Santen L, Krauth W
CNRS-Laboratoire de Physique Statistique, Ecole Normale Superieure, Paris, France.
Nature. 2000 Jun 1;405(6786):550-1. doi: 10.1038/35014561.
The glass transition can be viewed simply as the point at which the viscosity of a structurally disordered liquid reaches a universal threshold value. But this is an operational definition that circumvents fundamental issues, such as whether the glass transition is a purely dynamical phenomenon. If so, ergodicity gets broken (the system becomes confined to some part of its phase space), but the thermodynamic properties of the liquid remain unchanged across the transition, provided they are determined as thermodynamic equilibrium averages over the whole phase space. The opposite view claims that an underlying thermodynamic phase transition is responsible for the pronounced slow-down in the dynamics at the liquid-glass boundary. Such a phase transition would trigger the dynamic standstill, and then be masked by it. Here we perform Monte Carlo simulations of a two-dimensional system of polydisperse hard disks far within its glassy phase. The approach allows for non-local moves in a way that preserves micro-reversibility. We find no evidence for a thermodynamic phase transition up to very high densities; the glass is thus indistinguishable from the liquid on purely thermodynamic grounds.
玻璃化转变可以简单地看作是结构无序液体的粘度达到一个通用阈值的点。但这是一个操作性定义，回避了一些基本问题，比如玻璃化转变是否是一种纯粹的动力学现象。如果是这样，遍历性就会被打破（系统被限制在其相空间的某些部分），但只要液体的热力学性质是通过对整个相空间的热力学平衡平均值来确定的，那么在转变过程中这些性质就不会改变。相反的观点认为，潜在的热力学相变是导致液体 - 玻璃边界处动力学显著减慢的原因。这样的相变会引发动力学停滞，然后被其掩盖。在这里，我们对处于玻璃态相深处的二维多分散硬磁盘系统进行了蒙特卡罗模拟。该方法允许以保持微观可逆性的方式进行非局部移动。我们发现，直到非常高的密度都没有热力学相变的证据；因此，仅从热力学角度来看，玻璃与液体是无法区分的。
