Operator Valued Maps on Hilbert $C^*$-Modules

Abstract

We provide a characterization for operator valued completely bounded linear maps on Hilbert $C^*$-modules in terms of $\varphi$-maps. Also, we show that for every operator valued completely positive map $\varphi$ on a $C^*$-algebra $\mathcal{A}$, there is a unique (up to multiplication by a unitary operator) non-degenerate $\varphi$-map on each Hilbert $\mathcal{A}$-module.