Simulating chemical systems is highly sought after and computationally challenging, as the simulation cost exponentially increases with the system size. Quantum computers have been proposed as a computational means to overcome this bottleneck. Most efforts recently have been spent on determining the ground states of chemical systems. Hardness results and the lack of efficient heuristics for initial-state generation sheds doubt on the feasibility. Here we propose an inherently efficient approach for solving chemical simulation problems, meaning it requires quantum circuits of size scaling polynomially in relevant system parameters. If a set of assumptions can be satisfied, our approach finds good initial states by assembling initial states for dynamical simulation in a scattering tree. We discuss a variety of quantities of chemical interest that can be measured based on quantum simulation, e.g. of a reaction, succeeding the initial state preparation.

翻译：模拟化学系统是备受期待且计算上极具挑战的任务，因为模拟成本随系统规模呈指数增长。量子计算机已被提出作为克服这一瓶颈的计算手段。近期大多数研究致力于确定化学系统的基态。然而，初始态生成的难度结果及高效启发式算法的缺失，使该可行性受到质疑。本文提出一种本质高效的化学模拟问题求解方法，即所需量子电路规模随相关系统参数呈多项式增长。若一组假设条件得到满足，我们的方法通过散射树组装动力学模拟的初始态来寻找优质初始态。我们讨论了基于量子模拟可测量的多种化学感兴趣的量（例如反应过程中的量），这些测量可在初始态制备之后进行。