论文标题
抑制大尺度和相关双线的标量功率
Suppression of scalar power on large scales and associated bispectra
论文作者
论文摘要
[删节]已知原始标量功率谱的急剧截止值已知可以改善宇宙微波背景（CMB）数据的拟合度，与更标准化的速度相比，在慢速滚动通货膨胀中产生的几乎规模不变的功率谱。在较早的工作中，我们通过数值研究了具有动力学主导初始条件的模型中产生的标量双光谱的特征。在这项工作中，我们将场景与另外两个竞争场景（即通货膨胀和由于Starobinsky引起的模型）进行比较，这也以大尺度上的大致相似的方式抑制了标量功率。我们进一步考虑了另外两种情况，涉及有限持续时间的充气，其中标量场从通货膨胀吸引子开始，另一个开始，其中该场以较小的速度开始，然后向吸引子发展。如果在动力学主导的模型中，这些场景在大尺度上也表现出大尺度上的急剧下降。我们将所有模型的性能与功率光谱级别的Planck CMB数据进行比较。在所有这些情况下，我们还比较了标量非高斯参数$ f _ {_ {_ {\ rm nl}} $的标量非高斯参数的振幅和形状。有趣的是，我们发现，在模型中，在超支量表上施加了扰动的初始条件，对大型模式违反了标量双光谱的一致性关系，而在其他场景中，所有模式都满足了关系。标量双光谱的行为上的这些差异可以想象可以帮助我们在各种模型上进行观察区分，从而导致大致相似形状的标量功率谱。
[Abridged] A sharp cut-off in the primordial scalar power spectrum on large scales has been known to improve the fit to the cosmic microwave background (CMB) data when compared to the more standard, nearly scale invariant power spectrum that arises in slow roll inflation. In an earlier work, we had numerically investigated the characteristics of the scalar bispectrum generated in models with kinetically dominated initial conditions. In this work, we compare the scenario with two other competing scenarios (viz. punctuated inflation and a model due to Starobinsky) which also suppress the scalar power in a roughly similar fashion on large scales. We further consider two other scenarios involving inflation of a finite duration, one wherein the scalar field begins on the inflationary attractor and another wherein the field starts with a smaller velocity and evolves towards the attractor. These scenarios too exhibit a sharp drop in power on large scales if the initial conditions on the perturbations for a range of modes are imposed on super-Hubble scales as in the kinetically dominated model. We compare the performance of all the models against the Planck CMB data at the level of power spectra. We also compare the amplitudes and shapes of the scalar non-Gaussianity parameter $f_{_{\rm NL}}$ in all these cases which lead to scalar power spectra of similar form. Interestingly, we find that, in the models wherein the initial conditions on the perturbations are imposed on super-Hubble scales, the consistency relation governing the scalar bispectrum is violated for the large scale modes, whereas the relation is satisfied for all the modes in the other scenarios. These differences in the behavior of the scalar bispectra can conceivably help us observationally discriminate between the various models which lead to scalar power spectra of roughly similar shape.
