  It is demonstrated that the strong coupling of an electron gas to photons in
systems with broken time-reversal symmetry results in bound electron-photon
states which cannot be backscattered elastically. As a consequence, the
electron gas can flow without dissipation. This quantum macroscopic phenomenon
leads to the unconventional superconductivity which is analyzed theoretically
for a two-dimensional electron system in a semiconductor quantum well exposed
to an in-plane magnetic field.
