Principal Research Scientist
Phone: +44 (0)117 312 7012
FAX: +44 (0)117 312 9870
Quantum Information Processing Group
Hewlett-Packard Laboratories, Bristol
Bill graduated in 1989 with a BSc in Chemistry and Physics
(Waikato, New Zealand), followed by an MSc in Physics
(Waikato) in 1991 and a Dphil in Quantum Optics (Waikato) in
1994. He moved to the computer industry in early 1995 where
he worked on various projects. In July 1997 he accepted an
Australian Research Council Fellowship at the Department of
Physics in the University of Queensland, Australia. During
this fellowship he investigated multiparticle tests of
quantum mechanics and developed an interest in entanglement,
methods to characterise it and its practical use in QIP. In
2000 he became a senior researcher in the Australian Special
Centre for Quantum Information Processing). In November 2000
Bill joined HP Labs as a research scientist.
Bill has researched and published extensively in several
areas of Physics; from foundational issues of quantum
theory, quantum and atom optics through to quantum
information processing and quantum state and process
tomography, decoherence free subspaces and their application
to practical QIP. His current interests have focussed
- Quantum Information Processing and Computation
- The practical implementation for optical and solid state quantum
- Optical Information Processing including linear optical and weak
- The characterisation of quantum states and processes
- Short range quantum key distribution and potential applications
- High precision measurements and quantum metrology
Two of the areas he has been particularly involved with include:
- Qubus Computation: We have developed a radically new approach to
scalable quantum computing - a "qubus computer" - which realises qubit
measurement and quantum gates through interacting qubits with a quantum
communication bus mode. The qubits can be "static" matter qubits or
"flying" optical qubits. There is no requirement for direct
interaction between the qubits. Universal two-qubit quantum gates may
be affected by schemes which involve measurement of the bus mode, or by
schemes where the bus disentangles automatically and no measurement is
needed. In effect, the approach integrates together qubit degrees of
freedom for computation with quantum continuous variables for communication
- A hybrid quantum repeater using bright coherent light: Here we proposed
a quantum repeater protocol for long-distance quantum communication. In this
scheme, entanglement is created between qubits at intermediate stations of
the channel by using a weak dispersive light-matter interaction and
distributing the outgoing bright coherent light pulses among the stations.
Noisy entangled pairs of electronic spin are then prepared with high success
probability via homodyne detection and post selection. The local gates for
entanglement purification and swapping are deterministic and
measurement-free, based upon the same coherent-light resources and weak
interactions as for the initial entanglement distribution. With our system,
qubit-communication rates approaching 100~Hz over 1280~km with fidelities
near 99% are possible for reasonable local gate.
Several interesting recent publications include:
- P. Kok, W. J. Munro, Kae Nemoto, T. C. Ralph, J. P. Dowling and G. J.
Milburn, Linear optical quantum computing, in press RMP (2006)
- P. van Loock, T. D. Ladd, K. Sanaka, F. Yamaguchi, Kae Nemoto, W. J.
Munro, and Y. Yamamoto, Hybrid quantum repeater using bright coherent light,
Phys. Rev. Lett. 96, 240501 (2006)
- Fumiko Yamaguchi, Kae Nemoto and William J. Munro, Quantum error
correction via robust probe modes, Phys. Rev. A 73, 060302R (2006)
-T. P. Spiller, Kae Nemoto, Samuel L. Braunstein, W. J. Munro, P. van Loock
and G. J. Milburn, Quantum Computation by Communication, New J.
Phys. 8, 30 (2006)
- Peter P. Rohde, Timothy C. Ralph and William J. Munro, Practical
limitations in optical entanglement purification, Phys. Rev. A 73,
- T P Spiller and W J Munro, Towards a Quantum Information Technology
Industry, J. Phys.: Condens. Matter 18, 1 (2006).
- W. J. Munro, K. Nemoto and T. P. Spiller, Weak nonlinearities: a new route
to optical quantum computation, New J. Phys. 7, 137 (2005).
- T. P. Spiller, W. J. Munro, S. D. Barrett and P.Kok, An introduction to
quantum information porcessing: applications and realisations, Comptemporary
Physics 46, 407 (2005).
- W. J. Munro, K. Nemoto, R. G. Beausoleil, and T. P. Spiller, A
high-efficiency quantum non-demolition single photon number resolving
detector, Phys. Rev. A 71, 033819 (2005)
- Kae Nemoto and W. J. Munro, A near deterministic linear optical CNOT gate,
Phys. Rev. Lett 93, 250502 (2004)
- John H. Reina, Ray G. Beausoleil, Tim P. Spiller, and William J.
Munro, Radiative Corrections and Quantum Gates in Molecular Systems, Phys.
Rev. Lett 93, 250501
- T.C. Ralph, A. Gilchrist, G.J. Milburn, W.J. Munro and S. Glancy, Quantum
computation with optical coherent states, Phys. Rev. A 68,
- Stephen D. Bartlett and William J. Munro, Quantum Teleportation of Optical
Quantum Gates, Phys. Rev. Lett. 90, 117901 (2003);
- W.J.Munro, K.Nemoto, G.J.Milburn and S.L.Braunstein, Weak force detection
with superposed coherent states, Phys. Rev. A 66, 023819 (2002)
- D. F. V. James, P. G. Kwiat, W.~J. Munro and A. G. White, On the
Measurement of Qubits, Phys. Rev. A 64, 052312 (2001)