Microcanonical Analyses of Peptide Aggregation Processes

TL;DR

This paper demonstrates that microcanonical analysis reveals convex entropy and negative specific heat in peptide aggregation, offering a new perspective on phase transitions in finite systems through simulations of a hydrophobic-polar model.

Contribution

It introduces microcanonical analysis to study peptide aggregation transitions, highlighting its effectiveness in identifying first-order-like behaviors in finite systems.

Findings

Convex microcanonical entropy in transition region.

Negative microcanonical specific heat observed.

Microcanonical view aids in characterizing phase separation.

Abstract

We propose the use of microcanonical analyses for numerical studies of peptide aggregation transitions. Performing multicanonical Monte Carlo simulations of a simple hydrophobic-polar continuum model for interacting heteropolymers of finite length, we find that the microcanonical entropy behaves convex in the transition region, leading to a negative microcanonical specific heat. As this effect is also seen in first-order-like transitions of other finite systems, our results provide clear evidence for recent hints that the characterisation of phase separation in first-order-like transitions of finite systems profits from this microcanonical view.