title: Null values and quantum state discrìmination.
abstract: We present a measurement protocol for discriminating between two different quantum states of a qubit with high fidelity. The protocol, called null value, is comprised of a projective measurement performed on the system with a small probability (also known as partial collapse), followed by a tuned postselection. We report on an optical experimental implementation of the scheme. We show that our protocol leads to an amplified signal-to-noise ratio (as compared with a straightforward strong measurement) when discerning between the two quantum states.
authors.affiliation: Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Oded
authors.initials: O
authors.lastname: Zilberberg
authors.forename: Alessandro
authors.initials: A
authors.lastname: Romito
authors.forename: David J
authors.initials: DJ
authors.lastname: Starling
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Howland
authors.forename: Curtis J
authors.initials: CJ
authors.lastname: Broadbent
authors.forename: John C
authors.initials: JC
authors.lastname: Howell
authors.forename: Yuval
authors.initials: Y
authors.lastname: Gefen