The Application of the Light-Front Tamm-Dancoff Approximation to the Massive Schwinger Model.

Light-front field theory with the Tamm-Dancoff approximation is used to study the massive Schwinger model. After making a Tamm-Dancoff truncation of Fock space so that no more that four particles are allowed in any state, the coupled light-front Tamm-Dancoff integral equations for charge zero states are solved with basis function techniques, in which the two-particle and four-particle amplitudes are expanded in a finite basis. By extending Fock space to the 4-particle sector with some appropriate choices of basis functions, I am able to numerically compute spectra and wavefunctions for the first two states of the theory for arbitrary fermion mass. The known results for the ground state are readily reproduced and existing numerical results for the massive model are reproduced and improved. The aim of this work is to explore some basic features associated with the light-front Tamm-Dancoff approach and to develop numerical techniques for the bound state problems of light -front field theory.