scholarly journals Transversely trapping surfaces: Dynamical version

2020 ◽  
Vol 2020 (2) ◽  
Author(s):  
Hirotaka Yoshino ◽  
Keisuke Izumi ◽  
Tetsuya Shiromizu ◽  
Yoshimune Tomikawa
Keyword(s):  
Initial Data ◽  
Spacelike Hypersurface ◽  
Closed Surface ◽  
Spherically Symmetric ◽  
Trapped Surfaces ◽  
Strong Gravity ◽  
New Concepts ◽  
Gravity Fields ◽  
Trapped Surface ◽  
Symmetric Initial Data

Abstract We propose new concepts, a dynamically transversely trapping surface (DTTS) and a marginally DTTS, as indicators for a strong gravity region. A DTTS is defined as a two-dimensional closed surface on a spacelike hypersurface such that photons emitted from arbitrary points on it in transverse directions are acceleratedly contracted in time, and a marginally DTTS is reduced to the photon sphere in spherically symmetric cases. (Marginally) DTTSs have a close analogy with (marginally) trapped surfaces in many aspects. After preparing the method of solving for a marginally DTTS in the time-symmetric initial data and the momentarily stationary axisymmetric initial data, some examples of marginally DTTSs are numerically constructed for systems of two black holes in the Brill–Lindquist initial data and in the Majumdar–Papapetrou spacetimes. Furthermore, the area of a DTTS is proved to satisfy the Penrose-like inequality $A_0\le 4\pi (3GM)^2$, under some assumptions. Differences and connections between a DTTS and the other two concepts proposed by us previously, a loosely trapped surface [Prog. Theor. Exp. Phys. 2017, 033E01 (2017)] and a static/stationary transversely trapping surface [Prog. Theor. Exp. Phys. 2017, 063E01 (2017)], are also discussed. A (marginally) DTTS provides us with a theoretical tool to significantly advance our understanding of strong gravity fields. Also, since DTTSs are located outside the event horizon, they could possibly be related with future observations of strong gravity regions in dynamical evolutions.

scholarly journals FORMATION OF TRAPPED SURFACES FOR THE SPHERICALLY SYMMETRIC EINSTEIN–VLASOV SYSTEM

2010 ◽  
Vol 07 (04) ◽  
pp. 707-731 ◽  
Author(s):  
HÅKAN ANDRÉASSON ◽  
GERHARD REIN
Keyword(s):  
Initial Data ◽  
Event Horizon ◽  
Apparent Horizon ◽  
Cosmic Censorship ◽  
Einstein Equations ◽  
Spherically Symmetric ◽  
Asymptotically Flat ◽  
Trapped Surfaces ◽  
Matter Model ◽  
Trapped Surface

We consider the spherically symmetric, asymptotically flat, non-vacuum Einstein equations, using as matter model a collisionless gas as described by the Vlasov equation. We find explicit conditions on the initial data which guarantee the formation of a trapped surface in the evolution which in particular implies that weak cosmic censorship holds for these data. We also analyze the evolution of solutions after a trapped surface has formed and we show that the event horizon is future complete. Furthermore we find that the apparent horizon and the event horizon do not coincide. This behavior is analogous to what is found in certain Vaidya spacetimes. The analysis is carried out in Eddington–Finkelstein coordinates.

scholarly journals GLOBAL REGULARITY FOR A LOGARITHMICALLY SUPERCRITICAL DEFOCUSING NONLINEAR WAVE EQUATION FOR SPHERICALLY SYMMETRIC DATA

2007 ◽  
Vol 04 (02) ◽  
pp. 259-265 ◽  
Author(s):  
TERENCE TAO
Keyword(s):  
Wave Equation ◽  
Initial Data ◽  
Global Regularity ◽  
Spherically Symmetric ◽  
Supercritical Regime ◽  
Critical Equation ◽  
Critical Regularity ◽  
Spatial Dimensions ◽  
Symmetric Initial Data ◽  
Supercritical Wave Equation

We establish global regularity for the logarithmically energy-supercritical wave equation □u = u5 log (2 + u2) in three spatial dimensions for spherically symmetric initial data, by modifying an argument of Ginibre, Soffer and Velo for the energy-critical equation. This example demonstrates that critical regularity arguments can penetrate very slightly into the supercritical regime.

scholarly journals Formation of dynamically transversely trapping surfaces and the stretched hoop conjecture

2020 ◽  
Vol 2020 (5) ◽  
Author(s):  
Hirotaka Yoshino ◽  
Keisuke Izumi ◽  
Tetsuya Shiromizu ◽  
Yoshimune Tomikawa
Keyword(s):  
Black Holes ◽  
Initial Data ◽  
Apparent Horizon ◽  
Ring System ◽  
Conformally Flat ◽  
Trapped Surfaces ◽  
Marginally Trapped Surface ◽  
Spherical Topology ◽  
Hoop Conjecture ◽  
Trapped Surface

Abstract A dynamically transversely trapping surface (DTTS) is a new concept for an extension of a photon sphere that appropriately represents a strong gravity region and has close analogy with a trapped surface. We study formation of a marginally DTTS in time-symmetric, conformally flat initial data with two black holes, with a spindle-shaped source, and with a ring-shaped source, and clarify that $\mathcal{C}\lesssim 6\pi GM$ describes the condition for the DTTS formation well, where $\mathcal{C}$ is the circumference and $M$ is the mass of the system. This indicates that an understanding analogous to the hoop conjecture for the horizon formation is possible. Exploring the ring system further, we find configurations where a marginally DTTS with the torus topology forms inside a marginally DTTS with the spherical topology, without being hidden by an apparent horizon. There also exist configurations where a marginally trapped surface with the torus topology forms inside a marginally trapped surface with the spherical topology, showing a further similarity between DTTSs and trapped surfaces.

scholarly journals Holography abhors visible trapped surfaces

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Netta Engelhardt ◽  
Åsmund Folkestad
Keyword(s):  
Event Horizon ◽  
Direct Consequence ◽  
Cosmic Censorship ◽  
Event Horizons ◽  
Trapped Surfaces ◽  
Strong Gravity ◽  
Classical Gravity ◽  
Trapped Surface ◽  
Cosmic Censorship Conjecture

Abstract We prove that consistency of the holographic dictionary implies a hallmark prediction of the weak cosmic censorship conjecture: that in classical gravity, trapped surfaces lie behind event horizons. In particular, the existence of a trapped surface implies the existence of an event horizon, and that furthermore this event horizon must be outside of the trapped surface. More precisely, we show that the formation of event horizons outside of a strong gravity region is a direct consequence of causal wedge inclusion, which is required by entanglement wedge reconstruction. We make few assumptions beyond the absence of evaporating singularities in strictly classical gravity. We comment on the implication that spacetimes with naked trapped surfaces do not admit a holographic dual, note a possible application to holographic complexity, and speculate on the dual CFT interpretation of a trapped surface.

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