标题： 非常规宇宙学 显示英文标题

标题： Unconventional Cosmology

摘要： 我回顾两种与当前暴胀情景不同的宇宙学范式。 第一个替代方案是“物质反弹”，这是一种非奇异的反弹宇宙学，在收缩阶段具有物质主导的时期。 第二个是“涌现”情景，这可以在“弦气体宇宙学”的背景下实现。 我将比较这些情景与暴胀情景，并证明这三个模型都能导致大约尺度不变的宇宙扰动谱。 显示英文摘要

摘要： I review two cosmological paradigms which are alternative to the current inflationary scenario. The first alternative is the "matter bounce", a non-singular bouncing cosmology with a matter-dominated phase of contraction. The second is an "emergent" scenario, which can be implemented in the context of "string gas cosmology". I will compare these scenarios with the inflationary one and demonstrate that all three lead to an approximately scale-invariant spectrum of cosmological perturbations.