Comprehensive Studies of Extreme Phases of Nuclear Matter

现代物理学用四种基本力来描述物理实在：强核力、弱核力、电磁力和引力。强核力导致了一长串对宇宙存在至关重要的现象。例如，强力将原子核结合在一起，它为太阳和所有其他恒星的燃烧提供燃料，它控制着早期宇宙的命运。虽然描述强作用力（或量子色动力学，QCD）的基本方程在四十年前就被写下来了，但对它的性质仍然缺乏深入的理解。该项目将有助于推进对极高温度和密度下强作用力关键特征的理解。在大约10亿度的温度下，所有受到强核力作用的物质都会形成一种物质状态，称为夸克胶子等离子体。夸克胶子等离子体在大爆炸后的早期宇宙中普遍存在。夸克胶子等离子体可以在实验室中在世界上最高能量的对撞机设施中的超大型核碰撞中重新产生，例如欧洲的大型强子对撞机和美国的相对论重离子对撞机。PI将与他的研究生一起开展研究，以提高对核碰撞中夸克胶子等离子体形成和发展的理解。该项目将开发核碰撞的全面计算机模拟。这些高能碰撞的初始阶段由强的非线性胶子场主导。由于原子核的碰撞是随机的，碰撞参数也是随机的，所以我们将提供一个对胶子场的一个事件一个事件的蒙特卡罗模拟。系统最终达到近似的局部动力学平衡，进一步的时间演化可以由相对论耗散流体动力学跟踪。通过与LHC和RHIC数据的比较，可以确定夸克胶子等离子体的物态方程和重要的输运系数。该项目还将揭示夸克胶子等离子体与电磁探针（光子）的耦合。此外，PI和他的学生将研究初始强胶子场对非常快的夸克和胶子（喷流）以及重夸克的影响。它们都是研究夸克胶子等离子体性质的重要探针。该项目还将为计划在电子离子对撞机上进行的下一代对撞机实验提供工具。后者将允许系统地研究强胶子场以及在核环境中产生夸克和胶子喷流。

Physical reality is described in modern physics using four fundamental forces: the strong nuclear force, the weak nuclear force, the electromagnetic force, and gravity. The strong nuclear force is responsible for a long list of phenomena that are crucial to the existence of the universe. For example, the strong force holds together atomic nuclei, it fuels the burning of the sun and all other stars, and it governed the fate of the very early universe. Although the fundamental equations describing the strong force (or quantum chromodynamics, QCD) were written down four decades ago, an in-depth understanding of its properties is still lacking. This project will help advance the understanding of key features of the strong force at very high temperatures and densities. At temperatures of about 1,000,000,000,000 degrees all matter subject to the strong nuclear force forms a state of matter called quark gluon plasma. Quark gluon plasma was prevalent in the early universe milliseconds after the Big Bang. The quark gluon plasma can be recreated in the laboratory in collisions of very large nuclei in the highest energy collider facilities in the world, such as the Large Hadron Collider in Europe and the Relativistic Heavy Ion Collider in the US. The PI, working with his graduate students, will carry out research to improve the understanding of the formation and development of quark gluon plasma in nuclear collisions. This project will develop a comprehensive computational simulation of nuclear collisions. The initial phase of those collisions at high energy is dominated by strong, nonlinear gluon fields. Because nuclei collide in random configurations and with random impact parameters an event-by-event Monte Carlo simulation of gluon fields will be provided. The system eventually reaches approximate local kinetic equilibrium and the further time evolution can be followed up by relativistic dissipative fluid dynamics. Comparison to data from LHC and RHIC can determine the equation of state and important transport coefficients of quark gluon plasma. The project will also shed light on the coupling of quark gluon plasma to electromagnetic probes (photons). In addition, the PI and his students will study the effect of the initial strong gluon fields on very fast quarks and gluons (jets), and on heavy quarks. Both of those are important probes for properties of quark gluon plasma. The project will also provide tools for the next generation collider experiments planned at an electron ion collider. The latter will allow for a systematic study of strong gluon fields and the creation of quark and gluon jets in a nuclear environment.