The informational power of a quantum measurement is the maximum amount of
classical information that the measurement can extract from any ensemble of
quantum states. We discuss its main properties. Informational power is an
additive quantity, being equivalent to the classical capacity of a
quantum-classical channel. The informational power of a quantum measurement is
the maximum of the accessible information of a quantum ensemble that depends on
the measurement. We present some examples where the symmetry of the measurement
allows to analytically derive its informational power.Comment: 3 pages, 2 figures, published in the proceedings of the 11th Quantum
Communication, Measurement, and Computing (QCMC) conference, Vienna, Austria,
30 July-3 August, 201
