arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1012.5930hep-thastro-ph.CO
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de Sitter空间中的非线性西格玛模型

Non-linear sigma model in de Sitter space

Hiroyuki Kitamoto, Yoshihisa Kitazawa

摘要:

研究了de Sitter空间中非线性西格玛模型的红外动力学.在最小耦合无质量标量场的存在下,de Sitter对称性被动态破缺,物理常数变得依赖于时间。我们发现,非线性西格玛模型的耦合常数变得依赖于时间。红外对数的功率计数参数表明,宇宙学常数也具有时间依赖性。我们发现,这样的红外光谱抵消了微扰调查的两个回路的水平。我们进一步证明了在非线性西格玛模型的大$N$极限下宇宙学常数的非微扰非重整化。

英文摘要:

We investigate infra-red dynamics of the non-linear sigma model in de Sitter space. In the presence of minimally coupled massless scalar fields, the de Sitter symmetry is dynamically broken and physical constants become time dependent. We find that the coupling constant of the non-linear sigma model becomes time dependent. The power counting arguments of the infra-red logarithms indicate that the cosmological constant also acquires time dependence. We find that such infra-red logarithms cancel out in a perturbative investigation up to the two loop level. We further demonstrate a non-perturbative non-renormalization of the cosmological constant in the large $N$ limit of the non-linear sigma model.

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