BOUNDARY FLOWS IN MINIMAL MODELS

We discuss in this paper the behaviour of minimal models of conformal theory perturbed by the operator Phi(13) at the boundary. Using the RS OS restriction of the sine-Gordon model, adapted to the boundary probl em, a series of boundary flows between different set of conformally in variant boundary conditions are described. Generalizing the ''staircas e'' phenomenon discovered by Al. Zamolodchikov, we find that an analyt ic continuation of the boundary sinh-Gordon model provides a flow inte rpolating not only between all minimal models in the bulk, but also be tween their possible conformal boundary conditions. In the particular case where the bulk sinh-Gordon coupling is turned to zero, we obtain a boundary roaming trajectory in the c = 1 theory, that interpolates b etween all the possible spin s Kondo models. (C) 1998 Published by Els evier Science B.V. All rights reserved.