标题： 大质量矢量Curvaton的曲率扰动 显示英文标题

标题： Curvature Perturbations from a Massive Vector Curvaton

摘要： 我们研究了文献中提出的无鬼魅的宏观矢量curvaton模型，其中通过适当选择动能和质量函数避免了矢量背景期望值的快速下降。 到目前为止，该模型的curvaton扰动是假设这些函数为外部经典量进行计算的，并发现这些函数的某些特殊时间演化会导致矢量curvaton的尺度不变且统计各向同性的扰动。 然而，外部函数应被理解为源自某种额外场的期望值。 由于这些函数在暴胀期间需要表现出非平凡的演化，该场不能被简单地积分掉，特别是其扰动需要包含在计算中。 我们在该机制的一个最小实现中这样做，其中额外场被识别为暴胀场。 我们表明，除了模型参数的一个狭窄窗口外，与该场的相互作用通常会导致曲率扰动超出观测极限，从而违反统计各向同性。 显示英文摘要

摘要： We study a ghost-free model of massive vector curvaton proposed in the literature, where the quick decrease of the vector background expectation value is avoided by a suitable choice of kinetic and mass functions. The curvaton perturbations of this model have been so far computed assuming that these functions are external classical quantities, and it was found that some special time evolution of these functions leads to scale invariant and statistically isotropic perturbations of the vector curvaton. However, external functions should be understood as originating from the expectation value of some additional field. Since these functions need to present a non-trivial evolution during inflation, the field cannot be trivially integrated out, and, in particular, its perturbations need to be included in the computation. We do so in a minimal implementation of the mechanism, where the additional field is identified with the inflaton. We show that, except for a narrow window of model parameters, the interaction with this field generally causes the curvature perturbations to violate statistical isotropy beyond the observational limit.