de Sitter背景下的随机粒子产生
Stochastic Particle Production in a de Sitter Background
摘要：
我们探讨了非绝热粒子生产的de Sitter宇宙中的标量旁观者字段，通过允许这个字段的有效质量$m^2(t)$和非绝热事件之间的宇宙时间间隔随机变化。两个主要的情况下，被认为是取决于（非随机）的观众场的质量$M$：共形的情况下，与$M^2=2H^2$，和一个无质量的字段的情况。我们利用传输矩阵形式主义参数化的“占领数”方面的系统的演变，并与传输矩阵相关联的两个阶段，这些被用来构建观众场的演变。假设短时间的相互作用近似的Dirac-delta函数，我们数值跟踪这些参数的变化和字段在所有制度：子和超地平线弱和强散射。在所有情况下，观察到对数正态分布的场振幅，并且场振幅的对数近似满足视界外维纳过程的性质。我们推导出一个福克-普朗克方程的传输矩阵参数的演变，这使我们能够计算分析非平凡的分布和力矩的弱散射限制。
英文摘要：
We explore non-adiabatic particle production in a de Sitter universe for a scalar spectator field, by allowing the effective mass $m^2(t)$ of this field and the cosmic time interval between non-adiabatic events to vary stochastically. Two main scenarios are considered depending on the (non-stochastic) mass $M$ of the spectator field: the conformal case with $M^2=2H^2$, and the case of a massless field. We make use of the transfer matrix formalism to parametrize the evolution of the system in terms of the "occupation number", and two phases associated with the transfer matrix; these are used to construct the evolution of the spectator field. Assuming short-time interactions approximated by Dirac-delta functions, we numerically track the change of these parameters and the field in all regimes: sub- and super-horizon with weak and strong scattering. In all cases a log-normally distributed field amplitude is observed, and the logarithm of the field amplitude approximately satisfies the properties of a Wiener process outside the horizon. We derive a Fokker-Planck equation for the evolution of the transfer matrix parameters, which allows us to calculate analytically non-trivial distributions and moments in the weak-scattering limit.
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。
