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arXiv 1607.08609astro-ph.COgr-qchep-phhep-th
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超轻熵模暴胀中的累积效应

Cumulative effects in inflation with ultra-light entropy modes

Ana Achúcarro, Vicente Atal, Cristiano Germani, Gonzalo A. Palma

摘要:

在多场暴胀中,一个或多个非绝热模式可能会变轻,潜在地在宇宙微波背景中引起大水平的等曲率扰动。此外,如果这些光模耦合到绝热模,它们会影响它在超视界尺度上的演化。在这里,我们考虑的情况下,一个非绝热模式变得近似无质量(“超轻”),同时仍然耦合到绝热模式,一个典型的情况下出现的伪南布-戈德斯通玻色子或模量。这种超轻模式在超视界尺度上冻结,并作为曲率扰动的恒定源,使其随时间线性增长,并有效地抑制等曲率分量。我们确定了一个Stuckelberg一样的紧急转移对称性,这种行为的基础。由于暴胀持续许多e折叠,该源的积分效应增强了绝热模式的功率谱,同时保持非绝热谱近似不变。在这种情况下,在暴胀结束时,所有的涨落,绝热的和非绝热的,都由一个自由度支配。

英文摘要:

In multi-field inflation one or more non-adiabatic modes may become light, potentially inducing large levels of isocurvature perturbations in the cosmic microwave background. If in addition these light modes are coupled to the adiabatic mode, they influence its evolution on super horizon scales. Here we consider the case in which a non-adiabatic mode becomes approximately massless ("ultralight") while still coupled to the adiabatic mode, a typical situation that arises with pseudo-Nambu-Goldstone bosons or moduli. This ultralight mode freezes on super-horizon scales and acts as a constant source for the curvature perturbation, making it grow linearly in time and effectively suppressing the isocurvature component. We identify a Stuckelberg-like emergent shift symmetry that underlies this behavior. As inflation lasts for many e-folds, the integrated effect of this source enhances the power spectrum of the adiabatic mode, while keeping the non-adiabatic spectrum approximately untouched. In this case, towards the end of inflation all the fluctuations, adiabatic and non-adiabatic, are dominated by a single degree of freedom.

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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