Remarks on Causality in Relativistic Quantum Field Theory

Miklós Rédei, Stephen J. Summers
February 14, 2003
It is shown that the correlations predicted by relativistic quantum field theory in locally normal states between projections in local von Neumann algebras $\mathcal{A}(V_1),\mathcal{A}(V_2)$ associated with spacelike separated spacetime regions $V_1,V_2$ have a (Reichenbachian) common cause located in the union of the backward light cones of $V_1$ and $V_2$. Further comments on causality and independence in quantum field theory are made.