Scalar field collapse with an exponential potential

Chakrabarti, Soumya

doi:10.1007/s10714-017-2186-y

Cited by 8 publications

(4 citation statements)

References 70 publications

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“…For example, the seminal work of Christodoulou [39] showed that a naked singularity can occur in the spherical collapse of a scalar field, while Choptuik [40] developed a numerical study for a massless scalar field considering a family of solutions with the property that a critical parameter, p * , indicates the formation of black holes. Since then several works studied the critical behavior and the properties of the gravitational collapse of scalar fields [41][42][43][44][45][46][47][48].…”

Section: Generalized Brans-dicke Theoriesmentioning

confidence: 99%

Spacetime singularities in generalized Brans-Dicke theories

2018

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We study the formation of classical singularities in Generalized Brans-Dicke theories that are natural extensions to Brans-Dicke where the kinetic term is modified by a new coupling function ω(ϕ). We discuss the asymptotic limit ω(ϕ) → ∞ and show that the system generically does not approach General Relativity. Given the arbitrariness of ω(ϕ), one can search for coupling functions chosen specifically to avoid classical singularities. However, we prove that this is not the case. Homogeneous and spherically symmetric collapsing objects form singularities for arbitrary coupling functions. On the other hand, expanding cosmological scenarios are completely free of Big Rip type singularities. In an expanding universe, the scalar field behaves at most as stiff matter, which makes these cosmological solutions asymptotically approach General Relativity.

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Section: Generalized Brans-dicke Theoriesmentioning

confidence: 99%

Spacetime singularities in generalized Brans-Dicke theories

2018

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“…The possibilities of end product of a scalar field collapse, whether a naked singularity or a black hole, has also been explored in [6]. The variants of scalar field collapse and its consequences are demonstrated in [7,8,9,10,11,12,13,14,15,16,17] (see also [18,19,20,21,22,23]).…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic effect on scalar field collapse in higher curvature gravity

Banerjee

Paul

2019

Gen Relativ Gravit

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We consider a "Scalar-Maxwell-Einstein-Gauss-Bonnet" theory in four dimension, where the scalar field couples non-minimally with the Gauss-Bonnet (GB) term. This coupling with the scalar field ensures the non topological character of the GB term. In such higher curvature scenario, we explore the effect of electromagnetic field on scalar field collapse. Our results reveal that the presence of a time dependent electromagnetic field requires an anisotropy in the background spacetime geometry and such anisotropic spacetime allows a collapsing solution for the scalar field. The singularity formed as a result of the collapse is found to be a curvature singularity which may be point like or line like depending on the strength of the anisotropy. We also show that the singularity is always hidden from exterior by an apparent horizon. *

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“…One can also reduce the scalar field cosmology equations to a known type of equation whose solution has already been developed. In [29,32] we can see a method in which the Klein-Gordon equation which describes the dynamics of the scalar field is transformed to a first order non-linear differential equation. This equation immediately leads to the identification of some exact classes of scalar field potentials V (φ) for which the field equations can be solved exactly and there by obtaining analytical expressions for a(t), φ(t) and q(t) .…”

Section: Introductionmentioning

confidence: 99%

Exact Solutions and Constraints on the Dark Energy Model in FRW Universe

Joseph,

Saha

2019

Preprint

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The inflationary epoch and the late time acceleration of the expansion rate of universe can be explained by assuming a gravitationally coupled scalar field. In this article, we propose a new method of finding exact solutions in the background of flat Friedmann-Robertson-Walker (FRW) cosmological models by considering both scalar field and matter. We consider different forms of scalar field potential as a function of scale factor. Our method provides analytical expressions for equation of state parameter of scalar field, deceleration parameter and Hubble parameter. This method can be applied to various other forms of scalar field potential, to the early radiation dominated epoch and very early scalar field dominated inflationary dynamics. Since the method produces exact analytical expression for H(a) (i.e., H(z) as well) one can use this result to constrain the model parameters using Hubble parameter data at different redshifts. As an extension of the method, we also consider the inverse problem of reconstructing scalar field potential energy by assuming any general analytical expression of scalar field equation of state parameter as a function of scale factor.

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Scalar field collapse with an exponential potential

Cited by 8 publications

References 70 publications

Spacetime singularities in generalized Brans-Dicke theories

Spacetime singularities in generalized Brans-Dicke theories

Electromagnetic effect on scalar field collapse in higher curvature gravity

Exact Solutions and Constraints on the Dark Energy Model in FRW Universe

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