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，现在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），并在LHC（大型强子对撞机，欧洲核子研究中心）。在相对论能量下碰撞大原子核是在地面实验室中产生和研究热而致密的强相互作用物质的唯一可行方法。该程序旨在阐明QCD（量子色动力学）在平衡态和非平衡态的整体性质。短期目标涉及补充方面。其中之一是关于软强子探测器及其与QCD输运系数测定的联系，后者反过来又调节和量化偏离平衡的情况。更具体地说，我们试图隔离QCD的剪切和体粘滞系数，连同它们的温度依赖性。这一知识在研究致密的恒星物体及其形成过程中也很重要。另一个方面涉及穿透探针，因为我们试图了解QGP的真实的和虚拟光子的发射。它们携带着关于核碰撞早期动力学的重要信息，并且在现实的时间演化情景的帮助下，可以充当碰撞动力学所跨越的QCD不同阶段的温度计和粘度计。该计划涉及有限温度和密度下的场论的不同方面，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. **