content_image/335366.jpg content_image/335365.jpg content_image/335364.jpg
of the density operator ρ , we find the equations 

The master equation (25) is equivalent to the following equation for the mean value 〈O〉 = Tr ( O ρ ) of an arbitrary operator O : 

<img src='content_image/335366.jpg'>

<img src='content_image/335365.jpg'>

In particular, we find the equations 

<img src='content_image/335364.jpg'>

