Department of Physics, California Institute of Technology, Pasadena, 91125, USA.
Phys Rev Lett. 2011 Jul 1;107(1):017002. doi: 10.1103/PhysRevLett.107.017002. Epub 2011 Jun 30.
Recent experiments on the conductance of thin, narrow superconducting strips have found periodic fluctuations, as a function of the perpendicular magnetic field, with a period corresponding to approximately two flux quanta per strip area [A. Johansson et al., Phys. Rev. Lett. 95, 116805 (2005)]. We argue that the low-energy degrees of freedom responsible for dissipation correspond to vortex motion. Using vortex-charge duality, we show that the superconducting strip behaves as the dual of a quantum dot, with the vortices, magnetic field, and bias current respectively playing the roles of the electrons, gate voltage, and source-drain voltage. In the bias-current versus magnetic-field plane, the strip conductance displays regions of small vortex conductance (i.e., small electrical resistance) that we term "Weber blockade" diamonds, which are dual to Coulomb blockade diamonds in quantum dots.
最近对薄而窄的超导条的电导的实验发现,作为垂直磁场的函数,存在周期性波动,其周期对应于每条带面积约两个磁通量子[ Johansson 等人,Phys. Rev. Lett. 95, 116805 (2005)]。我们认为,导致耗散的低能自由度与涡旋运动相对应。利用涡旋电荷对偶性,我们表明超导条表现为量子点的对偶体,其中涡旋、磁场和偏置电流分别扮演电子、栅极电压和源漏电压的角色。在偏置电流与磁场的平面中,条带的电导显示出小涡旋电导(即小电阻)的区域,我们称之为“韦伯阻塞”菱形,这与量子点中的库仑阻塞菱形对偶。