REAL TUNNELING AND BLACK HOLE CREATION

We discuss the Hawking theory of quantum cosmology with regard to approximation at the lowest order of the Planck constant. At this level, the quantum scenario will be reduced to its classical evolutions in real and imaginary times. We restrict our attention to the so-called real tunneling case. It can be shown that, even at this level, there still exist some quantum effects, the classical field equation may not hold at the transition surface. One can introduce the concept of constrained gravitational instanton. It may play some important role in the scenario of black hole creation in the inflationary background at the Planckian era of the universe. From the constrained gravitational instanton, the real tunneling can occur through different ways. Consequently, it will lead to the creation of different parts of the black hole spacetime in the de Sitter background. The global aspects of the black hole creation are discussed.

Quantum Creation of a Black Hole

Using the Hartle–Hawking no-boundary proposal for the wave function of the universe, we can study the wave function and probability of a single black hole created at the birth of the universe. The black hole originates from a generalized gravitational instanton with conical singularities. The wave function and probability of a universe with a black hole are calculated at the W K B level. The probability of a black hole creation is the exponential of one quarter of the sum of areas of the black hole and cosmological horizons. One quarter of this sum is the total entropy of universe. We show that these arguments apply to all kinds of black holes in the de Sitter space background.

ON BLACK HOLE CREATION IN PLANCKIAN ENERGY SCATTERING

In a series of papers Amati, Ciafaloni and Veneziano and ’t Hooft conjectured that black holes occur in the collision of two light particles at planckian energies. In this talk based on [10] we discuss a possible scenario for such a process by using the Chandrasekhar-Ferrari-Xanthopoulos duality between the Kerr black hole solution and colliding plane gravitational waves.