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arXiv · hep-th/9912267

On the relation between Euclidean and Lorentzian 2D quantum gravity

J. Ambjorn·J. Correia·C. Kristjansen·R. Loll
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Abstract

Starting from 2D Euclidean quantum gravity, we show that one recovers 2D Lorentzian quantum gravity by removing all baby universes. Using a peeling procedure to decompose the discrete, triangulated geometries along a one-dimensional path, we explicitly associate with each Euclidean space-time a (generalized) Lorentzian space-time. This motivates a map between the parameter spaces of the two theories, under which their propagators get identified. In two dimensions, Lorentzian quantum gravity can therefore be viewed as a ``renormalized'' version of Euclidean quantum gravity.

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J. Ambjorn, J. Correia, C. Kristjansen, R. Loll. 1999-12-29. On the relation between Euclidean and Lorentzian 2D quantum gravity. https://doi.org/10.1016/s0370-2693(00)00058-7

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