Reply to Chakrabarty et al.: Particles move even in ideal glasses
Reply to Chakrabarty et al.: Particles move even in ideal glasses
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回复 Chakrabarty 等人：即使在理想的玻璃中，粒子也会移动
DOI：
10.1073/pnas.1513323112
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Kunimasa Miyazaki
中科院分区：
文献类型：
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作者：
Misaki Ozawa;Walter Kob;Atsushi Ikeda;Kunimasa Miyazaki
在他们的信中，Chakrabarty et al. (1)指出他们的弛豫动力学数据与我们的文献（2）中给出的热力学数据不一致。他们认为，从他们的结果和随机一级跃迁理论（3）的预测中，人们必须得出这样的结论：我们的构型熵SC“在数量上不准确”。在下文中，我们将证明这个结论不一定有效。Chakrabarty等人的主要论点。（1）（参考文献1的图1，左）的结论是，即使在玻璃相（定义为sc= 0）中，中间散射函数Fs（k，t）的自身部分也衰减为零，因此该相不可能是非遍历的。虽然这一观察结果很有趣，但它并不意味着上述结论。这可以通过考虑简单晶体的情况来看出。在晶体中，标记粒子的扩散常数是非零的（因为在非零温度下的晶体将具有有限浓度的缺陷），因此Fs（k，t）在很长时间内衰减到零。然而，从这一点我们不能得出结论说晶体是遍历系统，因为它的结构显然与时间无关（即集体关联函数不会衰减到零）。
In their letter, Chakrabarty et al.(1) point out that their data on the relaxation dynamics are inconsistent with the thermodynamic data presented in our paper (2). They argue that from their results and the predictions of the random first-order transition theory (3) one must conclude that our configurational entropy sc is “quantitatively not accurate.” In the following we will show that this conclusion is not necessarily valid. The main argument of Chakrabarty et al.(1)(figure 1, Left, of ref. 1) is that the self part of the intermediate scattering function Fs (k, t) decays to zero even in the glass phase (defined by sc= 0) and that hence this phase cannot be nonergodic. Although this observation is interesting, it does not imply the mentioned conclusion. This can be seen by considering the case of a simple crystal. In a crystal the diffusion constant of a tagged particle is nonzero (because a crystal at nonzero temperatures will have a finite concentration of defects) and hence Fs (k, t) decays to zero at long times. From this one can, however, not conclude that a crystal is an ergodic system because its structure is obviously independent of time (ie, the collective correlation functions do not decay to zero).