] 2 8 M ar 2 00 7 On the physical origin of the quantum Zeno effect

The quantum Zeno effect and electromagnetically induced transparency (EIT) phenomenon are the results of a specific population transfer in a three level systems. They are based on the inequality of forward and reversed processes. However, a more simple two level systems better suit now for experimental study of this fundamental property in optics. The concept of quantum Zeno effect (paradox) was introduced by Misra and Sudarshan in 1977 [1]. It is usually defined as " the inhibition of transitions between quantum states by frequent measurements " [2]. There is also somewhat miraculous, supernatural definition: " It describes the situation that an unstable particle, if observed continuously, will never decay " [3]. Probably, such mystical component makes this phenomenon so famous now. Later it was introduced the opposite phenomenon of the anti-Zeno effect [4, 5]. As the example of such phenomena the EIT effect can, probably, be discussed [6]. However, in this case the authors turn out to be not so superstitious and confine themselves to description of the phenomenon by the concept of the so-called dark state polariton [7]. This is the standard situation in the nonlinear optics, when the theorists substitute a task of physical explanation of a phenomenon for its mathematical description. The Bloch, Gross-Pitaevskii, Schrodinger and other equations are usually used for this purpose. The goal of this note is to point out that the physical base of the quantum Zeno effect and EIT phenomenon is the population transfer in a three level systems. The main problem here is that we do not understand and we can not explain the physical mechanism of population transfer in such systems. And what is more, we can not explain the physical mechanism of population transfer in the simplest two level systems. We can only describe this process using the Bloch equations in the framework of the rotating wave approximation model [8]. But the Bloch equations do not have clear physical sense. So, a mathematical description can not replace a physical explanation. In the absence of knowledge the superstition appears. For explanation of the physical mechanism of population transfer (for example in the case of the sweeping of resonance conditions) we should recognize the concept of inequality of forward and reversed processes in optics [9]. Unfortunately , the scientific community does not ready now to accept this idea. However , the ignoring of the inequality concept is rather foolish position, because