  We studied a system of polar self-propelled particles (SPPs) on a thin
rectangular channel designed into three regions of order-disorder-order. The
division of the three regions is made on the basis of the noise SPPs experience
in the respective regions. The noise in the two wide region is chosen lower
than the critical noise of order-disorder transition and noise in the middle
region or interface is higher than the critical noise. This make the geometry
of the system analogous to the Josephson Junction (JJ) in solid state physics.
Keeping all other parameters fixed, we study the properties of the moving SPPs
in the bulk as well as along the interface for different widths of the
junction. On increasing interface width, system shows a order-to-disorder
transition from coherent moving SPPs in the whole system to the interrupted
current for large interface width. Surprisingly, inside the interface we
observed the current reversal for intermediate widths of the interface. Such
current reversal is due to the strong randomness present inside the interface,
that makes the wall of the interface reflecting. Hence Our study give a new
interesting collective properties of SPPs at the interface which can be useful
to design devices like switch using active agents.
