title: Quantum filter for nonlocal polarization properties of photonic qubits.
abstract: We present an optical filter that transmits photon pairs only if they share the same horizontal or vertical polarization, without decreasing the quantum coherence between these two possibilities. Various applications for entanglement manipulations and multiphoton qubits are discussed.
authors.affiliation: CREST, Japan Science and Technology Corporation, Research Institute for Electronic Science, Hokkaido University, Kita-12 Nishi-6, Kita-ku, Sapporo 060-0812, Japan.
authors.forename: Holger F
authors.initials: HF
authors.lastname: Hofmann
authors.forename: Shigeki
authors.initials: S
authors.lastname: Takeuchi