  Given two unital C*-algebras equipped with states and a positive operator in
the enveloping von Neumann algebra of their minimal tensor product, we define
three parameters that measure the capacity of the operator to align with a
coupling of the two given states. Further we establish a duality formula that
shows the equality of two of the parameters for operators in the minimal tensor
product of the relevant C*-algebras. In the context of abelian C*-algebras our
parameters are related to quantitative versions of Arveson's Null Set Theorem
and to dualities considered in the theory of optimal transport. On the other
hand, restricting to matrix algebras we recover and generalise quantum versions
of Strassen's Theorem. We show that in the latter case our parameters can
detect maximal entanglement and separability.
