标题： 修正引力和能量条件 显示英文标题

标题： f(G) modified gravity and the energy conditions

摘要： 受弦论/M理论预测的启发，该预测认为标量场与高斯-博内不变量 \$ G \$ 的耦合对于非奇异早期宇宙学的出现至关重要，我们讨论了一种有趣替代引力理论的可行性，即修正的高斯-博内引力，并提出了由能量条件得出的可行性界限。具体而言，我们研究了文献中分析的一种特定的现实形式的 \$ f(G) \$，它能够解释晚期宇宙加速膨胀，并且已被发现可以消除暗能量模型中存在的有限时间未来奇异性，同时进一步检验了由弱能量条件施加于特定 \$ f(G) \$ 模型的相应可行性。 显示英文摘要

摘要： Motivated by string/M-theory predictions that scalar field couplings with the Gauss-Bonnet invariant, G, are essential in the appearance of non-singular early time cosmologies, we discuss the viability of an interesting alternative gravitational theory, namely, modified Gauss-Bonnet gravity, and present the viability bounds arising from the energy conditions. In particular, we consider a specific realistic form of f(G) analyzed in the literature that accounts for the late-time cosmic acceleration and that has been found to cure the finite-time future singularities present in the dark energy models, and further examine the respective viability of the specific f(G) model imposed by the weak energy condition.