论文标题
通过嘈杂的量子计算,在空间变形下计算苯的基态能
Calculating the ground state energy of benzene under spatial deformations with noisy quantum computing
论文作者
论文摘要
在本手稿中,我们使用变分量子质量(VQE)计算在空间变形下苯的基态能。该研究的主要目的是估计在近期设备上使用量子计算ANSATZE的可行性,以解决已知经典方法失败的区域中大量轨道的问题。此外,通过将我们的高级仿真平台与实际量子计算机相结合,我们对量子计算机固有的噪声如何影响结果提供了分析。我们研究的中心是硬件有效和量子统一耦合群集Ansatze(QUCC)。首先,我们发现硬件有效的ANSATZ有可能超过苯苯极变形的均值方法。但是,关键问题仍然处于平衡状态,从而阻止了实际的化学应用。此外,硬件有效的ANSATZ产生的结果很大程度上取决于参数的初始猜测 - 无论是在嘈杂的情况和无嘈杂的情况下 - 优化问题对它们的收敛性都比噪声更高。通过与实际量子计算实验进行比较证实了这一点。另一方面,QUCC ANSATZ替代方案表现出更深的电路。因此,噪声效应会增加,并且是如此极端,以至于该方法永远不会超越平均场理论。我们的双模拟器/8-16 QPU的QPU计算似乎对硬件噪声比射击噪声更为敏感,这给出了更多的迹象,可以进一步指示应将降噪工作定向到何处。最后,研究表明,QUCC方法可以更好地捕获系统的物理,因为可以将QUCC方法与H Uckel近似一起使用。我们讨论了超越这种近似值如何急剧提高这种困难问题的优化复杂性。
In this manuscript, we calculate the ground state energy of benzene under spatial deformations by using the variational quantum eigensolver (VQE). The primary goal of the study is estimating the feasibility of using quantum computing ansatze on near-term devices for solving problems with large number of orbitals in regions where classical methods are known to fail. Furthermore, by combining our advanced simulation platform with real quantum computers, we provided an analysis of how the noise, inherent to quantum computers, affects the results. The centers of our study are the hardware efficient and quantum unitary coupled cluster ansatze (qUCC). First, we find that the hardware efficient ansatz has the potential to outperform mean-field methods for extreme deformations of benzene. However, key problems remain at equilibrium, preventing real chemical application. Moreover, the hardware efficient ansatz yields results that strongly depend on the initial guess of parameters - both in the noisy and noiseless cases - and optimization issues have a higher impact on their convergence than noise. This is confirmed by comparison with real quantum computing experiments. On the other hand, the qUCC ansatz alternative exhibits deeper circuits. Therefore, noise effects increase and are so extreme that the method never outperform mean-field theories. Our dual simulator/8-16 qubits QPU computations of qUCC appears to be a lot more sensitive to hardware noise than shot noise, which give further indications about where the noise-reduction efforts should be directed towards. Finally, the study shows that qUCC method better captures the physics of the system as the qUCC method can be utilized together with the Huckel approximation. We discussed how going beyond this approximation sharply increases the optimization complexity of such a difficult problem.