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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/54258


    Title: 零自旋之動力聯絡的宇宙學探討;Some Cosmological Explorations of Dynamical Connection Modes of Spin-0
    Authors: 陳欣;Chen,Hsin
    Contributors: 物理研究所
    Keywords: 宇宙學;波因卡瑞規範理論;自旋密度;拉格朗日;Spin Density;Bianchi Cosmology;Effective Lagrangian;Poincar'e Gauge Theory
    Date: 2012-07-23
    Issue Date: 2012-09-11 18:40:56 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 在重力的波因卡瑞規範理論中僅存的兩種行為良好的動力聯絡模式分別為:spin-0+ 及spin-0-。 我們分別在兩種宇宙模型之下研究此兩種模式的動力特性。這兩種動態純量的扭稱模式所產生的效應可以用來解釋加速膨脹宇宙的現象。我們經由數值模擬的方式檢驗在近期漸進的範圍內的動力演化(近似對應到目前的宇宙); 在此案例中顯現出兩種動力扭稱模式為分立的,而宇宙加速膨脹的現象僅由spin-0+ 模式所決定。目前有一更一般化的BHN模型被提出探討。我們也研究了明顯各向同性的Bianchi 宇宙模型。我們也研究了A類第一及第九型與B類第五型的動力方程式,可以顯示出等效的拉格朗日量與漢米爾頓量可以良好的運作。我們也重新審視物質自旋密度在扭稱宇宙學中所扮演的角色,我們認為自旋密度並沒有直接驅動此種動力純量模式。In the Poincar'e gauge theory of gravity only two modes with well behaved dynamics have been found. They are effectively scalar modes, carrying spin-0+and spin-0-. We have investigated the dynamics of these modes in some cosmological models. The effects these twodynamic scalar torsion could account for the presentlyaccelerating universe. We had examined via numerical simulation the late timeasymptotic regime of the dynamical evolution (approximately corresponding to our current Universe); in that caseit turns out that the two dynamic torsion modes decouple, and the acceleration of theUniverse is determined only by the spin-0+ mode.Now a more general ansatz in the framework ofBHN PG model has been proposed. Rather than use a FLRW representation we have used a manifestly homogeneous Bianchi representation. The effective Lagrangian and Hamiltonianform of the dynamic equations for this model has been found for the isotropic Bianchi class A (type I, IX) and class B (type V) cosmologies.The role of the material spin density in torsion cosmology has been reconsidered,we argue that that the spin density does not directly drive the dynamic scalar modes.
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