Quantum Physics using Superconducting Artificial Atoms

2009 Fiscal Year Final Research Report

• Project/Area Number: 18201018
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Nanostructural science
• Research Institution: NTT Basic Research Laboratories
• Principal Investigator: SEMBA Kouichi NTT Basic Research Laboratories, 量子電子物性研究部, 主幹研究員 (50393773)
• Co-Investigator(Kenkyū-buntansha): YAMAGUCHI Hiroshi 日本電信電話(株)NTT物性科学基礎研究所, 量子電子物性研究部, 部長 (60374071) ; NAKANO Hayato 日本電信電話(株)NTT物性科学基礎研究所, 量子電子物性研究部, 主任研究員 (60393774) ; SAITO Shiro 日本電信電話(株)NTT物性科学基礎研究所, 量子電子物性研究部, 主任研究員 (90393777) ; KAKUYANAGI Kousuke 日本電信電話(株)NTT物性科学基礎研究所, 量子電子物性研究部, 社員 (40417093) ; OKAMOTO Hajme 日本電信電話(株)NTT物性科学基礎研究所, 量子電子物性研究部, 研究主任 (20350465) ; TANAKA Hirotaka 日本電信電話(株)NTT物性科学基礎研究所, 量子電子物性研究部, 研究主任 (80393776) ; WANG Ying-Dan 日本電信電話(株)NTT物性科学基礎研究所, 量子電子物性研究部, リサーチアソシエイト (40451083)
• Project Period (FY): 2006 – 2009
• Keywords: 人工原子 / 微小共振器 / 超精密計測 / 量子エレクトロニクス / メゾスピック系

Research Abstract

(1) We have succeeded to generate and observe the time evolution of the entanglement between microscopic two level system in the Josephson junction and electro-magnetic field in the superconducting transmission line resonator by using a mesoscopic flux-qubit as an entanglement generator and a part of readout device. (2) By using a Josephson bifurcation amplifier which is characterized by its very fast detection speed and small back action to the measured system, we have clarified the condition for the projection measurement of a quantum superposition state of a macroscopic superconducting artificial atom. (3) We have observed parity symmetry breaking in a strongly coupled flux-qubit microwave resonator circuit QED system. (collaboration with Walther Meissner Institut, Germany) (4) We have succeeded to detect ultra-small displacement of suspended mechanical resonator embedded as an arm of Nb-SQUID. The sensitivity of detection as small as 10fm which is 36 times of the standard quantum limit has been achieved. (collaboration with Delft university of technology, Netherlands)

Research Products

• [Journal Article] Quantum Time-evolution in Qubit Readout Process with a Josephson Bifurcation Amplifier (2009)
  • Author(s): Hayato Nakano, Shiro Saito, Kouichi Semba, Hideaki Takayanagi
  • Journal Title: Phys. Rev. Lett. 102 Pages: 257003
  • Peer Reviewed
• [Journal Article] Quantum State Control, Entanglement, and Readout of the Josephson Persistent-Current Qubit (2009)
  • Author(s): K. Semba, J. Johansson, K. Kakuyanagi. H. Nakano, S. Saito, H. Tanaka, H. Takayanagi
  • Journal Title: Quantum Information Processing 8 Pages: 199-215
  • Peer Reviewed
• [Journal Article] 超電導回路で共振器量子電磁力学実験が可能に!‘ジョセフソンCavity-QED (2009)
  • Author(s): 仙場浩一、齋藤志郎、角柳孝輔、中ノ勇人
  • Journal Title: 日本物理学会誌 1月号 Pages: 37-41
  • Peer Reviewed
• [Journal Article] Two-photon probe of the Jaynes-Cummings model and controlled symmetry breaking in circuit QED (2008)
  • Author(s): F. Deppe, M. Mariantoni, E.P. Menzel, A. Marx, S. Saito, K. Kakuyanagi, H. Tanaka, T. Meno, K. Semba, H. Takayanagi, E. Solano, R. Gross
  • Journal Title: Nature Physics 4 Pages: 686-691
  • Peer Reviewed
• [Journal Article] Motion detection of a micromechanical resonator embedded in a dc-SQUID (2008)
  • Author(s): S. Etaki, M. Poot, I. Mahboob, K. Onomitsu, H. Yamaguchi,, H.S. van der Zant
  • Journal Title: Nature Physics 4 Pages: 785-788
  • Peer Reviewed
• [Journal Article] Dephasing of a Superconductiong Flux Qubit (2007)
  • Author(s): K. Kakuyanagi, T. Meno, S. Saito, H. Nakano, K. Semba, H. Takayanagi, F. Deppe, A. Shnirman
  • Journal Title: Physical Review Letters 98 Pages: 047004
  • Peer Reviewed
• [Journal Article] Controllable Coupling between Flux Qubit and Nanomechanical Resonator by Magnetic Field (2007)
  • Author(s): Fei Xue, Y. D Wang, C.P. Sun, H. Okamoto, H. Yamaguchi, K. Semba
  • Journal Title: New Journal of Physics 9 Pages: 35
  • Peer Reviewed
• [Presentation] Quantum state control, entanglement, and readout of the Josephson persistent-current qubit (2009)
  • Author(s): K. Semba
  • Organizer: The 3rd International Workshop and School on Solid State Based Quantum Information Processing (QIP 2009)
  • Place of Presentation: Herrsching Munich, Germany(Invited talk)
  • Year and Date: 20090630-20090703
• [Presentation] Quantum control of the flux qubit coupled to microwave photon system. (2008)
  • Author(s): K. Semba
  • Organizer: Int. Coference on Solid State Quantum Information
  • Place of Presentation: SNS-Pisa, Italy(Invited talk)
  • Year and Date: 20081203-20081206
• [Presentation] Vacuum Rabi oscillations observed in a flux qubit LC-oscillator system W1. (2007)
  • Author(s): Kouichi Semba
  • Organizer: 0003: APS March Meeting 2007
  • Place of Presentation: Denver, Colorado USA(Invited talk)
  • Year and Date: 20070305-20070309
• [Book] Physical Realizations of Quantum Computing(ISBN981-256-473-X) (2006)
  • Author(s): F. Wilhelm, K. Semba
  • Total Pages: 38-107
  • Publisher: World Scientific Pub Co Inc.
• [Remarks]
  • URL: http://www.brl.ntt.co.jp/J/group_007/group_007.html
• [Patent(Industrial Property Rights)] 超伝導非線形共振回路を用いた、測定回路の常伝導転移を伴わない、磁束量子ビットの高速非熱的状態測定装置 (2009)
  • Inventor(s): 角柳孝輔, 仙場浩一
  • Industrial Property Rights Holder: 日本電信電話株式会社
  • Industrial Property Number: 特許特願2009-121380
  • Filing Date: 2009-05-19
• [Patent(Industrial Property Rights)] 素子状態読み出し装置、方法、および透過型ジョセフソン共振回路 (2009)
  • Inventor(s): 角柳孝輔、仙場浩一
  • Industrial Property Rights Holder: 日本電信電話株式会社
  • Industrial Property Number: 特許P2009-49631A
  • Acquisition Date: 2009-03-05