标题： 用宇宙学观测约束标量场暗能量 显示英文标题

标题： Constraining scalar field dark energy with cosmological observations

摘要： 过去十年的高精度宇宙学观测表明，我们宇宙的能量密度约有70%属于所谓的“暗能量”(DE)。观测显示，DE具有负的有效压强，因此与传统的能量来源不同，它加速宇宙的膨胀而不是减缓它。DE非常均匀，并且直到最近才成为主导成分。DE最简单的候选者是时间不变的宇宙学常数$\Lambda$。尽管在拟合现有数据方面取得成功，但宇宙学常数模型存在一些理论缺陷，因此考虑了其他DE模型。在一种这样的场景中，一个缓慢滚动其势能的宇宙标量场表现得像一个时间依赖的宇宙学常数。我使用了不同的独立宇宙学数据集，在缓慢滚动的宇宙标量场模型框架下限制DE能量密度的时间依赖性。目前的数据支持一个时间不变的宇宙学常数，但在高置信水平上不能排除时间依赖的DE。正在进行和计划中的宇宙学探测和调查将在未来十年提供更多的高质量数据。当新数据集可用时，我们将能够检测到DE的时间依赖性，或者将其限制到一个非常小的物理上不重要的值。 显示英文摘要

摘要： High precision cosmological observations in last decade suggest that about 70% of our universe's energy density is in so called "Dark Energy" (DE). Observations show that DE has negative effective pressure and therefore unlike conventional energy sources accelerates the cosmic expansion instead of decelerating it. DE is highly uniform and has become a dominant component only recently. The simplest candidate for DE is the time-independent cosmological constant $\Lambda$. Although successful in fitting available data, the cosmological constant model has a number of theoretical shortcomings and because of that alternative models of DE are considered. In one such scenario a cosmological scalar field that slowly rolls down its potential acts like a time-dependent cosmological constant. I have used different independent cosmological data sets to constrain the time dependence of DE's energy density in the framework of the slowly-rolling cosmological scalar field model. Present data favors a time-independent cosmological constant, but the time-dependent DE can not be ruled out at high confidence level. Ongoing and planned cosmological probes and surveys will provide more and better quality data over the next decade. When the new data sets are available we will be able to either detect the time dependence of DE or constrain it to a very small physically uninteresting value.