由超轻暗物质诱导的宇宙学扰动的量子场论
Quantum Field Theory Of Cosmological Perturbations Induced By Ultralight Dark Matter
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中文总结 AI 辅助
本研究构建第一性原理场论框架，探究超轻暗物质对宇宙学扰动的量子效应，发现其经典凝聚态不影响引力波传播，但量子压力可驱动特定原初引力波模式的参数共振，且该效应对超轻暗物质可忽略。
中文摘要 AI 辅助
原初扰动在物质主导时期的增长主要由暗物质驱动，超轻标量场（ULDM）是该角色的有前景候选者，传统上被建模为在经典高占据数区域运行。本研究中，我们开发了一个第一性原理场论框架，以研究ULDM在物质主导时期对线性宇宙学扰动的影响，明确保留其量子特性。我们为引力子场动力学推导了一个封闭方程，在绝热（WKB）近似下，采用非局域项的中点假设，针对ULDM场的一般高斯初始态计算并正则化其源项。规范固定后，我们发现与先前的论断相反，ULDM的经典凝聚态对引力波传播无影响；但由压缩态的量子压力诱导的随时间变化的引力子有效质量，可在特定原初引力波模式中驱动参数共振。在假设压缩谱为幂律的情况下，我们证明对于质量范围$m \backsim 10^{-21}{-}10^{-24}$ eV的非相对论性ULDM，在物质-辐射相等时，该增长可忽略不计。
英文摘要
The growth of primordial perturbations during the matter-dominated era is primarily driven by dark matter. Ultralight scalar fields (ULDM) are a promising candidate for this role, conventionally modeled as operating in a classical, high-occupation regime. In this work, we develop a first-principles field-theoretic framework to investigate the impact of ULDM on linear cosmological perturbations during matter domination, explicitly retaining its quantum nature. Deriving a closed equation for the graviton field dynamics, we compute and regularize its source terms for a generic Gaussian initial state of the ULDM field within the adiabatic (WKB) approximation, employing the middle-point working assumption for non-local terms. After gauge-fixing we find that, contrary to previous claims, the classical condensate of ULDM has no influence on gravitational wave propagation. However, the time-dependent graviton effective mass induced by quantum pressure of the squeezed state can drive parametric resonance in specific primordial gravitational wave modes. We demonstrate this growth is negligible for non-relativistic ULDM at matter-radiation equality under the assumption of a power-law squeezing spectrum for masses in the range $m \sim 10^{-21}{-}10^{-24}$ eV.
