论文标题
Palatini重力的迟到
Late time acceleration in Palatini gravity
论文作者
论文摘要
我们研究了二次校正$αr^2 $的效果和非微耦合$ ξϕ^2 r $对具有指数电位$ v（ϕ）= m^4 \ exp（-λc）$在Palatini palatini公式中的典型模型。我们使用动力学系统技术来分析模型的吸引子结构并揭示系统的可能轨迹。我们发现，二次校正不能在晚期动力学中发挥作用，除了参数$α$的较大值之外。尽管它可以在早期发挥作用。我们发现，从物质主导的阶段到加速膨胀阶段的可行发展，其动力学是由非最小耦合驱动的。这些演变对应于轨道结束的轨迹，因此充当宇宙常数。
We investigate the effect of the quadratic correction $αR^2$ and non-minimal coupling $ξϕ^2 R$ on a quintessence model with an exponential potential $V(ϕ) = M^4\exp(-λϕ)$ in the Palatini formulation of gravity. We use dynamical system techniques to analyze the attractor structure of the model and uncover the possible trajectories of the system. We find that the quadratic correction cannot play a role in the late time dynamics, except for unacceptably large values of the parameter $α$; although it can play a role at early times. We find viable evolutions, from a matter-dominated phase to an accelerated expansion phase, with the dynamics driven by the non-minimal coupling. These evolutions correspond to trajectories where the field ends up frozen, thus acting as a cosmological constant.
