To a real Hilbert space and a one-parameter group of orthogonal transformations we associate a C * -algebra which admits a free quasi-free state. This construction is a freeprobability analog of the construction of quasi-free states on the CAR and CCR algebras. We show that under certain conditions, our C * -algebras are simple, and the free quasi-free states are unique.The corresponding von Neumann algebras obtained via the GNS construction are free analogs of the Araki-Woods factors. Such von Neumann algebras can be decomposed into free products of other von Neumann algebras. For non-trivial one-parameter groups, these von Neumann algebras are type III factors. In the case the one-parameter group is nontrivial and almost-periodic, we show that Connes' Sd invariant completely classifies these algebras.
We prove several versions of Grothendieck's Theorem for completely bounded linear maps T : E → F * , when E and F are operator spaces. We prove that if E, F are C * -algebras, of which at least one is exact, then every completely bounded T : E → F * can be factorized through the direct sum of the row and column Hilbert operator spaces.Equivalently T can be decomposed as T = T r + T c where T r (resp. T c ) factors completely boundedly through a row (resp. column) Hilbert operator space. This settles positively (at least partially) some earlier conjectures of Effros-Ruan and Blecher on the factorization of completely bounded bilinear forms on C * -algebras. Moreover, our result holds more generally for any pair E, F of "exact" operator spaces. This yields a characterization of the completely bounded maps from a C * -algebra (or from an exact operator space) to the operator Hilbert space OH. As a corollary we prove that, up to a complete isomorphism, the row and column Hilbert operator spaces and their direct sums are the only operator spaces E such that both E and its dual E * are exact. We also characterize the Schur multipliers which are completely bounded from the space of compact operators to the trace class.
Abstract. By solving a free analog of the Monge-Ampère equation, we prove a noncommutative analog of Brenier's monotone transport theorem: if an n-tuple of self-adjoint non-commutative random variables Z 1 , . . . , Z n satisfies a regularity condition (its conjugate variables ξ 1 , . . . , ξ n should be analytic in Z 1 , . . . , Z n and ξ j should be close to Z j in a certain analytic norm), then there exist invertible non-commutative functions F j of an n-tuple of semicircular variables S 1 , . . . , S n , so that Z j = F j (S 1 , . . . , S n ). Moreover, F j can be chosen to be monotone, in the sense that F j = D j g and g is a non-commutative function with a positive definite Hessian. In particular, we can deduce that. Thus our condition is a useful way to recognize when an n-tuple of operators generate a free group factor. We obtain as a consequence that the q-deformed free group factors Γ q (R n ) are isomorphic (for sufficiently small q, with bound depending on n) to free group factors. We also partially prove a conjecture of Voiculescu by showing that free Gibbs states which are small perturbations of a semicircle law generate free group factors. Lastly, we show that entrywise monotone transport maps for certain Gibbs measure on matrices are well-approximated by the matricial transport maps given by free monotone transport.
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