Sugisaki Kenji
Graduate School of Science and Technology, Keio University, 7-1 Shinkawasaki, Saiwai-ku, Kawasaki, Kanagawa 212-0032, Japan.
Quantum Computing Center, Keio University, 3-14-1 Hiyoshi, Kohoku-ku Yokohama, Kanagawa 223-8522, Japan.
J Chem Theory Comput. 2023 Nov 14;19(21):7617-7625. doi: 10.1021/acs.jctc.3c00784. Epub 2023 Oct 24.
Quantum computers are capable of calculating the energy difference of two electronic states using the quantum phase difference estimation (QPDE) algorithm. The Bayesian inference-based implementations for the QPDE have been reported so far, but in this approach, the quality of the calculated energy difference depends on the input wave functions being used. Here, we report the inverse quantum Fourier transformation-based QPDE with of ancillary qubits, which allows us to compute the difference of eigenenergies based on the single-shot projective measurement. As proof-of-concept demonstrations, we report numerical experiments for the singlet-triplet energy difference of the hydrogen molecule and the vertical excitation energies of halogen-substituted methylenes (CHF, CHCl, CF, CFCl, and CCl) and formaldehyde (HCHO).
量子计算机能够使用量子相位差估计（QPDE）算法来计算两个电子态的能量差。到目前为止，已经报道了基于贝叶斯推理的QPDE实现方法，但在这种方法中，计算出的能量差的质量取决于所使用的输入波函数。在此，我们报告了基于逆量子傅里叶变换且带有辅助量子比特的QPDE，它使我们能够基于单次投影测量来计算本征能量的差值。作为概念验证演示，我们报告了关于氢分子单重态 - 三重态能量差以及卤代亚甲基（CHF、CHCl、CF、CFCl和CCl）与甲醛（HCHO）垂直激发能的数值实验。
