近日，德国汉堡大学的Stasis Chuchurka&Nina Rohringer及其研究团队取得一项新进展。经过不懈努力，他们提出X射线超荧光的厄米随机方法论。相关研究成果已于2024年6月14日在国际知名学术期刊《物理评论A》上发表。

据悉，最近引入的X射线放大自发辐射动力学建模的理论框架，是基于量子发射体密度矩阵和辐射场的随机采样，类似于其他相空间采样技术。虽然基于第一性原理并提供了有价值的理论见解，但原始的随机微分方程表现出发散性和数值不稳定性。

该研究团队通过扰动计算随机分量来解决这个问题。精确的形式体系准确地再现了自发辐射的性质，证明它普遍适用于描述近轴几何中X射线集体辐射的所有阶段，包括自发辐射、放大自发辐射和非线性状态。通过数值算例，研究人员分析了超荧光在一维近似下的主要特征。更重要的是，潜在的随机方程的单一实现能够完全对应并解释超荧光的单次实验观测结果。

附：英文原文

Title: Hermitian stochastic methodology for x-ray superfluorescence

Author: Stasis Chuchurka, Vladislav Sukharnikov, Nina Rohringer

Issue&Volume: 2024/06/14

Abstract: A recently introduced theoretical framework for modeling the dynamics of x-ray amplified spontaneous emission is based on stochastic sampling of the density matrix of quantum emitters and the radiation field, similarly to other phase-space sampling techniques. While based on first principles and providing valuable theoretical insights, the original stochastic differential equations exhibit divergences and numerical instabilities. Here, we resolve this issue by accounting the stochastic components perturbatively. The refined formalism accurately reproduces the properties of spontaneous emission and proves universally applicable for describing all stages of collective x-ray emission in paraxial geometry, including spontaneous emission, amplified spontaneous emission, and the nonlinear regime. Through numerical examples, we analyze key features of superfluorescence in a one-dimensional approximation. Importantly, single realizations of the underlying stochastic equations can be fully interpreted as individual experimental observations of superfluorescence.

DOI: 10.1103/PhysRevA.109.063705

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.109.063705