调和X射线汤姆逊散射的化学模型与贝特f和规则
Reconciling chemical models of X-ray Thomson Scattering with the Bethe $f$-sum rule
AI总结：
研究针对X射线汤姆逊散射实验常用的千原分解在满足贝特f和规则上的不足，提出基态物质动态结构因子千原分解的解析扩展，通过包含束缚-束缚跃迁等实现符合规则，模拟显示与标准模型有偏差，模型将开源。
AI中文摘要：
X射线汤姆逊散射（XRTS）是高能密度等离子体的关键诊断方法，即使在高温下也会呈现显著量子效应。XRTS实验通常用在化学图景中推导的千原分解来解释，该分解区分束缚电子和自由电子的贡献。尽管它是分析测量的实际标准，但以脉冲近似形式的标准束缚态处理无法满足基本理论约束，尤其是贝特f和规则（BFSR）。问题源于脉冲近似中平面波的使用以及束缚-束缚跃迁的不可忽略贡献。本文提出基态物质动态结构因子千原分解的最小解析扩展，使用类氢束缚-自由和束缚-束缚跃迁。证明只有明确包含束缚-束缚跃迁并精确处理束缚-自由贡献才能符合BFSR。最后，对原子氢的探测器光线追踪模拟表明与标准千原模型存在可实验检测的偏差。该模型将在开源XRTS库xDAVE中提供。
英文摘要：
X-ray Thomson scattering (XRTS) is a key diagnostic for high-energy-density plasmas, which can exhibit significant quantum effects even at elevated temperatures. XRTS experiments are commonly interpreted using the Chihara decomposition, that was derived in the chemical picture and, thus, separates contributions from bound and free electrons. Despite being the de-facto standard for analysing measurements, a well-known shortcoming is that the standard bound-state treatment in the form of the impulse approximation fails to satisfy fundamental theoretical constraints, most notably the Bethe $f$-sum rule (BFSR). The problem arises due to the usage of plane waves in the impulse approximation as well as non-negligible contributions from bound-bound transitions. In this work, we present a minimal analytical extension of the Chihara decomposition of the dynamic structure factor for matter in the ground state, using hydrogenic bound-free and bound-bound transitions. We demonstrate that compliance with the BFSR is only achieved when both bound-bound transitions are explicitly included and an exact treatment of the bound-free contribution is applied. Finally, detector ray-tracing simulations for atomic hydrogen demonstrate experimentally detectable deviations from the standard Chihara model. The model will be made available in the open source XRTS library xDAVE [Bellenbaum et al., Phys. Plasmas (in print), arxiv:2604.27237].
