Quantum filtering one bit at a time

Phys Rev Lett. 2011 Dec 23;107(26):260503. doi: 10.1103/PhysRevLett.107.260503. Epub 2011 Dec 22.

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.