Matter under extreme conditions: The theory of relativistic nuclear collisions

我的研究计划旨在提供目前在两个主要加速器设备上观察到的夸克-胶子等离子体(QGP)的定量特征：RHIC(相对论重离子对撞机，布鲁克海文国家实验室)和LHC(大型强子对撞机，CERN)。在相对论能量下碰撞大核是在地球实验室中产生和研究热而密集的强相互作用物质的唯一可行的方法。该程序旨在阐明QCD(量子色动力学)在平衡状态和非平衡状态下的整体性质。短期目标包括相辅相成的方面。其中之一涉及软强子探测器及其与QCD输运系数的确定的联系，QCD的输运系数反过来调节和量化偏离平衡的情况。更具体地说，我们试图分离QCD的剪切和体粘滞系数，以及它们与温度的关系。这些知识在研究致密星体及其形成过程中也很重要。另一个方面与穿透探测器有关，因为我们试图了解QGP发出的实光子和虚光子。它们携带着关于核碰撞早期动力学的重要信息，在现实的时间演化场景的帮助下，可以真正充当碰撞动力学跨越的QCD不同阶段的温度计和粘度计。该程序涉及有限温度和密度下的场论以及高级数值模拟的不同方面。

My research program aims to provide quantitative characterization of the quark-gluon plasma (QGP) now observed at two major accelerator facilities: RHIC (the Relativistic Heavy Ion Collider, Brookhaven National Laboratory), and at the LHC (the Large hadron Collider, CERN). Colliding large nuclei at relativistic energies is the only practical way to produce and study hot and dense strongly interacting matter in terrestrial laboratories. The program seeks to elucidate the bulk properties of QCD (Quantum Chromodynamics) in and out of equilibrium. The short term goals involve complementary aspects. One of them concerns soft hadronic probes and their connection to the determination of transport coefficients of QCD, which in turn regulate and quantify departures from equilibrium. More specifically, we seek to isolate the shear and bulk viscosity coefficients of QCD, together with their temperature-dependence. This knowledge is important also in the study of dense stellar objects, and of their formation. Another aspect concerns penetrating probes, as we seek to understand the emission of real and virtual photons from the QGP. These carry important information on the early-time dynamics of the nuclear collision, and can - with the help of a realistic time-evolution scenario - act literally as thermometers and as viscometers for the different phases of QCD spanned by the collision dynamics. The program involves different aspects of field theories at finite temperatures and densities, and of advanced numerical modelling. **