论文标题
定期分组和旅行销售人员用于数字量子模拟
Term Grouping and Travelling Salesperson for Digital Quantum Simulation
论文作者
论文摘要
通过评估哈密顿量的时间演化,量子动力学的数字模拟是最初提出的量子计算应用。然而,模拟哈密顿量的完整第二量化形式所需的大量量子门,使这种方法不适合造成高物理误差的门口保真度有限的近期设备。此外,由非交通术语引起的猪根误差会累积并损害整体电路保真度,从而导致算法错误。在本文中,我们提出了一种新的术语排序策略,即Max-Commute-TSP(MCTSP),同时减轻算法和物理错误。首先,与先前提出的优化相比,我们通过重新排序Pauli条款并将其划分为通勤家庭而提高了猪棍的保真度。我们通过构建和评估模拟不同分子汉密尔顿人的量子电路来证明这种方法的实用性,以及从我们的术语分组方法中改善忠诚度改善的理论解释。其次,我们描述了一种新的大门取消技术,该技术通过将栅极取消问题和基准测试实验配置为旅行销售人员问题来降低高门计数。最后,我们还提供了基准测试结果,以证明Max-Commute-TSP在现实噪声模型下通过量子电路模拟来减轻物理和算法误差的综合优势。
Digital simulation of quantum dynamics by evaluating the time evolution of a Hamiltonian is the initially proposed application of quantum computing. The large number of quantum gates required for emulating the complete second quantization form of the Hamiltonian, however, makes such an approach unsuitable for near-term devices with limited gate fidelities that cause high physical errors. In addition, Trotter error caused by noncommuting terms can accumulate and harm the overall circuit fidelity, thus causing algorithmic errors. In this paper, we propose a new term ordering strategy, max-commute-tsp (MCTSP), that simultaneously mitigates both algorithmic and physical errors. First, we improve the Trotter fidelity compared with previously proposed optimization by reordering Pauli terms and partitioning them into commuting families. We demonstrate the practicality of this method by constructing and evaluating quantum circuits that simulate different molecular Hamiltonians, together with theoretical explanations for the fidelity improvements from our term grouping method. Second, we describe a new gate cancellation technique that reduces the high gate counts by formulating the gate cancellation problem as a travelling salesperson problem, together with benchmarking experiments. Finally, we also provide benchmarking results that demonstrate the combined advantage of max-commute-tsp to mitigate both physical and algorithmic errors via quantum circuit simulation under realistic noise models.