标题： 从暴胀到再加热的引力波全谱分析 显示英文标题

标题： Full-Spectrum Analysis of Gravitational Wave Production from Inflation to Reheating

摘要： 在本工作中，我们系统地研究了在膨胀期和膨胀后时期引力波（GW）的产生。虽然膨胀期的GW可以很容易地从膨胀期间的张量扰动中得出，但膨胀后时期的GW则源自再加热期间的各种过程，并且需要详细的处理来进行定量分析。我们考虑了四种不同的产生通道：$(i)$纯膨胀子湮灭，$(ii)$由膨胀子衰变产生的引力子韧致辐射，$(iii)$由辐射催化引起的膨胀子-引力子转换，以及$(iv)$完全热化辐射粒子之间的散射。对于每个通道，我们求解相应的玻尔兹曼方程以获得GW谱，并推导出一个简单而准确的解析表达式。通过采用所有产生通道的一致处理方法，我们的分析首次得出了膨胀期和膨胀后时期产生的GW完整谱。我们发现，尽管在低频段膨胀期的GW占主导地位，但膨胀后的过程通常会产生高频率GW，这些GW具有相当高的能量密度，可能会显著超过膨胀期GW的能量密度。 显示英文摘要

摘要： In this work, we systematically study gravitational wave (GW) production during both the inflationary and post-inflationary epochs. While inflationary GWs can be readily derived from tensor perturbations during inflation, post-inflationary GWs arise from a variety of processes during reheating and require detailed treatment for quantitative analysis. We consider four distinct production channels: $(i)$ pure inflaton annihilation, $(ii)$ graviton bremsstrahlung from inflaton decay, $(iii)$ radiation-catalyzed inflaton-graviton conversion, and $(iv)$ scattering among fully thermalized radiation particles. For each channel, we solve the corresponding Boltzmann equation to obtain the GW spectrum and derive a simple yet accurate analytical expression for it. By employing a consistent treatment of all production channels, our analysis yields for the first time the full spectrum of GWs produced during the inflationary and post-inflationary epochs. We find that, while inflationary GWs dominate at low frequencies, post-inflationary processes generally produce high-frequency GWs with considerably high energy densities that may significantly exceed that of inflationary GWs.