Structural and non-isomorphism results for $q$-Araki-Woods factors

Abstract

It is proved that the $q$-Araki-Woods factor $\Gamma_q(\sH_\R, U)''$ associated with a strongly continuous orthogonal representation $U:\R\to \cO(\sH_\R)$ is strongly solid for all $q\in (-1,1)$ if the representation $U$ is almost periodic. We also show that the $q$-Araki-Woods factor $\Gamma_q(\sH_\R, U)''$ is not isomorphic to any free Araki-Woods factor for any $q\in (-1,1)\setminus\{0\}$ if the representation $U$ has nontrivial weakly mixing part or infinite dimensional almost periodic part with bounded spectrum.