  We study an active matter system comprised of magnetic microswimmers confined
in a microfluidic channel and show that it exhibits a new type of
self-organized behavior. Combining analytical techniques and Brownian dynamics
simulations, we demonstrate how the interplay of non-equilibrium activity,
external driving, and magnetic interactions leads to the condensation of
swimmers at the center of the channel via a non-equilibrium phase transition
that is formally akin to Bose-Einstein condensation. We find that the effective
dynamics of the microswimmers can be mapped onto a diffusivity-edge problem,
and use the mapping to build a generalized thermodynamic framework, which is
verified by a parameter-free comparison with our simulations. Our work reveals
how driven active matter has the potential to generate exotic classical
non-equilibrium phases of matter with traits that are analogous to those
observed in quantum systems.
