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Professor Timothy Ralph

Professor

Physics
Faculty of Science
ralph@physics.uq.edu.au
+61 7 334 69693

Overview

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.

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.

Qualifications

  • PhD, Australian National University
  • Bachelor of Science, Macquarie University

Publications

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Grants

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Supervision

  • Advancements in quantum information protocols using quantum optics

    Doctor Philosophy

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

    Doctor Philosophy

  • Quantum mechanics near closed timelike curves

    Doctor Philosophy

View all Supervision

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.

View all Available Projects

Publications

Book

Book Chapter

  • Optical quantum computation

    Ralph, Tim C. and Pryde, Geoff J. (2009). Optical quantum computation. Progress in optics. (pp. 209-269) edited by Emil Wolf. Oxford, United Kingdom: Elsevier. doi: 10.1016/S0079-6638(10)05409-0

  • Schrodinger Cat States for Quantum Information Processing

    Jeong, H. and Ralph, T. C. (2007). Schrodinger Cat States for Quantum Information Processing. Quantum Information with Continuous Variables of Atoms and Light. (pp. 159-177) edited by Nicolas J. Cerf, Gerd Leuchs and Eugene S. Polzik. London: Imperial College Press.

  • Schrödinger cat states for quantum information processing

    Jeong, Hyunseok and Ralph, Timothy C. (2007). Schrödinger cat states for quantum information processing. Quantum Information with Continuous Variables of Atoms and Light. (pp. 159-180) Imperial College Press. doi: 10.1142/9781860948169_0009

  • Quantum State Sharing

    Symul, T., Lance, A. M., Bowen, W. P., Lam, P. K., Sanders, B. C. and Ralph, T. C. (2006). Quantum State Sharing. Quantum Communications and Cryptography. (pp. 163-186) edited by A. Sergienko. New York: Taylor & Francis.

  • Squeezing from lasers

    Ralph, T. C. (2004). Squeezing from lasers. Quantum Squeezing. (pp. 141-170) edited by P D Drummond and Z Ficek. Berlin: Springer.

  • Quantum key distribution with continuous variable in optics

    Ralph, T. C. (2003). Quantum key distribution with continuous variable in optics. Quantum Information with Continuous Variables. (pp. 295-316) edited by Samuel L. Braunstein and Arun K. Pati. Netherlands: Kluwer Academic Publishers. doi: 10.1007/978-94-015-1258-9_21

Journal Article

Conference Publication

  • Maximisation of quantum correlations under local filtering operations

    Wollmann, Sabine, Ducuara, Andrés F., Qiang, Xiaogang, Tasker, Joel F., Zhou, Xiaoqi, Wang, Jianwei, Wilkes, Callum M., Loke, Thomas, Oagara, Sean, Kling, Laurent, Marshall, Graham D., Santagati, Raffaele, Ralph, Timothy C., Wang, Jingbo B., Oabrien, Jeremy L., Thompson, Mark G., Skrzypczyk, Paul and Matthews, Jonathan C. F. (2019). Maximisation of quantum correlations under local filtering operations. 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), Munich, Germany, 23 - 27 June 2019. Piscataway, NJ, United States: Institute of Electrical and Electronics Engineers. doi: 10.1109/CLEOE-EQEC.2019.8871647

  • Quantum algorithms on a four-qubit photonic controlled-shift gate

    Ho, Joseph, Patel, Raj B., Ralph, Timothy C. and Pryde, Geoff J. (2019). Quantum algorithms on a four-qubit photonic controlled-shift gate. Quantum Information and Measurement 2019, Rome, Italy , 4–6 April 2019. Washington, D.C.: OSA - The Optical Society. doi: 10.1364/QIM.2019.F5A.41

  • Generation of Schrödinger’s cat state in an optical double sideband mode

    Serikawa, Takahiro, Yoshikawa, Jun-ichi, Yonezawa, Hidehiro, Ralph, Timothy C., Huntington, Elanor H. and Furusawa, Akira (2018). Generation of Schrödinger’s cat state in an optical double sideband mode. CLEO: QELS_Fundamental Science, CLEO_QELS 2018, San Jose, CA, United States, 13–18 May 2018. Washington D.C., United States: OSA - The Optical Society. doi: 10.1364/CLEO_QELS.2018.FTh4G.6

  • The quest for nonclassicality using number-resolving single-photon detectors

    Abrahão, Raphael A., Shahandeh, Farid, Gillett, Geoff, Ringbauer, Martin, Weinhold, Till, Almeida, Marcelo P., Ralph, Timothy C. and White, Andrew G. (2018). The quest for nonclassicality using number-resolving single-photon detectors. Frontiers in Optics, FIO 2018, Washington, DC USA, 18-20 September 2018. Washington, D.C.: OSA - The Optical Society. doi: 10.1364/FIO.2018.JTu2A.55

  • Quantum enhancement of signal-to-noise ratio for arbitrary coherent states using heralded linear amplifiers

    Zhao, Jie, Dias, Josephine, Haw, Jing Yan, Bradshaw, Mark, Blandino, Remi, Symul, Thomas, Ralph, Timothy, Assad, Syed and Lam, Ping Koy (2017). Quantum enhancement of signal-to-noise ratio for arbitrary coherent states using heralded linear amplifiers. Conference on Lasers and Electro-Optics/Pacific Rim, CLEOPR 2017, Singapore, 31 July - 4 August 2017. Piscataway, NJ, United States: IEEE.

