论文标题
Landau-Zener在两个级别之间的过渡与连续体耦合
Landau-Zener transition between two levels coupled to continuum
论文作者
论文摘要
对于在两级系统中的Landau-Zener跃迁，最初在第一级别{\ em I}的粒子的概率可以在两个级别之间的隧道基质元素的正方形中生存下来并保持第一级。当第二级{\ em F}由于例如耦合到连续[V. M. Akulin和W. P. Schleicht，物理。修订版A {\ bf 46}，4110（1992）]。如果水平{\ em i}也将耦合到连续体，尽管比{\ em f}的弱弱弱，粒子是一个粒子，最终将逃脱。但是，在较短的时间内，由于与连续体的耦合，越过{\ em f}后，在{\ em f}穿越{\ em f}后找到粒子的可能性是{\ em emhangated}。如本文所示，这是二阶过程的结果，该过程是级别之间的{\ em附加耦合}。这种附加耦合的基本机制是从{\ em i}到连续体的虚拟隧道，然后将隧穿回到{\ em f}中。
For a Landau-Zener transition in a two-level system, the probability for a particle, initially in the first level, {\em i}, to survive the transition and to remain in the first level, depends exponentially on the square of the tunnel matrix element between the two levels. This result remains valid when the second level, {\em f}, is broadened due to e.g. coupling to continuum [V. M. Akulin and W. P. Schleicht, Phys. Rev. A {\bf 46}, 4110 (1992)]. If the level, {\em i}, is also coupled to continuum, albeit much weaker than the level {\em f}, a particle, upon surviving the transition, will eventually escape. However, for shorter times, the probability to find the particle in the level {\em i} after crossing {\em f} is {\em enhanced} due to the coupling to continuum. This, as shown in the present paper, is the result of a second-order process, which is an {\em additional coupling between the levels}. The underlying mechanism of this additional coupling is virtual tunneling from {\em i} into continuum followed by tunneling back into {\em f}.
