title: Quantum filtering one bit at a time.
abstract: In this Letter we consider the purification of a quantum state using the information obtained from a continuous measurement record, where the classical measurement record is digitized to a single bit per measurement after the measurements have been made. Analysis indicates that efficient and reliable state purification is achievable for one- and two-qubit systems. We also consider quantum feedback control based on the discrete one-bit measurement sequences.
authors.affiliation: Department of Electrical Engineering and Electronics, The University of Liverpool, Brownlow Hill, Liverpool, L69 3GJ, United Kingdom. jfralph@liv.ac.uk
authors.forename: Jason F
authors.initials: JF
authors.lastname: Ralph
authors.forename: Neil P
authors.initials: NP
authors.lastname: Oxtoby