  We present a theoretical analysis of quantum decay in which the survival
probability is replaced by a decay rate that is equal to the absolute value
squared of the wave function in the time representation. The wave function in
the time representation is simply the Fourier transform of the wave function in
the energy representation, and it is also the probability amplitude generated
by the Positive Operator Valued Measure of a time operator. The present
analysis endows time with a dynamical character in quantum decay, and it is
applicable only when the unstable system is monitored continuously while it
decays. When the analysis is applied to the Gamow state, one recovers the
exponential decay law. The analysis allows us to interpret the oscillations in
the decay rate of the GSI anomaly, of neutral mesons, and of fluorescence
quantum beats as the result of the interference of two resonances in the time
representation. In addition, the analysis allows us to show that the time of
flight of a resonance coincides with its lifetime.
