 Research
 Introduction
 Facilities
 Research Groups
 Astronomy and Astrophysics Group
 Atomic, Optical and Quantum Physics Group
 Experimental Condensed Matter and Material Science Group
 Theoretical and Computational Condensed Matter Group
 Experimental Nuclear and Particle Physics Group
 Area of Excellence Project
 HKUUCAS Joint Institute of Theoretical and Computational Physics
 Laboratory for Space Research
 Publications
 Prof. W. Yao and Prof. X.D. Cui’s paper titled ‘Valley polarization in MoS_{2} monolayers by optical pumping’ was highlighted in Ars Technica.
Highlight in Ars Technica
Atomic, Optical and Quantum Physics Group
People
Academic staff 
Research staff 
Students 
Prof. Hoi Fung CHAU Prof. Hoi Kwong LO Dr. Tran Trung LUU Prof. Zidan WANG Dr. Shizhong ZHANG 
Mr. Tao CHEN Dr. Shanshan DING Dr. Xinlong HAN Dr. Jeffrey Allan MAKI Dr. Zhen ZHENG Dr. Shangguo ZHU 
Mr. MinQuan HE (MPhil) Mr. Long Hin LI (PhD) Mr. Mingyang LIU (PhD) Mr. Ruibin LIU (PhD)

Research Activities
The group is focused on strongly interacting Fermi gases, synthetic spinorbit couplings in atomic gases; quantum cryptographic protocols; implementation of quantum computation and quantum simulation in cold atom and solidstate systems.
Prof. Chau focuses on the theoretical study of quantum information theory and quantum computation. The aim is to prove the security of various quantum cryptographic protocols as well as getting a better understanding of how to manipulate quantum information by quantum errorcorrection codes. In collaboration with researchers in HP Labs, Bristol, our group has recently proven that certain quantum key distribution scheme is unconditionally secure as well as obtained a U.S. patent on certain quantum key distribution protocols.
Prof. Wang investigates theoretically quantum information physics, and explores implementation of quantum computation and quantum simulation in physical systems, including superconducting quantum circuits and cold atoms as well as trapped ions. Current research interests extend to include topological quantum computing and quantum machine learning. Recently, his group has established a hybrid theory for realizing quantum machine learning tasks, taking the both advantages of discrete and continuous quantum variables.
Dr. Zhang studies ultracold atomic gases, which have emerged as a multidisciplinary subject and is at the interface of modern atomic and molecular physics, quantum optics and condensed matter physics. It proves to be an excellent laboratory for investigating strongly interacting quantum manybody systems and in particular correlated quantum phases and phase transitions. Current topics of interest include strongly interacting twocomponent Fermi gases and BECBCS crossover, synthetic gauge fields and spinorbit couplings in atomic gases, novel mixtures of bosons and fermions.
Dr. Luu’s research focuses on studying electronic processes in their native time scale, which requires tools that are extremely fast, i.e. as fast as hundreds of attosecond (1as = 1018 s). By combining high power laser pulses and strongfield physics, creation of attosecond pulses was made possible. The tools, either extreme ultraviolet or optical attosecond pulses, play a crucial role in timeresolved spectroscopy where the extreme temporal resolution allows one to initiate, follow, and control electronic processes in matters with the highest possible fidelity. Furthermore, they additionally enable studies of electronic properties of matters in a novel approach.
Some Representative Publications
Prof. H.F. Chau
 "DecoyState Quantum Key Distribution With More Than Three Types Of Photon Intensity Pulses", H. F. Chau, Physical Review A (Rapid Communications), 97, 040301(R) (2018).
 "Quantum Key Distribution Using Qudits That Each Encode One Bit Of Raw Key", H.F. Chau, Physical Review A, 92, 062324 (2015).
 "Metrics on Unitary Matrices and their Application to Quantifying the Degree of Noncommutativity between Unitary Matrices", H.F. Chau, Quantum Information and Computation, 11, 721740 (2011).
 "Unconditionally Secure Key Distribution in Higher Dimensions by Depolarization", H.F. Chau, IEEE Transactions on Information Theory, 51, 14511468 (2005).
 "Practical scheme to share a secret key through a quantum channel with a 27.6% Bit Error Rate", H. F. Chau, Physical Review A, 66, 060302(R): 14 (2002).
 "Unconditional Security of Quantum Key Distribution over Arbitrarily Long Distances", H.K. Lo and H.F. Chau, Science, 283, 20502056 (1999).
 "Is Quantum Bit Commitment Really Possible?", H.K. Lo and H.F. Chau, Physical Review Letters, 78, 34103413 (1997).
Prof. Z.D. Wang
 "Novel Z_{2} topological metals and semimetals", Y. X. Zhao and Z. D. Wang, Phys. Rev. Lett. 116, 016401 (2016).
 "Unified theory of PT and CP invariant topological metals and nodal superconductors", Y. X. Zhao, A. P. Schynder, and Z. D. Wang, Phys. Rev. Lett. 116, 156402 (2016).
 "Disordered Weyl semimetals and their topological family", Y.X. Zhao and Z.D. Wang, Phys. Rev. Lett., 114, 206602 (2015).
 "Topological classification and stability of Fermi surfaces", Y.X. Zhao and Z.D. Wang, Phys. Rev. Lett., 110, 240404 (2013).
 "Unconventional Geometric Quantum Computation", S.L. Zhu and Z.D. Wang, Phys. Rev. Lett., 91, 187902 (2003).
 "Implementation of Universal Quantum Gates Based on Nonadiabatic Geometric Phases", S.L. Zhu and Z.D. Wang, Phys. Rev. Lett., 89, 097902 (2002).
Dr. S.Z. Zhang
 "Evidence for Universal Relations Describing a Gas with pWave Interactions", C. Luciuk, S. Trotzky, S. Smale, Z. Yu, S. Zhang, and J. H. Thywissen, Nature Physics, 6, 599605 (2016)
 "Universal Relations for a Fermi Gas Close to a pWave Interaction Resonance", Z.H. Yu, J.H. Thywissen, S.Z. Zhang, Physical Review Letters, 115, 135304:15 (2015)
 “Transverse Demagnetization Dynamics of a Unitary Fermi Gas”, A.B. Bardon, S. Beattie, C. Luciuk, W. Cairncross, D. Fine, N.S. Cheng, G.J.A. Edge, E. Taylor, S.Z. Zhang, S. Trotzky, J.H. Thywissen, Science, 344, 722724 (2014)
 “Theory of quantum oscillations in the vortexliquid state of highT_{c} superconductors”,S. Banerjee, S.Z. Zhang, M. Randeria, Nature Communications, 4, 1700:17 (2013)
 "BoseEinstein condensates with spinorbit interaction", T.L. Ho and S.Z. Zhang, Physics Review Letter, 107, 150403 (2011)
 "BECBCS crossover induced by a synthetic nonabelian gauge field", J.P. Vyasanakere, S.Z. Zhang and V. Shenoy, Physics Review B, 84, 014512 (2011)
 "Atom loss maximum in ultracold Fermi gases", S.Z. Zhang and T.L. Ho, New Journal of Physics, 13, 055003 (2011)
 "Universal properties of the ultracold Fermi gas", S.Z. Zhang and A.J. Leggett, Physics Review A, 79, 023601 (2009)