Role of dissipative effects in the quantum gravitational onset of warm Starobinsky inflation in a closed universe
Role of dissipative effects in the quantum gravitational onset of warm Starobinsky inflation in a closed universe
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DOI：
10.1103/physrevd.104.106006
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发表时间：
2021-02
影响因子：
5
通讯作者：
Meysam Motaharfar;Parampreet Singh
中科院分区：
文献类型：
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作者：
Meysam Motaharfar;Parampreet Singh
在空间封闭的宇宙中，低能量尺度暴胀模型（如Starobinsky暴胀）的一个有问题的特征是，在暴胀开始之前，会发生一次再坍缩和一个大压缩奇点。在最近的一项工作中，由于非奇异循环演化和类滞后现象，这个问题可以在环量子宇宙学中成功地解决。但是，在某些非常不利的初始条件下，仍然很难出现通货膨胀。在这项工作中，我们探讨了耗散粒子产生的作用，这是典型的在热膨胀情景中，在上述设置。我们发现由这种耗散效应产生的熵使类滞后现象变得更强。因此，通货膨胀的开始通常是很快的，包括在非常不利的初始条件下，通货膨胀失败或在没有耗散效应的情况下显着延迟。我们从现象学上考虑了三种具有不同耗散系数形式的热暴胀情景，从动力学解和相空间图中发现，有利初始条件的相空间比冷暴胀大得多。
A problematic feature of low energy scale inflationary models, such as Starobinsky inflation, in a spatially closed universe is the occurrence of a recollapse and a big crunch singularity before inflation can even set in. In a recent work it was shown that this problem can be successfully resolved in loop quantum cosmology for a large class of initial conditions due to a non-singular cyclic evolution and a hysteresis-like phenomena. However, for certain highly unfavorable initial conditions the onset of inflation was still difficult to obtain. In this work, we explore the role of dissipative particle production, which is typical in warm inflation scenario, in the above setting. We find that entropy production sourced by such dissipative effects makes hysteresis-like phenomena stronger. As a result, the onset of inflation is quick in general including for highly unfavorable initial conditions where it fails or is significantly delayed in the absence of dissipative effects. We phenomenologically consider three warm inflation scenarios with distinct forms of dissipation coefficient, and from dynamical solutions and phase space portraits find that the phase space of favorable initial conditions turns out to be much larger than in cold inflation.