标题： 尺度不变的两测度理论中的Curvaton再加热 显示英文标题

标题： Curvaton reheating in a Scale Invariant Two Measures Theory

摘要： 在基于两个独立非黎曼体积形式（替代的一般协变积分测度密度）的尺度不变两测度理论中研究了curvaton再加热机制，这些体积形式定义在时空流形上且与度规无关。 该模型包含两个标量物质场，一个标量场（稀释子），它在尺度变换下变换，并且也将作为模型的暴胀场，另一个标量场，在尺度变换下不变换，并将起到curvaton场的作用。 引入适当形式的势能，使得相关作用量在全局Weyl-尺度对称性下保持不变。 在运动方程积分后，尺度不变性被自发地打破。 在转换到物理爱因斯坦框架后，我们得到：(i) 对于curvaton场的给定值，存在一个有效势能，该势能对于稀释子具有两个平坦区域，这允许对早期宇宙暴胀以及当前暗能量时期进行统一描述；(iii) 在对应于早期宇宙的相位中，curvaton具有恒定质量，并可以与稀释子解耦振荡，这可以同时负责再加热和理论中的扰动。 在此框架下，我们得到了模型中出现的不同参数的一些有趣约束； (iii) 对于特定参数范围，该模型具有一种非奇异的"涌现宇宙"解，该解描述了暴胀相之前的初始演化阶段。 最后，我们讨论了通过高曲率项效应对模型的推广，其中暴胀场和curvaton可以具有耦合振荡。 显示英文摘要

摘要： The curvaton reheating mechanism in a Scale Invariant Two Measures Theory defined in terms of two independent non-Riemannian volume forms (alternative generally covariant integration measure densities) on the space-time manifold which are metric independent is studied. The model involves two scalar matter fields, a dilaton, that transforms under scale transformations and it will be used also as the inflaton of the model and another scalar, which does not transform under scale transformations and which will play the role of a curvaton field. Potentials of appropriate form so that the pertinent action is invariant under global Weyl-scale symmetry are introduced. Scale invariance is spontaneously broken upon integration of the equations of motion. After performing transition to the physical Einstein frame we obtain: (i) For given value of the curvaton field an effective potential for the scalar field with two flat regions for the dilaton which allows for a unified description of both early universe inflation as well as of present dark energy epoch;(iii) In the phase corresponding to the early universe, the curvaton has a constant mass and can oscillate decoupled from the dilaton and that can be responsible for both reheating and perturbations in the theory. In this framework, we obtain some interesting constraints on different parameters that appear in our model; (iii) For a definite parameter range the model possesses a non-singular "emergent universe" solution which describes an initial phase of evolution that precedes the inflationary phase. Finally we discuss generalizations of the model, through the effect of higher curvature terms, where inflaton and curvaton can have coupled oscillations.