arXiv 1808.092822018-08gr-qcastro-ph.COhep-phhep-th

隐藏宇宙的张量界限

Tensor Bounds on the Hidden Universe

Adrian del Rio, Ruth Durrer, Subodh P. Patil

备注：: 14 pages, 4 figures, 3 appendices. Version accepted to JHEP; references added, updated bounds on $r$ incorporated
DOI：: 10.1007/JHEP12(2018)094

摘要：

在单时钟暴胀期间，绝热真空中的隐藏场（即仅与暴胀子引力耦合的场）通常只能通过虚效应影响可观测量。在对背景量（由某些主尺度上的观测值确定）重新归一化之后，剩下的只是关联函数中的对数运行，这些函数都被普朗克和慢滚抑制了。在本文中，我们将展示如何大量的隐藏字段可以部分地补偿这种抑制，并产生一个潜在的可观察的张量运行两点函数，一贯推断礼貌的一个大的$N$ remation。我们绕道来解决通货膨胀期间环路修正的某些微妙之处，扩展[1]的分析。我们的主要结果是，人们可以提取边界上的隐藏字段内容的宇宙从边界上违反的一致性关系之间的张量谱指数和张量标量比，是原始张量检测。这样的界限比天真的界限更具竞争力，天真的界限是从要求暴胀发生在引力的强耦合尺度之下推断出来的，如果与一致性关系的偏差可以限制在百分之一以下的水平。我们讨论了如何有意义地约束参数空间的各种现象学的情况下，解决自然与大量的物种（如“N-自然”）与CMB观测宇宙方差限制，并可能在未来的21厘米和引力波观测。

英文摘要：

During single clock inflation, hidden fields (i.e. fields coupled to the inflaton only gravitationally) in their adiabatic vacua can ordinarily only affect observables through virtual effects. After renormalizing background quantities (fixed by observations at some pivot scale), all that remains are logarithmic runnings in correlation functions that are both Planck and slow roll suppressed. In this paper we show how a large number of hidden fields can partially compensate this suppression and generate a potentially observable running in the tensor two point function, consistently inferable courtesy of a large $N$ resummation. We detour to address certain subtleties regarding loop corrections during inflation, extending the analysis of [1]. Our main result is that one can extract bounds on the hidden field content of the universe from bounds on violations of the consistency relation between the tensor spectral index and the tensor to scalar ratio, were primordial tensors ever detected. Such bounds are more competitive than the naive bound inferred from requiring inflation to occur below the strong coupling scale of gravity if deviations from the consistency relation can be bounded to within the sub-percent level. We discuss how one can meaningfully constrain the parameter space of various phenomenological scenarios and constructions that address naturalness with a large number of species (such as `N-naturalness') with CMB observations up to cosmic variance limits, and possibly future 21cm and gravitational wave observations.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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