标题： 胶体粒子在粘弹性浴中的势垒过渡路径时间 显示英文标题

标题： Transition path time over a barrier of a colloidal particle in a viscoelastic bath

摘要： 我们实验研究了亚微米颗粒成功穿越由两个光学镊子在两种典型的粘弹性流体（即水溶液和胶束溶液）中产生的能量势垒所需的过渡路径时间的统计特性。 我们发现实验分布与从粒子运动的广义朗之万方程导出的理论表达式之间有非常好的一致性。 我们的结果表明，在这种粘弹性流体中测得的平均过渡路径时间与势垒曲率存在非平凡的依赖关系，与相同零剪切粘度的牛顿流体中的结果相比，可以显著减少。 我们验证了平均过渡路径时间的减少可以用有效粘度来描述，该有效粘度在由产生势垒上不稳定运动的反应模式确定的频率下，定量地与线性微流变测量得到的粘度一致。 因此，我们的结果揭示了粒子在热激活逃逸出亚稳态过程中对线性响应的特性，即使是在非马尔可夫浴中发生也是如此。 显示英文摘要

摘要： We experimentally study the statistics of the transition path time taken by a submicron bead to successfully traverse an energy barrier created by two optical tweezers in two prototypical viscoelastic fluids, namely, aqueous polymer and micellar solutions. We find a very good agreement between our experimental distributions and a theoretical expression derived from the generalized Langevin equation for the particle motion. Our results reveal that the mean transition path time measured in such viscoelastic fluids have a non-trivial dependence on the barrier curvature and they can be significantly reduced when compared with those determined in Newtonian fluids of the same zero-shear viscosity. We verify that the decrease of the mean transition path time can be described in terms of an effective viscosity that quantitatively coincides with that measured by linear microrheology at a frequency determined by the reactive mode that gives rise to the unstable motion over the barrier. Therefore, our results uncover the linear response of the particle during its thermally activated escape from a metastable state even when taking place in a non-Markovian bath.