Fused integrable lattice models with quantum impurities and open boundaries

Abstract

The alternating integrable spin chain and the $RSOS(q_{1},q_{2};p)$ model in the presence of a quantum impurity are investigated. The boundary free energy due to the impurity is derived, the ratios of the corresponding $g$ functions at low and high temperature are specified and their relevance to boundary flows in unitary minimal and generalized coset models is discussed. Finally, the alternating spin chain with diagonal and non--diagonal integrable boundaries is studied, and the corresponding boundary free energy and $g$ functions are derived.