Mean field quantization of effective string

Abstract

Abstract I describe the recently proposed quantization of bosonic string about the meanfield ground state, paying special attention to the differences from the usual quantization about the classical vacuum which turns out to be unstable for d > 2. In particular, the string susceptibility index γ str is 1 in the usual perturbation theory, but equals 1/2 in the mean-field approximation that applies for 2 < d < 26. I show that the total central charge equals zero in the mean-field approximation and argue that fluctuations about the mean field do not spoil conformal invariance