GROUND STATE OF THE YUKAWA MODEL WITH CUTOFFS
Abstract
The ground state of the Yukawa model is considered. The Yukawa model describes the system of a Dirac field interacting with a Klein–Gordon field. By introducing ultraviolet cutoffs and spatial cutoffs, the total Hamiltonian is defined as a self-adjoint operator on a boson–fermion Fock space. It is shown that the total Hamiltonian has a positive spectral gap for all values of coupling constants. In particular, the existence of the ground state is proven.