LETTER: Pair Creation of Schwarzschild-anti-de Sitter Black Holes

For a spherically symmetric vacuum model with anegative cosmological constant, a complex constrainedinstanton is considered as the seed for the quantum paircreation of Schwarzschild-anti-de Sitter black holes. The relative creation probability isfound to be the exponential of the negative of the blackhole entropy. The black hole entropy is known to be onequarter of the black hole horizon area. In the absence of a general noboundary proposal foropen creation, the constrained instanton approach isused in treating both the open and closed pair creationsof black holes.