Phase diagram of a semiflexible magnetic polymer in three dimensions
Abstract
We study a semiflexible magnetic polymer in which each monomer carries a two-state spin, giving rise to coupled conformational, stiffness, and magnetic degrees of freedom. The model provides a minimal representation of nucleoprotein complexes in vivo, in which DNA bending rigidity and bridging proteins must be simultaneously accommodated. We employ Monte Carlo simulations on a face-centered-cubic (FCC) lattice, complemented by a variational free-energy upper-bound approach, to characterize the zero-field phase diagram as a function of bending stiffness and temperature. At low stiffness, we identify a first-order transition combining coil-to-globule collapse with a ferromagnetic-to-paramagnetic transition. At lower temperatures, an additional first-order transition separates the disordered globule from an ordered crystal characterized by nematic-like orientational order of the bond tangents. At high stiffness, the globule disappears, resulting in a direct first-order coil-to-crystal transition. These results demonstrate how chain stiffness and magnetic degrees of freedom couple to polymer conformation and reorganize the zero-field phase diagram. Our model connects the two limiting cases of flexible magnetic polymers and semiflexible homopolymers, the latter corresponding to the strong-field limit in which all spins are aligned.
Related
- Melting phase diagram of the two-dimensional electron solid in a perpendicular magnetic field
- Exact phase diagram of the XXZ Heisenberg chain in a staggered magnetic field
- The QCD phase diagram and critical end point at finite magnetic field from holography with neural networks
- The elasticity of semiflexible polymers with reversible spontaneous curvature in two dimensions
- Cooperation of itinerant and localized physics in the magnetic phase diagram of 214 Ruddlesden-Popper iridates
BibTeX
@misc{delimi2026phase,
title = {{Phase diagram of a semiflexible magnetic polymer in three dimensions}},
author = {Linda Delimi and Arpan Dey and Jean-Charles Walter},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.08958},
eprint = {2610.08958},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.08958},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Phase diagram of a semiflexible magnetic polymer in three dimensions
AU - Linda Delimi
AU - Arpan Dey
AU - Jean-Charles Walter
PY - 2026
DA - 2026/10/06
PB - arXiv
DO - 10.48550/arxiv.2610.08958
UR - https://arxiv.org/abs/2610.08958
AB - We study a semiflexible magnetic polymer in which each monomer carries a two-state spin, giving rise to coupled conformational, stiffness, and magnetic degrees of freedom. The model provides a minimal representation of nucleoprotein complexes in vivo, in which DNA bending rigidity and bridging proteins must be simultaneously accommodated. We employ Monte Carlo simulations on a face-centered-cubic (FCC) lattice, complemented by a variational free-energy upper-bound approach, to characterize the zero-field phase diagram as a function of bending stiffness and temperature. At low stiffness, we identify a first-order transition combining coil-to-globule collapse with a ferromagnetic-to-paramagnetic transition. At lower temperatures, an additional first-order transition separates the disordered globule from an ordered crystal characterized by nematic-like orientational order of the bond tangents. At high stiffness, the globule disappears, resulting in a direct first-order coil-to-crystal transition. These results demonstrate how chain stiffness and magnetic degrees of freedom couple to polymer conformation and reorganize the zero-field phase diagram. Our model connects the two limiting cases of flexible magnetic polymers and semiflexible homopolymers, the latter corresponding to the strong-field limit in which all spins are aligned.
ER -