Mathisen Thomas, Larson Jonas
Department of Physics, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden.
Entropy (Basel). 2018 Jan 3;20(1):20. doi: 10.3390/e20010020.
With the corresponding Liouvillian as a starting point, we demonstrate two seemingly new phenomena of the STIRAP problem when subjected to irreversible losses. It is argued that both of these can be understood from an underlying Zeno effect, and in particular both can be viewed as if the environment assists the STIRAP population transfer. The first of these is found for relative strong dephasing, and, in the language of the Liouvillian, it is explained from the explicit form of the matrix generating the time-evolution; the coherence terms of the state decay off, which prohibits further population transfer. For pure dissipation, another Zeno effect is found, where the presence of a non-zero Liouvillian gap protects the system's (adiabatic) state from non-adiabatic excitations. In contrast to full Zeno freezing of the evolution, which is often found in many problems without explicit time-dependence, here, the freezing takes place in the adiabatic basis such that the system still evolves but adiabatically.
以相应的刘维尔算符为起点，我们展示了受不可逆损耗影响时受激拉曼绝热通道（STIRAP）问题的两个看似新的现象。有人认为，这两种现象都可以从潜在的芝诺效应来理解，特别是这两种现象都可以被视为环境辅助了STIRAP布居转移。其中第一个现象是在相对较强的退相情况下发现的，用刘维尔算符的语言来说，它是从生成时间演化的矩阵的显式形式来解释的；态的相干项衰减，这阻止了进一步的布居转移。对于纯耗散情况，发现了另一种芝诺效应，其中非零的刘维尔间隙的存在保护了系统的（绝热）态免受非绝热激发。与在许多没有显式时间依赖性的问题中经常发现的完全芝诺演化冻结不同，这里的冻结发生在绝热基矢中，使得系统仍然在演化，但却是绝热地演化。
