# Bekenstein ## Nonexistence of Baryon Number for Static Black Holes \[Links: [DOI](https://doi.org/10.1103/PhysRevD.5.1239)\] \[Abstract: Wheeler has conjectured that black holes should have no well-defined baryon number, and that as a result the law of conservation of baryons should be transcended in black-hole physics. We show here that a static black hole cannot have any exterior classical scalar or massive vector fields. We consider the modifications that would arise from a quantum-theoretical treatment, and we conclude that such a black hole cannot interact with the exterior world via virtual mesons such as the π and ρ. Because of this we find no way for external measurements to assign unambiguously a baryon number to such a black hole in agreement with Wheeler's prediction.\] # Gibbons ## The Time Symmetric Initial Value Problem for Black holes \[Links: [PDF](https://link.springer.com/content/pdf/10.1007/BF01645614.pdf)\] \[Abstract: \] ## Refs - [[0274 Multi black hole solutions]] ## Summary - *shows* that marginally trapped surfaces correspond to minimal surfaces *inside* BHs - *proves* that these minimal surfaces must have the topology of a sphere - toroidal minimal surfaces are excluded ## Common min. surface v.s. sum of individual ones - it might be a ==mistake==! - the argument for why the common min. surface has smaller area assumes it is a *global* minimum # Press, Teukolsky ## Floating Orbits, Superradiant Scattering and the Black-hole Bomb \[Links: [Inspire](https://inspirehep.net/literature/864738)\] \[Abstract: Penrose and Christodoulou have shown how, in principle, rotational energy can be extracted from a black hole by orbiting and fissioning particles. Recently, Misner has pointed out that waves can also extract rotational energy (“[[0616 Superradiance|superradiant scattering]]” in which an impinging wave is amplified as it scatters off a rotating hole). As one application of super-radiant scattering, Misner has suggested the possible existence of “floating orbits”, that is, orbits in which a particle radiatively extracts energy from the hole at the same rate as it radiates energy to infinity; thereby it experiences zero net radiation reaction.\]