We discuss our present knowledge of ${\alpha }_s$, the fundamental running coupling or effective charge of Quantum Chromodynamics (QCD). A precise understanding of the running of ${\alpha }_s\left(Q^2\right)$ at high momentum transfer, $Q$, is necessary for any perturbative QCD calculation. Equally important, the behavior of ${\alpha }_s$ at low $Q^2$ in the nonperturbative QCD domain is critical for understanding strong interaction phenomena, including the emergence of mass and quark confinement. The behavior of ${\alpha }_s\left(Q^2\right)$ at all momentum transfers also provides a connection between perturbative and nonperturbative QCD phenomena, such as hadron spectroscopy and dynamics. We first sketch the origin of the QCD coupling, the reason why its magnitude depends on the scale at which hadronic phenomena are probed, and the resulting consequences for QCD phenomenology. We then summarize latest measurements in both the perturbative and nonperturbative domains. New theory developments include the derivation of the universal nonperturbative behavior of ${\alpha }_s\left(Q^2\right)$ from both the Dyson–Schwinger equations and light-front holography. We also describe theory advances for the calculation of gluon and quark Schwinger functions in the nonperturbative domain and the relation of these quantities to ${\alpha }_s$. We conclude by highlighting how the nonperturbative knowledge of ${\alpha }_s$ is now providing a parameter-free determination of hadron spectroscopy and structure, a central and long-sought goal of QCD studies.

我们讨论我们目前的知识${\alpha }_s$，量子色动力学 (QCD) 的基本运行耦合或有效电荷。准确理解运行情况${\alpha }_s（{问}^2）$在高动量传递时，$问$，对于任何微扰 QCD 计算都是必要的。同样重要的是，${\alpha }_s$处于低位${问}^2$非微扰 QCD 域中的量子力学对于理解强相互作用现象至关重要，包括质量和夸克禁闭的出现。的行为${\alpha }_s（{问}^2）$无论如何，动量传递还提供了微扰和非微扰 QCD 现象（例如强子光谱和动力学）之间的联系。我们首先概述 QCD 耦合的起源、其大小取决于探测强子现象的规模的原因，以及由此产生的 QCD 现象学后果。然后，我们总结了微扰和非微扰领域的最新测量结果。新的理论发展包括推导普遍的非微扰行为${\alpha }_s（{问}^2）$来自戴森-施温格方程和光前全息术。我们还描述了非微扰域中胶子和夸克施温格函数计算的理论进展以及这些量与${\alpha }_s$。最后，我们强调非微扰知识如何${\alpha }_s$现在提供强子光谱和结构的无参数测定，这是 QCD 研究的核心和长期追求的目标。