Infra-red effects of Non-linear sigma model in de Sitter space
Infra-red effects of Non-linear sigma model in de Sitter space
复制标题
德西特空间非线性西格玛模型的红外效应
DOI：
10.1103/physrevd.85.044062
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发表时间：
2012
影响因子：
5
通讯作者：
Yoshihisa Kitazawa
中科院分区：
文献类型：
--
作者：
Hiroyuki Kitamoto;Yoshihisa Kitazawa
我们扩展了对非线性Sigma模型中可能的De Sitter对称破缺机制的研究。量子涨落的标度不变性会使发出德西特对称性信号的宇宙学常数随时间变化。为了理解这种对称性破缺机制，我们研究了能量动量张量。我们证明了在一般的非线性Sigma模型中，前导红外对数抵消到微扰理论中的所有阶。当目标空间为球体时，De Sitter对称性在大范围内保持不变。对于对称性较差的目标空间，红外对数出现在三环水平。然而，有一个反义词可以准确地取消它。前导红外对数不会抵消更高导数的相互作用。我们研究了这样一个模型，其中红外对数首先出现在三环水平上。在大范围内的非微扰研究表明，它们最终会增长到与单圈效应一样大。
We extend our investigation on a possible de Sitter symmetry breaking mechanism in nonlinear sigma models. The scale invariance of the quantum fluctuations could make the cosmological constant time dependent signaling the de Sitter symmetry breaking. To understand such a symmetry breaking mechanism, we investigate the energy-momentum tensor. We show that the leading infrared logarithms cancel to all orders in perturbation theory in a generic nonlinear sigma model. When the target space is ansphere, the de Sitter symmetry is preserved in the largelimit. For a less symmetric target space, the infrared logarithms appear at the three-loop level. However, there is a counterterm to precisely cancel it. The leading infrared logarithms do not cancel for higher derivative interactions. We investigate such a model in which the infrared logarithms first appear at the three-loop level. A nonperturbative investigation in the largelimit shows that they eventually grow as large as the one-loop effect.