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相关论文: Comparing parametric and non-parametric velocity-d…

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We carry out a suite of cosmological simulations of modified action f(R) models where cosmic acceleration arises from an alteration of gravity instead of dark energy. These models introduce an extra scalar degree of freedom which enhances…

天体物理学 · 物理学 2008-12-30 Hiroaki Oyaizu , Marcos Lima , Wayne Hu

Domain walls form at phase transitions which break discrete symmetries. In a cosmological context they often overclose the universe (contrary to observational evidence), although one may prevent this by introducing biases or forcing…

宇宙学与河外天体物理 · 物理学 2018-05-28 J. R. C. C. C. Correia , I. S. C. R. Leite , C. J. A. P. Martins

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…

宇宙学与河外天体物理 · 物理学 2015-05-19 P. P. Avelino , R. Menezes , J. C. R. E. Oliveira

We use the Velocity-dependent One Scale Model for topological defect evolution to explore and classify the possible scaling solutions for string networks with time-varying tension, in cosmological and non-cosmological settings and under two…

高能物理 - 唯象学 · 物理学 2026-02-24 C. S. C. M. Coelho , A. -L. Y. Gschrey , C. J. A. P. Martins

A parametric reconstruction of the jerk parameter, the third order derivative of the scale factor expressed in a dimensionless way, has been discussed. Observational constraints on the model parameters have been obtained by Maximum…

广义相对论与量子宇宙学 · 物理学 2016-03-23 Ankan Mukherjee , Narayan Banerjee

We investigate observational constraints on cosmological parameters combining 15 measurements of the transversal BAO scale (obtained free of any fiducial cosmology) with Planck-CMB data to explore the parametric space of some cosmological…

宇宙学与河外天体物理 · 物理学 2020-08-10 Rafael C. Nunes , Santosh K. Yadav , J. F. Jesus , Armando Bernui

We have studied a cosmological model with a cosmological term of the form $\Lambda=3\alpha\fr{\dot R^2}{R^2}+\bt\fr{\ddot R}{R}+\fr{3\gamma}{R^2} \alpha, \ \bt \gamma$ are constants. The scale factor (R) is found to vary linearly with time…

广义相对论与量子宇宙学 · 物理学 2007-05-23 Arbab I. Arbab

A quantum expansion parameter, analogous to the Hubble parameter in cosmology, is defined for a free particle quantum wavefunction. By considering the universe as an initial single Gaussian quantum wavepacket whose mass is that of…

宇宙学与河外天体物理 · 物理学 2012-02-28 A. D. Ernest

We investigate a dark energy model driven by a planar domain-wall-like structure with a thickness comparable to, or larger than, the current Hubble radius, focusing on its intrinsic anisotropy and observational viability. Near the centre of…

宇宙学与河外天体物理 · 物理学 2026-05-20 Nobufusa Kobayashi , Yuichiro Tada , Fuminobu Takahashi , Takahiro Terada

Evolution of cosmic domain walls (DWs) settles to the scaling solution, which is often assumed to be independent of initial conditions. However, lattice simulations performed in this work reveal a clear dependence of the scaling DW area on…

高能物理 - 唯象学 · 物理学 2025-12-11 I. Dankovsky , S. Ramazanov , E. Babichev , D. Gorbunov , A. Vikman

We develop an analytic model to quantitatively describe the evolution of superconducting cosmic string networks. Specifically, we extend the velocity-dependent one-scale (VOS) model to incorporate arbitrary currents and charges on cosmic…

宇宙学与河外天体物理 · 物理学 2021-03-03 C. J. A. P. Martins , Patrick Peter , I. Yu. Rybak , E. P. S. Shellard

We investigate the dynamics of the generalized $\Lambda$CDM model, which the $\Lambda$ term is running with the cosmological time. The $\Lambda(t)$ term emerges from the covariant theory of the scalar field $\phi$ with the self-interacting…

宇宙学与河外天体物理 · 物理学 2017-09-29 Marek Szydlowski , Aleksander Stachowski

Averaging and evolving inhomogeneities are non-commuting operations. This implies the existence of deviations of an averaged model from the standard Friedmann-Lemaitre cosmologies. We quantify these deviations, encoded in a backreaction…

天体物理学 · 物理学 2013-03-26 Thomas Buchert , Martin Kerscher , Christian Sicka

We present the idea that replacing the cosmological constant $\Lambda$ in the $\Lambda$CDM model by a distribution of walls, with very low tension compared to what one would expect from new physics, could help explaining the tension in the…

宇宙学与河外天体物理 · 物理学 2024-06-13 Colin D. Froggatt , Holger Bech Nielsen

A type of exponential correction to General Relativity gives viable modified gravity model of dark energy. The model behaves as $R-2\Lambda$ at large curvature where an effective cosmological constant appears, but it becomes zero in flat…

广义相对论与量子宇宙学 · 物理学 2022-01-13 L. N. Granda

We extend the evolution mapping approach, originally proposed by Sanchez (2022) to describe non-linear matter density fluctuations, to statistics of the cosmic velocity field. This framework classifies cosmological parameters into shape…

宇宙学与河外天体物理 · 物理学 2024-10-15 Matteo Esposito , Ariel G. Sánchez , Julien Bel , Andrés N. Ruiz

We investigate the roles of the relativistic effect on the speed of evolution of a quantum system coupled with amplitude damping channels. We find that the relativistic effect speed-up the quantum evolution to a uniform evolution speed of…

量子物理 · 物理学 2024-01-30 N. A. Khan , M. Jan

The influence of considering a generalized dark matter (GDM) model, which allows for a non-pressure-less dark matter and a non-vanishing sound speed in the non-linear spherical collapse model is discussed for the Einstein-de Sitter-like…

宇宙学与河外天体物理 · 物理学 2020-08-26 F. Pace , Z. Sakr , I. Tutusaus

We investigate the time evolution of bias of cosmic density fields. We perform numerical simulations of the evolution of the cosmic web for the conventional $\Lambda$ cold dark matter ($\Lambda$CDM) model. The simulations cover a wide range…

宇宙学与河外天体物理 · 物理学 2022-12-07 J. Einasto , L. J. Liivamägi , M. Einasto

There are several studies proposing phenomenological consequences of a deformation of special and general relativity. Here, we cast novel constraints on the deformation parameter of a metric in the cotangent bundle accounting for a curved…

广义相对论与量子宇宙学 · 物理学 2020-11-18 J. J. Relancio , S. Liberati