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In the present paper an attempt has been made to study the flat fractal Friedmann - Robertson - Walker model filled with domain walls. We have obtained the fractal equation of deceleration parameter and tension of the domain wall. It is…

General Relativity and Quantum Cosmology · Physics 2020-06-23 D. D. Pawar , D. K. Raut , W. D. Patil

First order phase transitions in the early universe may have left a variety of experimentally accessible imprints. The dynamics of such transitions is governed by the density perturbations caused by the propagation of the bubble wall in the…

High Energy Physics - Phenomenology · Physics 2024-10-02 Carlo Branchina , Angela Conaci , Stefania De Curtis , Luigi Delle Rose , Andrea Guiggiani , Angel Gil Muyor , Giuliano Panico

A generalized dynamical equation for the scale factor of the universe is proposed to describe the cosmological evolution, of which the $\Lambda$CDM model is a special case. It also provides a general example to show the equivalence of the…

Astrophysics · Physics 2009-11-11 J. Ren , X. H. Meng

We investigated domain wall networks as a possible candidate to explain the present accelerated expansion of the universe. We discuss various requirements that any stable lattice of frustrated walls must obey and propose a class of `ideal'…

High Energy Physics - Phenomenology · Physics 2008-08-26 J. Menezes

In this paper we develop a common theoretical framework for the dynamics of thin featureless interfaces. We explicitly demonstrate that the same phase field and velocity dependent one-scale models characterizing the dynamics of relativistic…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 P. P. Avelino , R. Menezes , J. C. R. E. Oliveira

We study the Friedmann-Robertson-Walker model with dynamical dark energy modelled in terms of the equation of state $p_{x}=w_{x}(a(z)) \rho_{x}$ in which the coefficient $w_{x}$ is parameterized by the scale factor $a$ or redshift $z$. We…

General Relativity and Quantum Cosmology · Physics 2007-06-14 Marek Szydlowski , Orest Hrycyna

We solve the equations of motion for a scalar field with domain wall boundary conditions in a Friedmann-Robertson-Walker (FRW) spacetime. We find (in agreement with Basu and Vilenkin) that no domain wall solutions exist in de Sitter…

High Energy Physics - Phenomenology · Physics 2011-07-19 D. Boyanovsky , David E. Brahm , A. Gonzalez-Ruiz , R. Holman , F. I. Takakura

We show that space-time evolution of one-dimensional fermionic systems is described by nonlinear equations of soliton theory. We identify a space-time dependence of a matrix element of fermionic systems related to the {\it Orthogonality…

Exactly Solvable and Integrable Systems · Physics 2007-05-23 Eldad Bettelheim , Alexander G. Abanov , Paul Wiegmann

The canonical velocity-dependent one-scale (VOS) model for cosmic string evolution must be calibrated using high resolution numerical simulations, We exploit our state of the art graphics processing unit accelerated implementation of the…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-22 J. R. C. C. C. Correia , C. J. A. P. Martins

Domain wall networks have attracted renewed interest, particularly in relation to the dynamics of network collapse. Accurately describing this process is challenging and typically requires large scale numerical simulations. Here we adopt a…

We use the velocity-dependent one-scale model by Martins & Shellard to investigate the evolution of a GUT long cosmic string network in arbitrary Friedmann-Lemaitre models. Four representative models are used to show that in general there…

Astrophysics · Physics 2009-10-30 Carsten van de Bruck

Process of formation of the universe with its further expansion in the first evolution stage is investigated in the framework of Friedmann-Robertson-Walker metrics on the basis of quantum model, where a new type of matter is introduced,…

General Relativity and Quantum Cosmology · Physics 2013-01-17 Sergei P. Maydanyuk

We consider a model with two real scalar fields which admits phantom domain wall solutions. We investigate the structure and evolution of these phantom domain walls in an expanding homogeneous and isotropic universe. In particular, we show…

General Relativity and Quantum Cosmology · Physics 2017-08-16 P. P. Avelino , V. M. C. Ferreira , J. Menezes , L. Sousa

We discuss the evolution of linear perturbations about a Friedmann-Robertson-Walker background metric, using only the local conservation of energy-momentum. We show that on sufficiently large scales the curvature perturbation on spatial…

Astrophysics · Physics 2009-10-31 David Wands , Karim A. Malik , David H. Lyth , Andrew R. Liddle

A range of cosmological observations demonstrate an accelerated expansion of the Universe, and the most likely explanation of this phenomenon is a cosmological constant. Given the importance of understanding the underlying physics, it is…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-07 Karoline Loeve , Kristine Simone Nielsen , Steen H. Hansen

The motion of domain walls in ferromagnetic, cylindrical nanowires is investigated numerically by solving the Landau-Lifshitz-Gilbert equation for a classical spin model in which energy contributions from exchange, crystalline anisotropy,…

Condensed Matter · Physics 2009-11-10 R. Wieser , U. Nowak , K. D. Usadel

In this work, we use the dynamical system approach to explore the cosmological background evolution of the scalar-tensor representation of $f(R,T)$ gravity, where $R$ is the Ricci scalar and $T$ is the trace of the stress-energy tensor. The…

General Relativity and Quantum Cosmology · Physics 2024-04-04 Tiago B. Gonçalves , João Luís Rosa , Francisco S. N. Lobo

We show how to define a consistent braneworld cosmology in a model in which the brane is constructed as a field-theoretic domain wall of finite thickness. The Friedmann, Robertson-Walker metric is recovered in the region of the brane, but,…

High Energy Physics - Phenomenology · Physics 2009-02-18 Damien P. George , Mark Trodden , Raymond R. Volkas

We present a unified description of first-order cosmological phase transition dynamics that links the phenomenological friction model employed in hydrodynamic simulations to the microscopic treatment based on Boltzmann equations. We derive…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-26 Tomasz Krajewski , Marek Lewicki , Marco Merchand , Ignacy Nałęcz , Mateusz Zych

Along with experiments, numerical simulations are key to gaining insight into the underlying mechanisms governing domain wall motion in thin ferromagnetic systems. However, a direct comparison between numerical simulation of model systems…

Disordered Systems and Neural Networks · Physics 2021-04-08 Pamela C. Guruciaga , Nirvana Caballero , Vincent Jeudy , Javier Curiale , Sebastian Bustingorry