Prepared for submission to JHEP Quantum Gravity from Timelike Liouville theory Teresa Bautista,1 Atish Dabholkar,2;3;4 Harold Erbin5 1Max Planck Institute for Gravitational Physics (Albert Einstein Institute) Mühlenberg 1, D-14476 Potsdam, Germany 2International Centre for Theoretical Physics Strada Costiera 11, Trieste 34151 Italy 3Sorbonne Université, UPMC Univ Paris 06 UMR 7589, LPTHE, F-75005, Paris, France 4CNRS, UMR 7589, LPTHE, F-75005, Paris, France 5Ludwig–Maximilians–Universität München Theresienstraße 37, 80333 München, Germany E-mail:
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[email protected] Abstract: A proper definition of the path integral of quantum gravity has been a long-standing puzzle because the Weyl factor of the Euclidean metric has a wrong-sign kinetic term. We propose a definition of two-dimensional Liouville quantum gravity with cosmological constant using conformal bootstrap for the timelike Liouville theory coupled to supercritical matter. We prove a no-ghost theorem for the states in the BRST cohomology. We show that the four-point function constructed by gluing the timelike Liouville three-point functions is well defined and crossing symmetric (numerically) for external Liouville energies corresponding to all physical states in the BRST cohomology with the choice of the Ribault–Santachiara contour for the internal energy. arXiv:1905.12689v2 [hep-th] 19 Nov 2019 Keywords: quantum gravity, timelike Liouville theory Contents 1 Introduction2 2 Quantum gravity in two dimensions5 2.1 Generalities about