论文标题
中央自旋系统中无纠缠的动态量子增强感测
Dynamic quantum-enhanced sensing without entanglement in central spin systems
论文作者
论文摘要
我们通过使用由与许多周围旋转的中央旋转相互作用组成的量子多旋转系统提出动态量子传感方案。从广义的ISING环模型开始，我们研究了中央自旋的误差传播公式，它表明可以达到海森堡缩放率，而探针状态仅需要是产品状态。特别是，我们在极限情况下得出了动态量子渔民信息的分析形式，该信息明确表现出海森堡缩放。通过与数值结果进行比较，我们证明，当周围旋转之间的耦合强度比中央和周围旋转之间的耦合强度较弱时，可以通过分析结果很好地近似。这种分析结果指导我们找到适当的探针状态和适当的测量时间，以在现实情况下实现海森堡的缩放。此外，我们研究了各种在实用量子系统中很重要的效果，包括中央旋转Zeeman项，超精细相互作用的各向异性和超精细偶联强度的不均匀性。我们的结果表明，在逼真的量子中央自旋系统中，例如半导体量子点，动态量子增强的传感方案似乎是可行的。
We propose a dynamic quantum sensing scheme by using a quantum many-spin system composed of a central spin interacting with many surrounding spins. Starting from a generalized Ising ring model, we investigate the error propagation formula of the central spin and it indicates that Heisenberg scaling can be reached while the probe state only needs to be a product state. Particularly, we derive an analytical form of the dynamic quantum Fisher information in a limit case, which explicitly exhibits the Heisenberg scaling. By comparing with numerical results, we demonstrate that the general case can be well approximated by the analytical result when the coupling strength among the surrounding spins is much weaker than the coupling strength between the central and surrounding spins. This analytic result guides us to find the appropriate probe state and the proper measurement time, to achieve the Heisenberg scaling in realistic situations. Furthermore, we investigate various effects which are important in practical quantum systems, including the central spin Zeeman term, the anisotropy of the hyperfine interaction and the inhomogeneity of the hyperfine coupling strength. Our result indicates that the dynamic quantum-enhanced sensing scheme seems feasible in realistic quantum central spin systems, like semiconductor quantum dots.
