Möttönen Mikko, Vartiainen Juha J, Pekola Jukka P
Low Temperature Laboratory, Helsinki University of Technology, P.O. Box 3500, 02015 TKK, Finland.
Phys Rev Lett. 2008 May 2;100(17):177201. doi: 10.1103/PhysRevLett.100.177201. Epub 2008 Apr 28.
We present the first measurements of the Berry phase in a superconducting Cooper pair pump. A fixed amount of Berry phase is accumulated to the quantum-mechanical ground state in each adiabatic pumping cycle, which is determined by measuring the charge passing through the device. The dynamic and geometric phases are identified and measured quantitatively from their different response when pumping in opposite directions. Our observations, in particular, the dependencies of the dynamic and geometric effects on the superconducting phase bias across the pump, agree with the basic theoretical model of coherent Cooper pair pumping.
我们展示了超导库珀对泵中贝里相位的首次测量结果。在每个绝热泵浦循环中，固定量的贝里相位会累积到量子力学基态，这是通过测量流经该器件的电荷来确定的。通过在相反方向泵浦时它们不同的响应，动态相位和几何相位得以识别并定量测量。我们的观测结果，特别是动态和几何效应与跨泵浦的超导相位偏置的相关性，与相干库珀对泵浦的基本理论模型相符。
