Practical quantum computation of chemical and nuclear energy levels using quantum imaginary time evolution and Lanczos algorithms
Practical quantum computation of chemical and nuclear energy levels using quantum imaginary time evolution and Lanczos algorithms
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DOI：
10.1038/s41534-020-00290-1
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发表时间：
2019-12
影响因子：
7.6
通讯作者：
Kubra Yeter-Aydeniz;R. Pooser;G. Siopsis
中科院分区：
文献类型：
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作者：
Kubra Yeter-Aydeniz;R. Pooser;G. Siopsis
人们已经开发了各种方法来对物理和化学系统的基态和激发态进行量子计算，但其中许多方法要么需要大量辅助量子位，要么需要在存在噪声的情况下进行高维优化。Motta等人（2020）提出的量子时间演化（QITE）和量子Lanczos（QLanczos）方法避开了上述问题。在这项研究中，我们展示了这些算法的实际应用，以具有挑战性的量子计算的化学和核物理的相关性，使用氘结合能和分子氢结合和激发态能量为例。通过正确选择初始和最终状态，我们证明了QITE和QLanczos中的时间步长可以显着减少，这大大简化了所需的量子电路，并提高了与NISQ器件的兼容性。我们已经在云可访问的IBM Q量子计算机上进行了这些计算。与应用程序的读出误差减轻和理查森误差外推，我们已经得到的基态和激发态能量，以及同意从对角化得到的精确结果。
Various methods have been developed for the quantum computation of the ground and excited states of physical and chemical systems, but many of them require either large numbers of ancilla qubits or high-dimensional optimization in the presence of noise. The quantum imaginary-time evolution (QITE) and quantum Lanczos (QLanczos) methods proposed in Motta et al. (2020) eschew the aforementioned issues. In this study, we demonstrate the practical application of these algorithms to challenging quantum computations of relevance for chemistry and nuclear physics, using the deuteron-binding energy and molecular hydrogen binding and excited state energies as examples. With the correct choice of initial and final states, we show that the number of timesteps in QITE and QLanczos can be reduced significantly, which commensurately simplifies the required quantum circuit and improves compatibility with NISQ devices. We have performed these calculations on cloud-accessible IBM Q quantum computers. With the application of readout-error mitigation and Richardson error extrapolation, we have obtained ground and excited state energies that agree well with exact results obtained from diagonalization.