Cosmological dynamics of D-BIonic and DBI scalar field and coincidence problem of dark energy
Cosmological dynamics of D-BIonic and DBI scalar field and coincidence problem of dark energy
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DOI：
10.1103/physrevd.95.103520
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发表时间：
2017-03
影响因子：
5
通讯作者：
Sirachak Panpanich;K. Maeda;S. Mizuno
中科院分区：
文献类型：
--
作者：
Sirachak Panpanich;K. Maeda;S. Mizuno
我们研究了与物质流体耦合的D-仿生标量场和DBI标量场的宇宙动力学。对于指数势和指数耦合，我们找到了产生宇宙加速膨胀的新的解析标度解。由于物质流体的密度参数对于一定范围的耦合参数是一个吸引子，所以物质流体的密度参数可以是观测值，就像在具有正则标量场的耦合精华中一样。与通常的耦合精髓--给出观测密度参数的物质对的值太大而不能满足CMB的观测约束相反，我们证明了D-仿生理论可以给出类似的解，而物质耦合的值要小得多。因此，结合D-仿生理论具有屏蔽机制的事实，D-仿生理论可以解决所谓的符合问题以及暗能量问题。
We study the cosmological dynamics of D-BIonic and DBI scalar field, which is coupled to matter fluid. For the exponential potential and the exponential couplings, we find a new analytic scaling solution yielding the accelerated expansion of the Universe. Since it is shown to be an attractor for some range of the coupling parameters, the density parameter of matter fluid can be the observed value, as in the coupled quintessence with a canonical scalar field. Contrary to the usual coupled quintessence, where the value of matter couple giving observed density parameter is too large to satisfy observational constraint from CMB, we show that the D-BIonic theory can give similar solution with much smaller value of matter coupling. As a result, together with the fact that the D-BIonic theory has a screening mechanism, the D-BIonic theory can solve the so-called coincidence problem as well as the dark energy problem.