标题： 宇宙学3-膜解 显示英文标题

标题： Cosmological 3-Brane Solutions

摘要： 我们在具有一个额外空间维的膜宇宙场景中分析宇宙学方程。 我们证明，如果体空间能量-动量张量不为零，宇宙学方程可以简化为通常的4D弗里德曼类型。 然后我们将这些方程推广到有限厚度膜的情况。 我们还证明，当体空间能量-动量张量不为零时，可以通过一个膜对额外的空间维进行紧致化，并表明紧致化半径的稳定性意味着标准宇宙学，反之亦然。 对于有限厚度的膜，我们提供了一个解，使得4D普朗克尺度通过膜的厚度与基本尺度相关联。 在这种情况下，额外维度的紧致化是不必要的。 显示英文摘要

摘要： We analyze cosmological equations in the brane world scenario with one extra space-like dimension. We demonstrate that the cosmological equations can be reduced to the usual 4D Friedmann type if the bulk energy-momentum tensor is different from zero. We then generalize these equations to the case of a brane of finite thickness. We also demonstrate that when the bulk energy-momentum tensor is different from zero, the extra space-like dimension can be compactified with a single brane and show that the stability of the radius of compactification implies standard cosmology and vice versa. For a brane of finite thickness, we provide a solution such that the 4D Planck scale is related to the fundamental scale by the thickness of the brane. In this case, compactification of the extra dimension is unnecessary.