发表机构
Theory Center, IPNS, KEK; The Graduate University for Advanced Studies (SOKENDAI)（高能加速器研究机构理论中心粒子核结构研究部; 综合研究大学院大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究突破瞬时热平衡假设，分析微扰再加热中引力波的产生机制，揭示非热硬粒子群及各向同性化对引力波谱的影响，修正了深红外区的引力波谱指数。
AI 中文摘要
我们研究微扰再加热过程中的引力波产生，不假设暴胀子衰变产物发生瞬时热平衡。注入的高能粒子通过近共线分裂的介质级联（受朗道-波梅鲁克-迈达尔效应制约）热化，最终在热标度附近通过弹性散射实现各向同性化。完全热平衡前存在的非热硬粒子群，通过硬-软散射产生额外引力波成分，在注入标度转折以下满足Ω_GW∝f^(1/2)；同样的各向同性化会消除真空1/k轫致辐射软极的方向信息，将深红外谱从Ω_GW∝f改变为Ω_GW∝f^3。
英文摘要
We study gravitational-wave production during perturbative reheating without assuming instantaneous thermalization of the inflaton decay products. The injected energetic particles thermalize through an in-medium cascade of nearly collinear splittings subject to the Landau-Pomeranchuk-Migdal effect and are ultimately isotropized by elastic scatterings near the thermal scale. The non-thermal hard population present before complete thermalization produces an additional gravitational-wave component through hard-soft scatterings, with $Ω_{\mathrm{GW}}\propto f^{1/2}$ below the injection-scale turnover. The same isotropization erases the directional information underlying the vacuum $1/k$ bremsstrahlung soft pole, changing the deep-infrared spectrum from $Ω_{\mathrm{GW}}\propto f$ to $Ω_{\mathrm{GW}}\propto f^3$.
Comments40 pages, 2 figures
