Ultimate limits of approximate unambiguous discrimination

Research output: Contribution to journalArticlepeer-review

Abstract

Quantum hypothesis testing is an important tool for quantum information processing. Two main strategies have been widely adopted: in a minimum error discrimination strategy, the average error probability is minimized; while in an unambiguous discrimination strategy, an inconclusive decision (abstention) is allowed to vanish any possibility of errors when a conclusive result is obtained. In both scenarios, the testing between quantum states is relatively well understood, for example, the ultimate limits of the performance are established decades ago; however, the testing between quantum channels is less understood. Although the ultimate limit of minimum error discrimination between channels has been explored recently, the corresponding limit of unambiguous discrimination is unknown. In this paper, we formulate an approximate unambiguous discrimination scenario, and derive the ultimate limits of the performance for both states and channels. In particular, in the channel case, our lower bound of the inconclusive probability holds for arbitrary adaptive sensing protocols. For the special class of "teleportation-covariant"channels, the lower bound is achievable with maximum entangled inputs and no adaptive strategy is necessary.

Original languageEnglish (US)
Article number043276
JournalPhysical Review Research
Volume2
Issue number4
DOIs
StatePublished - Nov 23 2020
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Fingerprint

Dive into the research topics of 'Ultimate limits of approximate unambiguous discrimination'. Together they form a unique fingerprint.

Cite this