Carl W. Helstrom developed quantum detection and estimation methods for distinguishing signals and inferring parameters in optical systems. His work asks what information a quantum measurement can extract when the field itself limits accuracy. The Helstrom-Holevo bound expresses the minimum error probability for distinguishing two specified quantum states, connecting a statistical decision problem to an optimal quantum measurement.[ref]
https://opg.optica.org/josa/abstract.cfm?uri=josa-60-2-233. Estimation of Object Parameters by a Quantum-Limited Optical System, 1970
New to topics? Read the docs here!