论文标题
眼镜中的记忆效果：通过简单模型的kovacs效应揭示的对均衡系统的热力学的见解
Memory effects in glasses: insights into the thermodynamics of out of equilibrium systems revealed by a simple model of the Kovacs effect
论文作者
论文摘要
本文是在物理审查中接受出版的文章的扩展版本。除了其基本兴趣之外，我们在本文中研究的模型足够简单，足以用作均衡系统热力学的课程或教程的基础。它允许简单的数值计算和分析分析，以易于可行的示例突出显示重要概念。此版本包括对快速冷却和加热的研究，表现出负热量负能力的案例，以及有关熵的进一步讨论，这些熵未在物理审查E版本中提出。 眼镜是有趣的材料，因为它们使我们能够探索过平衡系统的困惑性能。其中之一是Kovacs效应，其中将玻璃带到一个平衡状态下，其中其所有热力学变量与平衡状态的玻璃变量相同，但仍会发展出来，在热力学变量返回起点。我们表明，一个简单的三州系统足以使用数值整合和精确的分析计算来研究这种现象。它还为虚拟温度的概念带来了一些启示，通常用于将标准热力学扩展到玻璃的不平衡性能。我们确认，独特的虚拟温度的概念无效，可以将其扩展以与系统中的各种放松过程建立联系。该模型还进一步了解了平衡系统的热力学。此外，我们表明，三态模型能够描述在玻璃杯中观察到的各种效果，例如Kovacs讨论的不对称松弛或在$ B_2O_3 $上测量的反向交叉。
This paper is an extended version of an article accepted for publication in Physical Review E. Besides its fundamental interest, the model that we investigate in this article is simple enough to be used as a basis for courses or tutorials on the thermodynamics of out of equilibrium systems. It allows simple numerical calculations and analytical analysis which highlight important concepts with an easily workable example. This version includes studies of fast cooling and heating, exhibiting cases with negative heat capacity, and further discussions on the entropy which are not presented in the Physical Review E version. Glasses are interesting materials because they allow us to explore the puzzling properties of out-of-equilibrium systems. One of them is the Kovacs effect in which a glass, brought to an out-of-equilibrium state in which all its thermodynamic variables are identical to those of an equilibrium state, nevertheless evolves, showing a hump in some global variable before the thermodynamic variables come back to their starting point. We show that a simple three-state system is sufficient to study this phenomenon using numerical integrations and exact analytical calculations. It also brings some light on the concept of fictive temperature, often used to extend standard thermodynamics to the out-of-equilibrium properties of glasses. We confirm that the concept of a unique fictive temperature is not valid, an show it can be extended to make a connection with the various relaxation processes in the system. The model also brings further insights on the thermodynamics of out-of-equilibrium systems. Moreover we show that the three-state model is able to describe various effects observed in glasses such as the asymmetric relaxation to equilibrium discussed by Kovacs, or the reverse crossover measured on $B_2O_3$.
