Debbie Leung profile picture

Institute for Quantum Computing (IQC)

Research Associate Faculty

Areas of research: Quantum Information

(519) 888-4567 x33604

http://www.math.uwaterloo.ca/~wcleung/

Research Interests
I study the capacity of communicating various form of data (quantum, private, or classical) through quantum channels, focusing on the superadditivity phenomenon. I also study how quantum entanglement, in particular, embezzlement of entanglement, plays a role in quantum information theory.
Positions Held
  • Tolman Postdoctoral Fellow, Theoretical Physics Institute for Quantum Information, Caltech, 2002-2005
  • Postdoctoral Fellow, Quantum Computation Mathematical Sciences Research Institute, Berkeley, 2002
  • Postdoctoral Fellow, Information group IBM T.J. Watson Research Center, 2000-2002
Awards
  • Alliance International Collaboration UKRI Quantum Grant (ALLRP), Natural Sciences and Engineering Research Council of Canada, 2025
  • NSERC Discovery grant, Natural Sciences and Engineering Research Council of Canada, 2024
  • NSERC QUORUM project, Natural Sciences and Engineering Research Council of Canada, 2023
  • Discovery Grant, Natural Sciences and Engineering Research Council of Canada (NSERC), 2016-2024
Recent Publications
  • Khanian, Z. B., & Leung, D. (2025). Quantum Reverse Shannon Theorem Revisited. arxiv:2504.07068v1
  • Grier, D., Leung, D., Li, Z., Pashayan, H., & Schaeffer, L. (2025). Streaming quantum state purification for general mixed states. arxiv:2503.22644v1
  • Liu, A. Z., & Leung, D. (2025). Fault-tolerant Preparation of Distant Logical Bell Pair -- with application in the magic square game. arxiv:2503.13673v1
  • Khanian, Z. B., Kuroiwa, K., & Leung, D. (2025). Rate-Distortion Theory for Mixed States. IEEE Transactions on Information Theory, 71(2), 1077-1095. doi:10.1109/tit.2024.3509825
  • Childs, A. M., Fu, H., Leung, D., Li, Z., Ozols, M., & Vyas, V. (n.d.). Streaming quantum state purification. Quantum, 9, 1603. doi:10.22331/q-2025-01-21-1603
  • Asadi, V. R., Kuroiwa, K., Leung, D., May, A., Pasterski, S., & Waddell, C. (2024). Conditional disclosure of secrets with quantum resources. doi:10.48550/arxiv.2404.14491
  • Khanian, Z. B., Kuroiwa, K., & Leung, D. (2023). Rate-Distortion Theory for Mixed States. In 2023 IEEE International Symposium on Information Theory (ISIT) Vol. 00 (pp. 749-754). Institute of Electrical and Electronics Engineers (IEEE). doi:10.1109/isit54713.2023.10206960
  • Leditzky, F., Leung, D., Siddhu, V., Smith, G., & Smolin, J. A. (2023). The Platypus of the Quantum Channel Zoo. IEEE Transactions on Information Theory, 69(6), 3825-3849. doi:10.1109/tit.2023.3245985
  • Leditzky, F., Leung, D., Siddhu, V., Smith, G., & Smolin, J. A. (2023). Generic Nonadditivity of Quantum Capacity in Simple Channels. Physical Review Letters, 130(20), 200801. doi:10.1103/physrevlett.130.200801
  • Kuroiwa, K., & Leung, D. (2023). Rate reduction of blind quantum data compression with local approximations based on the unstable structure of quantum states. Physical Review A, 107(5), 052421. doi:10.1103/physreva.107.052421
  • Girard, M., Leung, D., Levick, J., Li, C. -K., Paulsen, V., Poon, Y. T., & Watrous, J. (2022). On the Mixed-Unitary Rank of Quantum Channels. Communications in Mathematical Physics, 394(2), 919-951. doi:10.1007/s00220-022-04412-y
  • Khanian, Z. B., Kuroiwa, K., & Leung, D. (2022). Rate-Distortion Theory for Mixed States. doi:10.48550/arxiv.2208.11698
  • Tansuwannont, T., & Leung, D. (2022). Achieving Fault Tolerance on Capped Color Codes with Few Ancillas. PRX Quantum, 3(3), 030322. doi:10.1103/prxquantum.3.030322
  • Leditzky, F., Leung, D., Siddhu, V., Smith, G., & Smolin, J. A. (2022). The platypus of the quantum channel zoo. In 2022 IEEE International Symposium on Information Theory (ISIT) Vol. 00 (pp. 2433-2438). Institute of Electrical and Electronics Engineers (IEEE). doi:10.1109/isit50566.2022.9834678
  • Anshu, A., Leung, D., & Touchette, D. (2022). Incompressibility of Classical Distributions. IEEE Transactions on Information Theory, 68(3), 1758-1771. doi:10.1109/tit.2021.3130131
Seminars
  • Purifying noisy quantum states, Bristol Quantum Information Theory seminar, University of Bristol, 2024/12/04
  • The platypus of the quantum channel zoo and their generic nonadditivity, 2024/10/26
  • Purifying arbitrarily noisy quantum states, Hong Kong University of Science and Technology (Guangzhou), Quantum Information Tech Salon (QITS), 2024/10/10
  • Purifying arbitrarily noisy quantum states, Tutte colloquium, University of Waterloo, Combinatorics and Optimization, 2024/10/04
  • Christopher King Memorial Lecture, Beyond IID in Information Theory 12, University of Illinois Urbana-Champaign, Jul 29 -- Aug 02, 2024., 2024/07/31
  • Quantum Information and Computation, Stanford Program for Inspiring the Next Generation of Women in Physics (SPINWIP), Stanford University, Palo Alto (virtual). July 8-26, 2024., 2024/07/16
  • Additive quantities cannot be more than asymptotically continuous, InQubator for Quantum Simulation seminar, University of Washington, Seattle (virtual)., 2024/05/01
  • The platypus of the quantum channel zoo, Quantum Information and Computing seminar, Texas Tech University, Lubbock (virtual)., 2024/04/17
  • Purifying arbitrarily noisy quantum states, 2024 Center for Quantum Frontiers of Research \& Technology (QFort) Workshop, National Cheng Kung University, Tainan, Taiwan. April 15-17, 2024, 2024/04/17
  • Purifying arbitrarily noisy quantum states, Fundamental Limitations to Quantum Computation, Banff International Research Station, Alberta, Canada. March 4-8, 2024., 2024/03/07
  • Quantum state purification, Quantum Information Workshop, SwissMAP Research Station, Les Diablerets, Switzerland. February 26 - March 02, 2024., 2024/02/26
  • The platypus of the quantum channel zoo and their generic nonadditivity, Southwest Quantum Information and Technology, 25th Annual SQuInT Workshop, University of New Mexico, Albuquerque, New Mexico. October 26-28, 2023, 2023/10/26
  • Rate-Distortion Theory for Mixed States, Analytical and Combinatorial Methods in Quantum Information Theory II, International Centre for Mathematical Sciences, Edinburgh, United Kingdom, 2023/07/28
  • Rate distortion theory for mixed state quantum data compression, CMS meeting, University of Ottawa, 2023/06/03
  • Quantum channel capacities and the platypus of the quantum channel zoo, Quantum Days 2023, Quantum Information Theory session, 2023/01/18
  • The platypus of the quantum channel zoo and their generic nonadditivity, CMS 2022 Winter Meeting, Toronto, 2022/12/04