Monte Carlo simulation of single-chain square-well homopolymers

We present Monte Carlo simulations of the crystallisation transition of single-chain square-well homopolymers. We combine parallel tempering with a non-standard choice of tempering levels, a bespoke biasing strategy and a method to map results between different temperatures. We verify that our simulations mix well despite the strong ‘bottleneck’ when simulating chains of 128 beads. Our simulation approach resolves issues with reproducibility of MC simulations reported in prior work, particularly for the transition region between the expanded coil and crystalline region. We obtain highly reproducible results for both the free energy landscape and the inverse temperature, with low statistical noise. We outline a method to extract the free energy barrier, at any temperature, for any choice of order parameter, illustrating this technique by computing the free energy landscape as a function of the Steinhardt-Nelson order parameter for a range of temperatures