arXiv subjects

Joseph Harder

Publications and source records attributed to Joseph Harder.

2 recordsLinked to original sources

arXiv2015

Microphase separation in two dimensional suspensions of self-propelled spheres and dumbbells

We use numerical simulations to study the phase behavior of self-propelled spherical and dumbbellar particles interacting via micro-phase separation inducing potentials. Our results indicate that under the appropriate conditions, it is possible to drive the formation of two new active states; a spinning cluster crystal, i.e. an ordered mesoscopic phase having finite size spinning crystallites as lattice sites, and a fluid of living clusters, i.e. a two dimensional fluid where each "particle" is a finite size living cluster. We discuss the dynamics of these phases and suggest ways of extending their stability under a wide range of active forces.

cond-mat.soft↗

arXiv2014

Activity induced collapse and re-expansion of rigid polymers

We study the elastic properties of a rigid filament in a bath of self-propelled particles. We find that while fully flexible filaments swell monotonically upon increasing the strength of the propelling force, rigid filaments soften for moderate activities, collapse into metastable hairpins for intermediate strengths, and eventually re-expand when the strength of the activity of the surrounding fluid is large. This collapse and re-expansion of the filament with the bath activity is reminiscent of the behavior observed in polyelectrolytes in the presence of different concentrations of multivalent salt.

cond-mat.soft↗