本文選題：暗能量　切入點：修正的Chaplygin氣體　出處：《遼寧師范大學》2011年碩士論文　論文類型：學位論文

【摘要】：近些年來出現了大量的而且越來越精確的天文觀測數據,這對于宇宙學的研究給予了巨大的支持。按照Ia型超新星的觀測數據,我們了解到當今宇宙處于加速膨脹階段,當然微波背景輻射能譜的觀測和大尺度結構也能夠證明這一觀點。之后圍繞著怎樣從理論上解釋宇宙當今加速膨脹現象,人們提出的方法分為兩大類。第一類是修正愛因斯坦-希爾伯特作用量,即引力修正理論。第二類是認為在宇宙中均勻分布著一種新的、具有負壓強的成分,即暗能量。 本文首先介紹了宇宙學的理論基礎,包括標準宇宙學模型、暴脹理論,之后為了解釋當今宇宙的加速膨脹,介紹了幾種常見的暗能量模型。本文主要從兩個方面入手,對當今宇宙的加速膨脹問題進行理論研究。 首先,將全息暗能量作為修正的Chaplygin氣體(MCG)模型的暗能量成分,并且考慮宇宙中含有重子物質,而且暗物質和全息暗能量之間有相互作用。在模型分析中,通過推導給出了宇宙學量(密度參數、態(tài)參數、減速參數)的演化曲線,圖像告訴該模型的演化是從減速到加速膨脹的,可以解釋加速膨脹,態(tài)參數可以穿越-1,并且各宇宙學量的今天值也和當今觀測數據吻合的比較好,之后對模型進行了幾何診斷,具體包括s-r圖、q-r圖和ω-ω'圖,通過圖像我們不僅看到全息常數c和相互作用常數b對模型的演化起著非常重要的影響,而且也看到該模型和LCDM模型的差別。而且,本文也對模型做了Om診斷,通過圖像展示出HDE模型和LCDM模型的區(qū)別。 然后,通過在Brans-Dicke宇宙學中,推廣前人的工作到新的全息暗能量(NHDE)模型中。具體的,在非平直的Brans-Dicke宇宙中建立了NHDE模型和Quintessence, Tachyon, K-essence, Dilaton, CG模型的對應。不僅如此,本文還有重建了這些模型的場和勢,發(fā)現新全息Quintessence和新全息CG的場和勢在平直空間中、在一定的條件下則是相同的,但是在非平直宇宙中是完全不同的。對于新全息Quintessence和新全息CG模型,如果勢中參數滿足一定的條件,在Brans-Dicke理論下能夠解釋宇宙加速膨脹。另外值得注意的是,本文不僅在Brans-Dicke理論框架下給出了一些NHDE模型的新結果,而且在參數滿足一定條件時,Brans-Dicke理論退化為廣義相對論,可以得到一些前人得到的結果,這些結果在一定條件下也能夠描述宇宙的加速膨脹。
[Abstract]:In recent years, there have been large and increasingly accurate astronomical observations, which have given great support to the study of cosmology. According to the observational data of Type Ia supernova, we know that the universe is now in an accelerated expansion stage. Of course, observations of microwave background radiation spectra and large scale structures can also prove this view, and then revolve around how to theoretically explain the accelerating expansion of the universe today. The proposed methods can be divided into two categories: the first is the modification of Einstein Hilbert action, that is, the gravitational correction theory, and the second is that there is a new kind of uniform distribution in the universe, that is, dark energy, which has a strong negative pressure. This paper first introduces the theoretical basis of cosmology, including the standard cosmological model, inflation theory, and then, in order to explain the accelerating expansion of the universe today, several common dark energy models are introduced. A theoretical study of the accelerating expansion of the universe is carried out. Firstly, the holographic dark energy is considered as the dark energy component of the modified Chaplygin gas model, and the interaction between dark matter and holographic dark energy is considered in the model analysis. The evolution curve of cosmological quantities (density parameter, state parameter, deceleration parameter) is derived. The image shows that the evolution of the model is from deceleration to acceleration expansion, which can explain the accelerated expansion. The state parameters can traverse -1, and the present values of the cosmological quantities are in good agreement with today's observational data. Then the geometric diagnosis of the model is carried out, including the s-r map q-r diagram and 蠅-蠅 'graph. From the image we not only see that the holographic constant c and the interaction constant b play a very important role in the evolution of the model, but also see the difference between the model and the LCDM model. The difference between HDE model and LCDM model is shown by image. Then, by popularizing the previous work in Brans-Dicke cosmology to the new holographic dark energy model, the author establishes the correspondence between the NHDE model and the Quintessence, Tachyon, K-essence, Dilaton, CG models in the non-straight Brans-Dicke universe. In this paper, we also reconstruct the fields and potentials of these models and find that the fields and potentials of the new holographic Quintessence and the new holographic CG are the same in the flat space and under certain conditions. For the new holographic Quintessence model and the new holographic CG model, if the parameters in the potential satisfy certain conditions, the accelerating expansion of the universe can be explained under the Brans-Dicke theory. In this paper, we not only give some new results of the NHDE model under the framework of Brans-Dicke theory, but also degenerate the Brans-Dicke theory into general relativity when the parameters satisfy certain conditions. These results can also describe the accelerating expansion of the universe under certain conditions.
【學位授予單位】：遼寧師范大學
【學位級別】：碩士
【學位授予年份】：2011
【分類號】：P145.9

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