论文标题
爱因斯坦 - 加斯 - 邦网中的几乎无质量的重力与线性耦合意味着标量场的恒定滚动
A Nearly Massless Graviton in Einstein-Gauss-Bonnet Inflation with Linear Coupling Implies Constant-roll for the Scalar Field
论文作者
论文摘要
引人注目的GW170817事件表明，重力几乎是无质量的，因为从两个中子恒星中发出的伽玛射线几乎同时与引力波同时到达。因此，由于没有明显的理由相信，重力也必须在通货膨胀和通货膨胀后时代无质量。在这封信中，我们将调查限制的理论含义，即重力无质量地与爱因斯坦 - 高斯 - 邦网理论无质量，并以标量场与四个维高斯 - 基人不变性的线性耦合进行线性耦合。如我们所示，原始引力波的重力波速度等于一个，严重限制了标量场的动力学，并在其上施加了直接恒定滚动的演化。同样，如我们所示，与非线性耦合相比，与同一理论相比，具有线性耦合的GW170817兼容的Einstein-Gauss-Bonnet理论的原始标量扰动的光谱指数也有所不同。因此，该模型的现象学有望不同，我们也简要讨论了这个问题。此外，恒定的条件始终与非高斯性关系有关，因此有趣的是，与线性耦合的爱因斯坦 - 高斯 - 邦网理论中强加无质量的重力可能会导致非高斯主义，因此我们也简要讨论了这个问题。
The striking GW170817 event indicated that the graviton is nearly massless, since the gamma rays emitted from the two neutron stars merging arrived almost simultaneously with the gravitational waves. Thus, the graviton must also be massless during the inflationary and post-inflationary era, since there is no obvious reason to believe otherwise. In this letter we shall investigate the theoretical implications of the constraint that the graviton is massless to an Einstein-Gauss-Bonnet theory with linear coupling of the scalar field to the four dimensional Gauss-Bonnet invariant. As we show, the constraint of having gravitational wave speed of the primordial gravitational waves equal to one, severely restricts the dynamics of the scalar field, imposing a direct constant-roll evolution on it. Also, as we show, the spectral index of the primordial scalar perturbations for the GW170817-compatible Einstein-Gauss-Bonnet theory with linear coupling is different in comparison to the same theory with non-linear coupling. Thus the phenomenology of the model is expected to be different, and we briefly discuss this issue too. In addition, the constant-roll condition is always related to non-Gaussianities, thus it is interesting that the imposition of a massless graviton in an Einstein-Gauss-Bonnet theory with linear coupling may lead to non-Gaussianities, so we briefly discuss this issue too.
