RUI: Probing Quark Matter through Compact Star Oscillations

美国国家科学基金会资助的美国LIGO天文台最近发现了来自黑洞的引力波，这一发现激发了公众的想象力，为我们的宇宙打开了一扇新的观测窗口，就像伽利略时代望远镜的发现一样。科学界普遍认为，LIGO将很快探测到来自银河系众多中子星的引力波，这种引力波最早是在20世纪60年代通过射电脉冲观测到的。然而，与无线电波不同的是，引力波携带着中子星内部的信息，这将揭示高密度和高温下核物理的新见解。这个项目的重点是通过建立中子星及其发射信号的精确数学模型来提高探测中子星引力波的几率。结合核物理和天体物理学，PI将使用现代计算算法来估计影响中子星发射的引力波光谱的关键参数。这项研究的结果将降低搜索引力波信号的计算成本，完善现有的核物理模型，并培养科罗拉多州立大学长滩分校的几名研究生的科学研究方法。在这个项目中，PI将计算部分或全部由奇异夸克物质构成的致密恒星的非径向振荡模式，并将研究它们与引力波特征的相关性。目标是发现模式谱的趋势，可以用作中子星内部结构的引力波指纹。利用流体动力学和广义相对论的理论原理，辅以数值程序，本研究将促进对高密度核物理的理解及其对致密恒星振荡的影响。本研究的新方面包括研究夸克物质的成分梯度、超流动性和混合相对多组分奇异/混合恒星振荡谱的影响。本研究提出的方法包括用数值编码来求解致密恒星内部强引力时空中的流体动力学耦合方程。通过这些任务，本项目将有助于量化现实夸克物质状态方程的非径向振荡模式，识别振荡谱的鲁棒性和模型依赖性特征，并提出可以通过引力波探测器测试的中子星和奇异星之间的区别特征。

The recent discovery of gravitational waves from Black Holes by the NSF-funded US-based LIGO observatories has captured the public imagination and opened a new observational window to our Cosmos, much like the discovery of the telescope did in Galileo's time. There is broad consensus in the scientific community that LIGO will soon detect gravitational waves from numerous neutron stars in our Galaxy, which were first observed by radio pulses in the 1960s. Unlike radio waves however, gravitational waves carry information about the interior of neutron stars, which will reveal new insight into nuclear physics at high density and temperature. This project is focused on improving the odds of detecting the gravitational waves from neutron stars by constructing accurate mathematical models of neutron stars and the signals they emit. Integrating nuclear physics and astrophysics, the PI will use modern computational algorithms to estimate key parameters that affect the spectrum of gravitational waves emitted by neutron stars. Results from this research will reduce the computational cost of searching for gravitational wave signals, refine existing models of nuclear physics, and train several graduate students from CSU Long Beach in the methods of scientific research.In this project, the PI will calculate the non-radial oscillation modes of compact stars made in part or entirely of strange quark matter and will study their relevance to gravitational wave signatures. The goal is to discover trends in the mode spectrum that can be used as gravitational wave fingerprints of the inner structure of neutron stars. Using theoretical principles of fluid dynamics and general relativity, supplemented by numerical routines, this research will advance the understanding of nuclear physics at high density and its implications for compact star oscillations. Novel aspects of this research include investigating the impact of composition gradients, superfluidity, and mixed phases in quark matter on the oscillation spectrum of multi-component strange/hybrid stars. The proposed methods for this research involve numerical coding to solve coupled equations of fluid dynamics in strongly gravitating spacetime inside compact stars. Through these tasks, this project will help quantify the non-radial oscillation modes for realistic quark matter equations of state, identify robust and model-dependent features of the oscillation spectrum and propose distinguishing features between neutron stars and strange stars that can be tested by gravitational wave detectors.