Drude spectral density

Fig. 2 Population dynamics of the third excited state for TL (left) and TNL (right) truncation in different orders N of the system-bath coupling calculated using a Drude spectral density with r] = 0.544 and ujd = 0.5 a.u. (Reproduced from Ref. [28]. Copyright 2007, American Institute of Physics.)...

By using special forms of the so-called spectral density J(w) it is possible to treat memory effects in QMEs. The spectral density J(w) contains information on the frequencies of the environmental modes and their coupling to the system. Tanimura and coworkers [18,20,26] were the first to do calculations along the lines described here using spectral densities of Drude shape. This spectral densities lead to bath correlation functions with purely exponential... 

The Drude (sometimes called Debye) spectral density... 

The ZE is the high-friction (Smoluchowski) limit of eqn (13.9), in which 7b B, while 0b/1 b = 7d which assumes the Drude frequency cutoff parameter remains finite. It corresponds the bath spectral density in eqn (13.3) (and also in eqn (13.2)) to the form ... 

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