标题： 由$k$-本质退化动力学驱动的通胀与晚期加速膨胀 显示英文标题

标题： Inflation and late-time accelerated expansion driven by $k$-essence degenerate dynamics

摘要： 我们考虑了一种k-本质模型，在该模型中，单一标量场可以负责早期宇宙的原始膨胀和当前观测到的宇宙背景几何加速，同时允许宇宙有一个非奇异的de Sitter起源（它起源于de Sitter且终结于de Sitter）。 早期阶段由慢滚势驱动，而晚期阶段则由动力学维度约化过程驱动，该过程使标量场冻结在一个退化的曲面上，将其转变为一个宇宙常数。 这是通过提出一种可实现的稳定宇宙时间晶体来实现的，尽管对“移动基态”给出了不同的解释，在这种情况下没有运动，因为系统失去了自由度。 此外，该模型不存在超光速传播扰动、负能量和扰动不稳定性等问题。 显示英文摘要

摘要： We consider a k-essence model in which a single scalar field can be responsible for both primordial inflation and the present observed acceleration of the cosmological background geometry, while also admitting a nonsingular de Sitter beginning of the Universe (it arises from de Sitter and ends in de Sitter). The early one is driven by a slow-roll potential, and the late one is driven by a dynamical dimensional reduction process which freezes the scalar field in a degenerate surface, turning it into a cosmological constant. This is done by proposing a realizable stable cosmic time crystal, although giving a different interpretation to the ''moving ground stat'', in which there is no motion because the system loses degrees of freedom. Furthermore, the model is free of pathologies such as propagating superluminal perturbations, negative energies, and perturbation instabilities.