Quantum simulation algorithms for quantum chromodynamics

量子色动力学（QCD）是强作用力的理论，它是我们理解大量实验观测的核心，也是我们预测对撞机实验（如CERN的LHC）中新粒子发现的核心。量子色动力学在实际系统中成功应用的主要障碍之一是其固有的计算复杂性。许多重要的问题抵制反复努力找到有效的经典算法，以深入了解物质的基本构建块的行为。这自然促使我们考虑其他有希望的计算范式，这些范式有可能克服上述障碍，例如量子计算。量子计算的出现以费曼在1982年的洞察力为标志，即在经典计算机上模拟一般多体量子系统的演化需要指数级的资源。这是由于底层希尔伯特空间的维度与系统大小的指数缩放。相反，正如费曼所观察到的，量子系统本身的演化只需要多项式开销。从那时起，在量子信息操纵方面取得了稳步的理论进展，这刺激了新的信息处理协议的发展，这些协议主要依赖于物理系统的量子性质，并为可扩展的量子计算机提供应用。目前，有一个主要的理论和实验努力，实际上建立小型到中型的量子计算机。这一点，加上有形的实验进展开辟了道路，不仅为新的算法的进步，但也为定制的应用量子理论的一系列问题，以前是unaccessible.我们的目标是利用量子计算和模拟的物理系统的最新进展，以解决问题，在QCD以前是棘手的传统经典方法。这将使我们能够更深入地研究粒子相互作用，并激发新的有效量子方法来模拟自然界的基本力。

Quantum Chromodynamics (QCD) is the theory of strong force and it lies at the heart of our understanding of the plethora of experimental observations, as well as predictions for new particle discoveries in collider experiments like LHC at CERN. One of the major outstanding problems that stand in the way of the successful application of the QCD to real-world systems is its inherent computational complexity. Many important problems resist repeated efforts to find efficient classical algorithms to gain insight into the behaviour of basic building blocks of matter. This naturally leads us to consider other promising computational paradigms that have a potential to overcome the above obstacles such as quantum computing. The emergence of quantum computing was marked by Feynman's insight in 1982 that simulating the evolution of general many-body quantum systems on a classical computer requires exponential resources. This is due to the exponential scaling of the dimension of the underlying Hilbert space with the system size. In contrast, as Feynman observed, the evolution of the quantum system itself requires only polynomial overhead. Since then, there has been steady theoretical progress on manipulation of quantum information and this has stimulated the development of new information processing protocols which rely essentially on the quantum nature of the physical systems and provide applications for scalable quantum computers. Currently, there is a major theoretical and experimental effort towards actually building small to medium-sized quantum computers. This, together with tangible experimental advances opens up avenues not only for novel algorithmic advances but also for bespoke applications of quantum theory to a range of problems that were previously inaccessible.We aim to exploit recent advances in quantum computing and simulation of physical systems to solve problems in QCD that were previously intractable by traditional classical methods. This will allow us to delve deeper into particle interaction and inspire new efficient quantum methods for simulating fundamental forces of nature.