Coil-globule transition of a homopolymer chain in a square-well potential: Comparison between Monte Carlo canonical replica exchange and Wang-Landau sampling

TL;DR

This study compares Monte Carlo replica exchange and Wang-Landau sampling methods to analyze the coil-globule transition in a homopolymer with square-well interactions, aiming to efficiently reproduce phase diagrams and explore protein folding features.

Contribution

It provides a comparative analysis of two sampling techniques for homopolymer phase behavior and demonstrates their effectiveness in reproducing phase diagrams with reduced computational effort.

Findings

Replica exchange and Wang-Landau methods yield consistent results.

Short-chain simulations can accurately reproduce phase diagrams of longer chains.

The approach facilitates modeling of protein folding phenomena.

Abstract

We study the equilibrium properties of a flexible homopolymer where consecutive monomers are represented by impenetrable hard spheres that are tangent to each other, and non-consecutive monomers interact via a square-well potential. To this aim, we use both replica exchange canonical simulations and micro-canonical Wang-Landau techniques for relatively short chains, and perform a close comparative analysis of the corresponding results. These investigations are then further exploited to reproduce, at a much shorter scale and, hence, computational effort, the phase diagram previously studied with much longer chains. This opens up the possibility of improving the model and introduce specificities typical, among other examples, of protein folding.