论文标题
直接估计基态和激发状态之间的量子退火的能量差距
Direct estimation of the energy gap between the ground state and excited state with quantum annealing
论文作者
论文摘要
量子化学是量子信息技术的重要应用之一。尤其是，必须估计与分子相对应的靶标哈密顿的基态和激发状态之间的能量差距。在先前的方法中，分别估算了基态和激发态的能量，并且可以根据它们之间的减法来计算能隙。在这里，我们提出直接估计目标哈密顿量的基态和激发状态之间的能量差距，并通过量子退火。关键思想是将拉姆西型测量与量子退火相结合。这提供了一个具有能量间隙频率的振荡信号，信号的傅立叶变换让我们知道能量间隙。基于超导Qubits的典型参数，当我们估计哈密顿量的基态和第一个激发状态之间的能量差距时，我们会数值研究我们的方案的性能。我们表现出对基态和首先兴奋状态之间非绝热过渡的鲁棒性。我们的结果铺平了一种估计量子化学的量子差距的新方法。
Quantum chemistry is one of the important applications of quantum information technology. Especially, an estimation of the energy gap between a ground state and excited state of a target Hamiltonian corresponding to a molecule is essential. In the previous approach, an energy of the ground state and that of the excited state are estimated separately, and the energy gap can be calculated from the subtraction between them. Here, we propose a direct estimation of the energy gap between the ground state and excited state of the target Hamiltonian with quantum annealing. The key idea is to combine a Ramsey type measurement with the quantum annealing. This provides an oscillating signal with a frequency of the energy gap, and a Fourier transform of the signal let us know the energy gap. Based on typical parameters of superconducting qubits, we numerically investigate the performance of our scheme when we estimate an energy gap between the ground state and first excited state of the Hamiltonian. We show robustness against non-adiabatic transitions between the ground state and first-excited state. Our results pave a new way to estimate the energy gap of the Hamiltonian for quantum chemistry.
