LIGHT-CONE GAUGE QUANTIZATION OF 2D SIGMA-MODELS

This work describes the formulation of the manifestly ghost-free (spac etime) light-cone gauge for bosonic string theory with non-trivial spa cetime metric, antisymmetric tensor, dilaton and tachyon fields. The a ction is a general two-dimensional sigma model, corresponding to a clo sed string theory with a second order action in the Polyakov picture. The spacetime fields must have a symmetry generated by a null, covaria ntly constant spacetime vector in order for the light-cone gauge to be accessible. Also, the theory must be Weyl invariant. The conditions f or Weyl invariance are computed within the light-cone gauge, reproduci ng the usual beta functions. The calculation of the dilaton beta funct ion and the critical dimension is somewhat novel in this ghost-free th eory. Some exactly solvable light-cone theories are discussed.