Simulating time evolution with fully optimized single-qubit gates on parametrized quantum circuits
Simulating time evolution with fully optimized single-qubit gates on parametrized quantum circuits
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DOI：
10.1103/physreva.105.062421
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发表时间：
2021-11
影响因子：
2.9
通讯作者：
Kaito Wada;Rudy Raymond;Yu-ya Ohnishi;Eriko Kaminishi;M. Sugawara;Naoki Yamamoto;Hiroshi C. Watanabe
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作者：
Kaito Wada;Rudy Raymond;Yu-ya Ohnishi;Eriko Kaminishi;M. Sugawara;Naoki Yamamoto;Hiroshi C. Watanabe
我们提出了一种新的方法来顺序优化参数化量子电路中的任意单量子比特门，以模拟真实的和虚时间演化。该方法利用单量子位门的全自由度，因此可以潜在地获得更好的性能。具体地说，它同时优化了单量子比特门的轴和角度，而已知的方法要么在轴固定的情况下优化角度，要么反之亦然。它概括了已知的方法，并利用正弦成本函数参数化的轴和旋转角度。此外，我们演示了如何将其扩展到优化一组具有激发守恒约束的参数化双量子比特门，其中包括Hop和可重构分束器门。我们进行数值实验，显示所提出的方法的权力，找到典型的哈密顿与量子虚时间演化的参数化量子电路的基态。此外，我们表明该方法可以应用于真实的时间演化，并讨论了其模拟精度和硬件效率之间的权衡。
We propose a novel method to sequentially optimize arbitrary single-qubit gates in parameterized quantum circuits for simulating real and imaginary time evolution. The method utilizes full degrees of freedom of single-qubit gates and therefore can potentially obtain better performance. Specifically, it simultaneously optimizes both the axis and the angle of a single-qubit gate, while the known methods either optimize the angle with the axis fixed, or vice versa. It generalizes the known methods and utilizes sinusoidal cost functions parameterized by the axis and angle of rotation. Furthermore, we demonstrate how it can be extended to optimize a set of parameterized two-qubit gates with excitation-conservation constraints, which includes the Hop and the Reconfigurable Beam Splitter gates. We perform numerical experiments showing the power of the proposed method to find ground states of typical Hamiltonians with quantum imaginary time evolution using parameterized quantum circuits. In addition, we show the method can be applied to real time evolution and discuss the tradeoff between its simulation accuracy and hardware efficiency.