Preparation of metrological states in dipolar-interacting spin systems
Preparation of metrological states in dipolar-interacting spin systems
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DOI：
10.1038/s41534-022-00667-4
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发表时间：
2022-03
影响因子：
7.6
通讯作者：
Tian-Xing Zheng;Anran Li;Jude Rosen;Sisi Zhou;M. Koppenhöfer;Ziqi Ma;F. Chong;A. Clerk
中科院分区：
文献类型：
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作者：
Tian-Xing Zheng;Anran Li;Jude Rosen;Sisi Zhou;M. Koppenhöfer;Ziqi Ma;F. Chong;A. Clerk
自旋系统是量子增强计量学的一个有吸引力的候选者。在这里，我们发展了一种变分方法，在有限的量子比特控制下，在小的偶极相互作用自旋系综中产生双光子态。对于规则和无序的空间自旋配置，所产生的状态使传感超出标准量子极限（SQL），并为小自旋数，接近海森堡极限（HL）。根据电路深度和读出噪声的水平，所得到的状态类似于Greenberger-Horne-Zeilinger（GHZ）态或自旋压缩态（SSS）。在有限自旋极化和非马尔可夫噪声环境的存在下，SQL之外的感知保持不变。所开发的小自旋数（N≤ 10）的黑盒优化技术可直接应用于基于金刚石的纳米级场传感，其中传感器尺寸限制N和传统的挤压方法失败。
Spin systems are an attractive candidate for quantum-enhanced metrology. Here we develop a variational method to generate metrological states in small dipolar-interacting spin ensembles with limited qubit control. For both regular and disordered spatial spin configurations the generated states enable sensing beyond the standard quantum limit (SQL) and, for small spin numbers, approach the Heisenberg limit (HL). Depending on the circuit depth and the level of readout noise, the resulting states resemble Greenberger-Horne-Zeilinger (GHZ) states or Spin Squeezed States (SSS). Sensing beyond the SQL holds in the presence of finite spin polarization and a non-Markovian noise environment. The developed black-box optimization techniques for small spin numbers (N≤ 10) are directly applicable to diamond-based nanoscale field sensing, where the sensor size limitsNand conventional squeezing approaches fail.