Siyuan Han

Siyuan Han
  • Professor Emeritus
  • Physics & Astronomy

Contact Info

Call Me:
Gray-Little Hall, room 2112
1567 Irving Hill Rd.
Lawrence, KS 66045


2003-present: Professor, University of Kansas
1997-2003: Associate Professor, University of Kansas
1993-1997: Research Associate Professor, Physics & Astronomy, SUNY at Stony Brook


PhD in Condensed Matter Physics, Iowa State University, 1986
BS in Physics, University of Science and Technology of China, 1982


Quantum information science and technology, device physics and applications

  • Quantum information science, realization of quantum computation with solid state qubits, such as supercondting qubits based on Josephson junctions, and circuit QED.
  • Foundations of quantum mechanics. In particular, macroscopic quantum phenomena (e.g., Schrodinger's Cat).
  • Physics and applications of micro- and nano-scale devices.
  • Stochastic nonlinear dynamic systems.

The goal of our quantum computing project is to develop basic building blocks of a solid state quantum computer using superconducting quantum bits (qubits). In our case, a qubit is essentially a small ring of superconductor containing a Josephson junction. Electrical current in the ring flows without resistance (hence is called supercurrent) and in contrast to one's intuition the circulating current in the ring can flow in two opposite directions simultaneously - a direct consequence of quantum mechanics and one of the cornerstones of quantum computation. However, to maintain a qubit in such a quantum coherent state long enough for useful quantum computation is extremely difficult since interaction between the qubit and its electromagnetic environment can quickly destroy quantum coherence. Our objective is to identify and understand mechanisms of decoherence in superconducting qubits and to increase coherence time by optimizing qubit design, quantum gate implementation, control and readout circuits, material properties, and fabrication processes.

