EXACT BOUNDARY CRITICAL EXPONENTS AND TUNNELING EFFECTS IN INTEGRABLEMODELS FOR QUANTUM WIRES

Using the principles of the conformal quantum-field theory and the fin ite size corrections of the energy of the ground and various excited s tates, we calculate the boundary critical exponents of single- and mul ticomponent Bethe-Ansatz soluble models. The boundary critical exponen ts are given in terms of the dressed-charge matrix which has the same form as that of systems with periodic boundary conditions and is uniqu ely determined by the Bethe-ansatz equations. A Luttinger liquid with open boundaries is the effective low-energy theory of these models. As applications of the theory, the Friedel-oscillations due to the bound aries and the tunneling conductance through a barrier are also calcula ted. The tunneling conductance is determined by a nonuniversal boundar y exponent which governs its power law dependence on temperature and f requency.