标题： VCDM中的暴涨/反弹宇宙的双谱 显示英文标题

标题： Bispectrum from inflation/bouncing Universe in VCDM

摘要： 我们讨论了VCDM模型中的非线性相互作用，这是一个类型II最小修正引力模型，具有与广义相对论相同的自由度，但不能通过场重新定义与后者联系起来。 在早期宇宙的膨胀阶段，如果VCDM势不会改变膨胀子场的慢滚行为，则在领先阶上可以恢复慢滚膨胀的标准双谱结果。 另一方面，如果VCDM势占主导地位，相互作用可能会强烈偏离甚至违反马尔达西纳关于局域非高斯性的一致性关系。 此外，我们将该形式应用于最近引入的VCDM反弹模型，并表明双谱仍然符合当前的观测限制。 未来的局域非高斯性测量应该为检验模型的有效性提供试验场。 显示英文摘要

摘要： We discuss the non-linear interactions within the VCDM model, a type II minimally modified gravity model with the same number of degrees of freedom as in General Relativity but not connected to the latter by field redefinitions. During an inflationary phase in the early universe, if the VCDM potential does not modify the slow-roll behavior of the inflaton field, we recover, up to the leading order, the standard results for the bispectrum in slow-roll inflation. On the other hand, if the VCDM potential becomes dominant, the interactions can strongly deviate and even violate the Maldacena's consistency relation for the local non-Gaussianities. Furthermore, we apply the formalism to the recently introduced bouncing model in VCDM, and show that the bispectrum still respects current observational constraints. Future measurements on non-Gaussianities of the local type should provide the test ground for the model's validity.