Selected Publications

  • H.F. Yu, X.B. Zhu, Z.H. Peng, Ye Tian, D.J. Cui, G.H. Chen, D.Z. Zheng, X.N. Jing, Li Lu, S.P. Zhao, and Siyuan Han, Quantum Phase Diffusion in a Small Underdamped Josephson Junction,Phys. Rev. Lett. 107, 067004 (Aug. 3, 2011)
  • Guozhu Sun, Xueda Wen, Bo Mao, Yang Yu, Jian Chen, Weiwei Xu, Lin Kang, Peiheng Wu andSiyuan Han, Landau-Zener-Stuckelberg Interference of Microwave-Dressed States of a Superconducting Phase Qubit, Phys. Rev. B 83, 180507(R) (May 26, 2011)
  • Guozhu Sun, Xueda Wen, Bo Mao, Zhongyuan Zhou, Yang Yu, Peiheng Wu and Siyuan Han, Quantum Dynamics of a Microwave Driven Superconducting Phase Qubit Coupled to a Two-Level System, Phys. Rev. B 82, 132501 (Oct. 2010)
  • Guozhu Sun, Xueda Wen, Bo Mao, Yang Yu, Jian Chen, Peiheng Wu and Siyuan Han, Tunable Quantum Beam Splitters for Coherent Manipulation of a Solid State Tripartite Qubit System, Nature Comm. 1, doi:10.1038/ncomms1050, (2010) pdf
  • Xiao-Ling He, Chui-Ping Yang, Sheng Li, Jun-Yan Luo, and Siyuan Han, Quantum logical gates with four-level superconducting quantum interference devices coupled to a superconducting resonator, Phys. Rev. A 82, 024301 (Aug. 4, 2010)
  • H. F. Yu, X. B. Zhu, Z. H. Peng, W. H. Cao, D. J. Cui, Ye Tian, G. H. Chen, D. N. Zheng, X. N. Jing, Li Lu, and S. P. Zhao, and Siyuan Han, Quantum and classical resonant escapes of a strongly-driven Josephson junction, Phys. Rev. B 81, 144518 (April 2010)
  • R. Harris, J. Johansson, A.J. Berkley, M.W. Johnson, T. Lanting, Siyuan Han, P. Bunyk, E. Ladizinsky, T. Oh, I. Perminov, E. Tolkacheva, S. Uchaikin, E. Chapple, C. Enderud, C. Rich, M. Thom, J. Wang, B. Wilson, and G. Rose Experimental Demonstration of a Robust and Scalable Flux Qubit, Phys. Rev. B 81, 134510 (April 2010)
  • Bo Mao, Wei Qiu, and Siyuan Han, The temperature dependence of magnetism in dc SQUIDs and rf SQUID flux qubit in nT fields, Supercond. Sci. & Technol. 23, 045027 (March 2010)
  • R. HarrisF. BritoA.J. BerkleyJ. JohanssonM.W. JohnsonT. LantingP. BunykE. LadizinskyB. BumbleA. FungA. KaulA. KleinsasserS. Han, Synchronization of Multiple Coupled rf-SQUID Flux Qubits, New J. Phys. 11, 123022 (Dec. 2009)
  • R. Harris, T. Lanting, A. J. Berkley, J. Johansson, M. W. Johnson, P. Bunyk, E. Ladizinsky, N. Ladizinsky, T. Oh, and Siyuan Han, Compound Josephson-junction coupler for flux qubits with minimum crosstalk, Phys. Rev. B 80, 052506 (August 2009)
  • Guozhu Sun, Xueda Wen, Yiwen Wang, Shanhua Cong, Jian Chen, Lin Kang, Weiwei Xu, Yang Yu, Siyuan Han, and Peiheng Wu, Population inversion induced by Landau--Zener transition in a strongly driven rf superconducting quantum interference device. Appl. Phys. Lett. 94, 102502 (March 2009)
  • Sang-Kil Son, Siyuan Han, and Shih-I Chu, Floquet formulation for the investigation of multiphoton quantum interference in a superconducting qubit driven by a strong ac field, Phys. Rev. A 79, 032301 (March 2009)
  • Yang Yu, Shiliang Zhu, Guozhu Sun, Xueda Wen, Ning Dong, Jian Cheng, Peiheng Wu, andSiyuan Han, Quantum Jumps between Macroscopic Quantum States of Superconducting Qubit Coupled to a Microscopic Two-Level Syatem, Phys. Rev. Lett. 101, 157001 (October 2008)
  • R. Harris, M. W. Johnson, Siyuan Han, A. J. Berkley, J. Johannsson, P. Bunyk, S. Govorkov, M. C. Thom, S. Uchaikin, B. Bumble, A. Fung, A. Kaul, A. Kleinsasser, C.J.S. Truncik, M.H.S. Amin, and D. V. Averin, Probe temperature dependent noise in flux qubits via macroscopic resonant tunneling, Phys. Rev. Lett. 101, 117003 (Sept. 2008)
  • Sun Guozhu, Wang Yiwen, Cao Junyu, Chen Jian, Ji Zhengming, Kang Lin, Xu Weiwei, Yu Yang,Siyuan Han, and Wu Peiheng, Microwave-induced phase escape in a Josephson tunnel junction,Phys. Rev. B 77, 104531 (March 2008)
  • Zhongyuan Zhou, Shih-I Chu, and Siyuan Han, Relaxation and decoherence in a resonantly driven qubit, J. Phys. B: At. Mol, Opt. Phys. 41, 045506 (Feb. 2008)
