论文标题
量子旋转器和约瑟夫森交界处：紧凑型与扩展相和耗散量子相变
Quantum rotator and Josephson junction: compact vs. extended phase and dissipative quantum phase transition
论文作者
论文摘要
本文在旋转器和约瑟夫森结的量子理论中重新评估了旧难题的“紧凑型与扩展相”，以及这两个系统的类比，A粒子在周期性的电位中移动。这种困境实际上是困难，无论是否具有$φ$和$φ+2π$的状态是可区分的。过去，人们广泛接受的是，在约瑟夫森交界处，这些状态可以区分，就像在周期性潜力中移动的粒子一样。本文认为，具有$φ$和$φ+2π$阶段的状态是不可区分的，就像量子旋转器的特定示例中一样。但是，这不会导致修改常规理论的结论，从而预测了小约瑟夫森连接中的超导向绝缘状态的过渡。
The paper reassesses the old dilemma "compact vs. extended phase" in the quantum theory of the rotator and the Josephson junction and the analogy of these two systems with the a particle moving in a periodic potential. This dilemma is in fact the dilemma whether the states with the phases $φ$ and $φ+2π$ are distinguishable, or not. In the past it was widely accepted that in the Josephson junction these states are distinguishable like for a particle moving in a periodic potential. This paper argues that the states with the phases $φ$ and $φ+2π$ are indistinguishable as in a pendulum (a particular example of the quantum rotator). However, this does not lead to revision of the conclusions of the conventional theory predicting the transition from the superconducting to the insulating state in the small Josephson junction.
