标题： 多重标量场的宇宙尺度解 显示英文标题

标题： Cosmological Scaling Solutions for Multiple Scalar Fields

摘要： 在存在多个与多方完美流体耦合的纯量场的情况下，我们推导出宇宙比例解存在的广义 k-本质拉格朗日。 除了与辐射和物质时代动力学相关联的比例不动点外，我们还得到了一个与暗能量相关的纯量场主导解，并讨论了双场设置下它们的稳定性。 我们将一般结果应用于弦理论中出现的具有耦合指数势的两个规范场模型。 根据模型参数和初始条件，我们表明可以实现比例物质主导时期之后由吸引子引起的宇宙加速，无论是否与纯量场耦合。 不同类型的尺度解可以通过暗能量状态方程从高红移到今天的演化来区分彼此。 显示英文摘要

摘要： The general k-essence Lagrangian for the existence of cosmological scaling solutions is derived in the presence of multiple scalar fields coupled to a barotropic perfect fluid. In addition to the scaling fixed point associated with the dynamics during the radiation and matter eras, we also obtain a scalar-field dominated solution relevant to dark energy and discuss the stability of them in the two-field set-up. We apply our general results to a model of two canonical fields with coupled exponential potentials arising in string theory. Depending on model parameters and initial conditions, we show that the scaling matter-dominated epochs followed by an attractor with cosmic acceleration can be realized with/without the couplings to scalar fields. The different types of scaling solutions can be distinguished from each other by the evolution of the dark energy equation of state from high-redshifts to today.