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arXiv 1206.0891gr-qc
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多维宇宙学与GUP

Multi-Dimensional Cosmology and GUP

K. Zeynali, F. Darabi, H. Motavalli

摘要:

考虑一个具有四维时空和$d$维Ricci平坦内部空间扇区的FRW型度规的多维宇宙模型,该模型具有高维宇宙学常数.研究了交换和GUP情形下的经典宇宙学,得到了相应的正、负宇宙学常数的精确解。结果表明,当宇宙学常数为负时,对易和GUP情形分别得到小尺寸、长年龄和大尺寸、短年龄的有限尺寸宇宙。对于正的宇宙学常数,交换和GUP的情况下,在无限大的宇宙具有较晚的时间加速行为,与目前的观测结果很好地吻合。加速阶段在GUP情况下比交换情况更早开始。在对易和GUP两种情况下,无论宇宙学常数为正还是为负,内部空间都稳定在普朗克尺度以下,至少在宇宙的当前年龄内是这样。然后,我们通过推导Wheeler-DeWitt方程来研究量子宇宙学,得到了对易情况下的精确解和GUP情况下的微扰解,在GUP小参数下,对正和负宇宙学常数都是一阶的.结果表明,经典解和量子解之间存在良好的对应关系。

英文摘要:

We consider a multidimensional cosmological model with FRW type metric having 4-dimensional space-time and $d$-dimensional Ricci-flat internal space sectors with a higher dimensional cosmological constant. We study the classical cosmology in commutative and GUP cases and obtain the corresponding exact solutions for negative and positive cosmological constants. It is shown that for negative cosmological constant, the commutative and GUP cases result in finite size universes with smaller size and longer ages, and larger size and shorter age, respectively. For positive cosmological constant, the commutative and GUP cases result in infinite size universes having late time accelerating behavior in good agreement with current observations. The accelerating phase starts in the GUP case sooner than the commutative case. In both commutative and GUP cases, and for both negative and positive cosmological constants, the internal space is stabilized to the sub-Planck size, at least within the present age of the universe. Then, we study the quantum cosmology by deriving the Wheeler-DeWitt equation, and obtain the exact solutions in the commutative case and the perturbative solutions in GUP case, to first order in the GUP small parameter, for both negative and positive cosmological constants. It is shown that good correspondence exists between the classical and quantum solutions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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