Collective field theory of ideal anyon gas

It is shown that the uniform ground state of ideal anyon gas can be constructed in the large-N collective field formalism and the excitation spectrum is given. It indicates that the system has a massless mode. In this treatment we employ a new set of gauge invariant variables to bypass the singularity which inevitably exists in the conventional density-phase variables. We also discuss the system of anyons including the delta function potential. The collective solution corresponding to Jackiw and Pi soliton is constructed. (author)