标题： D-B离子和DBI标量场的宇宙学动力学及暗能量的巧合问题 显示英文标题

标题： Cosmological Dynamics of D-BIonic and DBI Scalar Field and Coincidence Problem of Dark Energy

摘要： 我们研究了与物质流体耦合的D-BIonic和DBI标量场的宇宙学动力学。 对于指数势和指数耦合，我们发现了一种新的解析标度解，导致宇宙的加速膨胀。 由于它被证明在某些耦合参数范围内是一个吸引子，物质流体的密度参数可以是观测值，就像具有规范标量场的耦合量子势一样。 与通常的耦合量子势不同，给出观测密度参数的物质耦合值太大，无法满足来自CMB的观测约束，我们表明D-BIonic理论可以用更小的物质耦合值给出类似的解。 因此，结合D-BIonic理论具有屏蔽机制的事实，D-BIonic理论可以解决所谓的巧合问题以及暗能量问题。 显示英文摘要

摘要： 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.