AI 中文总结
研究通过平面约瑟夫森结操控准粒子来探测超导体中库珀对动量，利用安德列夫反射产生大相位梯度并转移动量，证明安德列夫束缚态以特定角度喷射，将相位控制准粒子喷射确立为凝聚态动量转移的运动学探针。
AI 中文摘要
超导体中的库珀对动量与超导序参量的相位梯度相关。通常，该动量比费米动量小，难以测量。然而，约瑟夫森结能产生大的相位梯度，并通过安德列夫反射将库珀对动量转移到准粒子上。本文证明，沿弹道平面约瑟夫森结传播的安德列夫束缚态以与\(\Theta \sim \sqrt{\Delta/ \mu}\)成比例的相位控制角度喷射到相邻正常区域，其中\(\Delta\)是超导能隙，\(\mu\)是化学势。此角度参数上超过传统库珀对动量尺度\(\Delta/ \mu\)，即便在\(\Delta / \mu \ll 1\)的安德列夫近似 regime 中该现象也很显著。我们的结果将相位控制的准粒子喷射确立为凝聚态动量转移的运动学探针：与检测多普勒能量 shift 的现有探针不同，信号表现为发射准粒子在动量空间的偏转。
英文摘要
The Cooper pair momentum in a superconductor is associated with a phase gradient of the superconducting order parameter. In general, this momentum is small compared to the Fermi momentum, which makes it challenging to measure. Josephson junctions, however, enable the creation of large phase gradients and transfer of the Cooper pair momentum to quasiparticles via Andreev reflection. In this work we demonstrate that Andreev bound states propagating along ballistic planar Josephson junctions eject into an adjacent normal region at a phase-controlled angle that scales as $Θ\sim \sqrt{Δ/ μ}$, where $Δ$ is the superconducting gap and $μ$ is the chemical potential. This angle parametrically exceeds the conventional Cooper pair momentum scale $Δ/ μ$, and thus this phenomenon is sizeable even within the Andreev approximation regime $Δ/ μ\ll 1$. Our results establish phase-controlled quasiparticle ejection as a kinematic probe of condensate momentum transfer: unlike existing probes that detect the Doppler energy shift, the signal appears as a momentum-space deflection of emitted quasiparticles.
Comments21 pages, 6 figures
