Boson expansion methods in (1+1)-dimensional light-front QCD.

We derive a bosonic Hamiltonian from two dimensional QCD on the light-front. To obtain the bosonic theory we find that it is useful to apply the boson expansion method which is the standard technique in quantum many-body physics. We introduce bilocal boson operators to represent the gauge-invariant quark bilinears and then local boson operators as the collective states of the bilocal bosons. If we adopt the Holstein-Primakoff type among various representations, we obtain a theory of infinitely many interacting bosons, whose masses are the eigenvalues of the ’t Hooft equation. In the large N limit, since the interaction disappears and the bosons are identified with mesons, we obtain a free Hamiltonian with infinite kinds of mesons. PACS number(s); 11.10.Kk, 11.10.St, 11.15.Tk, 11.15.Pg To be published in Physical Review D Electronic address: [email protected]