Creation of open universes from de Sitter space

Abstract

Hawking^1,2 has shown that event horizons produce thermal radiation. I propose here a new cosmological model which has an early event horizon and in which the observed³ cosmic microwave background radiation is Hawking radiation. The model starts with de Sitter space—a space-time of constant curvature which is a solution to Einstein's vacuum field equations with a positive cosmological constant. Associated with an event E in de Sitter space there is a quantum barrier penetration tunnelling which leads to an open, negatively curved (k = −1) cosmology. This has an early exponential expansion phase but turns into a standard big-bang solution at late times. The geometry and quantum mechanical treatment within the future light cone of E are similar to that found in the Brout, Englert and Spindel (BES) theory^4,5. This model has the following advantages: (1) It has no singularities. (2) The observed isotropy of the cosmic microwave background is explained because the different regions we observe have all been in causal contact. (3) The temperature at early epochs (T₀ ∼ 10¹⁹ Ge V) is high enough to allow grand unified theories (GUTs) to produce the observed baryon excess from an initial thermal distribution through CP violations^6,7. (4) T₀ is correct to make the BES scenario work. (5) The early exponential expansion phase can naturally account for the observed large number n₀ ∼ 10⁸⁸ of particles within a volume a³ (where a is the radius of curvature) and the Guth⁸ flatness problem. (6) It predicts that our Universe is an open k = −1, Ω<1 cosmology consistent with the amount of mass detected in the universe so far^9–11. (7) The existence of the event horizon makes it possible to create from the original de Sitter space other k = −1 universes (perhaps an infinite number) which are entirely disjoint from our own and from each other.