Quantum multi-parameter estimation has recently attracted increased attention due to its wide applications, with a primary goal of designing high-precision measurement schemes for unknown parameters. While existing re...Quantum multi-parameter estimation has recently attracted increased attention due to its wide applications, with a primary goal of designing high-precision measurement schemes for unknown parameters. While existing research has predominantly concentrated on time-independent Hamiltonians, little has been known about quantum multi-parameter estimation for time-dependent Hamiltonians due to the complexity of quantum dynamics. This work bridges the gap by investigating the precision limit of multi-parameter quantum estimation for a qubit in an oscillating magnetic field model with multiple unknown frequencies. As the well-known quantum Cramer–Rao bound is generally unattainable due to the potential incompatibility between the optimal measurements for different parameters, we use the most informative bound instead which is always attainable and equivalent to the Holevo bound in the asymptotic limit. Moreover, we apply additional Hamiltonian to the system to engineer the dynamics of the qubit. By utilizing the quasi-Newton method, we explore the optimal schemes to attain the highest precision for the unknown frequencies of the magnetic field, including the simultaneous optimization of initial state preparation, the control Hamiltonian and the final measurement. The results indicate that the optimization can yield much higher precisions for the field frequencies than those without the optimizations. Finally,we study the robustness of the optimal control scheme with respect to the fluctuation of the interested frequencies, and the optimized scheme exhibits superior robustness to the scenario without any optimization.展开更多
2023年9月欧洲肿瘤内科学会在Amals of Oncology上发表了“2023年欧洲肿瘤内科学会临床实践指南:胰腺癌的诊断、治疗和随访”。该指南围绕胰腺癌(PC)的流行病学、诊断和治疗等方面提出建议。该指南指出了PC的高危人群与建议筛查方法,明...2023年9月欧洲肿瘤内科学会在Amals of Oncology上发表了“2023年欧洲肿瘤内科学会临床实践指南:胰腺癌的诊断、治疗和随访”。该指南围绕胰腺癌(PC)的流行病学、诊断和治疗等方面提出建议。该指南指出了PC的高危人群与建议筛查方法,明确了PC的诊断流程和各种影像学、分子生物学检查手段,提出了各型PC适宜的治疗方法。本文对该指南进行摘译,介绍了指导意见中PC临床诊疗的相关指导,以期为临床实践提供参考依据。展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 12075323)。
文摘Quantum multi-parameter estimation has recently attracted increased attention due to its wide applications, with a primary goal of designing high-precision measurement schemes for unknown parameters. While existing research has predominantly concentrated on time-independent Hamiltonians, little has been known about quantum multi-parameter estimation for time-dependent Hamiltonians due to the complexity of quantum dynamics. This work bridges the gap by investigating the precision limit of multi-parameter quantum estimation for a qubit in an oscillating magnetic field model with multiple unknown frequencies. As the well-known quantum Cramer–Rao bound is generally unattainable due to the potential incompatibility between the optimal measurements for different parameters, we use the most informative bound instead which is always attainable and equivalent to the Holevo bound in the asymptotic limit. Moreover, we apply additional Hamiltonian to the system to engineer the dynamics of the qubit. By utilizing the quasi-Newton method, we explore the optimal schemes to attain the highest precision for the unknown frequencies of the magnetic field, including the simultaneous optimization of initial state preparation, the control Hamiltonian and the final measurement. The results indicate that the optimization can yield much higher precisions for the field frequencies than those without the optimizations. Finally,we study the robustness of the optimal control scheme with respect to the fluctuation of the interested frequencies, and the optimized scheme exhibits superior robustness to the scenario without any optimization.
文摘2023年9月欧洲肿瘤内科学会在Amals of Oncology上发表了“2023年欧洲肿瘤内科学会临床实践指南:胰腺癌的诊断、治疗和随访”。该指南围绕胰腺癌(PC)的流行病学、诊断和治疗等方面提出建议。该指南指出了PC的高危人群与建议筛查方法,明确了PC的诊断流程和各种影像学、分子生物学检查手段,提出了各型PC适宜的治疗方法。本文对该指南进行摘译,介绍了指导意见中PC临床诊疗的相关指导,以期为临床实践提供参考依据。
