Bound states in weakly deformed waveguides: numerical vs analytical   results
  We have studied the emergence of bound states in weakly deformed and/or heterogeneous waveguides, comparing the analytical predictions obtained using a recently developed perturbative method, with precise numerical results, for different configurations (a homogeneous asymmetric waveguide, a heterogenous asymmetric waveguide and a homogeneous broken-strip). In all the examples considered in this paper we have found excellent agreement between analytical and numerical results, thus providing a numerical verification of the analytical approach. 
Paolo Amore, John P. Boyd, Francisco M. Fern\'andez, Martin Jacobo and   Petr Zhevandrov
physics.comp-ph