Quantum Zeno effect, nuclear conversion and photoionization in solids

The quantum Zeno effect in continuous passive observation of radioactive decay is described starting from the ''first principles''. It is argued, that in this case the quantum Zeno effect reduces to the influence of inelastic scattering of decay products in surrounded media to decay constant. A new class of quantum Zeno effects is introduced, which are named as open-quote open-quote threshold quantum Zeno effects close-quote close-quote (TQZE). It is shown, that TQZE could explain recently discovered deep suppression of the conversion decay of 1/2+-isomer of uranium-235 in the lattice of silver. TQZE predicts also some new phenomena, which may be observed in the near-threshold behavior of atomic photoionization cross-sections. Possible experimental manifestations of this new phenomena are discussed. Copyright copyright 1996 Academic Press, Inc