Quantum Zeno and anti-Zeno effects in an unstable system with two bound states

Abstract

We analyze the experimental observations reported by Fischer et al. [M.C. Fischer, B. Gutiérrez-Medina, M.G. Raizen, Phys. Rev. Lett. 87 (2001) 040402] by considering a system of coupled unstable bound quantum states | A 〉 and | B 〉 . The state | B 〉 is coupled to a set of continuum states | C Θ ( ω ) 〉 . We investigate the time evolution of | A 〉 when it decays into | C Θ ( ω ) 〉 via | B 〉 , and find that frequent measurements on | A 〉 leads to both the quantum Zeno effect and the anti-Zeno effects depending on the frequency of measurements. We show that it is the presence of | B 〉 which allows for the anti-Zeno effect.