  Efforts to identify dark matter by detecting nuclear recoils produced by dark
matter particles reveal low-energy backgrounds of unknown origin in different
types of detectors. In many cases, energy accumulation and delayed burst-like
releases of stored energy could provide an explanation. These dynamics follow
Prigogine's ideas on systems with energy and the general Self-Organized
Criticality scenario. We compare these models with properties of excess
backgrounds in cryogenic solid-state detectors, relaxation processes in glasses
and crystals, our observations of delayed luminescence in NaI(Tl), and make
predictions for more phenomena present in these systems and in superconducting
photon detectors and qubits. Experiments to create accurate phenomenological
models are needed.
