  We investigate boundary bound states of sine-Gordon model on the finite-size
strip with Dirichlet boundary conditions. For the purpose we derive the
nonlinear integral equation (NLIE) for the boundary excited states from the
Bethe ansatz equation of the inhomogeneous XXZ spin 1/2 chain with boundary
imaginary roots discovered by Saleur and Skorik. Taking a large volume (IR)
limit we calculate boundary energies, boundary reflection factors and boundary
Luscher corrections and compare with the excited boundary states of the
Dirichlet sine-Gordon model first considered by Dorey and Mattsson. We also
consider the short distance limit and relate the IR scattering data with that
of the UV conformal field theory.

High Energy Physics - Theory