Professor Timothy Ralph
Professor

Timothy Ralph

Email: 
Phone: 
+61 7 334 69693

Background

Professor Ralph obtained a BSc Hons from Macquarie University in 1989 and a PhD in Physics from The Australian National University in 1993. He has held three Australian Research Council Fellowships - Postdoctoral, QEII and Professorial. He is currently Node Director for the ARC Centre of Excellence for Quantum Computation and Communication Technology at the University of Queensland.

Availability

Professor Timothy Ralph is:
Available for supervision
Media expert

Fields of research

Physical Sciences

Qualifications

  • Bachelor (Honours) of Science (Advanced), Macquarie University
  • Doctor of Philosophy, Australian National University

Research interests

  • Linear Optics Quantum Computation.

    As part of the Centre for Quantum Computation and Communication Technology we are attempting to understand and implement simple quantum gates using the techniques of linear optics and measurement induced state projection.

  • Quantum Communication with Lasers.

    Quantum information techniques allow one to communicate with absolute security, amongst other applications. As part of the Centre for Quantum Computation and Communication Technology we are developing such secure communication protocols based on sending coherent states of light and measuring their amplitudes.

  • Relativistic Quantum Information.

    This project examines the interface between quantum mechanics, general relativity and information theory. It asks, both at a fundamental and practical level, what the ramifications for quantum information theory are when space-time curvature and rapid motion are introduced.

Search Professor Timothy Ralph’s works on UQ eSpace

429 works between 1991 and 2025
All (429) Journal Article (325) Book Chapter (7) Conference Publication (87) Book (2) Other Outputs (8)

1 - 20 of 429 works

2025

Book Chapter

Boson sampling

Lund, A. P. and Ralph, T. C. (2025). Boson sampling. Encyclopedia of mathematical physics. (pp. 42-56) edited by Richard Szabo and Martin Bojowald. Amsterdam, Netherlands: Elsevier. doi: 10.1016/B978-0-323-95703-8.00111-7

Boson sampling

2024

Journal Article

Noise transfer approach to GKP quantum circuits

Ralph, Timothy C., Winnel, Matthew S., Swain, S. Nibedita and Marshman, Ryan J. (2024). Noise transfer approach to GKP quantum circuits. Entropy, 26 (10) 874. doi: 10.3390/e26100874

Noise transfer approach to GKP quantum circuits

2024

Journal Article

Improving continuous-variable quantum channels with unitary averaging

Swain, S. Nibedita, Marshman, Ryan J., Rohde, Peter P., Lund, Austin P., Solntsev, Alexander S. and Ralph, Timothy C. (2024). Improving continuous-variable quantum channels with unitary averaging. Physical Review A, 110 (3) 032622. doi: 10.1103/physreva.110.032622

Improving continuous-variable quantum channels with unitary averaging

2024

Conference Publication

Quantum-amplified simultaneous quantum-classical communications

Zaunders, Nicholas, Wang, Ziqing, Ralph, Timothy C., Aguinaldo, Ryan and Malaney, Robert (2024). Quantum-amplified simultaneous quantum-classical communications. 2024 International Conference on Quantum Communications, Networking, and Computing (QCNC), Kanazawa, Japan, 1-3 July 2024. Piscataway, NJ, United States: IEEE. doi: 10.1109/qcnc62729.2024.00033

Quantum-amplified simultaneous quantum-classical communications

2024

Journal Article

Unitary averaging with fault and loss tolerance

Marshman, Ryan J., Singh, Deepesh, Ralph, Timothy C. and Lund, Austin P. (2024). Unitary averaging with fault and loss tolerance. Physical Review A, 109 (6) 062436. doi: 10.1103/physreva.109.062436

Unitary averaging with fault and loss tolerance

2024

Journal Article

Saturating the maximum success probability bound for noiseless linear amplification using linear optics

