Stochastic effects in axion inflation and primordial black hole formation
Stochastic effects in axion inflation and primordial black hole formation
复制标题
轴子膨胀和原始黑洞形成的随机效应
作者：
Alireza Talebian;Amin Nassiri;H. Firouzjahi
我们重新审视随机膨胀背景下的轴子膨胀模型，并研究与电磁场相关的随机噪声的影响。由于宇称破坏相互作用，规范场的一种极化被放大，从而产生大曲率扰动功率谱。考虑到跨越地平线时短模产生的随机冲击，我们得到了电磁场和轴子场长模的相应朗之万方程。结果表明，均值回复过程控制着电磁场的动力学，使得规范场的快子增长由扩散力平衡。随着膨胀结束时不稳定参数的增长，规范场扰动引起的大曲率扰动导致小质量原初黑洞（PBH）的大量产生。结果表明，产生的 PBH 遵循高斯统计。对 PBH 形成施加观测限制将之前对不稳定参数的限制放宽了约百分之五十。
We revisit the model of axion inflation in the context of stochastic inflation and investigate the effects of the stochastic noises associated to the electromagnetic fields. Because of the parity violating interaction, one polarization of the gauge field is amplified inducing large curvature perturbation power spectrum. Taking into account the stochastic kicks arising from the short modes at the time of horizon crossing we obtain the corresponding Langevin equations for the long modes of the electromagnetic and axion fields. It is shown that a mean-reverting process governs the dynamics of the electromagnetic fields such that the tachyonic growth of the gauge fields is balanced by the diffusion forces. As the instability parameter grows towards the end of inflation, the large curvature perturbations induced from gauge field perturbations lead to copious production of small mass primordial black holes (PBHs). It is shown that the produced PBHs follow a Gaussian statistics. Imposing the observational constraints on PBHs formation relaxes the previous bounds on the instability parameter by about fifty percents.
暴胀期间轴子规范场相互作用的非高斯性
影响因子：
6.4
作者：
Dimastrogiovanni E
通讯作者：
Dimastrogiovanni E