  • Quantum enhancement of signal-to-noise ratio for arbitrary coherent states using heralded linear amplifiers

    Zhao, Jie, Dias, Josephine, Haw, Jing Yan, Bradshaw, Mark, Blandino, Remi, Symul, Thomas, Ralph, Timothy, Assad, Syed and Lam, Ping Koy (2017). Quantum enhancement of signal-to-noise ratio for arbitrary coherent states using heralded linear amplifiers. Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR), Singapore, 31 July-4 August 2017. Piscataway, NJ, United States: IEEE. doi: 10.1109/CLEOPR.2017.8119107

  • Surpassing the no-cloning limit with a heralded hybrid linear amplifier

    Haw, Jing Yan, Zhao, Jie, Dias, Josephine, Assad, Syed M., Bradshaw, Mark, Blandino, Remi, Symul, Thomas, Ralph, Timothy C. and Lam, Ping Koy (2017). Surpassing the no-cloning limit with a heralded hybrid linear amplifier. Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR), Singapore, 31 July-4 August 2017. Piscataway, NJ, United States: IEEE. doi: 10.1109/CLEOPR.2017.8119040

  • Enhancing optical quantum channels

    Lund, Austin and Ralph, Timothy C. (2016). Enhancing optical quantum channels. SPIE, San Diego, CA, United States, 28–29 August 2016. Bellingham, WA, United States: SPIE. doi: 10.1117/12.2237438

  • Near-deterministic Bell measurement for multiphoton quantum information processing

    Lee, Seung-Woo, Park, Kimin, Ralph, Timothy C. and Jeong, Hyunseok (2016). Near-deterministic Bell measurement for multiphoton quantum information processing. 11th Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2015, Busan, Korea, 24-28 August 2015. Piscataway, NJ, United States: Institute of Electrical and Electronics Engineers . doi: 10.1109/CLEOPR.2015.7375885

  • New directions in optical quantum computing

    Ralph, T. C. (2016). New directions in optical quantum computing. 11th Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2015, Busan, South Korea, 24 - 28 August 2015. Piscataway, NJ, United States: Institute of Electrical and Electronics Engineers . doi: 10.1109/CLEOPR.2015.7375881

  • Boson sampling with continuous variable measurements

    Ralph, Timothy (2014). Boson sampling with continuous variable measurements. Frontiers in Optics, FiO 2016, Rochester, NY, 17-21 October 2016. Washington, D.C.: OSA - The Optical Society. doi: 10.1364/FIO.2016.FF1C.2

  • Discord as a quantum resource for bi-partite communication

    Chrzanowski, Helen M., Gu, Mile, Assad, Syed M., Symul, Thomas, Modi, Kevan, Ralph, Timothy C., Vedral, Vlatko and Lam, Ping Koy (2014). Discord as a quantum resource for bi-partite communication. 11th International Conference on Quantum Communication, Measurement and Computation, QCMC 2012, Vienna, Austria, 30 July- 3 August 2012. College Park, MD United States: American Institute of Physics. doi: 10.1063/1.4903110

  • Entanglement and simplified quantum information operations

    Patel, Raj B., Kocsis, Sacha, Ho, Joseph, Hall, Michael J. W., Ferreyrol, Franck, Bennet, Adam, Ralph, Timothy C. and Pryde, Geoff J. (2014). Entanglement and simplified quantum information operations. Frontiers in Optics 2014, Tucson, AZ, United States, 19–23 October 2014. Washington DC United States: Optical Society of America (OSA). doi: 10.1364/FIO.2014.FW4C.1

  • Experimental verification of quantum discord in continuousvariable states and operational significance of discord consumption

    Hosseini, Sara, Rahimi-Keshari, Saleh, Haw, Jing Yan, Assad, Syed M., Chrzanowski, Helen M., Janousek, Jiri, Symul, Thomas, Ralph, Timothy C., Lam, Ping Koy, Gu, Mile, Modi, Kavan and Vedral, Vlatko (2014). Experimental verification of quantum discord in continuousvariable states and operational significance of discord consumption. CLEO: QELS Fundamental Science (CLEO QELS 2014), San Jose, CA United States, 8-13 June 2014. Washington, DC United States: Optical Society of American (OSA). doi: 10.1364/cleo_qels.2014.fth3a.6

  • Quantum non-Gaussian and Gaussian states at multiple side-band frequencies

    Kuntz, Katanya B., Song, Hongbin, Webb, James G., Wheatley, Trevor A., Furusawa, Akira, Ralph, Timothy C. and Huntington, Elanor H. (2014). Quantum non-Gaussian and Gaussian states at multiple side-band frequencies. CLEO: QELS Fundamental Science (CLEO QELS 2014), San Jose, CA United States, 8-13 June 2014. Washington, DC United States: Optical Society of American (OSA). doi: 10.1364/cleo_qels.2014.fth3a.3

  • Bosonsampling with realistic single-photon sources

    Broome, Matthew A., Fedrizzi, Alessandro, Rahimi-Keshari, Saleh, Branczyk, Agata M., Dove, Justin, Aaronson, Scott, Ralph, Timothy C. and White, Andrew G. (2013). Bosonsampling with realistic single-photon sources. International Quantum Electronics Conference, IQEC 2013, Munich, Germany, 12 - 16 May 2013. Piscataway, NJ United States: I E E E. doi: 10.1109/CLEOE-IQEC.2013.6801699

