Cut-off kinks

We answer the question: If a vacuum sector Hamiltonian is regularized by an energy cutoff, how one-kink regularized? find that it not indeed normal modes of all energies are present in kink Hamiltonian, but rather decomposition field into mode operators yields coefficients which lie on constrained surface forces them to become small for above cutoff. This explains old observation cutoff leads incorrect one-loop mass. To arrive at our conclusion, we impose unitarily equivalent Hamiltonian. condition implies two Hamiltonians have same spectrum and so guarantees correct