Distinguishing quantum states using Clifford orbits

Understand

It is a fundamental property of quantum mechanics that information is lost as a result of performing measurements.

• Indeed, with every quantum measurement one can associate a number -- its POVM norm constant -- that quantifies how much the distinguishability of quantum states degrades in the worst case as a result of the measurement.
• This raises the obvious question which measurements preserve the most information in these sense of having the largest norm constant.
• While a number of near-optimal schemes have been found (e.g.