Research of Superconductive Chaos Generator Device "Josephson Tetrode"

超导混沌发生器装置“约瑟夫森四极管”的研究

• 批准号: 15560305
• 负责人: YOSHIMORI Shigeru
• 金额: $ 2.3万
• 依托单位: Takushoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560305/
• 关键词: Josephson Tetrode; Josephson effect; Chaos; Nonlinear dynamics; Chaos attractor; GL theory; Margin of generation; Bifurcation diagram; 動作マージン; リアプノフスペクトル; 決定論的カオス; FFT; 最大リアプノフ数; ヤコビアン; カルダノ法

In this research project, the generation of chaos in "Josephson tetrode", a four-terminal superconductive device made of five Josephson weak-link junctions was numerically demonstrated. This novel superconductive device can be applied to ultra-fast random signal generations at frequencies of hundreds of gigahertz.In the Josephson tetrode, two weak-link junctions are series-connected and other three junctions are parallel-connected. The dynamics of electrical voltages across the junctions were calculated when one of the normal resistances was varied. The generation of chaos was confirmed by using a bifurcation diagram, three-dimensional attractors and the Poincare sections.The bifurcation diagram can be interpreted as the quasi-periodicity-breakdown scenerio to chaos. The mechanism of chaos generation is a nonlinear frequency mixing among three independent voltages across the junctions.The Josephson tetrode was made of five step-edge type Josephson junctions. So two-dimensional Ginzburg-Landau equation was applied to the step-edge Josephson junction and the solution was analytically derived. The current-phase relationship and temperature dependence of the critical current were calculated.

在本研究计画中，数值模拟了由五个约瑟夫森弱连接结所组成的四端超导元件“约瑟夫森四极管”中混沌的产生。该器件采用两个弱连接结串联、三个弱连接结并联的结构，可用于产生频率为几百GHz的超快随机信号。当其中一个正常电阻变化时，计算了跨结的电压的动态。利用分岔图、三维吸引子和Poincare截面证实了混沌的产生，分岔图可以解释为混沌的准周期性破裂现象。混沌产生的机理是三个独立的跨接电压之间的非线性频率混合。为此，将二维Ginzburg-Landau方程应用于阶跃边约瑟夫森结，并得到了解析解。计算了临界电流的电流-相位关系和温度依赖性。

项目成果

Chaotic Oscillations in Josephson Tetrode

约瑟夫森四极管中的混沌振荡

• 发表时间: 2004
• 期刊: IEEE Trans. Appl. Super. Vol.14 No.12
• 作者: A.Uchida;H.Iida;N.Maki;M.Osawa;S.Yoshimori
• 通讯作者: S.Yoshimori

A.Uchida, K.Higa, T.Shiba, S.Yoshimori: "Generalized synchronization of chaos in He-Ne lasers"Physical Review E. 68・1-2. 016215-1-016215-7 (2003)

A.Uchida、K.Higa、T.Shiba、S.Yoshimori：“He-Ne 激光器中混沌的广义同步”物理评论 E. 68・1-2（2003 年）

Characteristics of chaos synchronization in semiconductor lasers subject to polarization-rotated optical feedback

• DOI: 10.1109/jqe.2006.870226
• 发表时间: 2006-03
• 期刊: IEEE Journal of Quantum Electronics
• 影响因子: 2.5
• 作者: N. Shibasaki;A. Uchida;S. Yoshimori;P. Davis