  • Shao-Xiong Li, Wei Qiu, Siyuan Han, Y.F. Wei, X.B. Zhu, C.Z. Gu, S.P. Zhao, and H.B. Wang, Observation of Macroscopic Quantum Tunneling in a Single Bi-2212 Surface Intrinsic Josephson Junction, Phys. Rev. Lett. 99, 037002 (July 2007)
  • Chui-Ping Yang and Siyuan Han, Local measurement for a set of n-qubit maximally entangled states in cavity QED, Phys. Rev. A 75, 052315 (2007)
  • Chui-Ping Yang and Siyuan Han, Rotation gate for a three-level superconducting quantum interference device qubit with resonant interaction, Phys. Rev. A 74, 044302 (2006)
  • Zhongyuan Zhou, Shih-I Chu, and Siyuan Han, A unified approach to realize universal quantum gates in a coupled two-qubit system with fixed always-on coupling, Phys. Rev. B 73, 104521 (2006)
  • Chui-Ping Yang and Siyuan Han, Realization of an n-qubit controlled-U gate with superconducting quantum interference devices or atoms in cavity QED, Phys. Rev. A 73, 032317 (2006)
  • Chui-Ping Yang and Siyuan Han, An n-qubit controlled phase gate with superconducting quantum interference devices coupled to a resonator, Phys. Rev. A 72, 032311 (2005)
  • Zhongyuan Zhou, Shih-I Chu, and Siyuan Han, Rapid optimization of working parameters of microwave-driven multi-level qubits for minimal gate leakage, Phys. Rev. Lett. 95, 120501 (2005)
  • Chui-Ping Yang and Siyuan Han, Extracting an arbitrary relative phase from a multiqubit two-component entangled state, Phys. Rev. A 72, 014306 (2005)
  • J. Mannik, S. Li, W. Qiu, W. Chen, V. Patel, S. Han, and J. E. Lukens, Crossover from Kramers to phase-diffusion switching in hysteretic DC-SQUIDs, Phys. Rev. B 71, 220509(R) (2005)
  • Chui-Ping Yang and Siyuan Han, Generation of Greenberger-Horne-Zeilinger entangled states with three SQUID qubits: a scheme with tolerance to non-uniform device parameters, Physica A 347, 253-267 (2005)
  • Chui-Ping Yang and Siyuan Han, Preparation of Greenberger-Horne-Zeilinger entangled states with multiple superconducting quantum interference device qubits/atoms in cavity QED, Phys. Rev. A 70, 062323 (2004)
  • Zhongyuan Zhou, Shih-I Chu, and Siyuan Han, Suppression of energy-relaxation-induced decoherence in L-type three-level SQUID flux qubits: A dark-state approach, Phys. Rev. B 70, 094513 (2004)
  • Chui-Ping Yang, Shih-I Chu, and Siyuan Han, Efficient many party controlled teleportation of multiqubit quantum information via entanglement, Phys. Rev. A 70, 022329 (2004)
  • Chui-Ping Yang, Shih-I Chu, and Siyuan Han, Quantum information transfer and entanglement with SQUID qubits in cavity QED: A dark-state scheme with tolerance to non-uniform device parameters,Phys. Rev. Lett. 92, 117902 (2004)
  • Chui-Ping Yang, Shih-I Chu, and Siyuan Han, Possible realization of entanglement, logical gates, and quantum information transfer with superconducting-quantum-interference-device qubits in cavity QED, Phys. Rev. A 67, 042311 (2003)
  • Yang Yu and Siyuan Han, Resonant Activation over an Oscillating Barrier in Under-damped Josephson Tunnel Junction, Phys. Rev. B 66, 054527 (2002)
  • Zhongyuan Zhou, Shih-I Chu, and Siyuan Han, Quantum computing with superconducting device: A three-level SQUID qubit, Phys. Rev. B 66, 054527 (2002)
  • Shaoxiong Li, Yang Yu, Yu Zhang, Wei Qiu, Siyuan Han, and Zhen Wang, Quantitative study of macroscopic quantum tunneling in a dc SQUID - A system with two degrees of freedom, Phys. Rev. Lett. 89, 098301 (2002)
  • Yang Yu, Siyuan Han, Xi Chu, Shih-I Chu, and Zhen Wang, Coherent temporal oscillations of macroscopic quantum states in a Josephson junction, Science 296, 889 (2002)
  • Siyuan Han, Yang Yu, Xi Chu, Shih-I Chu, and Zhen Wang, Time resolved measurement of disspation-induced decoherence in a josephson junction, Science 293, 1457 (2001)
  • Siyuan Han, R. Rouse, and J. E. Lukens. Observation of cascade two-photon-induced transitions between fluxoid states of a SQUID, Phys. Rev. Lett. 84, 1300 (2000)

Awards & Honors

1981: Guomoruo Award in Physics, USTC, China


Member, American Association for the Advancement of Science (AAAS)