Physical state representations and gauge fixing in string theory
We re-examine physical state representations in the covariant quantization of bosonic string. We especially consider one parameter family of gauge fixing conditions for the residual gauge symmetry due to null states (or BRST exact states), and obtain explicit representations of observable Hilbert space which include those of the DDF states. This analysis is aimed at giving a necessary ingredient for the complete gauge fixing procedures of covariant string field theory such as temporal or light-cone gauge.
[Show abstract] [Hide abstract] ABSTRACT: A single-parameter family of covariant gauge fixing conditions in bosonic string field theory is proposed. This is a natural string field counterpart to the covariant gauge in the conventional gauge theory, which includes the Landau gauge, as well as the Feynman (Siegel) gauge as special cases. The action in the Landau gauge is greatly simplified in such a manner that many of the component fields have no derivatives in their kinetic terms and appear in at most quadratic forms in the vertex.
- "since the conditioñ Qφ (0) = 0 reduces to L n φ (0) = 0 (n ≥ 1) if there is no ghost fields (c −n or b −n ) in φ (0) . It would be possible to take explicit basis of the set of states satisfying the conditioñ Q|f = 0 as well as we have analyzed in the old covariant theory for the states satisfying L n |f = 0 (n ≥ 1) . With such a basis of states, analysis of the a = ∞ gauge would become easier in various situations. "