Polymer escape from a metastable Kramers potential: path integral hyperdynamics study.

Area of Science:

• Computational physics and chemistry
• Polymer physics
• Statistical mechanics

Background:

• Studying polymer chain dynamics in metastable potentials is crucial for understanding molecular processes.
• Thermal noise can induce rare barrier crossing events, which are computationally challenging to simulate.
• Existing simulation methods struggle with the slow kinetics of these rare events.

Purpose of the Study:

• To extend the path integral hyperdynamics method for simulating polymer dynamics under a Kramers metastable potential.
• To investigate the influence of chain flexibility, stiffness, and self-avoidance on barrier crossing rates.
• To explore potential applications in efficient biopolymer separation techniques.

Main Methods:

• Extension of the path integral hyperdynamics method to polymer systems.
• Simulation of flexible, semiflexible, and self-avoiding polymer chains.
• Analysis of polymer radii of gyration relative to potential barrier dimensions.

Main Results:

• Flexible polymers show a decreasing crossing rate with increasing contour length, significantly exceeding the Kramers rate.
• Semiflexible polymers exhibit a decreasing rate with length, plateauing for longer chains, with optimal crossing at intermediate stiffness.
• Self-avoiding chains display a nonmonotonic rate dependence on length, decreasing initially then increasing.

Conclusions:

• The extended path integral hyperdynamics method effectively accelerates simulations of rare barrier crossing events for polymers.
• Polymer chain architecture (length, stiffness, self-avoidance) critically dictates barrier crossing dynamics.
• These findings provide a theoretical basis for developing novel biopolymer separation strategies.