title: Photon sorting, efficient bell measurements, and a deterministic controlled-Z gate using a passive two-level nonlinearity.
abstract: Although the strengths of optical nonlinearities available experimentally have been rapidly increasing in recent years, significant challenges remain to using such nonlinearities to produce useful quantum devices such as efficient optical Bell state analyzers or universal quantum optical gates. Here we describe a new approach that avoids the current limitations by combining strong nonlinearities with active Gaussian operations in efficient protocols for Bell state analyzers and controlled-sign gates.
authors.affiliation: Centre for Quantum Computation and Communication Technology, School of Mathematics and Physics, University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: T C
authors.initials: TC
authors.lastname: Ralph
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
authors.forename: I
authors.initials: I
authors.lastname: Söllner
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
authors.forename: S
authors.initials: S
authors.lastname: Mahmoodian
authors.affiliation: Centre for Quantum Computation and Communication Technology, School of Mathematics and Physics, University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: A G
authors.initials: AG
authors.lastname: White
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Lodahl