  The ability to carry electric current with zero dissipation is the hallmark
of superconductivity. It is this very property which is used in applications
from MRI machines to LHC magnets. But, is it indeed the case that
superconducting order is incompatible with dissipation? One notable exception,
known as vortex flow, takes place in high magnetic fields. Here we report
observation of dissipative superconductivity in far more basic configurations:
superconducting nanowires with superconducting leads. We provide evidence that
in such systems, normal current may flow in the presence of superconducting
order throughout the wire. The phenomenon is attributed to the formation of a
non-equilibrium state, where superconductivity coexists with dissipation,
mediated by the so-called Andreev quasiparticles. Besides promise for
applications such as single-photon detectors, the effect is a vivid example of
a controllable non-equilibrium state of a quantum liquid. Thus our findings
provide an accessible generic platform to investigate conceptual problems of
out-of-equilibrium quantum systems.
