Pair creation of de Sitter black holes on a cosmic string background
(January 2004)Abstract
We analyze the quantum process in which a cosmic string breaks in a de Sitter(dS) background, and a pair of neutral or charged black holes is produced atthe ends of the string. The energy to materialize and accelerate the pair comesfrom the positive cosmological constant and, in addition, from the stringtension. The compact saddle point solutions without conical singularities(instantons) or with conical singularities (sub-maximal instantons) thatdescribe this process are constructed through the analytical continuation ofthe dS C-metric. Then, we explicitly compute the pair creation rate of theprocess. In particular, we find the nucleation rate of a cosmic string in a dSbackground, and the probability that it breaks and a pair of black holes isproduced. Finally we verify that, as occurs with pair production processes inother background fields, the pair creation rate of black holes is proportionalto exp(S), where the gravitational entropy of the black hole, S, is given byone quarter of the area of the horizons present in the saddle point solutionthat mediates the process.