Tracial moment problems on hypercubes

In this paper we introduce the "tracial $K$-moment problem" and the "sequential matrix-valued $K$-moment problem" and show the equivalence of the solvability of these problems. Using a Haviland's theorem for matrix polynomials, we solve these $K$-moment problems for the case where $K$ is the hypercube $[-1,1]^n$.