  • Building a quantum repeater with quantum memories and noiseless amplifiers

    Lam, P. K., Hosseini, M., Campbell, G., Pinel, O., Sparkes, B., Twamley, J., Rebic, S., Chrzanowski, H. M., Assad, S., Bernu, J., Ralph, T. C., Walk, N., Symul, T. and Buchler, B. C. (2013). Building a quantum repeater with quantum memories and noiseless amplifiers. 10th Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2013, Kyoto, Japan, 30 June - 4 July 2013. Piscataway, NJ United States: I E E E. doi: 10.1109/CLEOPR.2013.6599943

  • Continuous-variable QKD with post-selection is secure

    Ralph, T. C., Walk, N., Symul, T. and Lam, P. K. (2013). Continuous-variable QKD with post-selection is secure. IEEE Photonics Society Summer Topical Meeting Series, PSSTMS 2013, Waikoloa, HI, 8 - 10 July 2013. Piscataway, NJ United States: I E E E. doi: 10.1109/PHOSST.2013.6614521

  • Direct characterization of any linear photonic device

    Rahimi-Keshari, Saleh, Broome, Matthew A., Fickler, Robert, Fedrizzi, Alessandro, Ralph, Timothy C. and White, Andrew G. (2013). Direct characterization of any linear photonic device. Conference on Lasers and Electro-Optics Europe & International Quantum Electronics Conference (CLEO/Europe-IQEC), Munich, Germany, 12-16 May, 2013. Piscataway, NJ, USA: IEEE. doi: 10.1109/CLEOE-IQEC.2013.6801733

  • Direct characterization of any linear photonic device

    Fedrizzi, Alessandro, Broome, Matthew A., White, Andrew G., Fickler, Robert, Rahimi-Keshari, Saleh and Ralph, Timothy C. (2013). Direct characterization of any linear photonic device. APS March Meeting 2013, Baltimore, MD, USA, 18–22 March, 2013. College Park, MD, United States: American Physical Society.

  • Discord as a consumable resource

    Gu, M., Chrzanowski, H. M., Assad, S. M., Symul, T., Modi, K., Ralph, T.C., Vedral, V. and Lam, P. K. (2013). Discord as a consumable resource. 10th Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2013, Kyoto, Japan, 30 June - 4 July 2013. Piscataway, NJ United States: I E E E. doi: 10.1109/CLEOPR.2013.6600227

  • Experimental bosonsampling

    Broome, M. A., Fedrizzi, A., Rahimi-Keshari, S., Dove, J., Aaronson, S., Ralph, T. C. and White, Andrew G. (2013). Experimental bosonsampling. CQO-X: The Tenth Rochester Conference on Coherence and Quantum Optics, 2013, with QIM 2: The Second International Conference on Quantum Information and Measurement, 2013, Rochester, NY, USA, 17-20 June, 2013. Washington, DC, USA: Optical Society of America. doi: 10.1364/QIM.2013.W5B.3

  • Experimental bosonsampling in a photonic circuit

    Broome, Matthew A., Fedrizzi, Alessandro, Rahimi-Keshari, Saleh, Dove, Justin, Aaronson, Scott, Ralph, Timothy C. and White, Andrew G. (2013). Experimental bosonsampling in a photonic circuit. IEEE Photonics Society Summer Topical Meeting Series, PSSTMS 2013, Waikoloa, HI, United States, 8 - 10 July 2013. Piscataway, NJ, United States: IEEE. doi: 10.1109/PHOSST.2013.6614564

  • Experimental bosonsampling in a tunable optical network

    Broome, Matthew A., Fedrizzi, Alessandro, Rahimi-Keshari, Saleh, Dove, Justin, Aaronson, Scott, Ralph, Timothy C. and White, Andrew G. (2013). Experimental bosonsampling in a tunable optical network. CLEO: QELS_Fundamental Science, CLEO:QELS FS 2013, San Jose, CA United States, 9 - 14 June 2013. San Jose, California United States: Quantum Simulators I (QW1C). doi: 10.1364/CLEO_QELS.2013.QW1C.3

  • Implementation of a quantum Fredkin gate using an entanglement resource

    Ferreyrol, F., Ralph, T. C. and Pryde, G. J. (2013). Implementation of a quantum Fredkin gate using an entanglement resource. CLEO/EUROPE - IQEC 2013: Conference on Lasers and Electro-Optics - International Quantum Electronics Conference, Munich, Germany, 13-16 May, 2013. Piscataway, NJ, USA: IEEE. doi: 10.1109/CLEOE-IQEC.2013.6801703

  • Unconditional security of Gaussian post-selected continuous variable quantum key distribution

    Walk, N., Symul, T., Lam, P. K. and Ralph, T. C. (2013). Unconditional security of Gaussian post-selected continuous variable quantum key distribution. 2013 Conference on Lasers and Electro-Optics Europe & International Quantum Electronics Conference (CLEO/Europe-IQEC 2013), Munich, 12-16 May 2013. Piscataway, NJ, United States: IEEE. doi: 10.1109/CLEOE-IQEC.2013.6801697

  • Virtual noiseless amplification

    Janousek, Jiri, Chrzanowski, Helen, Hosseini, Sarah, Assad, Syed, Symul, Thomas, Walk, Nathan, Ralph, Tim and Lam, Ping Koy (2013). Virtual noiseless amplification. CLEO/EUROPE - IQEC 2013: Conference on Lasers and Electro-Optics - International Quantum Electronics Conference, Munich, Germany, 13-16 May, 2013. Piscataway, NJ, USA: IEEE. doi: 10.1109/CLEOE-IQEC.2013.6801727

  • Continuous variable quantum key distribution: Security, repeaters and relativity

