title: Engineering two-photon high-dimensional states through quantum interference.
abstract: Many protocols in quantum science, for example, linear optical quantum computing, require access to large-scale entangled quantum states. Such systems can be realized through many-particle qubits, but this approach often suffers from scalability problems. An alternative strategy is to consider a lesser number of particles that exist in high-dimensional states. The spatial modes of light are one such candidate that provides access to high-dimensional quantum states, and thus they increase the storage and processing potential of quantum information systems. We demonstrate the controlled engineering of two-photon high-dimensional states entangled in their orbital angular momentum through Hong-Ou-Mandel interference. We prepare a large range of high-dimensional entangled states and implement precise quantum state filtering. We characterize the full quantum state before and after the filter, and are thus able to determine that only the antisymmetric component of the initial state remains. This work paves the way for high-dimensional processing and communication of multiphoton quantum states, for example, in teleportation beyond qubits.
authors.affiliation: Council for Scientific and Industrial Research (CSIR) National Laser Centre, PO Box 395, Pretoria 0001, South Africa.
authors.forename: Yingwen
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Council for Scientific and Industrial Research (CSIR) National Laser Centre, PO Box 395, Pretoria 0001, South Africa.; School of Physics, University of Witwatersrand, Johannesburg 2000, South Africa.
authors.forename: Filippus S
authors.initials: FS
authors.lastname: Roux
authors.affiliation: School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa.; National Institute for Theoretical Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa.
authors.forename: Thomas
authors.initials: T
authors.lastname: Konrad
authors.affiliation: Institute of Photonics and Quantum Science (IPaQS), Scottish Universities Physics Alliance (SUPA), Heriot-Watt University, Edinburgh EH14 4AS, UK.
authors.forename: Megan
authors.initials: M
authors.lastname: Agnew
authors.affiliation: Institute of Photonics and Quantum Science (IPaQS), Scottish Universities Physics Alliance (SUPA), Heriot-Watt University, Edinburgh EH14 4AS, UK.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Leach
authors.affiliation: School of Physics, University of Witwatersrand, Johannesburg 2000, South Africa.
authors.forename: Andrew
authors.initials: A
authors.lastname: Forbes
keywords: high-dimensional states; orbital angular momentum; quantum entanglement; quantum interference.