New Boundary Bound States in an Open Quantum Spin Chain

Abstract

New boundary bound states (BBS) are found of an integrable model with the magnetic impurities located at the edges of an open Heisenberg spin chain. These bound states carry the real energy and are formed by three or five imaginary modes of the rapidities. These imaginary modes of the rapidities give the non-zero antisymmetric wave functions and the moments of the centers of the bound states are zero. It means that these bound states are arisen by the magnetic impurities and localized at the edges of the correlated system. The Kondo screening occurs for the antiferromagnetic spin chain with the ferromagnetic impurities-electrons exchange interaction.