title: Quantum entanglement of high angular momenta.
abstract: Single photons with helical phase structures may carry a quantized amount of orbital angular momentum (OAM), and their entanglement is important for quantum information science and fundamental tests of quantum theory. Because there is no theoretical upper limit on how many quanta of OAM a single photon can carry, it is possible to create entanglement between two particles with an arbitrarily high difference in quantum number. By transferring polarization entanglement to OAM with an interferometric scheme, we generate and verify entanglement between two photons differing by 600 in quantum number. The only restrictive factors toward higher numbers are current technical limitations. We also experimentally demonstrate that the entanglement of very high OAM can improve the sensitivity of angular resolution in remote sensing.
authors.affiliation: Quantum Optics, Quantum Nanophysics, Quantum Information, University of Vienna, Vienna A-1090, Austria. robert.fickler@univie.ac.at
authors.forename: Robert
authors.initials: R
authors.lastname: Fickler
authors.forename: Radek
authors.initials: R
authors.lastname: Lapkiewicz
authors.forename: William N
authors.initials: WN
authors.lastname: Plick
authors.forename: Mario
authors.initials: M
authors.lastname: Krenn
authors.forename: Christoph
authors.initials: C
authors.lastname: Schaeff
authors.forename: Sven
authors.initials: S
authors.lastname: Ramelow
authors.forename: Anton
authors.initials: A
authors.lastname: Zeilinger