Calculation of Molecular Vibrational Spectra on a Quantum Annealer

Until recently molecular energy calculations using quantum computing hardware have been limited to gate-based quantum computers. In this paper, a new methodology is presented to calculate the vibrational spectrum of a molecule on a quantum annealer. The key idea of the method is a mapping of the ground state variational problem onto an Ising or quadratic unconstrained binary optimization (QUBO) problem by expressing the expansion coefficients using spins or qubits. The algorithm is general and represents a new revolutionary approach for solving the real symmetric eigenvalue problem on a quantum annealer. The method is applied to two chemically important molecules: O-2 (oxygen) and O-3 (ozone). The lowest two vibrational states of these molecules are computed using both a hardware quantum annealer and a software based classical annealer. Extension of the algorithm to higher dimensions is explicitly demonstrated for an N-dimensional harmonic oscillator (N

直到最近，使用量子计算硬件进行的分子能量计算一直局限于基于门的量子计算机。在本文中，提出了一种在量子退火机上计算分子振动光谱的新方法。该方法的关键思想是通过使用自旋或量子比特来表示展开系数，将基态变分问题映射到伊辛（Ising）或二次无约束二进制优化（QUBO）问题上。该算法具有通用性，代表了一种在量子退火机上解决实对称特征值问题的全新革命性方法。该方法应用于两个具有重要化学意义的分子：O - 2（氧）和O - 3（臭氧）。使用硬件量子退火机和基于软件的经典退火机计算了这些分子的最低两个振动状态。对于一个N维谐振子（N……（此处原文似乎不完整），明确展示了该算法向更高维度的扩展。