搜索

x
中国物理学会期刊

非厄米哈密顿量中的量子Fisher信息与参数估计

CSTR: 32037.14.aps.72.20230862

Quantum Fisher information and parameter estimation in non-Hermitian Hamiltonians

CSTR: 32037.14.aps.72.20230862
PDF
HTML
导出引用
  • 量子Fisher信息给出参数估计的最优精度极限, 在量子度量学中有重要的应用. 近年来, 在量子系统中实现非厄米哈密顿量的理论与实验研究受到广泛关注. 本文研究基于非厄米哈密顿量本征态的参数估计, 给出其中单参数与两参数估计的量子Fisher信息及其量子Cramér-Rao下界, 计算与分析非互易、具有增益-耗散的Su-Schrieffer-Heeger模型, 非厄米量子Ising链、拓扑陈绝缘体模型和二能级系统中动量及外场参数估计的量子Fisher信息. 结果表明: 在这几个非厄米模型中, 对于单参数估计, 量子Fisher信息在能隙闭合区域和例外点附近显著增大, 从而提高参数估计的精度极限; 对于两参数估计, 量子Fisher信息矩阵的行列式在能隙闭合和例外点附近同样明显增大, 拓扑区域比平庸区域的整体评估精度更高, 且由陈数确定两参数估计误差的拓扑下界.

     

    Quantum Fisher information bounds the ultimate precision limit in the parameter estimation and has important applications in quantum metrology. In recent years, the theoretical and experimental studies of non-Hermitian Hamiltonians realized in quantum systems have attracted wide attention. Here, the parameter estimation based on eigenstates of non-Hermitian Hamiltonians is investigated, and the corresponding quantum Fisher information and quantum Cramér-Rao bound for the single-parameter and two-parameter estimations are given. In particular, the quantum Fisher information about estimating intrinsic momentum and external parameters in the non-reciprocal and gain-and-loss Su-Schrieffer-Heeger models, and non-Hermitian versions of the quantum Ising chain, Chern-insulator model and two-level system are calculated and analyzed. For these non-Hermitian models, the results show that in the case of single-parameter estimation in these non-Hermitian models, the quantum Fisher information increases significantly in the gapless regime and near the exceptional points, which can improve the accuracy limit of parameter estimation. For the two-parameter estimation, the determinant of the quantum Fisher information matrix also increases obviously near the gapless and exceptional points. In addition, a higher overall accuracy can be achieved in the topological regime than in the trivial regime, and the topological bound in two-parameter estimation can be determined by the Chern number.

     

    目录

    /

    返回文章
    返回