论文标题
在LISA的模板重力波光谱中重建物理参数:一阶相变
Reconstructing physical parameters from template gravitational wave spectra at LISA: first order phase transitions
论文作者
论文摘要
在Millihertz重力波(GW)探测器(例如激光干涉仪空间天线(LISA))中,可以观察到早期宇宙中一阶相变的重力波背景。在本文中,我们介绍并测试了一种研究Lisa对重力波的敏感性,使用参数化模板作为对更完整的物理模型的近似值的敏感性。开发该方法的动机是提供一种较少计算密集型的方法,以对一阶相变的热力学参数或一般计算密集型模型执行马尔可夫链蒙特卡洛(MCMC)推断。从物理参数和经验模板的参数之间的地图开始,我们首先在经验参数上构造先验,其中包含有关物理参数的必要信息;然后,我们使用逆映射从经验模板上的快速MCMC上重建物理参数上的近似后期。我们测试了声音壳模型中的双重功率定律近似近似值的方法。重建方法大大减少了建议评估时间,尽管需要对映射进行一些预先计算,但此方法的总体上仍然是成本效益的。在两个测试用例中,具有信噪比$ \ sim 40 $,该方法恢复了物理参数和注入的重力波功率谱的频谱,至$ 95 \%$ $ proforty。在先前的Fisher矩阵分析中,我们发现相边界速度$ v _ {\ rm W} $预计将是热力学参数的最佳约束。在这项工作中,对于带有$ v _ {\ rm w} = 0.55 $的注入相过渡GW功率谱,我们在热力学参数上进行了直接示例,我们恢复了$ 0.630^{+0.17} _ { - 0.059} $,并为我们的重建样品样品$ 0.646^$ 0.05} $ 0.05} {+0.098}。
A gravitational wave background from a first order phase transition in the early universe may be observable at millihertz gravitational wave (GW) detectors such as the Laser Interferometer Space Antenna (LISA). In this paper we introduce and test a method for investigating LISA's sensitivity to gravitational waves from a first order phase transition using parametrised templates as an approximation to a more complete physical model. The motivation for developing the method is to provide a less computationally intensive way to perform Markov Chain Monte Carlo (MCMC) inference on the thermodynamic parameters of a first order phase transition, or on generally computationally intensive models. Starting from a map between the physical parameters and the parameters of an empirical template, we first construct a prior on the empirical parameters that contains the necessary information about the physical parameters; we then use the inverse mapping to reconstruct approximate posteriors on the physical parameters from a fast MCMC on the empirical template. We test the method on a double broken power law approximation to spectra in the sound shell model. The reconstruction method substantially reduces the proposal evaluation time, and despite requiring some precomputing of the mapping, this method is still cost-effective overall. In two test cases, with signal-to-noise $\sim 40$, the method recovers the physical parameters and the spectrum of the injected gravitational wave power spectrum to $95\%$ confidence. In previous Fisher matrix analysis we found the phase boundary speed $v_{\rm w}$ was expected to be the best constrained of the thermodynamic parameters. In this work, for an injected phase transition GW power spectrum with $v_{\rm w} = 0.55$, with a direct sample on the thermodynamic parameters we recover $0.630^{+0.17}_{-0.059}$ and for our reconstructed sample $0.646^{+0.098}_{-0.075}$.