Title: The Tilt of Primordial Gravitational Waves Spectra from BICEP2 Show Chinese title

Title: 从BICEP2获得的原初引力波谱的倾斜度

Abstract: In this paper we constrain the tilt of the spectra of primordial gravitational waves from Background Imaging of Cosmic Extragalactic Polarization (BICEP2) data only. We find $r=0.21_{-0.10}^{+0.04}$ and $n_t=-0.06_{-0.23}^{+0.25}$ (at $68\%$ C.L.) which implies that a scale-invariant primordial gravitational waves spectra is consistent with BICEP2 nicely. Our results provide strong evidence for supporting inflation model, and the alternative models, for example the ekpyrotic model which predicts $n_t=2$, are ruled out at more than $5\sigma$ significance. Show Chinese abstract

Abstract: 在本文中，我们仅从背景成像宇宙外星系偏振（BICEP2）数据中限制原初引力波谱的倾斜度。 我们发现$r=0.21_{-0.10}^{+0.04}$和$n_t=-0.06_{-0.23}^{+0.25}$（在$68\%$置信水平） 这表明一个尺度不变的原初引力波谱与 BICEP2 非常一致。 我们的结果为支持暴胀模型以及替代模型提供了有力证据，例如预测$n_t=2$的热大爆炸模型，在超过$5\sigma$显著性水平上被排除。