## Yi-Kai LiuI am a staff scientist at the National Institute of Standards and Technology (NIST), in the Applied and Computational Mathematics Division. I am also a Fellow and adjunct professor at the NIST-UMD Joint Center for Quantum Information and Computer Science (QuICS). I do research on quantum computation and theoretical computer science, in particular, quantum algorithms and complexity, quantum state tomography, machine learning, and quantum cryptography. Previously I was a postdoc in Computer Science at UC Berkeley, and a postdoc at the Institute for Quantum Information at Caltech. I received a PhD in computer science from UC San Diego, and a BA in mathematics from Princeton. You can reach me via e-mail at:yi-kai.liu |at| nist |dot| gov or at: yikailiu00 |at| gmail |dot| com
This page was last updated on: July 26, 2017. ## Some Recent TalksQuantum System Tomography, ARO/LPS Workshop on Quantum Characterization, Verification and Validation (QCVV), July 2017. QuICS is hosting QCrypt 2016, the 6th International Conference on Quantum Cryptography, Sept. 12-16, 2016, in Washington, DC! Tamper-Resistant Cryptographic Hardware in the Isolated Qubits Model, QCrypt 2014. Universal Low-rank Matrix Recovery using Pauli Measurements, 2012. Low-rank Methods for Learning Quantum States (joint work with S. Becker, B. Brown, J. Eisert, S. T. Flammia and D. Gross), Workshop on Low-rank Methods for Large-scale Machine Learning, NIPS 2010. Preparing Lattice Superpositions on a Quantum Computer, Workshop on Post-Quantum Information Security, Joint Quantum Institute, Oct. 2010. N-representability is QMA-complete (joint work with M. Christandl and F. Verstraete), Workshop on Quantum Marginals and Density Matrices, Fields Institute, July 2009. Quantum Algorithms Using the Curvelet Transform, STOC 2009. ## News ArticlesY.-K. Liu, "Quantum information: Show, don't tell," C. Boutin, "Quantum Physics Could Make Secure, Single-Use Computer Memories Possible," ## TeachingCS138 Computer Algorithms, Spring 2009 (a course on approximation algorithms for combinatorial optimization, at Caltech). ## Papers (or try the handy Arxiv listing)## Quantum CryptographyP. Bierhorst, E. Knill, S. Glancy, A. Mink, S. Jordan, A. Rommal, Y.-K. Liu, B. Christensen, S. W. Nam, L. K. Shalm, "Experimentally Generated Random Numbers Certified by the Impossibility of Superluminal Signaling," Arxiv:1702.05178. Y.-K. Liu, "Privacy amplification in the isolated qubits model," Y.-K. Liu, "Single-shot security for one-time memories in the isolated qubits model," Y.-K. Liu, "Building One-Time Memories from Isolated Qubits," ## Quantum State Tomography, and Machine LearningC. Shen, R. W. Heeres, P. Reinhold, L. Jiang, Y.-K. Liu, R. J. Schoelkopf, and L. Jiang, "Optimized Tomography of Continuous Variable Systems Using Excitation Counting," S. Kimmel and Y.-K. Liu, "Phase Retrieval Using Unitary 2-Designs," F. Krahmer and Y.-K. Liu, "Phase Retrieval Without Small-Ball Probability Assumptions," arXiv:1604.07281. - F. Krahmer and Y.-K. Liu, "Phase Retrieval Without Small-Ball Probability Assumptions: Stability and Uniqueness,"
*SampTA 2015*, pp.411-414, [link]. - F. Krahmer and Y.-K. Liu, "Phase Retrieval Without Small-Ball Probability Assumptions: Recovery Guarantees for PhaseLift,"
*SampTA 2015*, pp.622-626, [link].
J. Conroy, S. T. Davis, J. Kubina, Y.-K. Liu, D. P. O’Leary and J. D Schlesinger, "Multilingual Summarization: Dimensionality Reduction and a Step Towards Optimal Term Coverage," S. T. Flammia, D. Gross, Y.-K. Liu and J. Eisert, "Quantum Tomography via Compressed Sensing: Error Bounds, Sample Complexity, and Efficient Estimators," A. Anandkumar, D. P. Foster, D. Hsu, S. M. Kakade and Y.-K. Liu, "A Spectral Algorithm for Latent Dirichlet Allocation," M. Ohliger, V. Nesme, D. Gross, Y.-K. Liu and J. Eisert, "Continuous-variable quantum compressed sensing," ArXiv:1111.0853. S. T. Flammia and Y.-K. Liu, "Direct Fidelity Estimation from Few Pauli
Measurements," Y.-K. Liu, "Universal low-rank matrix recovery from Pauli
measurements," M. Cramer, M. B. Plenio, S. T. Flammia, R. Somma, D. Gross, S. D.
Bartlett, O. Landon-Cardinal, D. Poulin and Y.-K. Liu, "Efficient Quantum
State Tomography," O. Landon-Cardinal, Y.-K. Liu and D. Poulin, "Efficient Direct Tomography for Matrix Product States," ArXiv:1002.4632. D. Gross, Y.-K. Liu, S.T. Flammia, S. Becker and J. Eisert, "Quantum
state tomography via compressed sensing," ## Quantum Algorithms and ComplexityA. D. Bookatz, S. P. Jordan, Y.-K. Liu and P. Wocjan, "Quantum nonexpander problem is quantum-Merlin-Arthur-complete,"Phys. Rev. A 87, 042317 (2013) [link]; ArXiv:1210.0787.A. Ambainis, A. M. Childs and Y.-K. Liu, "Quantum property testing for bounded-degree graphs," Y.-K. Liu, "Quantum Algorithms Using the Curvelet Transform,"
Y.-K. Liu, "The Local Consistency Problem for Stoquastic and 1-D Quantum Systems," submitted. ArXiv:0712.1388. Y.-K. Liu, "The Complexity of the Consistency and N-representability Problems for Quantum States," PhD thesis, Univ. of California, San Diego, 2007. ArXiv:0712.3041. Y.-K. Liu, M. Christandl and F. Verstraete, "N-representability is
QMA-complete," Y.-K. Liu, "Consistency of Local Density Matrices is QMA-complete,"
## Other TopicsY.-K. Liu, V. Lyubashevsky and D. Micciancio, "On Bounded Distance
Decoding for General Lattices," Y.-K. Liu, "Gibbs States and the Consistency of Local Density
Matrices," Arxiv preprint:
quant-ph/0603012.
K. Levchenko and Y.-K. Liu, "Counting Solutions of Polynomial Equations"
[pdf].
A. Blanc, Y.-K. Liu and A. Vahdat, "Designing Incentives for
Peer-to-Peer Routing," My undergraduate senior thesis: original version or revised version (Aug. 26, 2002). ## Useful LinksNIST: QuICS seminar / Math Division seminar / Crypto reading groupBerkeley: EECS Department Calendar / Theory seminars / Quantum reading group Caltech: IQI Seminars / Physics Research Conference / CS Theory Seminar / IST Seminars / Technique (campus guide) |