CAR flows on type III factors and its extendability

Abstract

In this paper using one of the necessary conditions obtained for extendability in [BISSar], we prove that the CAR flows ([Amo01]) on type III factors arising from most quasi-free states are not extendable. As a consequence we find the super product system of CAR flows. We know from [Arv03] that CCR flows and CAR flows on type I factors with the same Arveson index are cocycle conjugate. But our result together with [BISSar] will show that CCR flows and CAR flows on type III factors are not cocycle conjugate.