Escape from the swampland with a spectator field
Escape from the swampland with a spectator field
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DOI：
10.1103/physrevd.101.103514
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发表时间：
2020-03
影响因子：
5
通讯作者：
Kazuhiro Kogai;Y. Tada
中科院分区：
文献类型：
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作者：
Kazuhiro Kogai;Y. Tada
在弦理论的背景下，对于低能有效场论不处于沼泽地（即紫外不完全类），已经提出了几个推测性的条件。特别是以德西特（de Sitter）和跨普朗克审查猜想为代表的近期一些条件似乎与早期宇宙的暴胀范式相冲突。我们首先指出，暴胀重复多次（多阶段暴胀）的情形可以很容易地与这些猜想相容。换句话说，我们放宽了对单一暴胀的约束，使得大尺度扰动至少持续约10个e - 折叠。在此背景下，我们接着研究一个旁观者场是否可以是大尺度上几乎尺度不变的原初扰动的一个来源。由于这种等曲率贡献，所产生的扰动一般呈现出非零的非高斯性。而且由于暴胀阶段的多重性，较小尺度上的扰动幅度可能与大尺度上的完全不同。这些特征将是未来观测中这一场景的确凿证据。
In the context of string theory, several conjectural conditions have been proposed for low energy effective field theories not to be in swampland, the UV-incomplete class. The recent ones represented by the de Sitter and trans-Planckian censorship conjectures in particular seem to conflict with the inflation paradigm of the early universe. We first point out that scenarios where inflation is repeated several times (multiphase inflation) can be easily compatible with these conjectures. In other words, we relax the constraint on the single inflation for the large scale perturbations to only continue at least around 10 e-folds. In this context, we then investigate if a spectator field can be a source of the almost scale-invariant primordial perturbations on the large scale. As a consequence of such an isocurvature contribution, the resultant perturbations exhibit the nonvanishing non-Gaussianity in general. Also the perturbation amplitude on smaller scales can be completely different from that on the large scale due to the multiplicity of inflationary phases. These signatures will be a smoking gun of this scenario by the future observations.