Enhanced dumbbell diffusion in a periodic potential by the elevator effect
Phys. Rev. E 114, 054105 – Published 4 November, 2026
DOI: https://doi.org/10.1103/gqjj-478f
Abstract
We present Brownian dynamics simulations of the random walk of a dumbbell—two beads connected by a spring—in a one-dimensional periodic potential and compare our results in limiting cases to theoretical analytical equations. The relevant parameters in this system are the spring constant, the equilibrium distance of the spring (relative to the periodicity of the potential), and the amplitude of the potential. Dumbbells with equilibrium distances that are half-integer multiples of the potential periodicity and with a sufficiently large spring constant exhibit enhanced diffusion. The diffusion constant can exceed that of a single bead in the same potential landscape. In this case, the dumbbell resembles a traction elevator, with the two connected beads acting as the elevator car and counterweight: the “elevator effect.”
