论文标题
最小的自调谐模型来解决宇宙常数问题
A minimal self tuning model to solve the cosmological constant problem
论文作者
论文摘要
观察到宇宙的膨胀正在加速，最简单的解决方案是经典的宇宙常数。但是，这将从量子真空中获得贡献，预计该量子比观测值大的数量级数量级很多，并且遭受了需要重复调谐的辐射不稳定性。在本文中，我们提出了一个最小的自我调谐标量场模型，该模型可以动态地取消大量的量子真空能量，避免Weinberg的No Go thorem，并在较低的能量尺度上产生加速的DE Sitter扩展，以解决问题的解决方案。我们的最小模型包含非规范的动能和线性电位，属于Horndeski理论的动力学重力编织子类，该子类并未被排除在外，并且位于已知的Fab四或矫正模型之外。我们在缓慢滚动和快速滚动的范围内找到分析解决方案，并在数值上求解运动方程以说明我们的模型。我们表明该模型允许物质主导的ERA，并且在真空能量密度的相变下，吸引子解决方案是稳定的。我们还考虑匹配观测所需的能量尺度。我们的模型显示了比以前假设的更广泛的成功自调模型的存在。
The expansion of the Universe is observed to be accelerating, with the simplest solution being a classical cosmological constant. However, this receives contributions from the quantum vacuum, which are predicted to be many orders of magnitude larger than observations, and suffers from radiative instabilities requiring repeated fine tuning. In this paper we present a minimal, self tuning scalar field model that can dynamically cancel a large quantum vacuum energy, avoiding Weinberg's No Go Theorem, and produce accelerated de Sitter expansion at a lower energy scale as a solution to the problem. Our minimal model, which contains a non canonical kinetic energy and a linear potential, belongs to the Kinetic Gravity Braiding subclass of Horndeski theory which is not observationally excluded, and lies outside of the known Fab Four or Well Tempered models. We find analytic solutions in the limits of slow roll and fast roll, and numerically solve the equations of motion to illustrate our model. We show that the model allows for a matter dominated era, and that the attractor solution is stable under a phase transition in the vacuum energy density. We also consider the energy scales required to match observations. Our model shows the existence of a wider class of successful self tuning models than previously assumed.
