Macroscopic Quantum Coherence Team

Team Leader

Jaw-Shen Tsai

  • Ph.D.
  • Jaw-Shen Tsai
  • Brief resume
    1983
    Ph.D., State University of New York at Stony Brook, USA
    1983
    Research Scientist, Microelectronics Research Laboratories, NEC
    2000
    Fellow, American Physical Society, USA
    2001
    Fellow, Nano Electronics Research Laboratories, NEC (-current)
    2001
    Team Leader, Macroscopic Quantum Coherence Team, RIKEN (-current)

Outline

Macroscopic Quantum Coherence Team

Macroscopic quantum scattering has been in Josephson qubit-based research observed. A nearly perfect reflection, inelastic scattering (resonance fluorescence), Mollow triplet, electromagnetically induced transparency, Autler-Townes doublet, optical pumped population inversion, amplification by stimulated emission and other very rich physics were revealed. One of the resulting series of papers has already been accepted by Science magazine. For the integration of the qubits, the previous qubit-based coupler was carefully analyzed by varying its bias point, resulting in a guideline for the coupler's optimization. For the long decoherence time, we correlated flux noise in a coupled flux qubit, and learned the dominant contribution local fluctuation in decoherence. Quantum non-demolition readout was successfully demonstrated. For the future quantum current standard, a new current turnstile was developed and its parallel operation was demonstrated. Surface/interface states of superconductors were studied and their influence upon tunnel barrier and leakage current was discovered. An aluminum-based nano-mechanical resonator was developed.

Recent Research Topic

An artificial atom (flux qubit) was positioned in a transmission line 1D open space
Fig. 1: An artificial atom (flux qubit) was positioned in a transmission line (1D open space)
Inset (red frame): As an example of macroscopic quantum scattering, result of inelastic scattering (resonance fluorescence) with clear observation of Mollow triplet was shown here.
Fig. 1
Reproduced, with permission, from O. Astafiev, et al. Resonance Fluorescence of a Single Artificial Atom, Science 2010, 327, 840. © (2012) AAAS

Selected Publications

  1. O. Astafiev, et al. Ultimate On-Chip Quantum Amplifier, Phys. Rev. Lett. 2010, 104, 183603.
  2. A. A. Abdumalikov Jr., et al. Electromagnetically induced transparency on a single artificial atom, Phys. Rev. Lett. 2010, 104, 193601.
  3. O. Astafiev. et al. Resonance Fluorescence of a Single Artificial Atom, Science 2010, 327, 840.
  4. O. Astafiev, et al. Single artificial-atom lasing, Nature 2007, 449, 588.
  5. A. O. Niskanen, et al. Quantum Coherent Tunable Coupling of Superconducting Qubits, Science 2007, 316, 723.
  6. F. Yoshihara, K. Harrabi, A. O. Niskanen, Y. Nakamura, J. S. Tsai, Decoherence of Flux Qubits due to 1/f Flux Noise, Phy. Rev. Lett. 2006, 97, 167001.
  7. O. Astafiev, Y. A. Pashkin, Y. Nakamura, T. Yamamoto, J. S. Tsai, Temperature Square Dependence of the Low Frequency 1/f Charge Noise in the Josephson Junction Qubits, Phy. Rev. Lett. 2006, 96, 137001.
  8. O. Astafiev, Y. A. Pashkin, T. Yamamoto, Y. Nakamura, J. S. Tsai, Quantum Noise in the Josephson Charge Qubit, Phy. Rev. Lett. 2004, 93, 267007.
  9. T. Yamamoto, Y. A. Pashkin, O. Astafiev, Y. Nakamura, J. S. Tsai, Demonstration of conditional gate operation using superconducting charge qubits, Nature 2003, 425, 941.
  10. Y. A. Pashkin, et al. Quantum oscillation in two coupled charge qubit, Nature 2003, 421, 823.

Core Members

Principal Investigator add delete
Jaw-Shen Tsai Team Leader    
Staff Scientist add delete
Yuri Pashkin Research Scientist    
Oleg V. Astafiev Research Scientist    
Fumiki Yoshihara ASI Research Scientist    
Kunihiro Inomata ASI Research Scientist    
Toshiyuki Miyazaki ASI Research Scientist    
Postdoctoral Fellow add delete
Pierre-Marie Billangeon Foreign Postdoctoral Researcher    
Zhihui Peng Postdoctoral Researcher    
Sergey Kafanov Postdoctoral Researcher    
Joonas Tapio Peltonen Postdoctoral Researcher    
Zhirong Lin Postdoctoral Researcher    
Student Trainee add delete
Technical Assistant add delete
Administrative Assistant add delete
Visiting Research Staff add delete
Other Staff add delete
Back to Top