User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse




Journal Article

The area-angular momentum inequality for black holes in cosmological spacetimes


Reiris,  Martin
Geometric Analysis and Gravitation, AEI-Golm, MPI for Gravitational Physics, Max Planck Society;

External Ressource
No external resources are shared
Fulltext (public)

(Preprint), 267KB

(Publisher version), 494KB

Supplementary Material (public)
There is no public supplementary material available

Clement, M. E. G., Reiris, M., & Simon, W. (2015). The area-angular momentum inequality for black holes in cosmological spacetimes. Classical and quantum gravity, 32(14): 145006. doi:10.1088/0264-9381/32/14/145006.

Cite as: http://hdl.handle.net/11858/00-001M-0000-0028-1D7C-2
For a stable marginally outer trapped surface (MOTS) in an axially symmetric spacetime with cosmological constant $\Lambda > 0$ and with matter satisfying the dominant energy condition, we prove that the area $A$ and the angular momentum $J$ satisfy the inequality $8\pi |J| \le A\sqrt{(1-\Lambda A/4\pi)(1-\Lambda A/12\pi)}$ which is saturated precisely for the extreme Kerr-deSitter family of metrics. This result entails a universal upper bound $|J| \le J_{\max} \approx 0.17/\Lambda$ for such MOTS, which is saturated for one particular extreme configuration. Our result sharpens the inequality $8\pi |J| \le A$, [7,14] and we follow the overall strategy of its proof in the sense that we estimate the area from below in terms of the energy corresponding to a "mass functional", which is basically a suitably regularised harmonic map $\mathbb{S}^2 \rightarrow \mathbb{H}^2 $. However, in the cosmological case this mass functional acquires an additional potential term which itself depends on the area. To estimate the corresponding energy in terms of the angular momentum and the cosmological constant we use a subtle scaling argument, a generalised "Carter-identity", and various techniques from variational calculus, including the mountain pass theorem.