论文标题
具有动力扭转的二次重力的一致通货膨胀宇宙学
Consistent inflationary cosmology from quadratic gravity with dynamical torsion
论文作者
论文摘要
重力理论的概念预测，不仅应该存在无质量的重力，还应存在带有重力的巨大颗粒。我们研究了具有动力扭转的二次重力中的宇宙学，其中重力可以解释为与庞加莱组相关的量规力。除了无质量的Spin-2 Graviton外，该模型还包含四个非块状质粒子物种：一个Spin-0，一个旋转1和一个自旋2。假设在紫外线极限和奇偶校验不变性中恢复了局部Weyl不变性，我们发现了最通用的Minisuperspace动作，描述了具有平坦空间几何形状的同质和各向同性宇宙。然后，我们将MinisuperSpace的作用转换为准内施泰因框架，其中田间空间是一种双曲线，并且场电位是Starobinsky样膨胀和自然通胀的组合。值得注意的是，得益于多场动力学，即使初始条件远离Starobinsky类似于Starobinsky的潜力，Starobinsky样的通货膨胀轨迹也可以实现。我们还研究了线性张量扰动，并发现与Starobinsky通货膨胀，自发平等违规以及无质量和巨大的Spin-2模式的混合的特征不同，这可能揭示了通过通货膨胀可观察到的重力的潜在性质。
The idea of gauge theories of gravity predicts that there should exist not only the massless graviton but also massive particles carrying the gravitational force. We study the cosmology in a quadratic gravity with dynamical torsion where gravity may be interpreted as a gauge force associated with the Poincaré group. In addition to the massless spin-2 graviton, the model contains four non-ghost massive particle species: a couple of spin-0, a spin-1 and a spin-2. Supposing the restoration of the local Weyl invariance in the UV limit and the parity invariance, we find the most general minisuperspace action describing a homogeneous and isotropic universe with a flat spatial geometry. We then transform the minisuperspace action to a quasi-Einstein frame in which the field space is a hyperboloid and the field potential is a combination of those of a Starobinsky-like inflation and a natural inflation. Remarkably, thanks to the multi-field dynamics, the Starobinsky-like inflationary trajectory can be realized even if the initial condition is away from the top of the Starobinsky-like potential. We also study linear tensor perturbations and find qualitatively different features than the Starobinsky inflation, spontaneous parity violation and mixing of the massless and massive spin-2 modes, which might reveal the underlying nature of gravity through inflationary observables.
