On the phase diagram of 2d Lorentzian Quantum Gravity

Abstract

The phase diagram of 2d Lorentzian quantum gravity (LQG) coupled to conformal matter is studied. A phase transition is observed at $c=c_{\mathrm{crit}}$ ($1/2<c_{\mathrm{crit}}<4$) which can be thought of as the analogue of the $c=1$ barrier of Euclidean quantum gravity (EQG). The non--trivial properties of the quantum geometry are discussed.

Comments: LATTICE99(gravity), 3 pages, espcrc2.sty, simulations available at http://www.nbi.dk/~ambjorn/lqg2/