New analytical tools to constrain fundamental physics with astrophysics

目前的宇宙学和粒子物理学范式一直在以更高的精确度进行测试。尽管如此，许多基本的问题仍然存在，关于负责在宇宙中创造宇宙结构的行为者的性质及其原始条件。这一挑战已经被观察界接受，数据的质量和多样性正在经历一场革命。与这一提议相关的是绘制宇宙大尺度(例如DES、BOSS、DESI或欧几里得)物质分布图的飞行任务，以及用射电望远镜精确观测非常快速旋转的中子星(脉冲星)的飞行任务，SKA是向前迈出的下一步。这项提议旨在开发分析工具，将这些高质量的观察转化为关于自然的定量信息。它分为两个方向，代表了PI的专业知识：i.暗物质场和脉冲星计时有确凿证据表明，宇宙中含有一种新形式的物质，其丰度是标准物质的5倍(我们可以在实验室操纵的物质)。这种新的物质形式在地球上没有被探测到，因此得名“暗物质”。为了直接探测暗物质，人们可以转向宇宙，寻找暗物质在众所周知的现象中可能发生影响的过程。在这方面，一个自然的候选者是脉冲星发出的无线电脉冲。在天体物理学中，确定这些信号的时间的精确度是无与伦比的，并且可能会被新的动力学的存在所改变。特别是，这些脉冲带来了关于其源运动的作用力、脉冲星在其中运动的介质的存在以及脉冲星和地球之间可能存在的背景的信息。不同的暗物质模型可以影响所有这些方面，人们可能会想知道当前和未来的数据可以限制(或检测)到什么程度！他们。脉冲星计时的这种相对未被探索的用途是这个子项目的目标。第一个提出的方向是研究超轻暗物质对脉冲星运动的影响，以及在当前和未来数据中可能检测到的影响。这个暗物质模型非常受欢迎，因为它与量子色动力学和弦理论有关。我们将提供强有力的约束(或证据！)在这些模型上，无论是在候选暗物质直接耦合到标准物质还是不直接耦合到标准物质的情况下。我们还将分析亮暗物质模型在无线电波传播中的作用。II.大尺度结构的分析技术暗物质和暗能量是宇宙中最大尺度上质量分布的关键因素。尽管如此，“黑暗部门”几乎不受限制。宇宙尺度上的质量分布的演变也对自然界的其他基本方面很敏感：中微子的质量值(目前未知)或宇宙膨胀期间物质的原始分布在这些观测中留下了痕迹。结构形成过程的非线性性质阻碍了观察与基本问题的联系。一种可能的策略是求助于计算机模拟。这些模拟非常耗时，而且运行模拟来回答所有基本问题是不切实际的。幸运的是，许多模型在轻微的非线性尺度上留下了签名，这可以用解析的方式来描述。这个子项目的目的是开发新的分析和有效的技术来理解结构形成的过程。我们将首先给出物质在几十MPC下分布的三点函数的精确预测。这包括将非常非线性的过程的影响参数化。这将针对不同的宇宙模型进行。然后，这些技术将被用来分析当前或未来的数据。

The current paradigms of cosmology and particle physics continue to be tested at always better precision. Still, many fundamental questions remain about the nature of the actors responsible to create the cosmological structures in the Universe and their primeval conditions. This challenge has been embraced by the observational community and the quality and diversity of data is experiencing a revolution. Relevant for this proposal are the missions that map the distribution of matter in the Universe at cosmological large scales (e.g. DES, BOSS, DESI or EUCLID) and the precise observations of very rapidly rotating neutron stars (pulsars) by radiotelescopes, with SKA representing the next step forward. This proposal aims at the development of analytical tools to turn these high-quality observations into quantitative information about Nature. It is divided into two directions representing the PI expertise:I. Dark matter fields and pulsar timingThere is solid evidence that the Universe contains a new form of matter 5 times more abundant than `standard matter' (matter we can manipulate in the laboratory). This new form of matter has not been detected on Earth, hence the name `dark matter'. To directly probe dark matter, one can turn to the Universe and look for processes where the influence of dark matter in well understood phenomena may take place. A natural candidate in this respect are the radio-pulses emitted by pulsars. The accuracy in the determination of the timing of these signals has no equal in astrophysics and may be modified by the presence of new dynamics. In particular, the pulses bring information about the forces responsible of the motions of their sources, the presence of a medium in which the pulsar moves and the possible existence of a background between the pulsar and Earth. Different dark matter models can influence all these aspects and one may wonder to which extend the current and future data can constrain (or detect!) them. This relatively unexplored use of pulsar timing is the objective of this sub-project. The first proposed direction is to study the influence of ultra-light dark matter in the motion of the pulsars, and its possible detection in current and future data. This model of dark matter is very popular due to its connection to quantum chromodynamics and string theory. We will provide strong constraints (or evidence!) on these models, both in the cases where the dark matter candidate is directly coupled or not directly coupled to standard matter. We will also analyze the effects of light dark matter models in the propagation of the radiowave.II. Analytical techniques for large scale structureDark matter and dark energy are key actors in the distribution of mass at the largest scales in the Universe. Still, the `dark sector' is almost unconstrained. The evolution of the mass distribution at cosmological scales is also sensitive to other fundamental aspects of Nature: the value of the mass of the neutrinos (currently unknown) or the primordial distribution of matter during cosmological inflation leave a trace in these observations. The connection of the observations to the fundamental questions is hindered by the non-linear nature of the process of structure formation. A possible strategy is to resort to computer simulations. These simulations are time consuming, and it is not practical to run simulations to answer all fundamental questions. Fortunately, many models leave signatures at mildly non-linear scales which may be described analytically. The aim of this sub-project is to develop new analytical and efficient techniques to understand the process of structure formation. We will first give a precise prediction of the 3-point function of the distribution of matter at dozens of Mpc. This includes parametrizing the effects of very non-linear processes. This will be done for different models of the Universe. These techniques will be then adapted to analyse current or future data.