Positive-energy spectrum condition
= Positive-energy spectrum condition
{title2=$\operatorname{spec}P^\mu\subseteq\overline V_+$}
The joint energy-momentum spectrum lies in the closed forward <light cone>. In axiomatic <quantum field theory>, this condition permits analytic continuation of <Wightman functions> in suitable complex spacetime domains. Together with <Lorentz invariance>, <microcausality> and the positivity of the physical state space, it is one of the hypotheses behind the <CPT theorem>.