AI 中文总结
该研究针对旁观者暗物质大尺度等曲率扰动过量问题，提出基于δ函数质量贡献的过滤机制，结合暴胀巨钟模型，实现等曲率谱的特定演化并确定暗物质丰度与约束。
AI 中文摘要
轻旁观者场为标量暗物质提供了颇具吸引力的暴胀起源，但它们的原初涨落往往会在大尺度上产生过量的等曲率扰动。我们开发了一种新颖的、可精确求解的过滤机制，该机制基于旁观者质量的一系列δ函数贡献，我们将其称为“kicks”，其稠密极限收敛为平滑的类库仑分布。该过滤器在暴胀期间产生的等曲率谱在大尺度上被强烈抑制，随动量在红外区按k³上升，在快速转折后于小尺度平滑趋近于常数平台。该构造受离散平移对称性的启发，允许建立有效场论（EFT） regime，其中辐射修正可被系统控制，且可通过暴胀巨钟模型（inflationary massive-clock model）实现。我们将该过滤器嵌入极简暗物质场景，其中旁观者凝聚体围绕二次势极小值振荡，表现为无压物质。在此框架下，旁观者暗物质质量直接与暴胀等曲率谱的转折尺度相关。我们确定了由此产生的暗物质丰度，并分析了相关的等曲率和 backreaction 约束。最严格的实现（即旁观者凝聚体在暴胀期间产生）倾向于相对较低的暴胀尺度。
英文摘要
Light spectator fields provide a compelling inflationary origin for scalar dark matter, but their primordial fluctuations often generate excessive isocurvature perturbations on large scales. We develop a novel, exactly solvable filtering mechanism based on a tower of $δ-$function contributions to the spectator mass, which we call kicks, whose dense limit converges to a smooth Coulomb-like profile. The filter produces a isocurvature spectrum during inflation that is strongly suppressed on large scales, rises with momenta as $k^3$ in the infrared, and, after a rapid turnover, smoothly approaches a constant plateau at small scales. This construction is motivated by a discrete translational invariance, admits an EFT regime in which radiative corrections can be systematically controlled, and can find a concrete realization in terms of an inflationary massive-clock model. We embed the filter in a minimal dark-matter scenario in which a spectator condensate oscillates about the minimum of a quadratic potential and behaves as pressureless matter. In this framework, the spectator dark-matter mass is directly related to the turnover scale of the inflationary isocurvature spectrum. We determine the resulting dark-matter abundance and analyze the relevant isocurvature and backreaction constraints. The most restrictive realization, in which the spectator condensate is generated during inflation, favors a relatively low inflationary scale.
Comments40 pages, 8 figures
