Theoretical and Numerical Studies of Astrophysical Quark Matter: Implications to Nuclear and Explosive Astrophysics

天体物理夸克物质的理论和数值研究：对核和爆炸天体物理学的影响

• 批准号: RGPIN-2018-04232
• 负责人: Ouyed, Rachid
• 金额: $ 2.99万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=712818
• 关键词: Theoretical; Numerical; Studies; Astrophysical; Quark

The search for quark matter and quark stars in the Universe: A longstanding aim of natural science is to understand the fundamental constituents of matter. Quarks and Gluons are the building blocks of the ordinary matter composed of neutrons and protons, and ordinarily remain hidden from us (i.e. they are trapped) inside protons and neutrons, requiring extreme temperature or pressure to liberate them. But nature might just do that in the ultra-dense cores of neutron stars offering us a natural laboratory to study how nuclei-free quarks can form. We developed the BURN-UD code (a first if its kind in the world) which captures the details of how neutrons inside neutron stars turn into quarks as they are squeezed by the force of gravity. We discovered that this transition can be explosive and converts the Neutron star to a Quark star (the Quark-Nova) releasing at least 10 times more energy than the most energetic Supernovae if harnessed this could be transformative to astrophysics with unique, neutrino and photon, signatures. We plan to search carefully for these signatures and improve our treatment of the physics of the explosion. Understanding how quarks can be freed from inside neutrons will advance our knowledge of matter at extreme conditions which could provide guidance for a new kind of experiments in Canada that could probe quark matter. The origin of heavy elements: The origin of the elements that make up our world is one of the oldest most fundamental scientific questions. Elements, including the carbon in our bodies and the iron that make up most of Earth, have been created by nuclear reactions in stars. However, the origin of elements beyond iron is still a mystery. They are attributed to a process called the r-process (rapid neutron capture process) which consists of seed nuclei (iron) exposed to a rich source of neutrons and ``gobbling up” as many of these neutrons as they can, yielding heavier elements. However, the site of the r-process is not known but Supernovae and colliding neutron stars are prime suspects since they produce a lots of neutrons and iron. A serious challenge is the fact that the nuclear processes governing these reactions are not well known and the properties of the extremely neutron-rich nuclei themselves are very hard to measure in laboratories. My research focuses on creating a software (a “sand-box”) for Canadian nuclear astrophysicists to simulate different astrophysical r-process sites while taking into account the uncertainties inherent to the underlying nuclear physics. Once these uncertainties are filtered out, THE astrophysical site for r-process can then be isolated. Knowing the exact site will have serious implications to the chemical evolution of the Universe. It will give us vital information about the properties of neutron-rich nuclei with direct bearing on many experiments being pursued at TRIUMF (Canada's national laboratory for particle and nuclear physics, Vancouver).

在宇宙中寻找夸克物质和夸克星：自然科学的一个长期目标是了解物质的基本成分，夸克和胶子是由中子和质子组成的普通物质的组成部分，通常对我们来说是隐藏的。 （即它们被困在）质子和中子内部，需要极端的温度或压力才能释放它们，但大自然可能会在中子星的超致密核心中做到这一点，为我们提供了一种可能。我们开发了 BURN-UD 代码（世界上第一个），它捕获了中子星内部的中子在受到外力挤压时如何变成夸克的细节。我们发现这种转变可能是爆炸性的，并将中子星转变为夸克星（夸克新星），释放出的能量至少是能量最高的超新星的 10 倍，如果加以利用，这可能会带来变革。具有独特的中微子和光子特征的天体物理学，我们计划仔细寻找这些特征，并改进我们对爆炸物理学的处理，了解夸克如何从内部中子中释放出来，这将增进我们对极端条件下物质的认识。为加拿大进行一种可以探测夸克物质的新型实验提供指导。 重元素的起源：构成我们世界的元素的起源是最古老、最基本的科学问题之一。元素，包括我们体内的碳和构成地球大部分的铁，都是由核反应产生的。然而，除了铁之外的元素的起源仍然是一个谜，它们归因于一种称为 r 过程（快速中子捕获过程）的过程，该过程由暴露于丰富的中子源和“的”种子核（铁）组成。 ‘吞噬’尽可能多然而，r 过程的地点尚不清楚，但超新星和碰撞中子星是主要嫌疑人，因为它们会产生大量中子和铁。控制这些反应的核过程尚不清楚，而且极富中子的原子核本身的特性很难在实验室中测量。我的研究重点是为加拿大核能创建软件（“沙箱”）。天体物理学家可以模拟不同的天体物理 r 过程地点，同时考虑到潜在核物理固有的不确定性，一旦这些不确定性被过滤掉，了解 r 过程的确切地点就会产生严重影响。它将为我们提供有关富中子核特性的重要信息，这些信息与 TRUMF（加拿大粒子与核物理国家实验室，温哥华）正在进行的许多实验直接相关。