Probing fundamental fields in strong gravity

目的：建立暗物质环境中黑洞(BHS)和黑洞双星(BHB)的数值相对论模拟和分析模型，比较和对比高质量和低质量候选黑洞，并确定每种情况的观测特征。背景：2015年LIGO探测到引力波是科学的一个突破性时刻。LIGO(和处女座)目前正处于第三次观测运行，到目前为止已报告了30多个新的候选事件，预计未来十年将有大量新数据被全球GW仪器网络探测到。这也将是LISA基于空间的任务准备的关键阶段，该任务将把我们的视野扩展到探测超大质量黑洞(SMBH)丰富的DM环境和来自早期宇宙的背景信号(~10-4-10-1赫兹)的频率。为了理解我们将收到的数据流的意义，我们需要充分理解当前理论做出的理论预测，例如广义相对论，包括可能与新物理学有关的偏差。一个特别令人感兴趣的效应是暗物质(DM)环境对BHS及其随后合并的影响。虽然Dm构成了宇宙能量收支的一大部分，但到目前为止，唯一证实的与其他物质的相互作用通道是通过引力相互作用。因此，研究DM在强重力环境中的行为可能是理解粒子物理学的唯一途径，例如，区分高质量和低质量粒子，并限制自我相互作用。DM环境导致的GW偏差预计很小，但合并阶段没有很好地量化，在特定情况下可能会增强影响。鉴于DM问题的重要性，以及探测器灵敏度的不断提高，这种影响值得进一步研究。方法：该项目将使用解析方法和最近开发的数值代码来研究孤立的BHS和BBH的低质量玻色子暗物质环境。该项目还将涉及开发一个完全广义相对论N体代码(作为GRChombo框架的一部分)，以研究强弯曲时空中候选重暗物质的行为，允许直接比较这两个质量案例，这将使我们能够辨别出各自潜在的可检测到的特征。很少有这样的混合NR/N体代码存在(据我们所知，只有一个)，目前还没有公开可用的。STFC目标：拟议的项目属于STFC粒子天体物理学主题宇宙信使基础物理路线图，特别是与以下问题相关：(2A)暗物质的性质是什么？(2E)宇宙中是否存在尚未直接或间接探测到的粒子？这些反过来又解决了STFC确定为其计划核心的科学挑战，即：(C)宇宙的基本成分和结构是什么，它们如何相互作用？(D)我们如何探索和了解宇宙的极端？这项工作也与LISA合作的工作包8.7有关，LISA合作是欧空局和NASA为空间引力波观测站执行的任务。影响：很有可能发现暗物质的特征并区分大质量和低质量候选物质。公开代码的开发也为其他研究人员提供了宝贵的资源。合作者：学生将与GRChombo团队(www.grchombo.org)合作，作为开发开放源码数值相对论代码的项目的一部分。这是英国主导的社区资源，与英特尔合作开发，作为其高性能计算(HPC)技术的旗舰示例。他们还将作为准成员加入LISA合作。

AIM: Develop numerical relativity simulations and analytic models of black holes (BHs) and black hole binaries (BHBs) in dark matter environments, comparing and contrasting the high and low mass candidates, and identifying observational signatures for each case. BACKGROUND: The 2015 detection of gravitational waves (GWs) by LIGO was a breakthrough moment for science. LIGO (and Virgo) are currently in their third observation run with over 30 new candidate events reported so far, and the next decade promises a deluge of new data detected by a world-wide network of GW instruments. It will also be a crucial stage in preparations for the LISA space based mission, which will expand our field of vision into frequencies which probe the rich DM environments of supermassive black holes (SMBHs) and background signals from the early universe (~ 10-4 - 10-1 Hz). To make sense of the data streams we will receive we need to fully understand the theoretical predictions that are made by current theories, such as General Relativity, including possible deviations relating to new physics. One effect which is of particular interest is the impact of dark matter (DM) environments on BHs and their subsequent merger. Whilst DM composes a significant fraction of the energy budget of the Universe, so far the only confirmed interaction channel with other matter is via gravitational interactions. Studies of the behaviour of DM in strong gravity environments may therefore be the only way to understand the particle physics, for example, to distinguish high mass and low mass particles, and constrain self interactions. The deviations in GWs resulting from DM environments are expected to be small for BH inspiral and ringdown, but the merger phase is not well quantified, and the effects there may be enhanced in specific situations. Given the importance of the DM question, and ever-increasing detector sensitivity, such effects merit further investigation. METHODS: The project will use analytic methods and recently developed numerical code to study low mass, bosonic dark matter environments for isolated BHs and BBHs. The project will also involve developing a fully general relativistic N-body code (as part of the GRChombo framework), to study the behaviour of heavy dark matter candidates in strongly curved spacetimes, permitting a direct comparison of the two mass cases which will allow us to discern potentially detectable signatures of each. Few such hybrid NR/N-body codes exist (to our knowledge, only one) and none are currently publicly available.RELEVANCE TO STFC GOALS: The proposed project falls within the STFC Roadmap for Particle Astrophysics theme Fundamental Physics with Cosmic Messengers, in particular, it is relevant to the questions: (2a) What is the nature of Dark Matter? (2e) Are there particles present in the universe which have not yet been detected either directly or indirectly?These in turn address the Science Challenges identified by STFC as core to its programme, namely: (C) What are the fundamental constituents and fabric of the universe and how do they interact? (D) How can we explore and understand the extremes of the universe? The work is also relevant to Work Packages 8.7 of the LISA collaboration, an ESA/NASA mission for a space based gravitational wave observatory. IMPACT: High - potential to discover signatures of dark matter and distinguish between high and low mass candidates. Development of publicly available code also provides an invaluable resource for other researchers. COLLABORATORS: The student will work with the GRChombo team (www.grchombo.org), as part of a project to develop an open source numerical relativity code. This is a UK-led community resource, developed in collaboration with Intel, as a flagship example of their High Performance Computing (HPC) technologies. They will also join the LISA collaboration as an associate member.