MEASURING THE STRING SUSCEPTIBILITY IN 2D SIMPLICIAL QUANTUM-GRAVITY USING THE REGGE APPROACH

We use Monte Carlo simulations to study pure 2D Euclidean quantum grav ity with R(2)-interaction on spherical topologies, employing Regge's f ormulation, We attempt to measure the string susceptibility exponent g amma(str) by using a finite-size scaling Ansatz in the expectation val ue of R(2), as has been done in a previous study by Beck and Vink (Nuc l. Phys. B 438 (1995) 320). By considerably extending the range and st atistics of their study we find that this Ansatz is plagued by large s ystematic errors. The R(2) specific String susceptibility exponent gam ma(str)' is found to agree with theoretical predictions, but its deter mination also is subject to large systematic errors and the presence o f finite-size scaling corrections. To circumvent this obstacle we sugg est a new scaling Ansatz which in principle should be able to predict both, gamma(str) and gamma(str)'. First results indicate that this req uires large system sizes to reduce the uncertainties in the finite-siz e scaling Ansatze. Nevertheless, our investigation shows that within t he achievable accuracy the numerical estimates are still compatible wi th analytic predictions, contrary to the recent claim by Beck and Vink .