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Anders Irbäck. Photo.

Anders Irbäck

Professor

Anders Irbäck. Photo.

Limitations of field-theory simulation for exploring phase separation: The role of repulsion in a lattice protein model

Author

  • Daniel Nilsson
  • Behruz Bozorg
  • Sandipan Mohanty
  • Bo Söderberg
  • Anders Irbäck

Summary, in English

Field-theory simulation by the complex Langevin method offers an alternative to conventional sampling techniques for exploring the forces driving biomolecular liquid–liquid phase separation. Such simulations have recently been used to study several polyampholyte systems. Here, we formulate a field theory corresponding to the hydrophobic/polar (HP) lattice protein model, with finite same-site repulsion and nearest-neighbor attraction between HH bead pairs. By direct comparison with particle-based Monte Carlo simulations, we show that complex Langevin sampling of the field theory reproduces the thermodynamic properties of the HP model only if the same-site repulsion is not too strong. Unfortunately, the repulsion has to be taken weaker than what is needed to prevent condensed droplets from assuming an artificially compact shape. Analysis of a minimal and analytically solvable toy model hints that the sampling problems caused by repulsive interaction may stem from loss of ergodicity.

Department/s

  • Computational Biology and Biological Physics

Publishing year

2022-01-04

Language

English

Publication/Series

The Journal of chemical physics

Volume

156

Issue

1

Document type

Journal article

Publisher

American Institute of Physics (AIP)

Topic

  • Other Physics Topics
  • Biophysics

Status

Published

ISBN/ISSN/Other

  • ISSN: 0021-9606