论文标题
宇宙学一阶相变的模型无关的能源预算
Model-independent energy budget of cosmological first-order phase transitions
论文作者
论文摘要
我们研究了一阶宇宙学相变的能量预算，这是预测所得引力波谱的重要因素。以前，该分析主要基于简化模型，例如状态袋方程。在这里，我们提出了一种与模型无关的方法，该方法完全符合损坏相中声速的温度依赖性。我们发现，在流体动力分析中输入的唯一相关数量是在破碎相中的声速和两个相之间的能量和压力差的线性组合，我们称为假曲线（在损坏相中归一化为焓）。假体量化了相变的强度，并得出相对论等离子体的能量量张量的常规痕迹（声音速度为三分之一）。我们在几种现实的相变模型中研究了这种方法，还提供了代码段，可用于确定给定相变强度和声音速度的效率系数。事实证明，我们的方法是适度强的相变的准确性达到百分比，而以前的方法充其量可以给出正确的数量级。
We study the energy budget of a first-order cosmological phase transition, which is an important factor in the prediction of the resulting gravitational wave spectrum. Formerly, this analysis was based mostly on simplified models as for example the bag equation of state. Here, we present a model-independent approach that is exact up to the temperature dependence of the speed of sound in the broken phase. We find that the only relevant quantities that enter in the hydrodynamic analysis are the speed of sound in the broken phase and a linear combination of the energy and pressure differences between the two phases which we call pseudotrace (normalized to the enthalpy in the broken phase). The pseudotrace quantifies the strength of the phase transition and yields the conventional trace of the energy-momentum tensor for a relativistic plasma (with speed of sound squared of one third). We study this approach in several realistic models of the phase transition and also provide a code snippet that can be used to determine the efficiency coefficient for a given phase transition strength and speed of sound. It turns out that our approach is accurate to the percent level for moderately strong phase transitions, while former approaches give at best the right order of magnitude.
