Date:
Wed, 07/12/201112:00-14:00
Title:
"The Black-Hole Bomb"
&
"Hairy Black Holes and Null Circular Geodesics"
Abstract:
A bosonic field impinging on a rotating black hole can be amplified as it scatters off the hole, a phenomena known as superradiant scattering. If in addition the field has a nonzero rest mass μ, the mass term effectively works as a mirror, reflecting the scattered wave back towards the black hole.
In this physical system, known as a black-hole bomb, the wave may bounce back and forth between the black hole and some turning point, amplifying itself each time. Consequently, the field grows exponentially over time and is unstable.
Former analytical estimations of the time scale associated with the instability were restricted to the regimes Mμ<<1 and Mμ>>1 (M=Mass of the black hole). In these two limits the growth rate of the field was found to be extremely weak.
In this work we provide, for the first time, an analytic treatment of the superradiant instability (the black-hole bomb mechanism) in the physically most interesting regime, Mμ=O(1), where the instability is most pronounced.
"The Black-Hole Bomb"
&
"Hairy Black Holes and Null Circular Geodesics"
Abstract:
A bosonic field impinging on a rotating black hole can be amplified as it scatters off the hole, a phenomena known as superradiant scattering. If in addition the field has a nonzero rest mass μ, the mass term effectively works as a mirror, reflecting the scattered wave back towards the black hole.
In this physical system, known as a black-hole bomb, the wave may bounce back and forth between the black hole and some turning point, amplifying itself each time. Consequently, the field grows exponentially over time and is unstable.
Former analytical estimations of the time scale associated with the instability were restricted to the regimes Mμ<<1 and Mμ>>1 (M=Mass of the black hole). In these two limits the growth rate of the field was found to be extremely weak.
In this work we provide, for the first time, an analytic treatment of the superradiant instability (the black-hole bomb mechanism) in the physically most interesting regime, Mμ=O(1), where the instability is most pronounced.