Elementary particles, 5

There is another consequence of the UV/IR connection: this connection makes the black hole microstates simultaneously composite as well as elementary.

They’re elementary because they can be thought of as some excitations of a collection of strings and branes. Even if you had a different theory, it would have to be able to calculate the black hole entropy from the number of excited states of “something”. This “something” would play the very same role as strings in perturbative string theory. And differently excited strings must be interpreted as different fields in spacetime – in an effective field theory. The same has to hold for “something” whatever it is.

On the other hand, the number of black hole microstates is so large that there must exist many ways to excite the “something”, some internal degrees of freedom.

— Event horizons and thermodynamics: more than an analogy

— Lubos Motl

2013.04.27 Saturday ACHK