Magneto-dilatonic Bianchi I cosmology: Isotropization and singularity problems
Magneto-dilatonic Bianchi I cosmology: Isotropization and singularity problems
复制标题
磁膨胀比安奇 I 宇宙学：各向同性和奇点问题
DOI：
10.1088/0264-9381/21/14/005
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发表时间：
2004
影响因子：
3.5
通讯作者：
G. N. Shikin
中科院分区：
文献类型：
--
作者：
K. Bronnikov;E. N. Chudayeva;G. N. Shikin
我们研究了充满全局单向电磁场Fμν的Bianchi-I时空的演化，该时空与无质量标量膨胀场根据定律Ψ（）FμνFμν相互作用，其中Ψ（）> 0是任意函数。一个定性的研究，除其他结果外，表明：（一）体积因子总是单调演变，（二）存在的模型，成为各向同性的后期时间和（iii）的扩展一般从一个奇点开始，但可以有特殊的模型开始从一个Killing地平线之前的静态阶段。所有这三个特征都被确认为通常考虑的情况下的精确解，λ = e2λ，λ =常数。特别是，各向同性模型被发现。在特殊情况下|λ| = 1，这对应于模型的字符串起源，字符串度量行为的研究和定性类似的爱因斯坦框架度量。在两个附录中，我们讨论和比较了任意Bianchi-I时空的四种不同的各向同性判据，并给出了它们的正则性条件。
We study the evolution of Bianchi-I spacetimes filled with a global unidirectional electromagnetic field Fμν interacting with a massless scalar dilatonic field according to the law Ψ()FμνFμν where Ψ() > 0 is an arbitrary function. A qualitative study, among other results, shows that (i) the volume factor always evolves monotonically, (ii) there exist models that become isotropic at late times and (iii) the expansion generically starts from a singularity but there can be special models starting from a Killing horizon preceded by a static stage. All three features are confirmed for exact solutions found for the case usually considered, Ψ = e2λ, λ = const. In particular, isotropizing models are found for . In the special case |λ| = 1, which corresponds to models of string origin, the string metric behaviour is studied and shown to be qualitatively similar to that of the Einstein frame metric. In the two appendices, we discuss and compare four different isotropization criteria for arbitrary Bianchi-I spacetimes and present their regularity conditions.