论文标题
来自Horndeski理论的暗能量模型的约束
Constraints on dark energy models from the Horndeski theory
论文作者
论文摘要
鉴于宇宙学的观察，我们从Horndeski重力理论中研究了暗能量模型。特别是，我们考虑了标量场和标量场和重力之间的衍生耦合的宇宙学模型。我们选择自我交互项，以具有标量字段的指数函数，并具有正向指数和负指数。对于具有积极指数的函数，我们的结果表明衍生性自我相互作用项在晚期宇宙中起重要作用。另一方面，为了重现正确的宇宙历史，标量场和重力之间的衍生耦合必须在辐射为主的阶段中占主导地位。但是，由于随着时间的流逝，这种耦合在当前宇宙中的重要性被认为可以忽略不计。此外，为我们的模型估计的引力波的传播速度在观察界内，我们的模型满足了对状态暗能量方程的观察性约束。
In light of the cosmological observations, we investigate dark energy models from the Horndeski theory of gravity. In particular, we consider cosmological models with the derivative self-interaction of the scalar field and the derivative coupling between the scalar field and gravity. We choose the self-interaction term to have an exponential function of the scalar field with both positive and negative exponents. For the function that has a positive exponent, our result shows that the derivative self-interaction term plays an important role in the late-time universe. On the other hand, to reproduce the right cosmic history, the derivative coupling between the scalar field and gravity must dominate during the radiation-dominated phase. However, the importance of such a coupling in the present universe found to be negligible due to its drastic decrease over time. Moreover, the propagation speed of gravitational waves estimated for our model is within the observational bounds, and our model satisfies the observational constraints on the dark energy equation of state.
