scholarly journals Gravitational collapse and the cosmological constant

2001 ◽  
Vol 63 (12) ◽  
Author(s):  
S. S. Deshingkar ◽  
S. Jhingan ◽  
A. Chamorro ◽  
P. S. Joshi
Keyword(s):  
Cosmological Constant ◽  
Gravitational Collapse

scholarly journals Vacuum Energy Decay from a q-Bubble

Physics ◽  
2019 ◽  
Vol 1 (3) ◽  
pp. 321-338 ◽  
Author(s):  
Frans R. Klinkhamer ◽  
Osvaldo P. Santillán ◽  
Grigory E. Volovik ◽  
Albert Zhou
Keyword(s):  
Cosmological Constant ◽  
Time Evolution ◽  
Gravitational Collapse ◽  
Vacuum Energy ◽  
Finite Size ◽  
Energy Scale ◽  
Gravitational Energy ◽  
Numerical Results ◽  
Field Energy ◽  
Spherical Bubble

We consider a finite-size spherical bubble with a nonequilibrium value of the q-field, where the bubble is immersed in an infinite vacuum with the constant equilibrium value q 0 for the q-field (this q 0 has already cancelled an initial cosmological constant). Numerical results are presented for the time evolution of such a q-bubble with gravity turned off and with gravity turned on. For small enough bubbles and a q-field energy scale sufficiently below the gravitational energy scale E Planck , the vacuum energy of the q-bubble is found to disperse completely. For large enough bubbles and a finite value of E Planck , the vacuum energy of the q-bubble disperses only partially and there occurs gravitational collapse near the bubble center.

INHOMOGENEOUS DUST COLLAPSE WITH COSMOLOGICAL CONSTANT

2005 ◽  
Vol 14 (03n04) ◽  
pp. 707-715 ◽  
Author(s):  
S. G. GHOSH
Keyword(s):  
Cosmological Constant ◽  
Gravitational Collapse ◽  
Dust Cloud ◽  
Cosmic Censorship ◽  
Space Time ◽  
De Sitter ◽  
Naked Singularities ◽  
Asymptotic Flatness ◽  
Sitter Background ◽  
Strong Curvature

We investigate the occurrence of naked singularities in the gravitational collapse of an inhomogeneous dust cloud in an expanding de Sitter background — a piece of Tolman–Bondi–de Sitter space–time. It turns out that the collapse proceed in the same way as in the Minkowski background, i.e., the strong curvature naked singularities form and thus violate the cosmic censorship conjecture. Our result unambiguously support the fact that the asymptotic flatness of space–time is not a necessary ingredient for the development of naked singularities.

scholarly journals SPHERICALLY SYMMETRIC GRAVITATIONAL COLLAPSE OF A DUST CLOUD IN EINSTEIN–GAUSS–BONNET GRAVITY

2011 ◽  
Vol 26 (28) ◽  
pp. 2135-2147 ◽  
Author(s):  
KANG ZHOU ◽  
ZHAN-YING YANG ◽  
DE-CHENG ZOU ◽  
RUI-HONG YUE
Keyword(s):  
Cosmological Constant ◽  
Gravitational Collapse ◽  
Dust Cloud ◽  
Spherically Symmetric ◽  
Relativistic Case ◽  
Bonnet Gravity ◽  
Profound Influence ◽  
Dimensional Spacetime ◽  
General Relativistic ◽  
Bonnet Term

We explore the gravitational collapse of a spherically symmetric dust cloud in the Einstein–Gauss–Bonnet gravity without a cosmological constant, and obtain three families of LTB-like solutions. It is shown that the Gauss–Bonnet term has a profound influence on the nature of singularities, and the global structure of spacetime changes drastically from the analogous general relativistic case. Interestingly, the formation of a naked, massive and uncentral singularity, allowed in five-dimensional spacetime, is forbidden if D≥6. Moreover, such singularity is gravitational strong and a serious counterexample to CCH.

scholarly journals GRAVITATIONAL COLLAPSE OF MASSLESS SCALAR FIELD WITH NEGATIVE COSMOLOGICAL CONSTANT IN (2+1) DIMENSIONS

2006 ◽  
Vol 15 (04) ◽  
pp. 545-557 ◽  
Author(s):  
R. CHAN ◽  
M. F. A. DA SILVA ◽  
JAIME F. VILLAS DA ROCHA
Keyword(s):  
Black Holes ◽  
Scalar Field ◽  
Cosmological Constant ◽  
Gravitational Collapse ◽  
Massless Scalar ◽  
Massless Scalar Field ◽  
Field Equations ◽  
Negative Cosmological Constant ◽  
Global Properties ◽  
Scalar Field Equations

The (2+1)-dimensional geodesic circularly symmetric solutions of Einstein-massless-scalar field equations with negative cosmological constant are found and their local and global properties are studied. It is found that one of them represents gravitational collapse where black holes are always formed.

Gravitational collapse with a cosmological constant

1991 ◽  
Vol 23 (4) ◽  
pp. 471-475 ◽  
Author(s):  
David Garfinkle ◽  
Chris Vuille
Keyword(s):  
Cosmological Constant ◽  
Gravitational Collapse

scholarly journals EFFECTS OF ELECTROMAGNETIC FIELD ON GRAVITATIONAL COLLAPSE

2009 ◽  
Vol 24 (31) ◽  
pp. 2551-2563 ◽  
Author(s):  
M. SHARIF ◽  
G. ABBAS
Keyword(s):  
Electromagnetic Field ◽  
Cosmological Constant ◽  
Perfect Fluid ◽  
Gravitational Collapse ◽  
Physical Significance ◽  
Spherically Symmetric ◽  
Junction Conditions ◽  
Positive Cosmological Constant ◽  
Symmetric Spacetimes ◽  
Apparent Horizons

In this paper, the effect of electromagnetic field has been investigated on the spherically symmetric gravitational collapse with the perfect fluid in the presence of positive cosmological constant. Junction conditions between the static exterior and non-static interior spherically symmetric spacetimes are discussed. We study the apparent horizons and their physical significance. It is found that electromagnetic field reduces the bound of cosmological constant by reducing the pressure and hence collapsing process is faster as compared to the perfect fluid case. This work gives the generalization of the perfect fluid case to the charged perfect fluid. Results for the perfect fluid case are recovered.

scholarly journals Gravitational collapse with a cosmological constant

2000 ◽  
Vol 61 (8) ◽  
Author(s):  
Dragoljub Markovic ◽  
Stuart L. Shapiro
Keyword(s):  
Cosmological Constant ◽  
Gravitational Collapse
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