Density matrix heat bath dynamics

In the above, the principles of how to study the dynamics of an isolated system by using the density matrix method have been shown. However, most experiments are performed for the system (or subsystem) embedded in a heat bath in this case the isolated system consists of the system plus heat bath. In the following the MEs shall be derived for the system embedded in heat bath. In this case, instead of pm, pnsnbfls b will be employed. Here s and b describe the system and heat bath, respectively. For the case in which the bath is much larger than the system, it may be assumed that the bath maintains thermal equilibrium and... 

In this section, the density matrix method shall be applied to study the ultrafast dynamics of the system embedded in a heat bath. Due to the use of the ultrashort pulse in the pumping lasers the dynamic behaviors of both population and coherence have to be considered [1,19-21],... 

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