论文标题
一个简单的均等违反重力模型而没有幽灵不稳定的模型
A simple parity violating gravity model without ghost instability
论文作者
论文摘要
在本文中，我们考虑了违反同等重力模型，而没有更高的衍生物，因此没有幽灵。该模型是由四及其衍生物构建的，并耦合到动态标量场（如轴）。它可以从远程引力框架内的Nieh-Yan项中降低。我们将此模型应用于宇宙学，并研究了其对宇宙学扰动理论的后果。我们发现，耦合的动态标量场在线性顺序上失去了独立的动力学，而违反术语本身的奇偶校验就像粘度一样。对于引力波，该模型在左手和右侧极化之间产生速度差，但没有产生幅度差异。
In this paper we consider a parity violating gravity model without higher derivatives, thus ghost free. This model is constructed from the tetrad and its derivatives and coupled to a dynamical scalar field, like axion. It can be reduced from the Nieh-Yan term within the framework of teleparallel gravity. We apply this model to cosmology and investigate its consequences on cosmological perturbation theory. We find that the coupled dynamical scalar field lost its independent dynamics at the linear order and the parity violating term itself behaves like a viscosity. For gravitational waves, this model produces velocity difference between left- and right-handed polarizations, but generates no amplitude discrepancy.
