发表机构
College of Mathematics and Physics, Beijing University of Chemical Technology; Department of Physics, Wuhan University of Technology; Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology; School of Science, Shenzhen Campus of Sun Yat-sen University; Sun Yat-sen University（北京化工大学理学院; 武汉理工大学物理系; 北京理工大学物理学院先进光电子量子架构与测量教育部重点实验室量子物理中心; 中山大学深圳校区理学院; 中山大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文在BCS框架下推导体超导体介电函数，并与Lindhard函数比较，验证其在轻暗物质直接探测中的适用性。
AI 中文摘要
介电函数对于描述凝聚态靶材中暗物质（DM）直接探测的多体屏蔽效应至关重要。当前的超导探测器分析采用自由电子Lindhard介电函数来模拟介质内效应，但这一近似在超导态下的有效性尚未得到检验。我们在Bardeen-Cooper-Schrieffer（BCS）框架内推导了体超导体的电子介电函数，并在随机相位近似中纳入了完整的Bogoliubov准粒子相干因子。与铝和硅化钨（WSi）的Lindhard函数的系统比较表明，在能量沉积ω≳5Δ时两者吻合良好，从而确立了Lindhard函数在此能区运行的超导DM探测器中的稳健近似地位。
英文摘要
The dielectric function is central to describing many-body screening effects in dark matter (DM) direct detection with condensed matter targets. Current superconducting detector analyses employ the free-electron Lindhard dielectric function to model in-medium effects, an approximation whose validity in the superconducting state remains untested. We derive the electronic dielectric function for bulk superconductors within the Bardeen-Cooper-Schrieffer (BCS) framework, incorporating the full Bogoliubov quasiparticle coherence factors in the random-phase approximation. A systematic comparison with the Lindhard function for aluminum and tungsten silicide (WSi) reveals good agreement for energy depositions $ω\gtrsim5Δ$, establishing the Lindhard function as a robust approximation for superconducting DM detectors operating in this regime.
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