Negative differential mobility of weakly driven particles in models of glass formers

Journal Article · Tue Apr 01 04:00:00 EDT 2008 · PHYSICAL REVIEW E

DOI:https://doi.org/10.1103/PhysRevE.78.011506· OSTI ID:950221

Jack, Robert L; Kelsey, David; Garrahan, Juan P; Chandler, David

We study the response of probe particles to weak constant driving in kinetically constrained models of glassy systems, and show that the probe's response can be non-monotonic and give rise to negative differential mobility: increasing the applied force can reduce the probe's drift velocity in the force direction. Other significant non-linear effects are also demonstrated, such as the enhancement with increasing force of the probe's fluctuations away from the average path, a phenomenon known in other contexts as giant diffusivity. We show that these results can be explained analytically by a continuous-time random walk approximation where there is decoupling between persistence and exchange times for local displacements of the probe. This decoupling is due to dynamic heterogeneity in the glassy system, which also leads to bimodal distributions of probe particle displacements. We discuss the relevance of our results to experiments.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Chemical Sciences Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 950221
• Report Number(s): LBNL-1643E
• Journal Information: PHYSICAL REVIEW E, Journal Name: PHYSICAL REVIEW E Vol. 78
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
APPROXIMATIONS
DECOUPLING
FLUCTUATIONS
GLASS
PROBES
VELOCITY