English

Incompatibility measures in multi-parameter quantum estimation under hierarchical quantum measurements

Quantum Physics 2022-06-28 v3

Abstract

The incompatibility of the measurements constraints the achievable precisions in multi-parameter quantum estimation. Understanding the tradeoff induced by such incompatibility is a central topic in quantum metrology. Here we provide an approach to study the incompatibility under general pp-local measurements, which are the measurements that can be performed collectively on at most pp copies of quantum states. We demonstrate the power of the approach by presenting a hierarchy of analytical bounds on the tradeoff among the precision limits of different parameters. These bounds lead to a necessary condition for the saturation of the quantum Cram\'er-Rao bound under pp-local measurements, which recovers the partial commutative condition at p=1 and the weak commutative condition at p=p=\infty. As a further demonstration of the power of the framework, we present another set of tradeoff relations with the right logarithmic operators(RLD).

Keywords

Cite

@article{arxiv.2109.05807,
  title  = {Incompatibility measures in multi-parameter quantum estimation under hierarchical quantum measurements},
  author = {Hongzhen Chen and Yu Chen and Haidong Yuan},
  journal= {arXiv preprint arXiv:2109.05807},
  year   = {2022}
}

Comments

34 pages, 5 figures, with improved bounds

R2 v1 2026-06-24T05:54:31.076Z