非局域引力的宇宙动力学

研究了非局域修改引力的宇宙动力学.发现幂律解是稳定的,而作为幂律解的极限情况德西特(de Sitter)解也是稳定的.在平坦空间中,对于一般的非局域项f,宇宙动力学系统中总存在一个临界点,当态参数w>1/3时,它是吸引子,而w<1/3时,它是鞍点.在非平坦空间中,当物质满足强能量条件时,宇宙动力学系统还存在另一个稳定吸引子,它对应着稳定膨胀的宇宙.数值计算结果证实了上述定性分析的结论.

On the cosmological dynamics of non-local gravity

In this paper,we investigate the cosmological dynamics of non-locally modified models of gravity.It is found that the usual power-law solutions are stable,and as a limit case the de Sitter solution is also stable which is in agreement with the result of previous work.Moreover,for general function f,we find there always exists a critical point (x =0,y =0,Ωm,=0 ) which is an attractor for w ＞ 1/3 and a saddle point for w ＜ 1/3 in spatially flat case.When the spatial curvature is taken into account,there exists another stable attractor when the matter satisfies the strong energy condition.Our numerical results verify our qualitative conclusions in different cases.