CAR flows on type III factors and their extendability
Abstract
In this paper we prove that the CAR flows on type III factors arising from a large class of quasi-free states are not extendable, in the sense of Bikram, Izumi, Srinivasan and Sunder.8 As a consequence, CAR flows and CCR flows on type III factors are not cocycle conjugate. This is in sharp contrast with the situation for the type I∞ factor, for which CAR and CCR flows are in fact conjugate. In addition, we also compute the super-product systems associated to CAR flows.