  We consider coupled quantum two-state systems (qubits) exposed to a global
relaxation process. The global relaxation refers to the assumption that qubits
are coupled to the same quantum bath with approximately equal strengths,
appropriate for long-wavelength environmental fluctuations. We show that
interactions do not spoil the picture of Dicke's subradiant and superradiant
states where quantum interference effects lead to striking deviations from the
independent relaxation picture. Remarkably, the system possess a stable
entangled state and a state decaying faster than single qubit excitations. We
propose a scheme how these effects can be experimentally accessed in
superconducting flux qubits and, possibly, used in constructing long-lived
entangled states.
