Causal Dynamical Triangulations and the Quest for Quantum Gravity

Abstract

Quantum Gravity by Causal Dynamical Triangulation has over the last few years emerged as a serious contender for a nonperturbative description of the theory. It is a nonperturbative implementation of the sum-over-histories, which relies on few ingredients and initial assumptions, has few free parameters and - crucially - is amenable to numerical simulations. It is the only approach to have demonstrated that a classical universe can be generated dynamically from Planckian quantum fluctuations. At the same time, it allows for the explicit evaluation of expectation values of invariants characterizing the highly nonclassical, short-distance behaviour of spacetime. As an added bonus, we have learned important lessons on which aspects of spacetime need to be fixed a priori as part of the background structure and which can be expected to emerge dynamically.

To appear in "Foundations of Space and Time", Cambridge Univ. Press, eds. G. Ellis, J. Murugan, A Weltman

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• Casimir Effect in the Horava-Lifshitz Gravity with a Cosmological Constant
• Can we see quantum gravity? Photons in the asymptotic-safety scenario
• Effects of Planck-scale-modified dispersion relations on the thermodynamics of charged black holes
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• The Construction of Spin Foam Vertex Amplitudes
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• Wilson loops in CDT quantum gravity
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• Generating Functionals for Spin Foam Amplitudes
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• Current Status of LHC Physics: Precision Theory View
• New Approach to GUTs
• Quantum fields in the non-perturbative regime - Yang-Mills theory and gravity
• A Reasonable Ab Initio Cosmological Constant Without Holography
• Birth and Growth of Two-dimensional Universe