Investigating strongly interacting Quantum Field Theories at finite density via holography

通过全息术研究有限密度下的强相互作用量子场论

• 批准号: 2601854
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2601854
• 关键词: Investigating; strongly; interacting; Quantum; Field

Quantum Field Theories at finite density of charges conserved in the relativistic domain (such as the baryonic charge in QCD) are not well understood in the regime of strong coupling. Perturbative approach at strong coupling is inadequate and the existing non-perturbative methods (lattice QFT) are constrained by the infamous sign problem. Meanwhile, strong interest in understanding finite density strongly coupled QFTs is prompted by two developments: new purpose-built heavy ion accelerators (FAIR and NICA) scheduled for launch in the next 2-3 years and dedicated precision observations of neutron stars and similar objects. FAIR and NICA will explore the phase diagram of QCD in the region of non-negligeable density with an overall aim of finding the conjectured critical point and investigating nuclear matter in its vicinity. Neutron star observations are aimed at understanding the structure of the cores described by exotic phases of QCD at super-high density. Theoretical understanding of these domains is extremely limited.The proposed line of research will investigate strongly coupled QFTs at finite chemical potential via holography (gauge-string duality). The main objective is to establish properties of the corresponding quantum fluid in this regime and especially in the vicinity of a critical point. This involves building fluid dynamics of chiral fluids to second order and investigating its properties at strong coupling using dual gravity methods and purpose-built QFT models. We hope to come across universal qualitative features in which case the impact on the field will be very significant. At the very least, we shall understand strongly coupled QFTs of a certain type at finite density, where very little is known at the moment.The plan involves, after some preparatory period, building a holographic dual of a known QFT with a conserved charge and investigating its transport properties at first and second order of the derivative expansion. Chiral fluid dynamics appears to have a number of distinct features (some of them are known from optically active media) which can be studies via probes normally used for quark-gluon plasma. At the same time, we shall build a bottom-up holographic model with a critical point to investigate possible signatures of critical behaviour of a strongly coupled chiral medium. A general formalism including the hierarchy f Kubo relations will be constructed.A second, more ambitious stage, will include computing finite coupling corrections to any of the results of stage one. Unfortunately, the existing string theory compactification results allowing one to explore systems with finite density were criticized in the literature as unreliable. Therefore, the first step would be establishing a reliable compactification scheme - this may be rather challenging technically and will be attempted only under favourable conditions.We plan to collaborate with theoretical physicists at University Victoria (Canada) and University of Edinburgh. This project falls within Quantum Field Theory (mostly), String Theory and Mathematical Physics research areas.

在相对论域中有限密度电荷守恒的量子场论（如QCD中的重子电荷）在强耦合的情况下还没有得到很好的理解。微扰方法在强耦合下是不够的，现有的非微扰方法（格QFT）受到臭名昭著的符号问题的限制。与此同时，两个发展促使人们对理解有限密度强耦合QFT产生了浓厚的兴趣：计划在未来2-3年内发射的新的专用重离子加速器（FAIR和NICA）以及对中子星和类似物体的专门精密观测。FAIR和NICA将探索QCD在不可忽略密度区域的相图，其总体目标是找到束缚临界点并研究其附近的核物质。中子星星观测的目的是理解超高密度下QCD奇异相所描述的核结构。理论上对这些领域的理解是非常有限的，建议的研究方向将通过全息术（规范弦对偶性）研究有限化学势下的强耦合QFT。我们的主要目标是建立相应的量子流体在这一制度，特别是在临界点附近的属性。这涉及到建立手性流体的流体动力学二阶和研究其在强耦合使用双重力方法和专用QFT模型的属性。我们希望能遇到普遍的质量特征，在这种情况下，对该领域的影响将非常重大。至少，我们将了解有限密度下某种类型的强耦合QFT，目前对此知之甚少。计划包括，经过一段时间的准备，建立一个已知的具有守恒电荷的QFT的全息对偶，并研究其在一阶和二阶导数展开下的输运性质。手征流体动力学似乎有许多独特的特征（其中一些是已知的光学活性介质），可以通过通常用于夸克胶子等离子体的探针进行研究。与此同时，我们将建立一个自底向上的全息模型与一个临界点，以调查可能的签名的临界行为的强耦合手征介质。第二个阶段是对第一阶段的结果进行有限耦合修正，这是一个更有挑战性的阶段。不幸的是，现有的弦理论紧化结果允许人们探索有限密度的系统，在文献中被批评为不可靠。因此，第一步将是建立一个可靠的紧化方案-这在技术上可能相当具有挑战性，只有在有利的条件下才会尝试。我们计划与维多利亚大学（加拿大）和爱丁堡大学的理论物理学家合作。这个项目福尔斯属于量子场论（大部分），弦理论和数学物理研究领域。