近日，韩国高等研究院Lee, Sangmin团队研究了相对论散射中的经典程函。这一研究成果发表在2025年11月6日出版的《高能物理杂志》上。

经典程函被定义为经典力学散射问题中所有散射观测量的生成元。其最初是作为量子S矩阵在经典极限下的对数形式被引入，但其经典本质要求建立独立于量子力学的定义与计算方法。

研究组构建了作为经典程函理论基础的经典相互作用绘景，并特别强调理论的普适性：在微扰理论中同时考虑哈密顿变形与辛变形，以对等方式处理粒子与场，且传播子的因果性规定在非相对论与相对论动力学中本质相同。针对电磁或引力背景中的探针粒子，研究组给出了微扰程函的全阶表达式，并在电磁场景中阐述了程函如何编码外场辐射信息。

附：英文原文

Title: Classical eikonal in relativistic scattering

Author: Kim, Sungsoo, Lee, Hojin, Lee, Sangmin

Issue&Volume: 2025-11-06

Abstract: The classical eikonal is defined to be the generator of all scattering observables in a scattering problem in classical mechanics. It was originally introduced as the log of the quantum S-matrix in the classical limit. But its classical nature calls for a definition and computational methods independent of quantum mechanics. In this paper, we formulate a classical interaction picture which serves as the foundation of the classical eikonal. Our emphasis is on generality. In perturbation theories, both Hamiltonian deformation and symplectic deformation are considered. Particles and fields are treated on a similar footing. The causality prescription of the propagator is essentially the same for non-relativistic and relativistic kinematics. For a probe particle in electromagnetic or gravitational background, we present all order formulas for the perturbative eikonal. In the electromagnetic setting, we also illustrate how the eikonal encodes the information on radiation of external fields.

DOI: 10.1007/JHEP11(2025)032

Source: https://link.springer.com/article/10.1007/JHEP11(2025)032