论文标题
$ f（r）= r+αr^2 $重力中的最强约束：恒星稳定性
Strongest constraint in $f(R) = R+ αR^2$ gravity: stellar stability
论文作者
论文摘要
在$ f（r）$重力理论的度量方法中，在存在标准物质和曲率流体的情况下，通常将四阶场方程作为有效的爱因斯坦方程（始终在约旦框架中，都会收集所有额外的术语）。在这张图片中，我们研究了$ f（r）= r+αr^2 $模型的强重力状态。特别是，我们专注于由普通物质的混合物组成的紧凑型恒星的稳定性 - 由状态的多粒子方程描述 - 以及在原本标准的爱因斯坦重力中的有效曲率流体，以便我们能够应用对相对恒星的径向绝热振荡的常规方程式。我们对自由参数的新限制是$α\ Lessim 2.4 \ times 10^8 \ \ text {cm}^2 $，以确保出色的稳定性，比以前的结果（基于单独基于Mass-Radius关系）在文献中的限制性高约100美元。
In the metric approach of $f(R)$ theories of gravity, the fourth-order field equations are often recast as effective Einstein equations in the presence of standard matter and a curvature fluid (which gathers all the extra terms), always in the Jordan frame. In this picture, we investigate the strong gravity regime of the $f(R) = R+ αR^2$ model. In particular, we focus on the stability of a compact star composed by a mixture of ordinary matter -- described by a polytropic equation of state -- and an effective curvature fluid in an otherwise standard Einstein gravity, so that we are able to apply the usual equations that govern the radial adiabatic oscillations of relativistic stars. Our new restriction on the free parameter is $α\lesssim 2.4 \times 10^8\ \text{cm}^2$ in order to guarantee stellar stability, about $100$ times more restrictive than previous results (based on mass-radius relations alone) in the literature.
