arXiv 1502.008112015-02-03gr-qcastro-ph.COhep-ph

宇宙学中的减速参数。部件I

Cosmology In Terms Of The Deceleration Parameter. Part I

Yu. L. Bolotin, V. A. Cherkaskiy, O. A. Lemets, D. A. Yerokhin, L. G. Zazunov

备注：: 67 pages, 6 figures. arXiv admin note: text overlap with arXiv:1104.4458, arXiv:1409.3352, arXiv:0708.3414, arXiv:gr-qc/0508052, arXiv:astro-ph/0402278, arXiv:astro-ph/0104349, arXiv:0807.0207 by other authors

摘要：

七十年代早期，艾伦·桑德奇（Alan Sandage）将宇宙学定义为寻找两个数字：哈勃参数${{H}_{0}}$和减速参数${{q}_{0}}$。两个基本宇宙学参数中的第一个（哈勃参数）描述了比例因子与时间的线性关系。把宇宙当作一个动力学系统，很自然地会假设它是非线性的：事实上，线性只不过是近似，而非线性代表了一般情况。很明显，未来的宇宙模型必须考虑到其演化的不同方面。一旦标度因子成为唯一的动力学变量，决定其时间依赖性的量就必须基本上存在于宇宙演化的各个方面。宇宙学演化的基本特征，包括静态和动态的，可以用参数${{H}_{0}}$和${{q}_{0}}$来表示。正是这些参数（以及标度因子的更高的时间导数）使我们能够构建宇宙膨胀的独立于模型的运动学。标度因子的时间依赖性反映了宇宙历史上的主要事件。此外，减速参数决定了哈勃球体的膨胀率，并决定了可观测星系数变化的动力学：根据减速参数的符号，这个数字要么增长（在减速膨胀的情况下），要么我们将在宇宙中保持绝对孤独（如果膨胀加速）。该报告的预期目的反映在其标题中--“减速参数方面的宇宙学”。我们想表明，实际上宇宙演化的任何方面都与减速参数紧密相关。

英文摘要：

In the early seventies, Alan Sandage defined cosmology as the search for two numbers: Hubble parameter ${{H}_{0}}$ and deceleration parameter ${{q}_{0}}$. The first of the two basic cosmological parameters (the Hubble parameter) describes the linear part of the time dependence of the scale factor. Treating the Universe as a dynamical system it is natural to assume that it is non-linear: indeed, linearity is nothing more than approximation, while non-linearity represents the generic case. It is evident that future models of the Universe must take into account different aspects of its evolution. As soon as the scale factor is the only dynamical variable, the quantities which determine its time dependence must be essentially present in all aspects of the Universe' evolution. Basic characteristics of the cosmological evolution, both static and dynamical, can be expressed in terms of the parameters ${{H}_{0}}$ and ${{q}_{0}}$. The very parameters (and higher time derivatives of the scale factor) enable us to construct model-independent kinematics of the cosmological expansion. Time dependence of the scale factor reflects main events in history of the Universe. Moreover it is the deceleration parameter who dictates the expansion rate of the Hubble sphere and determines the dynamics of the observable galaxy number variation: depending on the sign of the deceleration parameter this number either grows (in the case of decelerated expansion), or we are going to stay absolutely alone in the cosmos (if the expansion is accelerated). The intended purpose of the report is reflected in its title --- "Cosmology in terms of the deceleration parameter". We would like to show that practically any aspect of the cosmological evolution is tightly bound to the deceleration parameter.

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