论文标题
带有零剪切的S-Brane的ekpyrototic宇宙学
Ekpyrotic Cosmology with a Zero-Shear S-Brane
论文作者
论文摘要
在最近的一篇论文中，我们提出了一种机制，用于在收缩的ekpyrotic阶段与标准的大爆炸阶段之间的连续过渡：反弹是由S-Brane产生的，该S-Brane代表了较高的质量弦状态在低能量有效场理论中的效果。我们表明，宇宙学量表上的重力波获得了几乎尺度不变的光谱。在这里，我们研究了该设置中的宇宙学波动，假设S-Brane的剪切零。我们发现近乎尺寸的宇宙学扰动频谱和略有红色倾斜度。该方案产生了宇宙学观测值的两个一致性关系，这是第一个将张量与标量比与标量光谱倾斜有关的一致性关系，第二个将张量倾斜与标量倾斜有关。预测的张量与标量比在即将进行的CMB观测值的范围内。张量倾斜为蓝色。
In a recent paper we proposed a mechanism for a continuous transition between a contracting Ekpyrotic phase and the Standard Big Bang phase of expansion: the bounce is generated by an S-brane which represents the effects of higher mass string states in the low energy effective field theory. We showed that gravitational waves on cosmological scales obtain a nearly scale-invariant spectrum. Here, we study the cosmological fluctuations in this setup, assuming that the S-brane has zero shear. We find a nearly scale-invariant spectrum of cosmological perturbations with a slight red tilt. The scenario yields two consistency relations for cosmological observations, the first one relating the tensor to scalar ratio with the scalar spectral tilt, the second relating the tensor tilt to the scalar tilt. The predicted tensor to scalar ratio is within the reach of upcoming CMB observations. The tensor tilt is blue.
