Abou Bérengère, Gallet François
Laboratoire de Biorhéologie et Hydrodynamique Physico-chimique UMR CNRS 7057 and Fédération de Recherche Matières et Systèmes Complexes FR 2438, 2 Place Jussieu, Case 7056, 75251 Paris Cedex 05, France.
Phys Rev Lett. 2004 Oct 15;93(16):160603. doi: 10.1103/PhysRevLett.93.160603.
We present a direct experimental measurement of an effective temperature in a colloidal glass of laponite, using a micrometric bead as a thermometer. The nonequilibrium fluctuation-dissipation relation, in the particular form of a modified Einstein relation, is investigated with diffusion and mobility measurements of the bead embedded in the glass. We observe an unusual nonmonotonic behavior of the effective temperature: starting from the bath temperature, it is found to increase up to a maximum value, and then decrease back, as the system ages. We show that the observed deviation from the Einstein relation is related to the relaxation times previously measured in dynamic light scattering experiments.
我们展示了一种使用微米级珠子作为温度计对锂皂石胶体玻璃中的有效温度进行直接实验测量的方法。通过对嵌入玻璃中的珠子进行扩散和迁移率测量，研究了非平衡涨落耗散关系，其具体形式为修正的爱因斯坦关系。我们观察到有效温度呈现出一种不寻常的非单调行为：从浴温开始，随着系统老化，有效温度先升高至最大值，然后又降低。我们表明，观察到的与爱因斯坦关系的偏差与先前在动态光散射实验中测量的弛豫时间有关。