    Walk, Nathan, Ralph, Timothy C., Downes, Tony, Symul, Thomas and Lam, Ping Koy (2011). Continuous variable quantum key distribution: Security, repeaters and relativity. Washington, D.C.: Optical Society of America (OSA). doi: 10.1364/icqi.2011.qmf4

  • A functional interpretation of continuous variable quantum discord

    Assad, Syed, Chrzanowski, Helen, Symul, Thomas, Lam, Ping Koy, Ralph, Tim, Gu, Mile and Vedral, Vlatko (2011). A functional interpretation of continuous variable quantum discord. IQEC/CLEO Pacific Rim Conference 2011 incorporating ACOLS and ACOFT, Sydney, NSW, Australia, 28 August-1 September, 2011. Piscataway, NJ, United States: Institute of Electrical and Electronics Engineers. doi: 10.1109/IQEC-CLEO.2011.6194178

  • Adaptive optical phase estimation using time-symmetric quantum smoothing

    Wheatley, T. A., Berry, D. W., Yonezawa, H., Nakane, D., Arao, H., Pope, D. T., Ralph, T. C., Wiseman, H. M., Furusawa, A. and Huntington, E. H. (2011). Adaptive optical phase estimation using time-symmetric quantum smoothing. 10th International Conference on Quantum Communication, Measurement and Computing (QCMC), Brisbane, Australia, 19-23 July 2010. Melville, NY, United States: American Institute of Physics. doi: 10.1063/1.3630163

  • Photon number discrimination without a photon counter and reconstructing non-Gaussian states of light

    Chrzanowski, Helen, Bernu, Julien, Sparkes, Ben, Hage, Boris, Lund, Austin, Ralph, Tim, Lam, Ping Koy and Symul, Thomas (2011). Photon number discrimination without a photon counter and reconstructing non-Gaussian states of light. Conference on Lasers and Electro-Optics Pacific Rim, Sydney, Australia, 28 August - 1 September 2011.

  • Schrödinger kitten and cat states characterisation using only continuous variables and Gaussian resources

    Chrzanowski, H. M., Symul, T., Bernu, J., Hage, B., Lund, A., Ralph, T. C. and Lam, P. K. (2011). Schrödinger kitten and cat states characterisation using only continuous variables and Gaussian resources. 2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference, CLEO EUROPE/EQEC 2011, Munich, Germany, 22-26 May 2011. Piscataway, NJ United States: IEEE. doi: 10.1109/CLEOE.2011.5943387

  • Security of Post-selection based Continuous Variable Quantum Key Distribution against Arbitrary Attacks

    Walk, Nathan, Ralph, Timothy C., Symul, Thomas and Lam, Ping Koy (2011). Security of Post-selection based Continuous Variable Quantum Key Distribution against Arbitrary Attacks. Conference on Lasers and Electro-Optics (CLEO), Baltimore Md, May 01-06, 2011. NEW YORK: IEEE. doi: 10.1364/cleo_at.2011.jtuc4

  • Squeezing-enhanced adaptive optical phase estimation

    Yonezawa, Hidehiro, Nakane, Daisuke, Wheatley, Trevor A., Iwasawa, Kohjiro, Takeda, Shuntaro, Arao, Hajime, Berry, Dominic W., Ralph, Timothy C., Wiseman, Howard M., Huntington, Elanor and Furusawa, Akira (2011). Squeezing-enhanced adaptive optical phase estimation. Quantum Electronics and Laser Science Conference (QELS), Baltimore, MD, United States, 1-6 May 2011. Piscataway, NJ, United States: IEEE. doi: 10.1364/QELS.2011.QFD5

  • The Heisenberg picture for single photon states

    Pienaar, Jacques, Myers, Casey and Ralph, Timothy C. (2011). The Heisenberg picture for single photon states. 10th International Conference on Quantum Communication, Measurement and Computing (QCMC), Brisbane, Australia, 19-23 July 2010. Melville, NY, United States: American Institute of Physics. doi: 10.1063/1.3630189

  • Time ordering in spontaneous parametric down-conversion

    Branczyk, Agata M., Stace, Thomas M. and Ralph, T. C. (2011). Time ordering in spontaneous parametric down-conversion. 10th International Conference on Quantum Communication, Measurement and Computing (QCMC), Brisbane, Australia, 19-23 July 2010. Melville, NY, United States: American Institute of Physics. doi: 10.1063/1.3630207

  • Adaptive optical phase estimation

    Nakane, D., Wheatley, T. A., Berry, D. W., Yonezawa, H., Arao, H., Pope, D. T., Ralph, T. C., Wiseman, H. M., Huntington, E. H. and Furusawa, A. (2010). Adaptive optical phase estimation. CLEO/QELS: 2010 Laser Science to Photonic Applications. Conference on Lasers and Electro-Optics (CLEO) and Quantum Electronics and Laser Science Conference (QELS), San Jose, CA, USA, 16-21 May, 2010. Piscataway, NJ, USA: IEEE. doi: 10.1364/CLEO.2010.JThF4

  • Advances in photonic quantum information science

    Politi, Alberto, Matthews, Jonathan C. F., Laing, Anthony, Peruzzo, Alberto, Kalasuwan, Pruet, Zhou, Xiao-Qi, Rodas, Maria, Cryan, Martin J., Rarity, John G., Stefanov, Andre, Ralph, Timothy C., Yu, Siyuan, Thompson, Mark G. and O'Brien, Jeremy L. (2010). Advances in photonic quantum information science. CLEO/QELS: 2010 Laser Science to Photonic Applications. Conference on Lasers and Electro-Optics (CLEO) and Quantum Electronics and Laser Science Conference (QELS), San Jose, CA, USA, 16-21 May, 2010. Piscataway, NJ, USA: IEEE. doi: 10.1364/IPRSN.2010.IMA2

