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Title: Real tunneling geometries and the large-scale topology of the universe

Journal Article · · Physical Review, D (Particles Fields); (USA)
 [1];  [2]
  1. Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge (United Kingdom)
  2. Department of Physics, University of California, Santa Barbara, CA (USA)

If the topology and geometry of spacetime are quantum-mechanically variable, then the particular classical large-scale topology and geometry observed in our universe must be statistical predictions of its initial condition. This paper examines the predictions of the no boundary'' initial condition for the present large-scale topology and geometry. Finite-action real tunneling solutions of Einstein's equation are important for such predictions. These consist of compact Riemannian (Euclidean) geometries joined to a Lorentzian cosmological geometry across a spacelike surface of vanishing extrinsic curvature. The classification of such solutions is discussed and general constraints on their topology derived. For example, it is shown that, if the Euclidean Ricci tensor is positive, then a real tunneling solution can nucleate only a single connected Lorentzian spacetime (the unique conception theorem). Explicit examples of real tunneling solutions driven by a cosmological constant are exhibited and their implications for cosmic baldness described. It is argued that the most probable large-scale spacetime predicted by the real tunneling solutions of the no-boundary'' initial condition has the topology {bold R}{times}{ital S}{sup 3} with the de Sitter metric.

OSTI ID:
6223184
Journal Information:
Physical Review, D (Particles Fields); (USA), Vol. 42:8; ISSN 0556-2821
Country of Publication:
United States
Language:
English