Guanzon, Joshua J., Winnel, Matthew S., Singh, Deepesh, Lund, Austin P. and Ralph, Timothy C. (2024). Saturating the maximum success probability bound for noiseless linear amplification using linear optics. PRX Quantum, 5 (2) 020359. doi: 10.1103/prxquantum.5.020359

Saturating the maximum success probability bound for noiseless linear amplification using linear optics

2024

Journal Article

Deterministic preparation of optical squeezed cat and Gottesman-Kitaev-Preskill states

Winnel, Matthew S., Guanzon, Joshua J., Singh, Deepesh and Ralph, Timothy C. (2024). Deterministic preparation of optical squeezed cat and Gottesman-Kitaev-Preskill states. Physical Review Letters, 132 (23) 230602. doi: 10.1103/physrevlett.132.230602

Deterministic preparation of optical squeezed cat and Gottesman-Kitaev-Preskill states

2024

Journal Article

Classical-quantum dual encoding for laser communications in space

Winnel, Mathew, Wang, Ziqing, Malaney, Robert, Aguinaldo, Ryan, Green, Jonathan and Ralph, Timothy C. (2024). Classical-quantum dual encoding for laser communications in space. New Journal of Physics, 26 (3) 033012, 1-14. doi: 10.1088/1367-2630/ad295a

Classical-quantum dual encoding for laser communications in space

2024

Journal Article

Measurement-based Lorentz-covariant Bohmian trajectories of interacting photons

Foo, Joshua, Lund, Austin P. and Ralph, Timothy C. (2024). Measurement-based Lorentz-covariant Bohmian trajectories of interacting photons. Physical Review A, 109 (2) 022229. doi: 10.1103/physreva.109.022229

Measurement-based Lorentz-covariant Bohmian trajectories of interacting photons

2024

Journal Article

Falling into the past: geodesics in a time travel metric

MacLaurin, Colin, Costa, Fabio and Ralph, Timothy C. (2024). Falling into the past: geodesics in a time travel metric. Universe, 10 (2) 95, 1-14. doi: 10.3390/universe10020095

Falling into the past: geodesics in a time travel metric

2023

Journal Article

Noiseless linear amplification and loss-tolerant quantum relay using coherent-state superpositions

Guanzon, Joshua J., Winnel, Matthew S., Lund, Austin P. and Ralph, Timothy C. (2023). Noiseless linear amplification and loss-tolerant quantum relay using coherent-state superpositions. Physical Review A, 108 (3) 032411, 1-14. doi: 10.1103/physreva.108.032411

Noiseless linear amplification and loss-tolerant quantum relay using coherent-state superpositions

2023

Journal Article

Enhancing quantum teleportation efficacy with noiseless linear amplification

Zhao, Jie, Jeng, Hao, Conlon, Lorcán O., Tserkis, Spyros, Shajilal, Biveen, Liu, Kui, Ralph, Timothy C., Assad, Syed M. and Lam, Ping Koy (2023). Enhancing quantum teleportation efficacy with noiseless linear amplification. Nature Communications, 14 (1) 4745, 1-8. doi: 10.1038/s41467-023-40438-z

Enhancing quantum teleportation efficacy with noiseless linear amplification

2023

Journal Article

Protecting classical-quantum signals in free-space optical channels

Villaseñor, E., Winnel, M. S., Ralph, T. C., Aguinaldo, R., Green, J. and Malaney, R. (2023). Protecting classical-quantum signals in free-space optical channels. Physical Review A, 107 (6) 062616, 6. doi: 10.1103/physreva.107.062616

Protecting classical-quantum signals in free-space optical channels

2023

Journal Article

Pump depletion in optical parametric amplification

Xing, Wanli and Ralph, T. C. (2023). Pump depletion in optical parametric amplification. Physical Review A, 107 (2) 023712. doi: 10.1103/physreva.107.023712

Pump depletion in optical parametric amplification

2022

Journal Article

Comparison of techniques for distillation of entanglement over a lossy channel

Mauron, Caroline and Ralph, Timothy C. (2022). Comparison of techniques for distillation of entanglement over a lossy channel. Physical Review A, 106 (6) 062603. doi: 10.1103/physreva.106.062603

