标题： 标量高斯-博内理论中的早期宇宙解 显示英文标题

标题： Early-time cosmological solutions in scalar-Gauss-Bonnet theory

摘要： 我们考虑一个包含爱因斯坦项、标量场和二次高斯-博内特项的引力理论。 我们关注早期宇宙的动力学，并证明当曲率较强时，里奇标量在早期时间不会影响宇宙学解。 然后我们考虑一个纯标量-GB理论，其耦合函数为二次形式：对于负的耦合参数，我们得到始终包含暴胀的德西特相的解，而对于正的耦合函数，我们则发现没有奇点的膨胀解。 显示英文摘要

摘要： We consider a gravitational theory that contains the Einstein term, a scalar field and the quadratic Gauss-Bonnet term. We focus on the early-universe dynamics, and demonstrate that the Ricci scalar does not affect the cosmological solutions at early times, when the curvature is strong. We then consider a pure scalar-GB theory with a quadratic coupling function: for a negative coupling parameter, we obtain solutions that contain always an inflationary, de Sitter phase, while for a positive coupling function, we find instead expanding singularity-free solutions.