Quantum Anti-Zeno Effect in Nuclear β Decay

The acceleration of decay induced by frequency measurements, namely the quantum anti-Zeno effect (AZE), was first predicted by Kofman and Kurizki [Nature 405 (2000) 546]. The effect of the frequency measurements on nuclear β decay rate is analyzed based on the time-dependent perturbation theory. We present a detailed calculation of the decay rates of 3 H, 60 Co ( β − type), 22 Na, 106 Ag ( β + type) and 18 F, 57 Co and 111 Sn (EC type) under frequency measurements. It is found that the effects of frequency measurements on the decay rates of β + and β − cases are different from the case of EC, and the smaller the β decay energy is, the more favorable it is to observe the AZE in experiment. Based on our analysis, it is suggested that possible experimental candidates should have a small decay energy and a reasonable half life (such as 3 H) for observing the AZE in β decay.