Active Brownian ring polymers

Area of Science:

• Polymer Physics
• Soft Matter Physics
• Statistical Mechanics

Background:

• Semiflexible polymers exhibit complex behavior influenced by both bending and tension.
• Active matter introduces nonthermal fluctuations and directed motion, altering equilibrium properties.
• Ring polymers present unique topological and conformational constraints compared to linear chains.

Purpose of the Study:

• To analytically investigate the conformational and dynamical properties of semiflexible active Brownian ring polymers.
• To understand how activity influences normal-mode fluctuations and relaxation dynamics.
• To characterize the impact of activity on ring swelling and diffusive motion.

Main Methods:

• Analytical investigation using the Gaussian semiflexible polymer model.
• Incorporation of activity via a Gaussian, non-Markovian stochastic process.
• Analysis of the fluctuation spectrum of normal-mode amplitudes and mean square displacement.

Main Results:

• Elevated activity leads to dominance of tension modes over bending modes, enhancing conformational fluctuations.
• The fluctuation spectrum shows a crossover from quadratic to quartic dependence on mode number.
• Increased activity promotes swelling of the mean square ring diameter and enhances diffusive dynamics, altering regimes of motion.

Conclusions:

• Activity significantly alters the conformational and dynamical properties of semiflexible ring polymers.
• Tension modes become dominant at high activity, leading to enhanced fluctuations and ring swelling.
• The diffusive dynamics are strongly influenced by activity, with a gradual disappearance of the subdiffusive regime.