@article{f65b77c75f3340f88310490dc4dd70a1,
title = "Demonstration of quantum-limited discrimination of multicopy pure versus mixed states",
abstract = "We demonstrate an optical receiver that achieves the quantum Chernoff bound for discriminating coherent states from thermal states in the multicopy scenario. In contrast, we find that repeated use of the receiver approaching the Helstrom bound for single-copy measurement is suboptimal in this multicopy case. Furthermore, for a large class of multicopy discrimination tasks between a pure and a mixed state, we prove that any Helstrom-bound achieving single-copy receiver is suboptimal by a factor of at least 2 in error-probability exponent compared to the multicopy quantum Chernoff bound. This behavior has a classical analog in the performance gap between soft-decision and hard-decision receivers for detecting a multicopy signal embedded in white Gaussian noise.",
author = "Arunkumar Jagannathan and Michael Grace and Olivia Brasher and Shapiro, {Jeffrey H.} and Saikat Guha and Habif, {Jonathan L.}",
note = "Funding Information: Research at USC was sponsored by the Army Research Office and was accomplished under Grant No. W911NF-20-1-0235. M.G. and S.G. acknowledge support from the DARPA IAMBIC Program under Contract No. HR00112090128. J.H.S. acknowledges support from the MITRE Corporation's Quantum Moonshot Program. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Office, DARPA, or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein. Publisher Copyright: {\textcopyright} 2022 American Physical Society.",
year = "2022",
month = mar,
doi = "https://doi.org/10.1103/PhysRevA.105.032446",
language = "English (US)",
volume = "105",
journal = "Physical Review A",
issn = "2469-9926",
publisher = "American Physical Society",
number = "3",
}