Non-Exponential Decay of Unstable Quantum System: 縲鰀 small Q value s-wave (SQS) decay 縲鰀

We study the decay process of an unstable quantum system, especially the deviation from the exponential decay law. We show that the exponential period no longer exists in the case of the s-wave decay with small Q value, where Q value is the difference between the energy of the initially prepared state and the minimum energy of the continuous eigenstates in the system. We also derive the quantitative condition that this kind of the decay process takes place and discuss what kind of system is suitable to observe the decay.