本文關(guān)鍵詞：有相互作用的廣義Chaplygin氣體動(dòng)力學(xué)分析及參數(shù)擬合　出處：《上海師范大學(xué)》2016年碩士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 宇宙加速 GCG 相互作用 參數(shù)擬合

【摘要】：對(duì)Ia型超新星的觀測(cè)發(fā)現(xiàn)宇宙是加速膨脹的,宇宙加速膨脹即尺度因子的二階導(dǎo)數(shù)a大于0,由弗里德曼方程可知,要使a大于0則需要場(chǎng)方程右邊多出一個(gè)提供負(fù)壓強(qiáng)的部分。這個(gè)負(fù)壓強(qiáng)不僅抵消了物質(zhì)引力產(chǎn)生的減速效果還進(jìn)一步地使宇宙加速膨脹,這部分稱(chēng)為暗能量。研究表明宇宙學(xué)常數(shù)和quintessence場(chǎng)可作為暗能量的候選者。然而觀測(cè)發(fā)現(xiàn)暗物質(zhì)與暗能量在當(dāng)前量級(jí)相同,此即引出了巧合性問(wèn)題,即為什么當(dāng)前宇宙的暗物質(zhì)和暗能量量級(jí)相同,是巧合還是必然?基于這個(gè)問(wèn)題,追蹤場(chǎng)、K-sessence、Chaplygin氣體等模型被提了出來(lái),閱讀文獻(xiàn)時(shí)發(fā)現(xiàn)如果用上述幾個(gè)模型對(duì)冷暗物質(zhì)做一個(gè)耦合則會(huì)一定程度上緩解巧合性問(wèn)題。會(huì)得出一些與初始條件無(wú)關(guān)的宇宙學(xué)演化模式。而考慮Chaplygin氣體與冷暗物質(zhì)部分相互作用時(shí)發(fā)現(xiàn)其不僅能緩解巧合性問(wèn)題,還可以統(tǒng)一暗物質(zhì)與暗能量,具體表現(xiàn)為宇宙早期a趨向于0時(shí)表現(xiàn)出暗物質(zhì)的性質(zhì),晚期時(shí)ω趨向于-1(ω為態(tài)方程參數(shù))表現(xiàn)出暗能量的性質(zhì)。本文在解決了自治系統(tǒng)奇性的基礎(chǔ)上,對(duì)GCG與DM相互作用項(xiàng)最簡(jiǎn)單的幾種情況進(jìn)行了討論。分別是及Q=-3βHp8(β為無(wú)量綱參數(shù),ρm,ρ8,ρtot分別表示物質(zhì)密度,Chaplygin氣體密度和物質(zhì)密度與Chaplygin氣體密度之和)。分別對(duì)各自的自治系統(tǒng)的性質(zhì)進(jìn)行了分析,討論了臨界點(diǎn)處的性質(zhì),得出了符合宇宙加速膨脹的結(jié)果,并與標(biāo)準(zhǔn)的ACDM模型做了比較。
[Abstract]:Observations of type Ia supernovae discovered that the universe is accelerating expansion, the accelerated expansion of the universe is the two derivative of the scale factor of a is greater than 0, by the Freedman equation, to make a more than 0 to the right of a multi field equation provides negative pressure part. The negative pressure not only offset the effect of gravitational deceleration produced the further that the accelerated expansion of the universe, this part is called dark energy. The results indicate that the cosmological constant and the quintessence field can be used as a candidate of dark energy. However, the observation that dark matter and dark energy in the same order of magnitude, which leads to the coincidence problem, that is why the current cosmic dark matter and dark energy in the same order that is a coincidence or a necessity? Based on this problem, tracking field, K-sessence, Chaplygin gas model is proposed, the reading of the literature found that if a coupling of cold dark matter with the model He will to some extent alleviate the coincidence problem. Come about the initial conditions of cosmological evolution mode. And considering the Chaplygin gas and the cold dark matter interaction and found that it can not only alleviate the coincidence problem, can also unified the dark matter and dark energy, the specific performance of the early universe when a tends to 0 the nature of dark matter, late tend to -1 (omega Omega for equation of state parameters) exhibit the properties of dark energy. In the base of solving the singular autonomous system, GCG on the interaction between DM and the most simple situations are discussed respectively. And Q=-3 Hp8 (beta beta the dimensionless parameters, P M, P 8, P tot respectively matter density, Chaplygin density and the material density and the density of Chaplygin gas and) respectively. The nature of their respective autonomous systems are analyzed, discussed the nature of the critical point, the character The result of the accelerated expansion of the universe is compared with the standard ACDM model.

【學(xué)位授予單位】：上海師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：P159

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 韋浩;;Cosmological Constraints on the Sign-Changeable Interactions[J];Communications in Theoretical Physics;2011年11期

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本文編號(hào)：1425393