2018 PhD Graduations

This year we have seven students graduating from our centre. It is hard to say goodbye, but we are also thrilled to see that all of them will continue their academic pursuit in world-leading institutions. Below is a brief description of each of our graduating student’s achievements and future plans. Congratulations and we wish you all a brilliant future! QSI is proud of all of you!

Yinan Li
(Principal supervisor: Runyao Duan, co-supervisor: Youming Qiao)

Yinan has started as a postdoc at the Centrum Wiskunde & Informatica (CWI) of Netherlands, hosted by Prof Ronald de Wolf and Asst/Prof Michael Walter. His research during his PhD spanned from quantum information and computation to computational complexity. He published several papers joint with CQSI members, including one at the Communications in Mathematical Physics (CMP) and one at
the Annual Symposium on Foundations of Computer Science (FOCS). The CMP paper tackles the tripartite to bipartite entanglement transformation by SLOCC, and the FOCS paper makes progress on a hard instance of the group isomorphism problem.

Xin Wang
(Supervisor: Runyao Duan, external supervisor: Andreas Winter)

Xin completed his PhD in quantum information in 2018. His thesis, ‘Semidefinite Optimization for Quantum Information’, uses convex optimization to study the structure of quantum entanglement and the limitations of information processing in a quantum world. The results in his thesis were presented as four talks in the top-tier conference Quantum Information Processing (QIP) and published in top-tier refereed journals such as Physical Review Letters and IEEE Transactions on Information Theory (11 publications in top-tier refereed journals including PRL, TIT, and CMP). He developed quantitative approaches to exploit the power of entanglement and, in particular, proved the irreversibility of a well-motivated entanglement theory, resolving a long-standing open problem in quantum information theory. He notably established a systematic framework of semidefinite programs to evaluate the communication capabilities of quantum channels. Moreover, he separated the quantum Lovász number and the entanglement-assisted zero-error capacity, resolving an intriguing open problem in zero-error information theory. Starting from this September, he will be a Hartree Postdoctoral Fellow at the Joint Center for Quantum Information and Computer Science (QuICS) at the University of Maryland, College Park.

Shufeng Kong
(Supervisor: Sanjiang Li)

Shufeng did his PhD research on constraint propagation, a central process in solving (distributed) constraint satisfaction problems (CSPs). His PhD studies focused on efficient local consistency algorithms including arc-consistency and (directional) path-consistency in a distributed manner, which will be helpful to model and solve many practical problems in planning and scheduling in an efficient and distributed way while protecting the privacy of individual agents. During his PhD study, he published six high-quality research articles, including leading international journal articles in the Journal of Autonomous Agents and Multi-Agent Systems, The Computer Journal, and Annals of Mathematics and Artificial Intelligence, as well as top international conference presentations in CP (2015), AAMAS (2017) and AAAI (2018). He submitted his PhD thesis on Jun 29, 2018, and will continue his research as a Postdoctoral researcher at Cornell University under the supervision of Profs Carla Gomes and Bart Selman, both of whom are Fellows of AAAI.

Ryan Mann
(Supervisor: Michael Bremner)

Ryan's research has been on the complexity of combinatorial structures and how this influences the complexity of quantum computers. This has seen him craft a conjecture that links the average-case complexity of the Jones polynomial to the complexity of quantum circuit sampling. More recently he has identified a new FPTAS for the Ising model that extends the region that is classically efficiently computable. This work was invited to a workshop organised by Prof Alistair Sinclair from UC Berkeley. From 2018 to 2019, Ryan worked with UTS QSI as a postdoctoral research associate.  Dr Ryan Mann is now Research Associate with the University of Bristol.  Here, he studies the relationship between quantum physics and combinatorial structures to answer problems arising in quantum algorithms and complexity. The combinatorial structures that he works with include the Tutte polynomial in algebraic graph theory and matroid theory, the Jones polynomial in knot theory, and the Ising-Potts polynomial in statistical physics.

Kun Fang
(Supervisor: Runyao Duan and Mingsheng Ying)

Kun’s thesis is titled Distillation and Simulation in Quantum Information. During his PhD study, Mr. Fang used the techniques of convex optimization, especially semidefinite programming, to study two kinds of fundamental tasks, i.e., distillation and simulation in quantum information theory. He investigated these tasks in a unified framework of resource theory and focused on their computation and characterization with finite resources. In particular, his research on quantum coherence theory (two accepted papers by Physical Review Letters) contributed to a better understanding of the operational power of different free operations. After his graduation, he will do his postdoc with Hamza Fawzi in the Department of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge.

Ji Guan
(Principal supervisor: Mingsheng Ying, co-supervisor: Yuan Feng)

Ji started his PhD at UTS:QSI in August 2014. He has been working on the theory and application of quantum Markov chains, a very important topic in the analysis of quantum protocols and programs, and has produced a stream of important achievements that impact the research field. For example, he (with his collaborators) developed a new decomposition technique, namely periodic decomposition, for quantum Markov chains, and gave several characterizations of limiting states in terms of aperiodicity and irreducibility. He also presented a new algorithm to find a maximum dimensional noiseless subsystem using the decomposition techniques. This work has been published in Journal of Computer and System Sciences. He is also interested in super-activation of quantum memory with entanglement and found some interesting new phenomena which distinguish classical memory cells and quantum memory cells. He will continue his research as a Postdoctoral researcher at the Institute of Software, Chinese Academy of Sciences.

Hao-Chung Cheng
(Supervisor: Min-Hsiu Hsieh)

Hao-Chung's scientific research interests include classical and quantum information theory, statistical signal processing, coding theory and machine learning. During his PhD, Hao-Chung has built an outstanding track record. He has five journal publications, seven refereed conference proceedings, and two preprints on arXiv. His work has been widely recognized with invited/contributed talks at international conferences on Information theory (ITW/ISIT) and the most prestigious quantum information workshop (QIP). He is currently a Research Associate with A/Professor Min-Hsiu Hsieh at UTS, and he will join Centre for Mathematical Sciences, Department of Applied Mathematics and Theoretical Physics, University of Cambridge as a Postdoctoral Fellow.