Zusammenfassung
We carry out a Kaluza-Klein reduction of the Einstein-Hilbert action along
the ignorable coordinates of stationary and axisymmetric black holes. Rigid
diffeomorphism invariance of the \$m\$-ignorable coordinates then become a global
\$SL(m,R)\$ gauge symmetry of the reduced theory. Mass and angular momentum of
the black holes are related to generators of an \$SL(2,R)\$ subgroup of the full
symmetry. Related to each angular momentum there is also an \$SL(2,R)\$ subgroup.
On the horizon, this \$SL(2,R)\$ can be extended to the full Witt algebra, which
is an exact symmetry of the reduced action when the black hole temperature is
zero. So on the horizon, the Kaluza-Klein reduced action is a conformal field
theory. The infinite dimensional symmetries are explicitly broken when the
system is at a finite temperature, i.e. when the black hole temperature is
nonzero.
Nutzer