The Kerr-Fermi Sea

Understand

The presence of a massive scalar field near a Kerr black hole is known to produce instabilities associated with bound superradiant modes.

• In this paper we show that for massive fermions, rather than inducing an instability, the bound superradiant modes condense and form a Fermi sea which extends well outside the ergosphere.
• The shape of this Fermi sea in phase space and various other properties are analytically computed in the semiclassical WKB approximation.
• The low energy effective theory near the black hole is described by ripples in the Fermi surface.