Energy relaxations

[guoro...@gmail.com]

Dear all,

Recently I am running the tutorials in Pyxaid. I am wondering why the energy relaxation has a different tendency as literature. 

In the published papers, we can see that the energy relaxations has a drop tendency as the time increasing, but why here it is oscillating ( the green line).

Thanks! 

R Guo

[Alexey Akimov]

Dear R. Guo,

The energy relaxation is system-specific. If there are nearby energy states, one would expect some population fluctuations. The larger the separation, the smaller the amplitude of such fluctuations (preferable transitions down energy). The oscillations are also characteristic to coherent evolution (e.g. larger dephasing time) - in the limit of 2-level system one gets the Rabi oscillations. In the TSH one can include both decoherence (to dampen the oscillations) and energy bias (e.g. transitions up in energy are less likely). 

Best,

Alexey