  A quantum field theory is described which is a supersymmetric classical
model. -- Supersymmetry generators of the system are used to split its
Liouville operator into two contributions, with positive and negative spectrum,
respectively. The unstable negative part is eliminated by a positivity
constraint on physical states, which is invariant under the classical
Hamiltonian flow. In this way, the classical Liouville equation becomes a
functional Schroedinger equation of a genuine quantum field theory. Thus, 't
Hooft's proposal to reconstruct quantum theory as emergent from an underlying
deterministic system, is realized here for a field theory. Quantization is
intimately related to the constraint, which selects the part of Hilbert space
where the Hamilton operator is positive. This is seen as dynamical symmetry
breaking in a suitably extended model, depending on a mass scale which
discriminates classical dynamics beneath from emergent quantum mechanical
behaviour.