  • Coherent state quantum key distribution with continuous-wave laser beams

    Symul, T., Sharma, V., Ralph, T. C. and Lam, P. K. (2010). Coherent state quantum key distribution with continuous-wave laser beams. OFC/NFOEC 2010: Conference on Optical Fiber Communication, collocated National Fiber Optic Engineers Conference, San Diego, CA, USA, 21-25 March, 2010. Piscataway, NJ, United States: I E E E. doi: 10.1364/OFC.2010.OWC6

  • Event operators and quantum gates

    Pienaar, Jacques and Ralph, Timothy C. (2010). Event operators and quantum gates. FFP10: Tenth International Symposium. Frontiers of Fundamental and Computational Physics 2009, Perth, WA, Australia, 24-26 November, 2009. College Park, MD, United States: American Institute of Physics. doi: 10.1063/1.3460194

  • Generation of a comb of vacuum squeezing over 2.4 GHz for multiplexed communication

    Heurs, M., Webb, J. G., Ralph, T. C. and Huntington, E. H. (2010). Generation of a comb of vacuum squeezing over 2.4 GHz for multiplexed communication. CLEO/QELS: 2010 Laser Science to Photonic Applications. Conference on Lasers and Electro-Optics (CLEO) and Quantum Electronics and Laser Science Conference (QELS), San Jose, CA, USA, 16-21 May, 2010. Piscataway, NJ, USA: IEEE. doi: 10.1364/QELS.2010.QFA2

  • Quantum information science with photonic chips

    Politi, Alberto, Matthews, Jonathan C. F., Laing, Anthony, Peruzzo, Alberto, Kalasuwan, Pruet, Zhou, Xiao-Qi, Verde, Maria Rodas, Rarity, John G., Stefanov, Andre, Ralph, Timothy C., Thompson, Mark G. and O'Brien, Jeremy L. (2010). Quantum information science with photonic chips. ECOC 2010: 36th European Conference and Exhibition on Optical Communication, Torino, Italy, 19-23 September, 201. Piscataway, NJ, United States: Institute of Electrical and Electronics Engineers. doi: 10.1109/ECOC.2010.5621301

  • Full characterization of quantum optical detectors

    Coldenstrodt-Ronge, H. B., Worsley, A. P., Lundeen, J. S., Feito, A., Pregnell, K. L., Silberhorn, Ch., Mosley, P. J., Smith, B. J., Puentes, G., Thomas-Peter, N., Ralph, T. C., Eisert, J., Plenio, M. B. and Walmsley, I. A. (2009). Full characterization of quantum optical detectors. CLEO/Pacific Rim 2009: 8th Pacific Rim Conference on Lasers and Electro-Optics, Shanghai, China, 30 August–3 September, 2009. Piscataway, NJ, USA: IEEE. doi: 10.1109/CLEOPR.2009.5292056

  • Noiseless linear amplification and distillation of entanglement

    Xiang, G. Y., Ralph, T. C., Lund, A. P., Walk, N. and Pryde, Geoff J. (2009). Noiseless linear amplification and distillation of entanglement. ACOLS ACOFT 09, The University of Adelaide, 29/11/09 -3/12/09. South Australia: The University of Adelaide.

  • Nondeterministic noiseless linear amplification of quantum systems

    Ralph, T. C. and Lund, A. P. (2009). Nondeterministic noiseless linear amplification of quantum systems. Quantum Communication, Measurement and Computing (QCMC): Ninth International Conference on QCMC, Calgary, Canada, 19-24 August 2008. United States: American Institute of Physics. doi: 10.1063/1.3131295

  • Quantum optical adaptive phase estimation of sidebands

    Wheatley, T. A., Huntington, E. H., Berry, D. W., Wiseman, H. M. and Ralph, T. C. (2008). Quantum optical adaptive phase estimation of sidebands. Conference on and Quantum Electronics and Laser Science Conference Lasers and Electro-Optics, QELS 2008, San Jose, CA, 4 - 9 May 2008. Piscataway, NJ United States: I E E E. doi: 10.1109/QELS.2008.4553149

  • The CHSH-bell inequality and Tsirelson's bound with postselection

    Berry, D. W., Hyunseok, J., Stobinska, M. and Ralph, T. C. (2008). The CHSH-bell inequality and Tsirelson's bound with postselection. Conference on and Quantum Electronics and Laser Science Conference Lasers and Electro-Optics, QELS 2008, San Jose, CA, 4 - 9 May 2008. Piscataway, NJ United States: I E E E. doi: 10.1109/QELS.2008.4553020

  • The quantum noise limits to simultaneous intensity and frequency stabilization of solid-state lasers

    Huntington, E. H., Harb, C. C., Heurs, M. and Ralph, T. C. (2007). The quantum noise limits to simultaneous intensity and frequency stabilization of solid-state lasers. 2007 European Conference on Lasers and Electro-Optics and the International Quantum Electronics Conference, CLEO, , , June 17, 2007-June 22, 2007. NEW YORK: Optical Society of America. doi: 10.1109/CLEO.2007.4453689

  • Can gravitational curvature induce decorrelation of optical entanglement

    Downes, T., Milburn, G. J. and Ralph, T. C. (2007). Can gravitational curvature induce decorrelation of optical entanglement. Quantum Communications and Quantum Imaging V, San Diego, USA, 26 August 2007. BELLINGHAM: SPIE-INT SOC OPTICAL ENGINEERING. doi: 10.1117/12.740085

