Geometry of conformally symmetric generalized Vaidya spacetimes

Hansraj, Chevarra; Goswami, Rituparno; Maharaj, S. D.

doi:10.1142/s0219887823501153

Cited by 7 publications

(2 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently the aforementioned formalisms have provided further insight into tidal forces and gravitational waves [50], the CMB [51] and the behaviour of f (R) gravity [52]. They have further found application in specific spacetimes of physical interest including a general spacetime admitting conformal symmetry [53], Vaidya spacetime [54], LRS spacetimes [55,56] and the Kerr spacetime [57] involving higher order terms. Spacetime decomposition has briefly been investigated in higher dimensions [58,59].…”

Section: Covariant Spacetime Decompositionmentioning

confidence: 99%

The mass gap in five dimensional Einstein–Gauss–Bonnet black holes: a geometrical explanation

Hansraj,

Goswami,

Maharaj

2024

Class. Quantum Grav.

Self Cite

View full text Add to dashboard Cite

It is well known that, unlike in higher dimensional general relativity (GR), we cannot have a black hole with an arbitrarily small mass in five dimensional Einstein–Gauss–Bonnet gravity. When we study the dynamical black hole formation via the radiation collapse in the radiating Boulware–Deser spacetime in five dimensions, the central zero mass singularity is weak, conical and naked, and the horizon forms only when a finite amount of matter, that depends on the coupling constant of the Gauss–Bonnet term, falls into the central singularity. To understand this phenomenon transparently and geometrically, we study the radiating Boulware–Deser spacetime in five dimensions using a 1+1+3 spacetime decomposition, for the first time. We find that the geometric and thermodynamic quantities can be expressed in terms of the gravitational mass and the Gauss–Bonnet (GB) parameter and separate each of them into their Gauss–Bonnet and matter parts. Drawing comparisons with five dimensional GR at every step, we explicitly show how the mass gap arises for a general mass function M(v) and what functions for M(v) make certain geometrical quantities well defined at the central singularity. We show in the case of self-similar radiation collapse in the modified theory, the central singularity is not a sink for timelike geodesics and is extendable. This clearly demonstrates how the GB invariant affects the nature of the final state of a continual collapse in this modified theory.

show abstract

Section: Covariant Spacetime Decompositionmentioning

confidence: 99%

The mass gap in five dimensional Einstein–Gauss–Bonnet black holes: a geometrical explanation

Hansraj,

Goswami,

Maharaj

2024

Class. Quantum Grav.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Hence all the physics and geometry of the spacetime are described by well defined kinematic and dynamic scalar variables that generate the field equations. The 1+1+2 covariant method has generated new results in studies involving LRS spacetimes [31], the Kerr spacetime [32], the Vaidya spacetime [33] and a general spacetime admitting conformal symmetry [34].…”

Section: +1+formalismmentioning

confidence: 99%

What makes a shear-free spherical perfect fluid be inhomogeneous with tidal effects?

Hakata

Goswami

Hansraj

et al. 2023

Preprint

View full text Add to dashboard Cite

This is an important and natural question as the spacetime shear, inhomogeneity and tidal effects are all intertwined via the Einstein field equations. Though many solutions with these properties exist in the literature, in this paper we identify, via a geometrical analysis, the important physical reason behind these solutions. We show that such scenarios are possible for limited classes of equations of state that are solutions to a highly nonlinear and fourth order differential equation. To show this, we use a covariant semitetrad spacetime decomposition and present a novel geometrical classification of shear-free Locally Rotationally Symmetric (LRS-II) perfect fluid self-gravitating systems, in terms of the covariantly defined fluid acceleration and the fluid expansion. Noteworthily, we deduce the governing differential equation that gives the possible limited equations of state of matter.

show abstract

What makes a shear-free spherical perfect fluid be inhomogeneous with tidal effects?

Hakata,

Goswami,

Hansraj

et al. 2023

Gen Relativ Gravit

View full text Add to dashboard Cite

This is an important and natural question as the spacetime shear, inhomogeneity and tidal effects are all intertwined via the Einstein field equations. Though many solutions with these properties exist in the literature, in this paper we identify, via a geometrical analysis, the important physical reason behind these solutions. We show that such scenarios are possible for limited classes of equations of state that are solutions to a highly nonlinear and fourth order differential equation. To show this, we use a covariant semitetrad spacetime decomposition and present a novel geometrical classification of shear-free locally rotationally symmetric perfect fluid self-gravitating systems, in terms of the covariantly defined fluid acceleration and the fluid expansion. Noteworthily, we deduce the governing differential equation that gives the possible limited equations of state of matter.

show abstract

Geometry of conformally symmetric generalized Vaidya spacetimes

Cited by 7 publications

References 46 publications

The mass gap in five dimensional Einstein–Gauss–Bonnet black holes: a geometrical explanation

The mass gap in five dimensional Einstein–Gauss–Bonnet black holes: a geometrical explanation

What makes a shear-free spherical perfect fluid be inhomogeneous with tidal effects?

What makes a shear-free spherical perfect fluid be inhomogeneous with tidal effects?

Contact Info

Product

Resources

About