论文标题
二维超低玻色气中的约瑟夫森连接动力学
Josephson junction dynamics in a two-dimensional ultracold Bose gas
论文作者
论文摘要
我们研究了约瑟夫森连接动力学在二维（2D）Bose气体中的临界电流的Berezinskii-Kosterlitz-thouless（BKT）缩放量表，这是由Luick \ textit {etal。} arxiv：1908.097776的二维（2D）玻璃量。使用经典场动力学，我们确定该系统的动力学机制，作为温度和屏障高度的函数。作为中心可观察的，我们确定流相关关系，作为这些制度的定义特性。除了理想的连接体制外，我们还找到了多模制，第二谐波制度和一个过度阻尼的制度。对于理想的连接体制，我们得出了临界电流的分析估计值，该估计可以预测BKT缩放。我们在数值上为不同的系统大小演示了这种缩放行为。临界电流的估计值与数值模拟和实验非常一致。此外，我们显示了由于散装中的声子激发而导致的超电流阻尼，以及连接处的涡流 - 抗反应对的成核。
We investigate the Berezinskii-Kosterlitz-Thouless (BKT) scaling of the critical current of Josephson junction dynamics across a barrier potential in a two-dimensional (2D) Bose gas, motivated by recent experiments by Luick \textit{et al.} arXiv:1908.09776. Using classical-field dynamics, we determine the dynamical regimes of this system, as a function of temperature and barrier height. As a central observable we determine the current-phase relation, as a defining property of these regimes. In addition to the ideal junction regime, we find a multimode regime, a second-harmonic regime, and an overdamped regime. For the ideal junction regime, we derive an analytical estimate for the critical current, which predicts the BKT scaling. We demonstrate this scaling behavior numerically for varying system sizes. The estimates of the critical current show excellent agreement with the numerical simulations and the experiments. Furthermore, we show the damping of the supercurrent due to phonon excitations in the bulk, and the nucleation of vortex-antivortex pairs in the junction.