  • Continuous variable quantum cryptography: Post-selection with thermal noise

    Assad S., Alton D.J., Symul T., Lam P.K., Weedbrook C. and Ralph T. (2007). Continuous variable quantum cryptography: Post-selection with thermal noise. 2007 European Conference on Lasers and Electro-Optics and the International Quantum Electronics Conference, CLEO, Munich, June 17, 2007-June 22, 2007. doi: 10.1109/CLEOE-IQEC.2007.4386770

  • Improving fidelity of skewed output states of optical zeno gates

    Leung P.M. and Ralph T.C. (2007). Improving fidelity of skewed output states of optical zeno gates. 2007 Quantum Electronics and Laser Science Conference, QELS, Baltimore, MD, May 6, 2007-May 11, 2007. doi: 10.1109/QELS.2007.4431700

  • Measuring photon anti-bunching from sideband squeezing with continuous-variable techniques

    Grosse N.B., Symul T., Stobinska M., Ralph T.C. and Lam P.K. (2007). Measuring photon anti-bunching from sideband squeezing with continuous-variable techniques. 2007 European Conference on Lasers and Electro-Optics and the International Quantum Electronics Conference, CLEO, Munich, June 17, 2007-June 22, 2007. Optical Society of America. doi: 10.1109/CLEOE-IQEC.2007.4386953

  • Schrodinger cat states for quantum information processing

    Jeong, Hyunseok and Ralph, Timothy C. (2007). Schrodinger cat states for quantum information processing. Quantum Information Processing and Communication Workshop, Prague Czech Republic, 2005. COVENT GARDEN: IMPERIAL COLL PRESS. doi: 10.1142/9781860948169_0009

  • A complete quantum cryptographic system using a continuous wave laser

    Sharma, Vikram, Lance, Andrew M., Symul, Thomas, Weedbrook, Christian, Ralph, Timothy C. and Lam, Ping Koy (2006). A complete quantum cryptographic system using a continuous wave laser. Conference on Microelectronics - Design, Technology and Packaging II, Brisbane Australia, Dec 12-14, 2005. BELLINGHAM: SPIE-INT SOC OPTICAL ENGINEERING. doi: 10.1117/12.651721

  • A model for non-linear quantum evolution based on time displaced entanglement

    Ralph, T. C. (2006). A model for non-linear quantum evolution based on time displaced entanglement. Quantum Communications and Quantum Imaging IV, San Diego, USA, 13 August, 2006. Bellingham, USA: SPIE. doi: 10.1117/12.680097

  • Efficient coherent state quantum computing by adaptive measurements

    Lund A.P. and Ralph T.C. (2006). Efficient coherent state quantum computing by adaptive measurements. Quantum Electronics and Laser Science Conference, QELS 2006, Long Beach, CA, May 21, 2006-May 21, 2006. Optical Society of America. doi: 10.1109/CLEO.2006.4628964

  • Homodyne measurement of average photon number

    Webb, J. G., Ralph, T. C. and Huntington, E. H. (2006). Homodyne measurement of average photon number. Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference, CLEO/QELS 2006, , , May 21, 2006-May 26, 2006. Optical Society of America. doi: 10.1109/CLEO.2006.4628675

  • Successful quantum key distribution with simultaneous quadrature measurement in the presence of 90% line loss

    Symul, T., Lance, A. M., Sharma, V., Lam, P. K., Weedbrook, C. and Ralph, T. C. (2005). Successful quantum key distribution with simultaneous quadrature measurement in the presence of 90% line loss. doi: 10.1109/EQEC.2005.1567468

  • Using entanglement in photonic qubit measurements

    Pryde, G. J., O'Brien, J. L., White, A. G., Ralph, T. C., Bartlett, S. D. and Wiseman, H. M. (2005). Using entanglement in photonic qubit measurements. Optics and photonics 2005: Quantum Communications and Quantum Imaging III, San Diego, CA, United States, 31 July - 4 August 2005. Bellingham, WA, United States: S P I E - International Society for Optical Engineering. doi: 10.1117/12.616166

  • Coherent manipulation of quantum optical sideband modes

    Huntington, E. H., Milford, G. N., Robilliard, C. and Ralph, T. C. (2005). Coherent manipulation of quantum optical sideband modes. Optical Society of America. doi: 10.1109/qels.2005.1548743

  • Quantum gate characterization in an extended Hilbert space

    Rohde, Peter P., Pryde, G. J., O'Brien, J. L. and Ralph, Timothy C. (2005). Quantum gate characterization in an extended Hilbert space. Optical Society of America.

  • Linear optical quantum computation with parity encoding

    Gilchrist A., Hayes A.J.F. and Ralph T.C. (2005). Linear optical quantum computation with parity encoding. 2005 Quantum Electronics and Laser Science Conference (QELS), Baltimore, MD, May 22, 2005-May 27, 2005. Optical Society of America. doi: 10.1109/qels.2005.1548654

  • Investigation of two qubit quantum gates in linear optics

    Ralph, T. C., Langford, N. K., Bell, T. B., O'Brien, J. L., Pryde, G. J., White, A. G. and Milburn, G. J. (2004). Investigation of two qubit quantum gates in linear optics. Quantum Communications and Quantum Imaging, San Diego, USA, 6-8 August 2003. Bellingham, WA, U.S.A.: SPIE. doi: 10.1117/12.505078

  • Photon number diagram for characterizing continuous variable entanglement. , pp. 315-323

