Spin systems are an attractive candidate for quantum-enhanced metrology. Here we develop a variational method to generate metrological states in small dipolar-interacting ensembles with limited qubit controls and unknown spin locations. The generated states enable sensing beyond the standard quantum limit (SQL) and approaching 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.
@article{arxiv.2203.03084,
title = {Preparation of Metrological States in Dipolar-Interacting Spin Systems},
author = {Tian-Xing Zheng and Anran Li and Jude Rosen and Sisi Zhou and Martin Koppenhöfer and Ziqi Ma and Frederic T. Chong and Aashish A. Clerk and Liang Jiang and Peter C. Maurer},
journal= {arXiv preprint arXiv:2203.03084},
year = {2023}
}
Comments
6 pages, 4 figures, 1 table in main text. 21 pages, 8 figures, 3 tables in supplemental material