Joint Extension of States of Subsystems for a CAR System

@inproceedings{Araki2004JointEO,
title={Joint Extension of States of Subsystems for a CAR System},
author={Huzihiro Araki and Hirokazu Moriya},
year={2004}
}

The problem of existence and uniqueness of a state of a joint system with given restrictions to subsystems is studied for a Fermion system, where a novel feature is non-commutativity between algebras of subsystems. For an arbitrary (finite or infinite) number of given subsystems, a product state extension is shown to exist if and only if all states of subsystems except at most one are even (with respect to the Fermion number). If the states of all subsystems are pure, then the same condition is… CONTINUE READING