The universe from scratch

By J. Ambjrn, J. Jurkiewicz, R. Loll. 2005

143 citations recorded by the source corpus.

A fascinating and deep question about nature is what one would see if one could probe space and time at smaller and smaller distances. Already the 19th century founders of modern geometry contemplated the possibility that a piece of empty space that looks completely smooth and structureless to the naked eye might have an intricate microstructure at a much smaller scale. Our vastly increased understanding of the physical world acquired during the 20th century has made this a certainty. The laws of quantum theory tell us that looking at spacetime at ever smaller scales requires ever larger energies and, according to Einstein's theory of general relativity, this will alter spacetime itself: it will acquire structure in the form of curvature. What we still lack is a definitive theory of quantum gravity to give us a detailed and quantitative description of the highly curved and quantum-fluctuating geometry of spacetime at this so-called Planck scale. This article outlines a particular approach to constructing such a theory, that of Causal Dynamical Triangulations, and its achievements so far in deriving from first principles why spacetime is what it is, from the tiniest realms of the quantum to the large-scale structure of the universe.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/56c3d0ae28f11c93f0cfd9da73e08dea1b5bd344

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Citations in the corpus

Colored Group Field Theory (2009, background): “GFT’s arise naturally in several discrete approaches to quantum gravity, like Regge calculus [11], dynamical triangulations [12,13] or spin foam models [14,15] (see also [16] for further details).”
Nonperturbative quantum de Sitter universe (2008, background): “s, which (in Lorentzian signature) would inevitably be associated with causality violations in the form of degeneracies in the light cone structure, as has been discussed elsewhere (see, for example, [10]). 5 for the action (see [4] for details) SEH E = 1 16π2G Z d4x √ g(−R +2Λ) → SRegge E = −(κ 0 +”