Error Sensitivity to Environmental Noise in Quantum Circuits for Chemical State Preparation

详细信息    查看全文

• 作者：Nicolas P. D. Sawaya ; Mikhail Smelyanskiy ; Jarrod R. McClean ; Alán Aspuru-Guzik
• 刊名：Journal of Chemical Theory and Computation
• 出版年：2016
• 出版时间：July 12, 2016
• 年：2016
• 卷：12
• 期：7
• 页码：3097-3108
• 全文大小：551K
• 年卷期：0
• ISSN：1549-9626

文摘

Calculating molecular energies is likely to be one of the first useful applications to achieve quantum supremacy, performing faster on a quantum than a classical computer. However, if future quantum devices are to produce accurate calculations, errors due to environmental noise and algorithmic approximations need to be characterized and reduced. In this study, we use the high performance qHiPSTER software to investigate the effects of environmental noise on the preparation of quantum chemistry states. We simulated 18 16-qubit quantum circuits under environmental noise, each corresponding to a unitary coupled cluster state preparation of a different molecule or molecular configuration. Additionally, we analyze the nature of simple gate errors in noise-free circuits of up to 40 qubits. We find that, in most cases, the Jordan–Wigner (JW) encoding produces smaller errors under a noisy environment as compared to the Bravyi–Kitaev (BK) encoding. For the JW encoding, pure dephasing noise is shown to produce substantially smaller errors than pure relaxation noise of the same magnitude. We report error trends in both molecular energy and electron particle number within a unitary coupled cluster state preparation scheme, against changes in nuclear charge, bond length, number of electrons, noise types, and noise magnitude. These trends may prove to be useful in making algorithmic and hardware-related choices for quantum simulation of molecular energies.