Quantum states and the Hadamard form. II. Energy minimization for spin-½ fields

We investigate properties of the states of a Hermitian spin-{} field in a Robertson-Walker spacetime constructed by an energy-minimization requirement. It is shown that the singularity structure of the commutator function 〈[^Ψ(x),^-Ψ(x^')]〉 for these states is such that current renormalization theory yields an infinite value for the renormalized expectation value of the trace of the stress tensor.