标题： 二次Palatini引力中由自由标量场产生的紧致物体 显示英文标题

标题： Compact objects in quadratic Palatini gravity generated by a free scalar field

摘要： 我们研究广义相对论（GR）解空间与度规-仿射形式中类型为$f(R,Q)$的基于里奇的引力理论（RBGs）之间的对应关系，其中$Q=R_{(\mu\nu)}R^{(\mu\nu)}$。 我们关注标量物质的情况，并表明当考虑GR框架中的自由无质量标量时，会出现重要的简化，这使得可以建立任意$f(R,Q)$拉格朗日量的对应关系。 我们将分析具体化为一个二次$f(R,Q)$理论，并使用 Jannis-Newman-Winicour 的球对称静态解作为种子，在目标理论中生成新的致密物体。 我们发现两种不同类型的解出现，一种代表裸奇点，另一种对应于在所有位置具有有限曲率标量的不对称虫洞。 然而，后一类解在测地线上是不完整的。 显示英文摘要

摘要： We study the correspondence that connects the space of solutions of General Relativity (GR) with that of Ricci-based Gravity theories (RBGs) of the $f(R,Q)$ type in the metric-affine formulation, where $Q=R_{(\mu\nu)}R^{(\mu\nu)}$. We focus on the case of scalar matter and show that when one considers a free massless scalar in the GR frame, important simplifications arise that allow to establish the correspondence for arbitrary $f(R,Q)$ Lagrangian. We particularize the analysis to a quadratic $f(R,Q)$ theory and use the spherically symmetric, static solution of Jannis-Newman-Winicour as seed to generate new compact objects in our target theory. We find that two different types of solutions emerge, one representing naked singularities and another corresponding to asymmetric wormholes with bounded curvature scalars everywhere. The latter solutions, nonetheless, are geodesically incomplete.