In this study, we explicitly calculate information and fidelity of an $r$-rank projective measurement on a completely unknown state in a $d$-dimensional Hilbert space. We also show a tradeoff between information and fidelity at the level of a single outcome and discuss the efficiency of measurement with respect to fidelity.

• Received 13 September 2011

DOI:https://doi.org/10.1103/PhysRevA.85.022124