Comparison of techniques for distillation of entanglement over a lossy channel

2022

Journal Article

Achieving the ultimate end-to-end rates of lossy quantum communication networks

Winnel, Matthew S., Guanzon, Joshua J., Hosseinidehaj, Nedasadat and Ralph, Timothy C. (2022). Achieving the ultimate end-to-end rates of lossy quantum communication networks. npj Quantum Information, 8 (1) 129, 1-9. doi: 10.1038/s41534-022-00641-0

Achieving the ultimate end-to-end rates of lossy quantum communication networks

2022

Journal Article

Distributing entanglement in first-generation discrete- and continuous-variable quantum repeaters

Dias, Josephine, Winnel, Matthew S., Munro, William J., Ralph, T. C. and Nemoto, Kae (2022). Distributing entanglement in first-generation discrete- and continuous-variable quantum repeaters. Physical Review A, 106 (5) 052604, 1-9. doi: 10.1103/physreva.106.052604

Distributing entanglement in first-generation discrete- and continuous-variable quantum repeaters

2022

Journal Article

Universal quantum computation with optical four-component cat qubits

Su, Daiqin, Dhand, Ish and Ralph, Timothy C. (2022). Universal quantum computation with optical four-component cat qubits. Physical Review A, 106 (4) 042614. doi: 10.1103/physreva.106.042614

Universal quantum computation with optical four-component cat qubits

2022

Journal Article

Berry phase from the entanglement of future and past light cones: detecting the timelike Unruh effect

Quach, James Q., Ralph, Timothy C. and Munro, William J. (2022). Berry phase from the entanglement of future and past light cones: detecting the timelike Unruh effect. Physical Review Letters, 129 (16) 160401, 1-6. doi: 10.1103/physrevlett.129.160401

Berry phase from the entanglement of future and past light cones: detecting the timelike Unruh effect

2022

Journal Article

Billiard-ball paradox for a quantum wave packet

Bishop, Lachlan G, Ralph, Timothy C and Costa, Fabio (2022). Billiard-ball paradox for a quantum wave packet. Classical and Quantum Gravity, 39 (17) 175007, 1-27. doi: 10.1088/1361-6382/ac8198

Billiard-ball paradox for a quantum wave packet

Current funding

  • 2024 - 2027
    Deployable Quantum Relay (DSP Multi-Party Collaborative Project led by Griffith University)
    Commonwealth Defence Science and Technology Group
    Open grant
  • 2023 - 2025
    Quantum Communications with Continuous Variables (UNSW subcontract agreement)
    University of New South Wales
    Open grant
  • 2018 - 2025
    ARC Centre of Excellence for Quantum Computation and Communication Technology (CQC2T) (ARC Centre of Excellence administered by UNSW)
    University of New South Wales
    Open grant

