宇宙学中各种物质的动力学及其对宇宙演化的影响一直是很重要的研究课题。建立在广义相对论基础上的经典宇宙学很好地描述了大爆炸之后的宇宙演化，但大爆炸奇点一直是经典理论无法有效解释的难题，这暗示着在时空曲率非常大，能量密度极高时，广义相对论不再能给出可靠的预言，我们需要量子引力来描述这个领域的物理。另一方面，观测表明当今的宇宙正在经历一个加速膨胀阶段，一般认为，加速膨胀是被一种无处不在的负压物质—暗能量所推动的，与之相比，所有可见物质的能量密度在宇宙中占的比重极其微小。作为量子引力的主要候选者之一，圈量子引力在宇宙学中应用取得了重大成功。由圈量子引力得到的圈量子宇宙学成功地解决大爆炸奇点问题—大爆炸奇点被大反弹取代，而大反弹本身是个纯粹的量子几何效应，无需引入任何特殊物质。本文就是在圈量子宇宙学有效理论的框架下研究一种暗能量模型。我们研究了具有平方反比势能的快子场在圈量子宇宙学中的动力学，我们发现这种快子场可以在晚期演化中使宇宙以近似的幂律膨胀。此外，我们还考虑了在模型中加入一个绝热指标0 < γ < 2的正压理想流体。加入流体后，我们的宇宙学动力系统是个自治系统。通过对相平面进行分析，我们讨论了该自治系统的稳定性。我们发现系统至多存在五个固定点，只其中两个可能是稳定的。这两个稳定节点解（吸引子）对应着两种不同的宇宙学结果，我们分别对其进行了讨论。对于快子场主导的解，我们进行了更为深入的探讨，我们发现如果将快子场看做两种行为分别类似于暗能量和暗物质的部分，我们有可能得到两种符合宇宙历史的演化轨迹，这两种演化轨迹也会对宇宙最终的演化作出不同的预言。

The dynamics of various matters and their infuences on the evolution of the universe are always of great interest in cosmology. Classical cosmology, which is based on general relativity, gives a good description on the evolutionary picture of the universe after big bang. However, the big bang singularity cannot be soundly resolved by classical theory, which indicates when the curvature is very large, and the energy is extremely high, general relativity can no longer give valid predictions. Quantum gravity is called for to describe physics in this regime. On the other hand, observation shows that the universe is currently undergoing an accelerated expansion. It is normally considered that the accelerated expansion is driven by an ubiquitous matter with negative pressure—dark energy, compared with which, the energy density of all the visible matter only holds a tiny small fraction in the universe. As a primary candidate for final theory of quantum gravity, loop quantum gravity achieved great success in its application in cosmology. Loop quantum cosmology, which is derived from loop quantum gravity, successfully solved the big bang singularity by replacing it with a big bounce, while the big bounce itself is purely a quantum geometrical effect with no need to include exotic matter.The research of dark energy in this paper is based on the effective theory of loop quantum cosmology. The dynamical behavior of tachyon field with an inverse potential is investigated in loop quantum cosmology. It reveals that the late time behavior of tachyon field with this potential leads to an approximate power-law expansion. In addition, an additional barotropic perfect fluid with the adiabatic index 0 < γ < 2 is added, and the dynamical system is shown to be an autonomous one. The stability of this autonomous system is discussed using phase plane analysis. There exist up to five fixed points with only two of them possibly stable. The two stable node (attractor) solutions are specified, and their cosmological indications are discussed. For the tachyon dominated solution, the further discussion is stretched to the possibility of considering tachyon field as a combination of two parts which respectively behave like dark matter and dark energy. It is shown that two kinds of viable evolution trajectories can be found, and they would lead to different predictions of the final evolution picture of the universe.The dynamics of various matters and their infuences on the evolution of the universe are always of great interest in cosmology. Classical cosmology, which is based on general relativity, gives a good description on the evolutionary picture of the universe after big bang. However, the big bang singularity cannot be soundly resolved by classical theory, which indicates when the curvature is very large, and the energy is extremely high, general relativity can no longer give valid predictions. Quantum gravity is called for to describe physics in this regime. On the other hand, observation shows that the universe is currently undergoing an accelerated expansion. It is normally considered that the accelerated expansion is driven by an ubiquitous matter with negative pressure—dark energy, compared with which, the energy density of all the visible matter only holds a tiny small fraction in the universe. As a primary candidate for final theory of quantum gravity, loop quantum gravity achieved great success in its application in cosmology. Loop quantum cosmology, which is derived from loop quantum gravity, successfully solved the big bang singularity by replacing it with a big bounce, while the big bounce itself is purely a quantum geometrical effect with no need to include exotic matter.The research of dark energy in this paper is based on the effective theory of loop quantum cosmology. The dynamical behavior of tachyon field with an inverse potential is investigated in loop quantum cosmology. It reveals that the late time behavior of tachyon field with this potential leads to an approximate power-law expansion. In addition, an additional barotropic perfect fluid with the adiabatic index 0 < γ < 2 is added, and the dynamical system is shown to be an autonomous one. The stability of this autonomous system is discussed using phase plane analysis. There exist up to five fixed points with only two of them possibly stable. The two stable node (attractor) solutions are specified, and their cosmological indications are discussed. For the tachyon dominated solution, the further discussion is stretched to the possibility of considering tachyon field as a combination of two parts which respectively behave like dark matter and dark energy. It is shown that two kinds of viable evolution trajectories can be found, and they would lead to different predictions of the final evolution picture of the universe.