发表机构
Indian Institute of Technology, Guwahati（印度理工学院古瓦哈提分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对原初引力波源的简并问题，本文提出利用宽带光谱形状打破简并，通过对比标量与规范场诱导引力波的光谱特征，发现紫外光谱可作为不依赖整体归一化的源机制诊断依据。
AI 中文摘要
来自不同原初机制的随机引力波背景可产生完全相同的峰值频率与振幅，掩盖其物理起源。本文研究表明，宽带光谱形状可打破这种简并度。在相同原初谱轮廓与宇宙学演化条件下，对比标量诱导和规范场诱导的引力波，发现即便匹配了峰值频率与振幅，它们的光谱仍保留着不同的源相关特征。两种机制虽具有通用的深红外行为，但它们的张量源核会产生不同的峰值形态与紫外渐近标度。尤其，紫外光谱可作为对 underlying 源机制的直接诊断，且对整体归一化不敏感。分析显示，宽带光谱信息包含仅从峰值可观测量无法获取的额外源相关特征。
英文摘要
Stochastic gravitational-wave backgrounds from different primordial mechanisms can exhibit identical peak frequencies and amplitudes, leaving their origin degenerate. We show that this degeneracy can be broken by the broadband spectral response of the gravitational-wave source. By comparing scalar-induced and gauge-field-induced gravitational waves with the same primordial spectral profile and cosmological evolution, we isolate the imprint of the tensor-source dynamics. Although both mechanisms exhibit the same infrared scaling, they develop distinct spectral shapes near the peak and different ultraviolet asymptotes. The local spectral index $n_{\rm gw}$ and its running $α_{\rm gw}$ further characterize this source-dependent evolution, providing a spectral fingerprint beyond the peak observables. These results show that broadband, multi-frequency observations can probe the production mechanism of a primordial gravitational-wave background even when its peak frequency and amplitude are degenerate.
Comments5+2 pages,4 figures. This version has been submitted to the journal
