String theory seems to ive a unitary description of physics in the
nei hbourhood of certain black holes.A nice example of this is the
AdS/CFT conjecture,where processes in the near-horizon region of sev-
eral black branes are described by a conformal field theory which is
unitary.However,it is hard to understand from the CFT where exactly
Hawkin sarument oeswron.
An alternative but related pro ram for understanding these issues
was started by t Hooft,who considered the near-horizon region of the
Schwarzschild black hole,namely flat space.The interactions between
outgoin Hawkin radiation and ingoin particles,which near the black
hole are boosted to the speed of light,can then be simulated by the
gravitational interactions between massless particles.An S -matrix for
their scatterin can then readily be computed.For a review on the
S -matrix Ansatz we further refer to [1 ].
In this note we discuss the quantum mechanical properties of this
model,and its possible relation to the AdS/CFT conjecture