Professor Timothy Ralph

Professor

School of Mathematics and 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

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

Publications

View all Publications

Supervision

  • Doctor Philosophy

  • Doctor Philosophy

  • Doctor Philosophy

View all Supervision

Available Projects

  • 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 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.

  • 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

  • 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

  • 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.

  • 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

  • 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.

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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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.

  • 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

  • Rahimi-Keshari, Saleh, Ralph, Timothy C. and Caves, Carlton M. (2016). Efficient classical simulation of quantum-optics experiments. CLEO: QELS Fundamental Science 2016, San Jose, CA United States, 5–10 June 2016. Washington, DC United States: Optica. doi: 10.1364/CLEO_QELS.2016.FTh4C.2

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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.

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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.

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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.

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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.

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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.

  • 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.

  • 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.

  • 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.

  • 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

  • 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

  • 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

  • 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

  • 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.

  • 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

  • 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.

  • 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.

  • 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

  • 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.

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

  • 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.

  • 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

  • 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

  • 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

  • Doctor Philosophy — Principal Advisor

  • Doctor Philosophy — Principal Advisor

  • Doctor Philosophy — Principal Advisor

  • Doctor Philosophy — Principal Advisor

  • Doctor Philosophy — Principal Advisor

  • Master Philosophy — Principal Advisor

  • Doctor Philosophy — Associate Advisor

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.

  • 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 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.

  • 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.