Horizons in matter: black hole hair vs. Null Big Bang

Abstract

It is shown that only particular kinds of matter (in terms of the "radial" pressure to density ratio $w$) can coexist with Killing horizons in black-hole or cosmological space-times. Thus, for arbitrary (not necessarily spherically symmetric) static black holes, admissible are vacuum matter ($w=-1$, i.e., the cosmological constant or some its generalization) and matter with certain values of $w$ between 0 and -1, in particular, a gas of disordered cosmic strings ($w=-1/3$). If the cosmological evolution starts from a horizon (the so-called Null Big Bang scenarios), this horizon can co-exist with vacuum matter and certain kinds of phantom matter with $w\ge -3$. It is concluded that normal matter in such scenarios is entirely created from vacuum.

4 pages, essay written for the Gravity Research Foundation 2009 Awards for Essays on Gravitation, awarded a honorable mention

References in corpus (4)

• Regular homogeneous T-models with vacuum dark fluid
• Black holes can have curly hair
• General static black holes in matter
• Matter sources for a Null Big Bang

Cited by in corpus (2)

• Nonsingular Chaplygin gas cosmologies in universes connected by wormhole
• Isotropization in Chaplygin matter universes connected by a wormhole