37.
This paper is a direct continuation of [1] where we began the study of the integrable structures in Conformal Field Theory.
We show here how to construct the operators ${\bf Q}_{\pm}(\lambda)$ which act in the highest weight Virasoro module and commute
for different values of the parameter λ. These operators appear to be the CFT analogs of the
Q - matrix of Baxter [2], in particular they satisfy Baxter's famous
T-
Q equation. We also show that under natural assumptions about analytic properties of the operators as the functions of λ the Baxter's relation allows one to derive the nonlinear integral equations of Destri-de Vega (DDV)
[3] for the eigenvalues of the
Q-operators. We then use the DDV equation to obtain the asymptotic expansions of the
Q - operators at large λ; it is remarkable that unlike the expansions
of the
T operators of [1], the asymptotic series for
Q(λ) contains the “dual” nonlocal Integrals of Motion along with the local ones. We also discuss an intriguing relation between
the vacuum eigenvalues of the
Q - operators and the stationary transport properties in the boundary sine-Gordon model. On this basis we propose a number
of new exact results about finite voltage charge transport through the point contact in the quantum Hall system.
Received: 2 December 1996 / Accepted: 11 March 1997
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