  Controlling the flow of matter down to micrometer-scale confinement is of
central importance in materials and environmental sciences, with direct
applications in nano-microfluidics, drug delivery and biothechnology. Currents
of microparticles are usually generated with external field gradients of
different nature [e.g., electric, magnetic, optical, thermal or chemical ones]
which are difficult to control over spatially extended regions and samples.
Here we demonstrate a general strategy to assemble and transport polarizable
microparticles in fluid media through combination of confinement and magnetic
dipolar interactions. We use a homogeneous magnetic modulation to assemble
dispersed particles into rotating dimeric state and frustrated binary lattices,
and generate collective edge currents which arise from a novel,
field-synchronized particle exchange process. These dynamic states are similar
to cyclotron and skipping orbits in electronic and molecular systems, thus
paving the way toward understanding and engineering similar processes at
different length scales across condensed matter.
