AI 中文总结
该研究在类RS2暴胀膜世界框架下，建立连续场介导的暴胀关联函数谱表示，发现原初关联函数的对数振荡因卡鲁扎-克莱因引力子连续谱的叠加而退相干，偏差编码了连续高能谱结构。
AI 中文摘要
宇宙学对撞机信号通常针对孤立的大质量粒子进行讨论，这类粒子的交换会在原初关联函数中产生特征性的对数振荡。在本研究中，我们探讨当交换态形成连续质量谱时，该信号会如何发生改变。我们首先为连续场介导的暴胀关联函数建立谱表示：在软极限下，种子函数的非解析部分被表示为谱权重相对于对数动量变量的傅里叶-拉普拉斯变换。该表示表明，连续谱会叠加不同频率的时钟信号，可使单个大质量粒子对应的尖锐振荡发生退相干。随后，我们在类RS2的暴胀膜世界中实现这一机制，其中暴胀子定域于五维AdS体中的德西特膜上；张量部分包含一个定域的无质量引力子和一个始于m=3H/2的卡鲁扎-克莱因（KK）引力子连续谱。我们推导了KK波函数，并确定了由膜上连续波函数所确定的膜谱权重。将该权重应用于暴胀子四点函数，我们得到了一个平滑的种子函数，而非持续的对数时钟振荡。这一行为源于连续谱始于零时钟频率，且KK谱权重在阈值附近消失。我们的结果提供了一个具体的高维示例，其中标准宇宙学对撞机信号的偏差编码了连续高能谱的结构。
英文摘要
Cosmological collider signals are usually discussed for isolated massive particles, whose exchange produces characteristic logarithmic oscillations in primordial correlators. In this work, we study how this signal is modified when the exchanged states form a continuous mass spectrum. We first develop a spectral representation for inflationary correlators mediated by a continuum field. In the soft limit, the non-analytic part of the seed function is expressed as a Fourier--Laplace transform of the spectral weight with respect to logarithmic momentum variables. This representation shows that a continuum superposes clock signals with different frequencies and can dephase the sharp oscillation associated with a single massive particle. We then realize this mechanism in an RS2-like inflationary braneworld, where the inflaton is localized on a de Sitter brane in a five-dimensional AdS bulk. The tensor sector contains a localized massless graviton and a continuum of Kaluza-Klein gravitons starting at \(m=3H/2\). We derive the KK wavefunctions and identify the brane spectral weight fixed by the continuum wavefunction on the brane. Applying this weight to the inflaton four-point function, we find a smooth seed function rather than a persistent logarithmic clock oscillation. This behavior follows from the fact that the continuum starts at zero clock frequency, while the KK spectral weight vanishes near threshold. Our results provide a concrete higher-dimensional example in which deviations from the standard cosmological collider signal encode the structure of a continuum high-energy spectrum.
Comments48pages, 7 figures
