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 Poincar\'{e} 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.

中文翻译：

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来自二次引力和动力扭转的一致暴胀宇宙学

引力规范理论的思想预测，不仅应该存在无质量的引力子，还应该存在携带引力的大质量粒子。我们研究了具有动力学扭转的二次引力中的宇宙学，其中引力可以被解释为与庞加莱\'{e} 群相关的规范力。除了无质量自旋 2 引力子之外，该模型还包含四种非重影质量粒子：一对自旋 0、自旋 1 和自旋 2。假设在 UV 极限和奇偶不变性中恢复局部 Weyl 不变性，我们找到了描述具有平坦空间几何形状的同质各向同性宇宙的最一般的微型超空间行为。然后，我们将微型超空间行为转换为准爱因斯坦框架，其中场空间是双曲面，场势是类似 Starobinsky 的暴胀和自然暴胀的组合。值得注意的是，由于多场动力学，即使初始条件远离类 Starobinsky 势能的顶部，也可以实现类 Starobinsky 暴胀轨迹。我们还研究了线性张量扰动，并发现了与 Starobinsky 暴胀、自发奇偶性违反以及无质量和有质量的自旋 2 模式的混合在性质上不同的特征，这可能通过暴胀观测揭示引力的潜在性质。即使初始条件远离类 Starobinsky 势能的顶部，也可以实现类 Starobinsky 暴胀轨迹。我们还研究了线性张量扰动，并发现了与 Starobinsky 暴胀、自发奇偶性违反以及无质量和有质量的自旋 2 模式的混合在性质上不同的特征，这可能通过暴胀观测揭示引力的潜在性质。即使初始条件远离类 Starobinsky 势能的顶部，也可以实现类 Starobinsky 暴胀轨迹。我们还研究了线性张量扰动，并发现了与 Starobinsky 暴胀、自发奇偶性违反以及无质量和有质量的自旋 2 模式的混合在性质上不同的特征，这可能通过暴胀观测揭示引力的潜在性质。