On the Quantum Theory of the Anharmonic Oscillator in Functional Space
Dynamics of quantum field theory can be formulated by functional equations. For strong interaction nonperturbative solutions of these functional equations are required. For the investigation of solution procedures the model of an anharmonic oscillator is used, because of its structural equivalence with dressed one- and two-particel states of field theory. To perform a variational solution procedure a scalar product for the state functionals is introduced and its existence is proven. The scalar product definition admits a mapping of the physical Hilbert space on the functional space. Therefore a “functional” quantum theory seems to be possible. The whole procedure can be transferred to relativistic invariant field theories, provided these theories are regularized to give finite results at all.