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Friedmann–Lemaître–Robertson–Walker metric

About: Friedmann–Lemaître–Robertson–Walker metric is a research topic. Over the lifetime, 4113 publications have been published within this topic receiving 87752 citations. The topic is also known as: FLRW metric.


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Journal ArticleDOI
TL;DR: In this article, exact solutions of the Dirac equation in open and closed Robertson-Walker spaces are presented, and a set of massive solutions for static metrics is given for the case of nontrivial and arbitrary expansion factors.
Abstract: Exact solutions of the Dirac equation in open and closed Robertson–Walker spaces are presented. A set of massive solutions is given for static metrics. In the case of nontrivial and arbitrary expansion factors, massless solutions are obtained via a conformal transformation. The set of massless solutions in open Robertson–Walker spaces is shown to be complete.

29 citations

Journal ArticleDOI
Li-Ming Cao1
TL;DR: In this article, the deformation equation of a spacelike submanifold with an arbitrary codimension is given by a general construction without using local frames, and the thermodynamics of trapping horizons is related to these deformation equations in two different formalisms: with and without introducing quasilocal energy.
Abstract: The deformation equation of a spacelike submanifold with an arbitrary codimension is given by a general construction without using local frames. In the case of codimension-1, this equation reduces to the evolution equation of the extrinsic curvature of a spacelike hypersurface. In the more interesting case of codimension-2, after selecting a local null frame, this deformation equation reduces to the well known (cross) focusing equations. We show how the thermodynamics of trapping horizons is related to these deformation equations in two different formalisms: with and without introducing quasilocal energy. In the formalism with the quasilocal energy, the Hawking mass in four dimension is generalized to higher dimension, and it is found that the deformation of this energy inside a marginal surface can be also decomposed into the contributions from matter fields and gravitational radiation as in the four dimension. In the formalism without the quasilocal energy, we generalize the definition of slowly evolving future outer trapping horizons proposed by Booth to past trapping horizons. The dynamics of the trapping horizons in FLRW universe is given as an example. Especially, the slowly evolving past trapping horizon in the FLRW universe has close relation to the scenario of slow-roll inflation. Up to the second order of the slowly evolving parameter in this generalization, the temperature (surface gravity) associated with the slowly evolving trapping horizon in the FLRW universe is essentially the same as the one defined by using the quasilocal energy.

29 citations

Journal ArticleDOI
TL;DR: In this paper, a non-flat geometry is considered which contains the interacting generalized ghost pilgrim dark energy with cold dark matter, and some well-known cosmological parameters (evolution parameter, squared speed of sound, planes and statefinder) are constructed in this scenario.
Abstract: This work is based on pilgrim dark energy conjecture which states that phantom-like dark energy possesses the enough resistive force to preclude the formation of black hole. The non-flat geometry is considered which contains the interacting generalized ghost pilgrim dark energy with cold dark matter. Some well-known cosmological parameters (evolution parameter ($\omega_{\Lambda}$) and squared speed of sound) and planes ($\omega_{\Lambda}$-$\omega_{\Lambda}'$ and statefinder) are constructed in this scenario. The discussion of these parameters is totally done through pilgrim dark energy parameter ($u$) and interacting parameter ($d^2$). It is interesting to mention here that the analysis of evolution parameter supports the conjecture of pilgrim dark energy. Also, this model remains stable against small perturbation in most of the cases of $u$ and $d^2$. Further, the cosmological planes correspond to $\Lambda$CDM limit as well as different well-known dark energy models.

29 citations

Journal ArticleDOI
TL;DR: In this paper, a previously unexplored branch of homogeneous and isotropic background solutions in ghost-free massive bigravity with consistent double-matter coupling was studied, and self-inflated FLRW cosmologies with an accelerated early-time period during the radiation-dominated era were found.
Abstract: We study a previously largely unexplored branch of homogeneous and isotropic background solutions in ghost-free massive bigravity with consistent double matter coupling. For a certain family of parameters we find `self-inflated' FLRW cosmologies, i.e. solutions with an accelerated early-time period during the radiation-dominated era. In addition, these solutions also display an accelerated late-time period closely mimicking GR with a cosmological constant. Interestingly, within this family, the particular case of $\beta_1=\beta_3=0$ gives bouncing cosmologies, where there is an infinite contracting past, a non-zero minimum value of the scale factor at the bounce, and an infinite expanding future.

29 citations

Journal ArticleDOI
TL;DR: In this article, the distance redshift for partially filled-beam optics in pressure-free Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) cosmology is shown to be the Lam\'e equation.
Abstract: The differential equation governing the distance redshift for partially filled-beam optics in pressure-free Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) cosmology is shown to be the Lam\'e equation. The distance redshift $D(z)$ discussed is appropriate for observations in inhomogeneous cosmologies for which lensing by masses external to the observing beam is negligible and for which lensing by transparent matter within the beam can be approximated by a homogeneous mass density expanding with the FLRW background. Some solutions of the derived Lam\'e equation are given in terms of Weierstrass elliptic integrals. A new simplified and useful expression for filled-beam $D(z)$ in standard flat FLRW is also given.

29 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023150
2022352
2021196
2020204
2019214
2018191