翻訳と辞書 Words near each other ・ Pi Epsilon ・ Pi Eridani ・ Pi function ・ Pi Gamma Mu ・ Pi Glilot bombing attempt ・ Pi Goun Tong ・ Pi Gruis ・ Pi Guangye ・ Pi helix ・ Pi Herculis ・ Pi Hongyan ・ Pi Hydrae ・ Pi in the Sky ・ Pi interaction ・ Pi Islands ・ Pi Josephson junction ・ Pi Kappa Alpha ・ Pi Kappa Chi ・ Pi Kappa Delta ・ Pi Kappa Lambda ・ Pi Kappa Phi ・ Pi Kappa Sigma ・ Pi Kharabeh Darrehna ・ Pi Kogi Enavot ・ Pi Lambda Phi ・ Pi Lambda Sigma ・ Pi Lambda Theta ・ Pi Leonis ・ Pi Lupi ・ Pi Mensae Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Pi Josephson junction ： ウィキペディア英語版 Pi Josephson junction A Josephson Junction is a quantum mechanical device, which is made of two superconducting electrodes separated by a barrier (insulating tunnel barrier, thin normal metal, etc.). A $\backslash pi$ Josephson junction is a specific example of a Josephson junction which has a Josephson phase φ of $\backslash pi$ in the ground state i.e. when no external current or magnetic field is applied. ==Background== The supercurrent ''Is'' through a conventional Josephson junction (JJ) is given by ''Is = Icsin(φ)'', where φ is the phase difference of the superconducting wave functions of the two electrodes, i.e. the Josephson phase.〔 〕 The critical current ''Ic'' is the maximum supercurrent that can flow through the Josephson junction. In experiment, one usually applies some current through the Josephson junction and the junction reacts by changing the Josephson phase. From the above formula it is clear that the phase ''φ = arcsin(I/Ic)'', where ''I'' is the applied (super)current. Since the phase is $2\backslash pi$-periodic, i.e. $\backslash phi$ and $\backslash phi+2\backslash pi\; n$ are physically equivalent, without losing generality, we restrict the discussion below to the interval . When no current (''I'' = 0) is passing through the Josephson junction, e.g. when the junction is disconnected, the junction is in the ground state and the Josephson phase across it is zero (φ = 0). The phase can also be $\backslash phi=\backslash pi$, also resulting in no current through the junction. It turns out that the state with $\backslash phi=\backslash pi$ is ''unstable'' and corresponds to the Josephson energy maximum, while the state φ = 0 corresponds to the Josephson energy minimum and ''is'' a ground state. In certain cases one may obtain a Josephson junction where the critical current is negative (''Ic < 0''). In this case, the first Josephson relation becomes :$I\_s\; =\; -|I\_c|\backslash sin(\backslash phi)\; =\; |I\_c|\backslash sin(\backslash phi+\backslash pi)$ Obviously, the ground state of such a Josephson junction is $\backslash phi=\backslash pi$ and corresponds to the Josephson energy minimum, while the conventional state φ = 0 is unstable and corresponds to the Josephson energy maximum. Such a Josephson junction with $\backslash phi=\backslash pi$ in the ground state is called a $\backslash pi$ Josephson junction. $\backslash pi$ Josephson junctions have quite unusual properties. For example, if one connects (shorts) the superconducting electrodes with the inductance ''L'' (e.g. superconducting wire), one may expect the spontaneous supercurrent circulating in the loop, passing through the junction and through inductance clockwise or counterclockwise. This supercurrent is spontaneous and belongs to the ground state of the system. The direction of its circulation is chosen at random. This supercurrent will of course induce a magnetic field which can be detected experimentally. The magnetic flux passing through the loop will have the value from 0 to a half of magnetic flux quanta, i.e. from 0 to Φ0/2, depending on the value of inductance ''L''. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pi Josephson junction」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.