Phase  and   Group velocity

Definitionen

Needs["Graphics`MultipleListPlot`"];
f[x_, t_, dk_, 
          dw_] := (E^(-I (x - t)))  Cos[
            dk x  -  dw t];
\(\(p[t_, dk_, dw_] := 
        Block[{}, 
					xx\  = \ 
            Range[0, 100,  .4]; 
					tt\  = \ 
            f[xx, t, dk, dw]; 
					tb\  = \ 
            Transpose[{xx, 
                Abs[tt]\^2}]; 
					tr\ \  = \ 
            Transpose[{xx, 
                Re[tt]}]; 
					\(MultipleListPlot[tb, 
              tr, PlotJoined -> 
                True, 
						PlotStyle -> {{Thickness[0.005], Hue[ .6]}, {Thickness[0.005], Hue[1]}}, 
              SymbolShape -> 
                None];\)
					];\)\)
ω = 1;
k = 1;

Simulation

dω  =  0.02;
dk  =  
        0.1;

 (*Phase velocity :    (Subscript[v, ph])  =  (ω/k)  =  
            1;  *) 
 (*group velocity :    (Subscript[v, g])   =  d(ω/dk)  =   .2;   *) 


Do[p[t, dk, dω], {t, 0, 50, 1}];
SelectionMove[EvaluationNotebook[], After, 
        EvaluationCell];
SelectionMove[EvaluationNotebook[], Next, 
        CellGroup];
FrontEndTokenExecute["OpenCloseGroup"];