Reconstructing the Universe

Abstract

We provide detailed evidence for the claim that nonperturbative quantum gravity, defined through state sums of causal triangulated geometries, possesses a large-scale limit in which the dimension of spacetime is four and the dynamics of the volume of the universe behaves semiclassically. This is a first step in reconstructing the universe from a dynamical principle at the Planck scale, and at the same time provides a nontrivial consistency check of the method of causal dynamical triangulations. A closer look at the quantum geometry reveals a number of highly nonclassical aspects, including a dynamical reduction of spacetime to two dimensions on short scales and a fractal structure of slices of constant time.

52 pages, 20 postscript figures, added references

References in corpus (5)

• Spectral Dimension of the Universe
• Quantum Gravity at Astrophysical Distances?
• Proper Time Flow Equation for Gravity
• Semiclassical Universe from First Principles
• Counting a black hole in Lorentzian product triangulations

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