Cosmological dynamics of dark matter Bose-Einstein condensation
Cosmological dynamics of dark matter Bose-Einstein condensation
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DOI：
10.1103/physrevd.83.123515
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发表时间：
2011-05
影响因子：
5
通讯作者：
T. Harko
中科院分区：
文献类型：
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作者：
T. Harko
一旦宇宙玻色子气体的临界温度低于临界温度，在宇宙的宇宙历史中就会发生玻色-爱因斯坦凝聚过程。在玻色-爱因斯坦凝聚模型中，暗物质可以被描述为一种非相对论性的牛顿引力凝聚，其密度和压力通过正压状态方程联系起来，正压指数等于1。在目前的工作中，我们在宇宙学背景下研究玻色-爱因斯坦凝聚过程，假设这个过程可以被描述（至少近似地）为一阶相变。我们分析了与早期宇宙物理描述相关的物理量，即能量密度、温度和尺度因子，在玻色-爱因斯坦凝聚（相变）之前、期间和之后的演变。我们还详细考虑了宇宙通过混合凝聚-正常暗物质相演化的时代，其中有单调增长的玻色-爱因斯坦暗物质成分。表征玻色-爱因斯坦凝聚的一个重要参数是凝聚暗物质分数，它的时间演化描述了转换过程的时间动力学。详细分析了该参数在宇宙凝聚过程中的行为。为了研究宇宙动力学和进化，我们同时使用解析和数值方法。凝聚态暗物质和玻色-爱因斯坦相变的存在可能极大地改变了早期宇宙的宇宙学演化，以及大尺度结构的形成过程。
Once the critical temperature of a cosmological boson gas is less than the critical temperature, a Bose-Einstein Condensation process can always take place during the cosmic history of the universe. In the Bose-Einstein Condensation model, dark matter can be described as a non-relativistic, Newtonian gravitational condensate, whose density and pressure are related by a barotropic equation of state, with barotropic index equal to one. In the present work, we study the Bose-Einstein Condensation process in a cosmological context, by assuming that this process can be described (at least approximately) as a first order phase transition. We analyze the evolution of the physical quantities relevant for the physical description of the early universe, namely, the energy density, temperature and scale factor, before, during and after the Bose-Einstein Condensation (phase transition). We also consider in detail the epoch when the universe evolved through a mixed condensate - normal dark matter phase, with a monotonically growing Bose-Einstein dark matter component. An important parameter characterizing the Bose-Einstein Condensation is the condensate dark matter fraction, whose time evolution describes the time dynamics of the conversion process. The behavior of this parameter during the cosmological condensation process is also analyzed in detail. To study the cosmological dynamics and evolution we use both analytical and numerical methods. The presence of the condensate dark matter and of the Bose-Einstein phase transition could have modified drastically the cosmological evolution of the early universe, as well as the large scale structure formation process.