Implementation of measurement reduction for the variational quantum eigensolver
Implementation of measurement reduction for the variational quantum eigensolver
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DOI：
10.1103/physrevresearch.3.033195
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发表时间：
2020-12
影响因子：
4.2
通讯作者：
Alexis Ralli;P. Love;A. Tranter;P. Coveney
中科院分区：
文献类型：
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作者：
Alexis Ralli;P. Love;A. Tranter;P. Coveney
变异量子本素算法的一个局限性是估计感兴趣的哈密顿量不同项所需的大量测量步骤。单一分区通过将哈密顿量的问题转换为包含较少术语的问题，从而减少了这一开销。我们探索了所需转换的两个不同电路结构 - 一个由一系列旋转构建，另一个是单位型（LCU）的线性组合。为了评估性能，我们模拟了化学汉密尔顿人，并研究了H2和LIH的基态。即使在存在噪音的情况下，这两种实现都是成功的。旋转序列实现提供了最大的好处，而LCU的概率性质降低了其有效性。据我们所知，这项工作还展示了LCU在量子硬件上的第一个实验实现。
One limitation of the variational quantum eigensolver algorithm is the large number of measurement steps required to estimate different terms in the Hamiltonian of interest. Unitary partitioning reduces this overhead by transforming the problem Hamiltonian into one containing fewer terms. We explore two different circuit constructions of the transformation required - one built by a sequence of rotations and the other a linear combination of unitaries (LCU). To assess performance, we simulated chemical Hamiltonians and studied the ground states of H2 and LiH. Both implementations are successful even in the presence of noise. The sequence of rotations realization offers the greatest benefit, whereas the probabilistic nature of LCU reduces its effectiveness. To our knowledge, this work also demonstrates the first experimental implementation of LCU on quantum hardware.