Quote:
Originally posted by Atticus Grinch
There exists a "virtual world" in which Godwin's Law is not only suspended, but completely transposed? Fascinating. The mathematicians posited such a possibility, but we thought they were mad. Mad, I say! Now I see it is we who are mad!
|
A black hole is an object that is described by a spacetime geometry that is a solution to the Einstein equation. In string theory at large distance scales, solutions to the Einstein equation are only modified by very small corrections. .
string theories contain objects called p-branes and D-branes. Since a point can be thought of as a zero-brane, a natural generalization of a black hole is a black p-brane. And there are also BPS black p-branes.
But there's also a relationship between black p-branes and D-branes. At large values of the charge, spacetime geometry is a good description of of a black p-brane system. But when the charge is small, the system can be described by a bunch of weakly interacting D-branes.
This was a fantastic result for string theory. But can we now say that D-branes provide the fundamental quantum microstates of a black hole that underlie black hole thermodynamics? The D-brane calculation is only easily performed for the supersymmetric BPS black objects. Most black holes in the Universe probably have very little if any electric or magnetic charge, and are very far from being BPS objects. It's still a challenge to compute the black hole entropy for such an object using D-branes.
