AI 中文总结
研究远距离自旋纠缠面临的耦合权衡问题，提出通过磁振子与计算基外跃迁耦合的协议打破权衡，分析了自旋为两个氮空位中心的设置，模拟得出不同速率下的保真度和成功概率。
AI 中文摘要
通过共享磁振子总线纠缠远距离自旋通常面临权衡：更强的自旋-磁振子耦合会提高纠缠保真度，但也会增加自旋衰减率。我们提出了一种打破这种权衡的协议。磁振子仅与计算基之外的跃迁耦合，在此跃迁中创建贝尔态。我们的协议是概率性的，弱耦合会降低成功概率，但不会降低保真度。我们分析了一种设置，其中自旋是磁线附近的两个氮空位（NV）中心。在没有NV退相的情况下，对于任意弱耦合，该协议都能达到最大纠缠态的单位保真度。在我们通过蒙特卡罗波函数方法进行的模拟中，NV-磁振子耦合被设为磁振子线宽的三分之一。考虑到有限的NV退相，我们预测对于最先进的速率，保真度>0.99，对于中等速率，最佳保真度为0.91，两者的成功概率均为0.6%。
英文摘要
Entangling distant spins via a shared magnonic bus typically faces a tradeoff: stronger spin-magnon coupling increases the entanglement fidelity, but also the spin decay rate. We propose a protocol that breaks this tradeoff. The magnons couple only to a transition outside the computational basis, in which the Bell state is created. Our protocol is probabilistic, and weak coupling reduces the success probability but not the fidelity. We analyze a setup where the spins are two nitrogen-vacancy (NV) centers near a magnetic wire. In the absence of NV dephasing, the protocol reaches unit fidelity with a maximally entangled state, for arbitrarily weak coupling. In our simulations via the Monte-Carlo wavefunction approach, the NV-magnon coupling is taken to be one-third of the magnon linewidth. Considering finite NV dephasing, we predict a fidelity of >0.99 for a state-of-the-art rate, and an optimal fidelity of 0.91 for a moderate rate, both at 0.6% success probability.
Comments9 pages of main content with 9 pages of appendix
