TY  - JOUR
AU  - Nilsson, Daniel
AU  - Bozorg, Behruz
AU  - Mohanty, Sandipan
AU  - Söderberg, Bo
AU  - Irbäck, Anders
TI  - Limitations of field-theory simulation for exploring phase separation: The role of repulsion in a lattice protein model
JO  - The journal of chemical physics
VL  - 156
IS  - 1
SN  - 0021-9606
CY  - Melville, NY
PB  - American Institute of Physics
M1  - FZJ-2022-00122
SP  - 015101 -
PY  - 2022
AB  - 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 a loss of ergodicity.
LB  - PUB:(DE-HGF)16
C6  - 34998327
UR  - <Go to ISI:>//WOS:000739267900004
DO  - DOI:10.1063/5.0070412
UR  - https://juser.fz-juelich.de/record/904792
ER  -