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Direct Evaluation of Rare Events in Active Matter from Variational Path Sampling
Avishek Das1, Benjamin Kuznets-Speck2, David T Limmer1,3,4,5
1Department of Chemistry, University of California, Berkeley, California 94720, USA.
Physical Review Letters
|January 28, 2022
Summary
We developed a new simulation method to study rare events in active matter. This method reveals that increased activity in the fluid can speed up conformational changes in passive solutes.
Area of Science:
- Physics
- Statistical Mechanics
- Soft Matter
Background:
- Active matter systems are driven far from equilibrium by local energy injection.
- Studying rare events, like state transformations, is challenging due to nonequilibrium dynamics.
Purpose of the Study:
- To develop a simulation method for evaluating rare event rates and mechanisms in nonequilibrium systems.
- To investigate the effect of active bath activity on the conformational changes of a passive solute.
Main Methods:
- A variational optimization of a control force was employed to make rare events typical.
- The method provides an exact rate estimate using a ratio of path partition functions.
- Applied to a passive solute undergoing conformational changes in an active fluid.
Main Results:
- The simulation method successfully evaluated the rate and mechanism of conformational switching.
- Increasing activity in the active fluid was found to enhance the switching rate of the passive solute.
- Results align with theoretical bounds from stochastic thermodynamics.
Conclusions:
- The developed simulation method is effective for studying rare events in generic active matter systems.
- Active bath properties significantly influence the dynamics of embedded passive components.
- This work provides insights into the interplay between activity and conformational dynamics in nonequilibrium systems.
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