Matter under extreme conditions: The theory of relativistic nuclear collisions

我的研究计划旨在提供夸克-胶子等离子体（QGP）的定量表征，目前在两个主要的加速器设施：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，欧洲核子研究中心）观察到。在地球实验室中，以相对论能量碰撞大原子核是产生和研究热而致密的强相互作用物质的唯一可行方法。该计划旨在阐明QCD（量子色动力学）的体积性质在平衡和不平衡。短期目标包括互补的方面。其中之一涉及软强子探针及其与QCD输运系数的确定的联系，QCD输运系数反过来调节和量化偏离平衡。更具体地说，我们试图分离出QCD的剪切和体积粘度系数，以及它们的温度依赖性。这些知识对于研究致密恒星及其形成也很重要。另一个方面涉及穿透探测器，因为我们试图了解从QGP发射的实光子和虚光子。它们携带着关于核碰撞早期动力学的重要信息，并且可以-在现实时间演化场景的帮助下-作为温度计和粘度计，用于碰撞动力学跨越的QCD的不同阶段。该计划涉及有限温度和密度下场论的不同方面，以及先进的数值模拟。**

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. **