Sugisaki Kenji, Toyota Kazuo, Sato Kazunobu, Shiomi Daisuke, Takui Takeji
Department of Chemistry and Molecular Materials Science, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
JST PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
J Phys Chem Lett. 2021 Mar 25;12(11):2880-2885. doi: 10.1021/acs.jpclett.1c00283. Epub 2021 Mar 16.
Recently, a quantum algorithm that is capable of directly calculating the energy gap between two electronic states having different spin quantum numbers without inspecting the total energy of the individual electronic states was proposed. This quantum algorithm guarantees an exponential speedup, like quantum phase estimation (QPE)-based full-CI, with much lower costs. In this work, we propose a modified quantum circuit for the direct calculations of spin state energy gaps to reduce the number of qubits and quantum gates, extending the quantum algorithm to the direct calculation of vertical ionization energies. Numerical quantum circuit simulations for the ionization of light atoms (He, Li, Be, B, C, and N) and small molecules (HF, BF, CF, CO, O, NO, CN, F, HO, and NH) revealed that the proposed quantum algorithm affords the vertical ionization energies within 0.1 eV of precision.
最近，有人提出了一种量子算法，该算法能够直接计算具有不同自旋量子数的两个电子态之间的能隙，而无需考察各个电子态的总能量。这种量子算法保证了指数级的加速，类似于基于量子相位估计（QPE）的全组态相互作用（full-CI），且成本要低得多。在这项工作中，我们提出了一种用于直接计算自旋态能隙的改进量子电路，以减少量子比特数和量子门数，并将该量子算法扩展到垂直电离能的直接计算。对轻原子（He、Li、Be、B、C和N）和小分子（HF、BF、CF、CO、O、NO、CN、F、HO和NH）电离的数值量子电路模拟表明，所提出的量子算法能够以0.1 eV的精度给出垂直电离能。
