Two-dimensional O(3) model coupled to two-dimensional quantum gravity

It has been suggested that the peak in the specific heat observed numerically for random surface actions with extrinsic curvature on dynamical lattices might be the result of a low mass bound state in an asymptotically free theory, rather than the signal for a real phase transition. The O(3) model on a fixed lattice displays just such behavior, but in general peaks appear to be weakened when the models concerned are put on dynamical lattices (i.e., coupled to two-dimensional quantum gravity). We therefore perform simulations of the O(3) model on dynamical 3 graphs to see if there is still a peak in the specific heat and compare the results with those on fixed lattices. © 1994 The American Physical Society.