scholarly journals Closed Trapped Surfaces in Cosmology

2003 ◽  
Vol 35 (8) ◽  
pp. 1309-1319 ◽  
Author(s):  
George F. R. Ellis
Keyword(s):  
Trapped Surfaces

scholarly journals Nonlinear dynamics of flux compactification

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Maxence Corman ◽  
William E. East ◽  
Matthew C. Johnson
Keyword(s):  
Flux Compactifications ◽  
Nonlinear Evolution ◽  
Einstein Equations ◽  
Accelerated Expansion ◽  
Positive Cosmological Constant ◽  
Flux Compactification ◽  
Trapped Surfaces ◽  
Slow Roll ◽  
Form Field ◽  
Lower Dimensional

Abstract We study the nonlinear evolution of unstable flux compactifications, applying numerical relativity techniques to solve the Einstein equations in D dimensions coupled to a q-form field and positive cosmological constant. We show that initially homogeneous flux compactifications are unstable to dynamically forming warped compactifications. In some cases, we find that the warping process can serve as a toy-model of slow-roll inflation, while in other instances, we find solutions that eventually evolve to a singular state. Analogous to dynamical black hole horizons, we use the geometric properties of marginally trapped surfaces to characterize the lower dimensional vacua in the inhomogeneous and dynamical settings we consider. We find that lower-dimensional vacua with a lower expansion rate are dynamically favoured, and in some cases find spacetimes that undergo a period of accelerated expansion followed by contraction.

Black Holes and Trapped Surfaces

2010 ◽  
Author(s):  
José M. M. Senovilla ◽  
Alfredo Macias ◽  
Marco Maceda
Keyword(s):  
Black Holes ◽  
Trapped Surfaces

DOES PRESSURE ACCENTUATE GENERAL RELATIVISTIC GRAVITATIONAL COLLAPSE AND FORMATION OF TRAPPED SURFACES?

2013 ◽  
Vol 22 (05) ◽  
pp. 1350021 ◽  
Author(s):  
ABHAS MITRA
Keyword(s):  
General Relativity ◽  
Gravitational Collapse ◽  
Fluid Pressure ◽  
Free Fall ◽  
Newtonian Gravity ◽  
Tangential Pressure ◽  
Trapped Surfaces ◽  
Imperfect Fluid ◽  
Newtonian Case ◽  
General Relativistic

It is widely believed that though pressure resists gravitational collapse in Newtonian gravity, it aids the same in general relativity (GR) so that GR collapse should eventually be similar to the monotonous free fall case. But we show that, even in the context of radiationless adiabatic collapse of a perfect fluid, pressure tends to resist GR collapse in a manner which is more pronounced than the corresponding Newtonian case and formation of trapped surfaces is inhibited. In fact there are many works which show such collapse to rebound or become oscillatory implying a tug of war between attractive gravity and repulsive pressure gradient. Furthermore, for an imperfect fluid, the resistive effect of pressure could be significant due to likely dramatic increase of tangential pressure beyond the "photon sphere." Indeed, with inclusion of tangential pressure, in principle, there can be static objects with surface gravitational redshift z → ∞. Therefore, pressure can certainly oppose gravitational contraction in GR in a significant manner in contradiction to the idea of Roger Penrose that GR continued collapse must be unstoppable.

Outer trapped surfaces and their apparent horizon

1997 ◽  
Vol 38 (3) ◽  
pp. 1593-1604 ◽  
Author(s):  
Marcus Kriele ◽  
Sean A. Hayward
Keyword(s):  
Apparent Horizon ◽  
Trapped Surfaces

A condition for forming trapped surfaces

1988 ◽  
Vol 5 (7) ◽  
pp. 1029-1032 ◽  
Author(s):  
C J S Clarke
Keyword(s):  
Trapped Surfaces
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