar and tensor adiabatic modes in the near-horizon regime could lead to geometries beyond…

General Relativity and Quantum Cosmology · Physics 2025-04-02 Jorge Noreña , Thiago S. Pereira , Sean K. Reynolds

This work sets out to compute the corrections to the Euler-Heisenberg effective action that arise from spacetime-dependent background anisotropies that violate Lorentz symmetry. To accomplish our task, we evaluate the functional determinant…

High Energy Physics - Theory · Physics 2026-03-24 Wagno Cesar e Silva , João Paulo S. Melo , José A. Helayël-Neto

The entropy per particle in most Monte-Carlo simulations is size dependent due to correlated energy fluctuations. Guided by nanothermodynamics, we find a constraint for the Ising model that enhances the fluctuations and lowers the free…

Statistical Mechanics · Physics 2009-04-28 Ralph V. Chamberlin , George H. Wolf

The main aim of this study is to examine the behaviour of physical parameters of an anisotropic compact star model demonstrating spherical symmetry in F(Q) modified gravity. To evaluate the behaviour and the stability of an anisotropic…

General Relativity and Quantum Cosmology · Physics 2025-05-26 Sat Paul , Jitendra Kumar , S. K. Maurya

A number of disordered systems exhibit local anisotropy in the fractal or multifractal correlation and in the resulting scaling behavior, which contain wealth of information on the system. Here, we demonstrate that the spatial dielectric…

If one is willing to give up the cherished hypothesis of spatial isotropy, many interesting cosmological models can be developed beyond the simple anisotropically expanding scenarios. One interesting possibility is presented by shear-free…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-22 Thiago S. Pereira , Guillermo A. Mena Marugán , Saulo Carneiro

This study presents a universal relation for anisotropic neutron stars, called the $I-f-C$ relation, which accounts for the local anisotropic pressure using the Quasi-Local (QL) Model proposed by Horvat et al. \cite{QL_Model} to describe…

Nuclear Theory · Physics 2024-01-09 Sailesh Ranjan Mohanty , Sayantan Ghosh , Pinku Routaray , H. C. Das , Bharat Kumar

We introduce a simple yet powerful {\it analytic} method which obtains the structure of cosmic microwave background anisotropies to better than 5-10\% in temperature fluctuations on {\it all} scales. It is applicable to {\it any} model in…

Astrophysics · Physics 2009-07-17 Wayne Hu , Naoshi Sugiyama
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