The parameter estimation of the Hamiltonian of an unknown quantum system is essential in quantum information processing. However, the general methods based on quantum state tomography and process tomography are resource demanding and challenging in large quantum systems. On the other hand, if the interaction form of a system is known, one can adopt the quantum quench protocol to reconstruct the generic many-body Hamiltonian with local interactions, requiring significantly lower complexity and measurement cost compared to the general tomography technique. Here we report an experimental demonstration of the quench method to determine the scalar coupling constants in a three-spin chain. In the experiments, we demonstrate that how the quality of the estimation is affected by the duration of the quench and the number of input states. Our results show that the quantum quench protocol is a promising strategy to implement Hamiltonian estimation for many-body systems, especially when the cost of measurement is crucial in practical cases.

中文翻译：

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哈密​​顿层析成像的量子猝灭实验实现

未知量子系统的哈密顿量的参数估计在量子信息处理中至关重要。但是，基于量子状态层析成像和过程层析成像的常规方法在大型量子系统中对资源的要求很高且具有挑战性。另一方面，如果系统的相互作用形式是已知的，则可以采用量子猝灭协议来重建具有局部相互作用的通用多体哈密顿量，与一般的层析成像技术相比，其所需的复杂度和测量成本大大降低。在这里，我们报告淬火方法的实验演示，以确定三自旋链中的标量耦合常数。在实验中，我们证明了猝灭的持续时间和输入状态数如何影响估计的质量。