Force on curved & soft walls
In the absence of external torques, averaging active particle equations of motion gives:
For a closed box the total force and current will both be zero independent of wall potential.
Are there any remaining surprises in the absence of wall reorientation?
Curved wall?
N. Nikola, A.P. Solon, Y. Kafri, M. Kardar, J. Tailleur, R. Voiturie, Phys. Rev. Lett. 117, 098001 (2016);
Sinusoidal wall: Density is non-uniform, depending on curvature as well as potential
Ratchet: Asymmetric walls support a current and net force:
Sinusoidal wall: Pressure is curvature dependent, largest at the bottom of the trench!
Activity-induced line/surface tension?
The dependence of pressure on curvature is reminiscent of Laplace's law:
Bendable soft boundary:
Reduction in line tension lead to modulational instability:
A flexible chain (worm) spontaneously curves and moves:
