A noncommutative moment problem
A noncommutative moment problem
We prove a noncommutative moment theorem and relate it to Connes’ problem of embedding finite factor von Neumann algebras into an ultraproduct of the hyperfinite $\mathrm {II}_1$ factor. We include a linear-algebraic equivalent of Connes’ problem, which asks for a characterization of all noncommutative polynomials which have positive trace when …