Exact Identification of a Quantum Change Point

Understand

The detection of change points is a pivotal task in statistical analysis.

• In the quantum realm, it is a new primitive where one aims at identifying the point where a source that supposedly prepares a sequence of particles in identical quantum states starts preparing a mutated one.
• We obtain the optimal procedure to identify the change point with certainty---naturally at the price of having a certain probability of getting an inconclusive answer.
• We obtain the analytical form of the optimal probability of successful identification for any length of the particle sequence.