Past funding

  • 2021 - 2024
    A Space-Based Quantum Communications Platform using Continuous Variables (ARC Linkage Project led by University of NSW)
    University of New South Wales
    Open grant
  • 2019 - 2021
    Enabling quantum information technology with 60 photons and beyond
    United States Asian Office of Aerospace Research and Development
    Open grant
  • 2019 - 2020
    Platform independent studies on optimising quantum repeater architectures (Australian Department of Defence grant administered by QuintessenceLabs Pty Ltd)
    Quintessencelabs Pty Ltd
    Open grant
  • 2017 - 2020
    Quantum Key Distribution (QKD) System
    Quintessencelabs Pty Ltd
    Open grant
  • 2011 - 2018
    ARC Centre of Excellence for Quantum Computation and Communication Technology (ARC COE administered by the University of New South Wales)
    University of New South Wales
    Open grant
  • 2011 - 2013
    Quantum Optics and Quantum Information
    Vice-Chancellor's Senior Research Fellowship
    Open grant
  • 2010
    Quantum memory
    Australian National University
    Open grant
  • 2008 - 2012
    Quantum repeater technologies for continuous variable (ARC Discovery Project DP0879277 administered by ANU)
    Australian National University
    Open grant
  • 2006 - 2010
    Optical Quantum Computation
    ARC Discovery Projects
    Open grant
  • 2003 - 2010
    ARC Centre of Excellence for Quantum Computer Technology (UNSW lead institution)
    ARC Centres of Excellence
    Open grant
  • 2003 - 2005
    Quantum Photonics- Travel Award
    Australian National University
    Open grant
  • 2002 - 2004
    Towards Quantum Computation with Light
    UQ Foundation Research Excellence Awards - DVC(R) Funding
    Open grant
  • 2002 - 2004
    ARC Discovery Project - Quantum Photonics with continuous laser beams
    Australian National University
    Open grant
  • 2001 - 2004
    Experimental Implementation of Efficient Linear Optics Quantum Computation
    United States Army Research Office
    Open grant
  • 2000
    Optical entangler for Quantum Communication
    Australian National University
    Open grant
  • 2000 - 2005
    Quantum Information with Continuous Variables
    ARC Australian Research Fellowship/QEII F/ship
    Open grant
  • 2000
    Quantum information with continuous variables
    UQ New Staff Research Start-Up Fund
    Open grant

Availability

Professor Timothy Ralph is:
Available for supervision

Before you email them, read our advice on how to contact a supervisor.

Available projects

  • Optical Quantum Computation

    As part of the Centre for Quantum Computation and Communication Technology we are attempting to understand and implement optical quantum computation using the techniques of linear optic networks and measurement induced state projection. Projects are available examining intemediate scale protocols and algorithms as well as large scale architectures.

  • Quantum communication with lasers

    Quantum information techniques allow one to communicate with absolute security, amongst other applications. As part of the Centre for Quantum Computation and Communication Technology we are developing such secure communication protocols based on sending coherent and squeezed states of light and measuring their amplitudes. Projects concerning quantum repeaters for extending communication links and satellite to ground quantum communication are available.

  • Relativistic quantum information

    Projects are available that involve examining the interface between quantum mechanics, general relativity and information theory. They ask, both at a fundamental and practical level, what the ramifications for quantum information theory are when space-time curvature, rapid motion and/or very fast transformations are introduced.

Supervision history

Current supervision

  • Doctor Philosophy

    Production of quantum communication systems capable of operating onboard low-earth orbit satellites and developing integrated quantum and classical satellite communication protocols.

    Principal Advisor

  • Doctor Philosophy

    Practical applications of quantum sampling algorithms

    Principal Advisor

  • Master Philosophy

    Quantum effects in general relativistic spacetimes

    Principal Advisor

  • Doctor Philosophy

    Production of quantum communication systems capable of operating onboard low-earth orbit satellites and developing integrated quantum and classical satellite communication protocols.

    Principal Advisor

  • Master Philosophy

    Resolving paradoxes of closed timelike curves

    Principal Advisor

  • Doctor Philosophy

    Quantum mechanics near closed timelike curves

    Principal Advisor

  • Doctor Philosophy

    Beyond quantum field theory on a curved background

    Principal Advisor

  • Doctor Philosophy

    Demonstration of relativistic Bohmian trajectories of photons

    Associate Advisor

    Other advisors: Dr Daniel Peace, Associate Professor Jacqui Romero

  • Doctor Philosophy

    Thermodynamic fluctuation relations for gravitating quantum systems

    Associate Advisor

    Other advisors: Dr Carolyn Wood, Dr Laura Henderson

Completed supervision

Enquiries

Contact Professor Timothy Ralph directly for media enquiries about:

  • Laser noise - physics
  • Optics - quantum
  • Physics
  • Quantum information
  • Quantum key distribution with continuous variables
  • Quantum optics
  • Quantum physics
  • Teleportation

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