    Bowen, W. P., Hsu, M. T. L., Symul, T., Lance, A. M., Buchler, B. C., Schnabel, R., Treps, N., Bachor, H.-A., Ralph, T. C. and Lam, P. K. (2004). Photon number diagram for characterizing continuous variable entanglement. , pp. 315-323. Laser Spectroscopy, Palm Cove, Queensland Australia, 14th -18th July, 2003. SINGAPORE: WORLD SCIENTIFIC PUBL CO PTE LTD. doi: 10.1142/9789812703002_0048

  • An experimental investigation of criteria for continuous variable entanglement

    Bowen, W. P., Schnabel, R., Treps, N., Bachor, H. A., Lam, P. K. and Ralph, T. C. (2003). An experimental investigation of criteria for continuous variable entanglement. Trends in Optics and Photonics Series: Quantum electronics and Laser Science (QELS), , , June 1, 2003-June 6, 2003. Institute of Electrical and Electronics Engineers Inc.. doi: 10.1109/EQEC.2003.1314210

  • Construction of a non-deterministic 2-photon CNOT gate

    O'Brien, J. L., Pryde, G. J., White, A. G., Ralph, T. C., Bell, T. B., Langford, N. K. and Milburn, G. J. (2003). Construction of a non-deterministic 2-photon CNOT gate. Trends in Optics and Photonics Series: Quantum electronics and Laser Science (QELS), Baltimore, MD, United States, 1-6 June 2003. Washington, DC, United States: Institute of Electrical and Electronics Engineers. doi: 10.1109/QELS.2003.237941

  • Continuous variable quantum teleportation and quantum secret sharing

    Lam, P. K., Bowen, W. P., Treps, N., Buckler, B. C., Schnabel, R., Symul, T., Lance, A. M., Sanders, B. C., Tyc, T. and Ralph, T. C. (2003). Continuous variable quantum teleportation and quantum secret sharing. 2003 European Quantum Electronics Conference, EQEC 2003, Munich, Germany, 22-27 June 2003. Piscataway, NJ United States: Institute of Electrical and Electronics Engineers. doi: 10.1109/EQEC.2003.1314268

  • Continuous-variable polarization entanglement

    Korolkova, N, Heersink, J, Silberhorn, C, Leuchs, G, Ralph, TC and Loudon, R (2003). Continuous-variable polarization entanglement. 6th International Conference on Quantum Communication, Measurement and Computing (QCMC 02), Cambridge Ma, Jul 22-26, 2002. PRINCETON: RINTON PRESS, INC.

  • Efficient linear optical quantum computation

    Pryde, G.J., O'Brien, J.L., Bell, T.B., Langford, N.K., Milburn, G.J., Ralph, T.C. and White, AG (2003). Efficient linear optical quantum computation. 6th International Conference on Quantum Communication, Measurement and Computing (QCMC 02), Cambridge, MA, United States, 22-26 July 2002. Princeton, NJ, United States: Rinton Press.

  • Efficient linear optics quantum computation

    Gilchrist, A., Kendon, V., Milburn, G. J., Munro, W. J., Ralph, T. C. and White, A. G. (2003). Efficient linear optics quantum computation. 6th International Conference on Quantum Communication, Measurement and Computing (QCMC 02), Cambridge, Massachusetts USA, 22-26 July 2002. New Jersey, USA: Rinton Press.

  • Efficient linear optics quantum computation

    Milburn, G.J., Ralph, T., Gilchrist, A., White, A., Munro, W.J. and Kendon, V (2003). Efficient linear optics quantum computation. 6th International Conference on Quantum Communication, Measurement and Computing (QCMC 02), Cambridge, MA, United States, 22-26 July 2002. Princeton, NJ, United States: Rinton Press.

  • Experimental linear optics controlled-NOT gates

    Pryde G.J., O'Brien J.L.O., White A.G., Ralph T.C., Bell T.B., Langford N.K. and Milburn G.J. (2003). Experimental linear optics controlled-NOT gates. European Quantum Electronics Conference, EQEC 2003, Munich, , June 22, 2003-June 27, 2003. Institute of Electrical and Electronics Engineers Inc.. doi: 10.1109/EQEC.2003.1314242

  • Optical experiments beyond the quantum limit: Squeezing entanglement and teleportation

    Schnabel, R., Bowen, W. P., Treps, N., Buchler, B. C., Ralph, T. C., Lam, P. K. and Bachor, H. A. (2003). Optical experiments beyond the quantum limit: Squeezing entanglement and teleportation. Russian Federation: Optical Society of America. doi: 10.1134/1.1576832

  • Optical squeezing in temporal, polarization, and spatial domains

    Symul, T., Bowen, W. P., Schnabel, R., Treps, N., Buchler, B. C., Ralph, T. C., Lance, A. M., Grosse, N. B., Dolinska, A., Wu, J. W., Gao, J. R., Fabre, C., Bachor, H.-A. and Lam, P. K. (2003). Optical squeezing in temporal, polarization, and spatial domains. Fluctuations and Noise in Photonics and Quantum Optics II, Santa Fe, NM, USA, 2nd June, 2003. Bellingham, USA: SPIE. doi: 10.1117/12.497081

  • Quantum computation based on linear optics

    Ralph, T. C., Munro, W. J. and Milburn, G. J. (2003). Quantum computation based on linear optics. Quantum Optics in Computing and Communications, Shanghai, China, 16 October 2002. Bellingham, USA: SPIE. doi: 10.1117/12.483016

  • Quantum computation with coherent states

    Gilchrist, A., Ralph, T.C., Munro, W.J. and Milburn, G.J. (2003). Quantum computation with coherent states. 6th International Conference on Quantum Communication, Measurement and Computing (QCMC 02), Cambridge, MA, United States, 22-26 July 2002. Princeton, NJ, United States: Rinton Press.

