Coordinator project

对玻璃化转变的基本理解构成了统计物理和材料科学的重大挑战之一。它解决了无序系统中缓慢的合作过程，其中粒子重排和传输的机制在很大程度上是未知的。外场有很强的影响，因为外部驱动的时间尺度和内在的结构重新安排可以很容易地匹配。外场对熔体性质和玻璃化转变有重要影响，研究过冷液体对受控外场的非线性响应将有助于我们理解复杂的物理基础。外部操作和加工也具有巨大的技术影响，例如，对最终的固体性能。过冷液体在降低温度时会自行失去平衡，即使外场的缓慢熄灭也很容易使过冷液体失去平衡。因此，测试玻璃成型系统中的非线性响应处于研究非平衡和非晶态材料的前沿。我们的研究单位(RU)研究了强外场和慢合作动力学在玻璃形成系统中的联合效应，以了解远离平衡条件下的复杂结构、弛豫和输运现象。RU使用强大的机械和电场来洞察玻璃化转变过程中的粒子运动。所研究的材料范围从过冷合金、胶体分散体、分子玻璃形成器到离子液体、颗粒介质和无序介质。实验技术包括力学、介电和电导光谱，而理论方法包括非平衡计算机模拟的变体、模式耦合和动力学理论、势能图以及连续时间随机游走分析。虽然在研究组的第一个资助期为联合调查制定了共同框架和方法，但在第二个资助期，异质动力、由此产生的异质运输的长度尺度以及在强载荷或偏向下的瞬时反应将是持续合作的统一主题。

The fundamental understanding of the glass transition constitutes one of the grand challenges in Statistical Physics and Materials Science. It addresses slow cooperative processes in disordered systems where the mechanisms of particle rearrangements and transport are largely unknown. External fields have strong effects, as the time scales of external drive and intrinsic structural rearrangements can easily be made to match. External fields have significant effects on melt properties and the glass transition, and the investigation of the nonlinear response of supercooled liquids to controlled external fields will considerably contribute to our understanding of the complex underlying physics. External manipulations and processing also have an enormous technological impact, e.g., for the final solid properties. Supercooled liquids fall out of equilibrium by themselves upon lowering the temperature, and are also easily driven out of equilibrium by even slow quenches of external fields. Testing the nonlinear response in glassforming systems thus lies at the frontier of studying non-equilibrium and amorphous materials. Our research unit (RU) investigates the combined effects of strong external fields and slow cooperative dynamics in glass-forming systems in order to understand the complex structural, relaxational, and transport phenomena under conditions far from equilibrium. The RU uses strong mechanical and electric fields to obtain insights into the particle motion at the glass transition. Investigated materials range from supercooled alloys, colloidal dispersions, molecular glass formers to ionic fluids, granular media, and disordered media. Experimental techniques include mechanical, dielectric, and conductivity spectroscopy, while theoretical methods include variants of non-equilibrium computer simulations, mode coupling and kinetic theory, potential energy landscape, as well as continuous time random walk analysis. While in the first funding period of the RU common frameworks and approaches were developed for the joint investigations, in the second funding period the heterogeneous dynamics, the resulting length scales of heterogeneous transport, and the transient response under strong applied load or bias will be unifying themes of the continuing collaborations.