Quantum control with quantum Zeno effects

作为一种新的量子控制方法，我们提出了利用量子Zeno效应和反Zeno效应。在这些效应中，人们可以用非幺正过程（如观察和弛豫）来操纵量子系统的运动。尽管存在非么正性，但概率是守恒的。相干性或退相干的破坏起着至关重要的作用。我们甚至可以使用芝诺效应来创造连贯性。作为测试系统，我们采用了在量子光学实验中使用方便的光抽运系统。我们发现，在这个熟悉的系统中，芝诺效应起着非常重要的作用。结果表明，在强抽运极限下，由于芝诺效应而不是通过光抽运的布居转移，原子的极化相对于水平磁场保持不变。光抽运退相干引起的Zeno效应抑制了塞曼跃迁。实验证明，随着入射光强的增加，光吸收率渐近减小到零。

As a new method of quantum control, we proposed the use of the quantum Zeno effects and the anti Zeno effects. In these effects one can manipulate the motion of quantum systems with non-unitary processes such as observation and relaxation. In spite of the non-unitarity, the probability is conserved. The destruction of the coherence or the decoherence plays a crucial role. We can even create the coherence using the Zeno effect. As a testing system, we used the optical pumping system which has been conveniently utilized in quantum optical experiments. We found that in this familiar system the Zeno effect plays a very important role. It turned out that in the strong pumping limit the atomic polarization is maintained against the horizontal magnetic field owing to the Zeno effect rather than the population transfer via optical pumping. The Zeno effect induced by the optical pumping decoherence inhibits the Zeeman transition. It is verified experimentally that the light absorption decreases asymptotically to zero as the incident light intensity, increased.