  • Quantum information processing with Schrodinger cats

    Nemoto, K., Gilchrist, A. G., Munro, W. J., Ralph, T. C., Braunstein, S. L. and Milburn, G. J. (2003). Quantum information processing with Schrodinger cats. Fluctuations and Noise in Photonics and Quantum Optics, Santa Fe, NM, USA, 2 June, 2003. Bellingham, USA: SPIE. doi: 10.1117/12.497230

  • Optical quantum information processing: Experiments with CW laser light

    Bachor, HA, Lam, PK, Bowen, W, Schnabel, R, Bennetts, S, Buchler, B, Andersen, UL and Ralph, TC (2001). Optical quantum information processing: Experiments with CW laser light. 1st International Conference on Experimental Implementation of Quantum Computation, Sydney Australia, Jan 16-19, 2001. PRINCETON: RINTON PRESS, INC.

  • Optical quantum information processing: experiments with CW laser light

    Bachor, Hans-A., Lam, P. K., Bowen, W. P., Schnabel, R., Bennetts, S., Buchler, B. C. and Ralph, T. C. (2001). Optical quantum information processing: experiments with CW laser light. 1st International Conference on Experimental Implementation of Quantum Computation, Australian National Maritime Museum, Sydney, 16th-19th January, 2001. Rinton Press Inc.

  • Teleportation criteria: form and signifcance

    Ralph, T. C. (2001). Teleportation criteria: form and signifcance. TAMU-ONR Workshop, Jackson, Wyoming, USA, 26-30 July, 1999. Berlin / Heidelberg: Springer. doi: 10.1007/3-540-40894-0_17

  • Bell-type correlations from continuous variable measurements

    Ralph, T. C., Munro, W. J. and Polkinghorne, R. (2000). Bell-type correlations from continuous variable measurements. AIP 2000, Adelaide University, 10-15 Dec, 2000. Australia: Australian Institute of Physics.

  • Quantum information with continuous variables

    Ralph, T. C. (2000). Quantum information with continuous variables. 2000 IQEC, Nice Acropolis, France, 10-15 September, 2000. US: IEEE.

  • Quantum key distribution with continuous variables

    Ralph, T. C. (2000). Quantum key distribution with continuous variables. QELS 2000, The Moscone Convention Center, San Francisco, California, 7-12 May, 2000. US: Optical Society of America.

  • Feedback control of the intensity noise of injection locked lasers

    Huntington, EH, Harb, CC, Buchler, BC and Ralph, TC (1999). Feedback control of the intensity noise of injection locked lasers. Conference on Laser Resonators II, San Jose Ca, Jan 27-29, 1999. BELLINGHAM: SPIE-INT SOC OPTICAL ENGINEERING. doi: 10.1117/12.349268

  • Experiments and theory of laser noise: Consequences for squeezing and injection locking

    Bachor, HA, Taubman, MS, Ralph, TC, Harb, CC, White, AG and McClelland, DE (1996). Experiments and theory of laser noise: Consequences for squeezing and injection locking. ICONO 95 Conference - Atomic and Quantum Optics: High-Precision Measurements, St Petersburg Russia, Jun 27-Jul 01, 1995. BELLINGHAM: SPIE - INT SOC OPTICAL ENGINEERING. doi: 10.1117/12.239824

  • Progress in the Search for the Optimum Light-Source - Squeezing Experiments with a Frequency Doubler

    Bachor, HA, Ralph, TC, Taubman, MS, White, AG, Harb, CC and McClelland, DE (1995). Progress in the Search for the Optimum Light-Source - Squeezing Experiments with a Frequency Doubler. Workshop on Non-Classical Light/Satellite Meeting on Application of Techniques and Methods of Non-Classical Light - Gravitational Wave Detection, Quantum Cryptography and Quantum Computing, Corvara Italy, Jan 28-Feb 04, 1995. BRISTOL: IOP PUBLISHING LTD. doi: 10.1088/1355-5111/7/4/024

Other Outputs

Grants (Administered at UQ)

PhD and MPhil Supervision

Current Supervision

  • Advancements in quantum information protocols using quantum optics

    Doctor Philosophy — Principal Advisor

    Other advisors:

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

    Doctor Philosophy — Principal Advisor

    Other advisors:

  • Quantum mechanics near closed timelike curves

    Doctor Philosophy — Principal Advisor

  • Quantum effects in general relativistic spacetimes

    Master Philosophy — Principal Advisor

  • Demonstration of relativistic Bohmian trajectories of photons

    Doctor Philosophy — Associate Advisor

    Other advisors:

  • Practical applications of quantum sampling algorithms

    Doctor Philosophy — Associate Advisor

    Other advisors:

Completed Supervision

Possible Research Projects

Note for students: The possible research projects listed on this page may not be comprehensive or up to date. Always feel free to contact the staff for more information, and also with your own research ideas.

  • 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.

This staff member is a UQ Expert for media in the following fields:

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

They are happy to lend their expertise to your articles or broadcasts and share their research discoveries and insights with the community via media channels.

For additional assistance with story ideas, general advice and information or help with seeking further experts, please email the UQ Media Team or telephone (07) 3365 1120.

Links

ResearcherID: A-1858-2011

ORCID: 0000-0003-0692-8427

Personal Profile: Link

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