Recursive sampling simulations of 3D gravity coupled to scalar fermions

We study numerically the phase structure of a model of 3D gravity interacti ng with scalar fermions. We measure the 3D counterpart of the "string" susc eptibility exponent as a function of the inverse Newton coupling alpha. We show that there are two phases separated by a critical point around alpha(c ) congruent to 2. The numerical results support the hypothesis that the pha se structures of 3D and 2D simplicial gravity are qualitatively similar, th e inverse Newton coupling in 3D playing the role of the central charge of m atter in 2D. (C) 2000 Elsevier Science B.V. All rights reserved.