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arXiv 2408.05591astro-ph.COhep-ph
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温波暗物质中的自由流动

Free Streaming in Warm Wave Dark Matter

Siyang Ling, Mustafa A. Amin

AI总结:

本研究提出计算暴胀后标量场自由流动效应的数值框架,给出初始条件方案并通过Klein-Gordon方程演化场,分析引力、自由流动及自相互作用对密度扰动的影响,开源相关代码,对轻/超轻暗物质结构形成研究有重要意义。

摘要:

我们提出了一个用于数值计算暴胀后产生的标量场中自由流动效应的框架。首先,我们给出了设置场中初始条件的详细方案,该方案使我们能够确定场的功率谱(在亚视界长度尺度上达到峰值,且不存在均匀场模式),更重要的是,它还能正确复现大长度尺度上密度扰动的行为,与超视界绝热扰动一致。随后我们利用空间非均匀的Klein-Gordon方程演化场,其中纳入了膨胀效应以及辐射源化的度规扰动。我们展示了引力如何增强、自由流动又如何抹除场的初始绝热密度扰动,从而更多地揭示出底层的、不随时间演化的白噪声等曲率密度反差。此外,我们还探究了场的非引力自相互作用(包括振荡子形成)对抑制动力学的影响。作为本文工作的一部分,我们将代码${\sf{Cosmic-Fields-Lite}}$(${\sf{CFL}}$)公开发布。对于观测可及的特征而言,我们的工作与轻/超轻暗物质场中的结构形成尤为相关。

英文摘要:

We provide a framework for numerically computing the effects of free-streaming in scalar fields produced after inflation. First, we provide a detailed prescription for setting up initial conditions in the field. This prescription allows us to specify the power spectra of the fields (peaked on subhorizon length scales and without a homogeneous field mode), and importantly, also correctly reproduces the behaviour of density perturbations on large length scales consistent with superhorizon adiabatic perturbations. We then evolve the fields using a spatially inhomogeneous Klein-Gordon equation, including the effects of expansion and radiation-sourced metric perturbations. We show how gravity enhances, and how free streaming erases the initially adiabatic density perturbations of the field, revealing more of the underlying, non-evolving, white-noise isocurvature density contrast. Furthermore, we explore the effect of non-gravitational self-interactions of the field, including oscillon formation, on the suppression dynamics. As part of this paper, we make our code, ${\sf{Cosmic-Fields-Lite}}$ (${\sf{CFL}}$), publicly available. For observationally accessible signatures, our work is particularly relevant for structure formation in light/ultralight dark matter fields.

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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