Positive and negative drag, dynamic phases, and commensurability in coupled one-dimensional channels of particles with Yukawa interactions

Abstract

We introduce a simple model consisting of two or three coupled one-dimensional channels of particles with Yukawa interactions. For the two channel system, when an external drive is applied only to the top or primary channel, we find a transition from locked flow where particles in both channels move together to decoupled flow where the particles in the secondary or undriven channel move at a slower velocity than the particles in the primary or driven channel. Pronounced commensurability effects in the decoupling transition occur when the ratio of the number of particles in the top and bottom channels is varied, and the coupling of the two channels is enhanced when this ratio is an integer or a rational fraction. Near the commensurate fillings, we find additional features in the velocity-force curves caused by the slipping of individual vacancies or incommensurations in the secondary channels. For three coupled channels, when only the top channel is driven we find a remarkably rich variety of distinct dynamic phases, including multiple decoupling and recoupling transitions. These transitions produce pronounced signatures in the velocity response of each channel. We also find regimes where a negative drag effect can be induced in one of the non-driven channels. The particles in this channel move in the opposite direction from the particles in the driven channel due to the mixing of the two different periodic frequencies produced by the discrete motion of the particles in the two other channels. In the two channel system, we also demonstrate a ratchet effect for the particles in the secondary channel when an asymmetric drive is applied to the primary channel. This ratchet effect is similar to that observed in superconducting vortex systems when there is a coupling between two different species of vortices.

Open circuit voltage generated by dragging superconducting vortices with a dynamic pinning potential

“…A similar coupling has been explored in other bi-layer systems, such as the coupling between vortex lattice and an electron gas in superconductor-semiconductor hybrids [9], the Coulomb interaction in two coupled electronic layers (electron-drag effect) [10,11], and the interplay between the vortex lattices and corotating optical lattices [12]. Recently, a somewhat related physics concerning coupled onedimensional channels of particles with Yukawa interactions has been theoretically addressed in [13]. In this case, a transition from locked flow, where particles in both the driving and the dragged channels move together, to decoupled flow, where the particles in the undriven channel move at a lower velocity than the particles in the driven channel, has been reported.…”

Colloidal lattice shearing and rupturing with a driven line of particles

“…In this superconducting system, the interaction between vortices in neighboring layers is attractive, while in the colloidal system, the interactions between colloids in the driven and undriven regions are repulsive. The response of repulsively interacting particles in coupled one-dimensional wires has been studied for classical electrons 40 and particles with Yukawa interactions 41,42 . In these systems, a commensurate state can form when the number of particles in each layer is the same, producing a well defined coupling-decoupling transition when one layer is driven.…”

Dynamically induced locking and unlocking transitions in driven layered systems with quenched disorder

“…14(b); however, we expect that for other parameter values, more commensuration effects would be observable and that additional dynamical locking regimes would also appear at other fillings. Commensuration effects are also observed in two layer and three layer systems without pinning when only one layer is driven [39]. In these systems the commensuration effects occur at fillings where the channels are more strongly coupled, so that the drive at which relative slip begins to occur between the channels is much higher than for incommensurate fillings.…”

“…We also study commensuration effects by varying the particle density in one channel relative to the density in other channels. We drive all of the layers of particles; previous studies of this type of model considered transformer geometries with the drive applied to only one layer [38,39]. Despite the apparent simplicity of our model, we find that even the two layer system has a wide variety of dynamical phases and exhibits all the salient features found for elastic and plastic depinning phenomena, including a peak effect at the transition between the two types of depinning.…”