标题： 原初引力波在非Bunch-Davies初始态下对CMB三阶谱的印记 显示英文标题

标题： Imprints of primordial gravitational waves with non-Bunch-Davies initial states on CMB bispectra

摘要： 已经证明，与Bunch-Davies初始状态相比，具有非Bunch-Davies初始状态的标量和张量模式可以增强原初三阶谱的振幅，尤其是在扁平三角形构型中的波数模式。 然而，在非Bunch-Davies标量模式的情况下，也发现傅里叶空间中的这些增强在宇宙微波背景（CMB）涨落的三阶谱中有所减少。 在本文中，我们表明，来自张量模式的增强部分被减少到与标量模式不同的程度，这使得在具有与广义相对论相同二次和三次张量扰动算子的引力理论中，非Bunch-Davies效应无法被观测到。 此外，我们给出了可能通过CMB实验检测到增强效果的引力理论示例。 显示英文摘要

摘要： It has been shown that both scalar and tensor modes with non-Bunch-Davies initial states can enhance the amplitudes of the primordial bispectra compared to those with the Bunch-Davies state, especially for wavenumber modes in a flattened triangle configuration. However, in the case of the non-Bunch-Davies scalar modes, it has also been found that those enhancements in Fourier space are somewhat reduced in bispectra of cosmic microwave background (CMB) fluctuations. In this paper, we show that the enhancement resulting from the tensor modes is partially reduced to a degree differing from that of the scalar modes, which makes the non-Bunch-Davies effects unobservable in gravitational theories with the same quadratic and cubic operators of the tensor perturbations as general relativity. Furthermore, we present examples of gravitational theories yielding enhancements that would potentially be detected through CMB experiments.