The gravitationally enhanced friction can reduce the speed of the inflaton to realize an ultraslow-roll inflation, which will amplify the curvature perturbations. The amplified perturbations can generate a sizable amount of primordial black holes (PBHs) and induce simultaneously a significant background gravitational waves (SIGWs). In this paper, we investigate the primordial non-Gaussianity of the curvature perturbations in the inflation with gravitationally enhanced friction. We find that when the gravitationally enhanced friction plays a role in the inflationary dynamics, the non-Gaussianity is noticeably larger than that from the standard slow-roll inflation. During the regime in which the power spectrum of the curvature perturbations is around its peak, the non-Gaussianity parameter changes from negative to positive. When the power spectrum is at its maximum, the non-Gaussianity parameter is near zero [$\sim \mathcal{O}(0.01)$]. Furthermore, the primordial non-Gaussianity promotes the formation of PBHs, while its effect on SIGWs is negligible.

中文翻译：

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具有重力增强摩擦的膨胀中的原始非高斯性

重力增强的摩擦可以降低暴胀子的速度以实现超慢滚动暴胀，这将放大曲率扰动。放大的扰动可以产生相当数量的原始黑洞（PBH），并同时引发显着的背景引力波（SIGW）。在本文中，我们研究了具有重力增强摩擦的暴胀中曲率扰动的原始非高斯性。我们发现，当重力增强的摩擦在膨胀动力学中起作用时，非高斯性明显大于标准慢滚动膨胀的非高斯性。在曲率扰动的功率谱在其峰值附近的状态下，非高斯参数从负变为正。$～\mathcal{○}(0.01)$]。此外，原始非高斯性促进了 PBHs 的形成，而其对 SIGWs 的影响可以忽略不计。