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We study the cosmological evolution of the field equations in the context of Einstein-Aether cosmology by including a scalar field in a spatially flat Friedmann--Lema\^{\i}tre--Robertson--Walker spacetime. Our analysis is separated into two…

General Relativity and Quantum Cosmology · Physics 2020-01-17 Andronikos Paliathanasis , G. Papagiannopoulos , Spyros Basilakos , John D. Barrow

Differentiable models of physical systems provide a powerful platform for gradient-based algorithms, with particular impact on parameter estimation and optimal control. Quantum systems present a particular challenge for such…

Quantum Physics · Physics 2025-09-09 David L. Craig , Natalia Ares , Erik M. Gauger

Computational advances have fundamentally transformed the landscape of numerical simulations, enabling unprecedented levels of complexity and precision in modeling physical phenomena. While these high-fidelity simulations offer invaluable…

Fluid Dynamics · Physics 2025-09-09 Shinhoo Kang , Emil M. Constantinescu

(Abridged) Despite the success of Cold Dark Matter (CDM) in explaining a wide range of observations, the microscopic nature of dark matter is still unknown. Attempts to detect WIMPs, the most commonly studied form, have not yet succeeded.…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-31 Bohua Li , Tanja Rindler-Daller , Paul R. Shapiro

Differential geometry (DG) based solvation models are a new class of variational implicit solvent approaches that are able to avoid unphysical solvent-solute boundary definitions and associated geometric singularities, and dynamically…

Numerical Analysis · Mathematics 2015-10-28 Bao Wang , Guowei Wei

From a phenomenological point of view, we analyze the dynamics of the Universe at late times by introducing a polynomial and hyperbolic bulk viscosity into the Einstein field equations respectively. We constrain their free parameters using…

General Physics · Physics 2019-10-01 A. Hernández-Almada

A linear relationship between the Hubble expansion parameter and the time derivative of the scalar field is explored in order to derive exact cosmological, attractor-like solutions, both in Einstein's theory and in Brans-Dicke gravity with…

General Relativity and Quantum Cosmology · Physics 2010-10-27 Olga Arias , Tame Gonzalez , Yoelsy Leyva , Israel Quiros

As an alternative to dark energy it has been suggested that we may be at the center of an inhomogeneous isotropic universe described by a Lemaitre-Tolman-Bondi (LTB) solution of Einstein's field equations. In order to test such an…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Antonio Enea Romano

Presented cosmological model is 3D brane world sheet moved in extra dimension with variable scale factor. Analysis of the geodesic motion of the test particle gives settle explanation of the Pioneer effect. It is found that for considered…

General Relativity and Quantum Cosmology · Physics 2007-05-23 W. B. Belayev

We present a quantum solver for partial differential equations based on a flexible matrix product operator representation. Utilizing mid-circuit measurements and a state-dependent norm correction, this scheme overcomes the restriction of…

Quantum Physics · Physics 2026-04-22 Pia Siegl , Greta Sophie Reese , Tomohiro Hashizume , Nis-Luca van Hülst , Dieter Jaksch

We study the most general cosmological model with real scalar field which is minimally coupled to gravity. Our calculations are based on Friedmann-Lemaitre-Robertson-Walker (FLRW) background metric. Field equations consist of three…

General Relativity and Quantum Cosmology · Physics 2023-03-22 Medine Ildes , Metin Arik

We present a relativistic model describing a thin disk surrounded by a halo in presence of an electromagnetic field. The model is obtained by solving the Einstein-Maxwell equations on a particular conformastatic spacetime background and by…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Antonio C. Gutiérrez-Piñeres , Guillermo A. González , Hernando Quevedo

The stochastic Allen-Cahn equation with multiplicative noise involves the nonlinear drift operator ${\mathscr A}(x) = \Delta x - \bigl(\vert x\vert^2 -1\bigr)x$. We use the fact that ${\mathscr A}(x) = -{\mathcal J}^{\prime}(x)$ satisfies a…

Analysis of PDEs · Mathematics 2017-08-11 Ananta K. Majee , Andreas Prohl

We develop a comprehensive framework in which the existence of solutions to the semiclassical Einstein equation (SCE) in cosmological spacetimes is shown. Different from previous work on this subject, we do not restrict to the conformally…

Mathematical Physics · Physics 2021-12-01 Hanno Gottschalk , Daniel Siemssen

This research addresses the numerical simulation of the Boltzmann transport equation for semiconductor devices by proposing a multidimensional self-adaptive numerical simulation framework. This framework is applied to two important…

Numerical Analysis · Mathematics 2025-09-22 Zeyu Zhang , Xiaoyu Zhang , Zhigang Song , Qing Fang

We construct an approximate solution to the cosmological perturbation theory around Einstein-de Sitter background up to the fourth-order perturbations. This could be done with the help of the specific symmetry condition imposed on the…

General Relativity and Quantum Cosmology · Physics 2021-03-17 Szymon Sikora , Krzysztof Głód

We address the problem of predicting the next state of a dynamical system governed by unknown temporal partial differential equations (PDEs) using only a short trajectory. While standard transformers provide a natural black-box solution to…

Machine Learning · Computer Science 2025-04-29 Rudy Morel , Jiequn Han , Edouard Oyallon

Physical systems are governed by partial differential equations (PDEs). The Navier-Stokes equations describe fluid flows and are representative of nonlinear physical systems with complex spatio-temporal interactions. Fluid flows are…

Fluid Dynamics · Physics 2022-10-05 Deniz A. Bezgin , Aaron B. Buhendwa , Nikolaus A. Adams

Our paper introduces a new theoretical framework called the Fractional Einstein--Gauss--Bonnet scalar field cosmology, which has important physical implications. Using fractional calculus to modify the gravitational action integral, we…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-12 Bayron Micolta-Riascos , Alfredo D. Millano , Genly Leon , Byron Droguett , Esteban González , Juan Magaña

Contents: 1) Introduction and a few excursions [A word on the role of explicit solutions in other parts of physics and astrophysics. Einstein's field equations. "Just so" notes on the simplest solutions: The Minkowski, de Sitter and anti-de…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Jiri Bicak