发表机构
School of Physics, University of Hyderabad（海德拉巴大学物理学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出通量可调四端正常金属-超导体结，通过调控磁通量与中心结跳跃实现100%效率的拓扑保护完美交叉安德烈耶夫反射，为固态量子信息处理提供非局域纠缠产生的高鲁棒性架构。
AI 中文摘要
通过库珀对分裂产生非局域纠缠电子对对于固态量子信息处理至关重要，但由于电子隧穿（ET）和局域安德烈耶夫反射（AR）等竞争输运过程，分离潜在的交叉安德烈耶夫反射（CAR）极具挑战性。本文提出一种通量可调的四端正常金属-超导体结，可实现确定性、100%效率的CAR。研究表明，在恰好半个磁通量量子（φ=π）时，相消的阿哈罗诺夫-玻姆干涉和派尔斯干涉分别从结构上禁止ET和AR；通过调节中心结的跳跃，电子反射也被抑制至零。利用柯西辐角原理，证明该抑制表现为量子化拓扑绕数，保证拓扑保护的单位CAR概率。该区域的特征是严格为正的交叉关联散粒噪声，为库珀对分裂提供明确实验信号，且完美CAR在超导能隙内近乎宽带，对结构无序具有极强鲁棒性，为确定性非局域纠缠产生提供高韧性架构。
英文摘要
Generating non-locally entangled electron pairs via Cooper-pair splitting is vital for solid-state quantum information processing. However, isolating the underlying crossed Andreev reflection (CAR) is challenging due to competing transport processes like electron tunneling (ET) and local Andreev reflection (AR). Here, we propose a flux-tunable four-terminal normal metal-superconductor junction that achieves deterministic, 100\% efficient CAR. We demonstrate that at exactly half a magnetic flux quantum ($ϕ=π$), exact destructive Aharonov-Bohm and Peierls interferences structurally forbid ET and AR respectively. By tuning the central junction hopping, electron reflection is also suppressed to zero. Using the Cauchy argument principle, we prove that this suppression manifests as a quantized topological winding number, guaranteeing a topologically protected unit CAR probability. We establish that this regime is characterized by a strictly positive cross-correlation shot noise, providing an unambiguous experimental signature of Cooper-pair splitting. Furthermore, this perfect CAR is nearly broadband within the superconducting gap and remarkably robust against structural disorder, offering a highly resilient architecture for deterministic nonlocal entanglement generation.
Comments5 pages, 5 figures. Comments are welcome
