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Stationary Phase [12 pts]

The following wave packet describes a familiar event involving a classical particle:

eqnarray288

where

displaymath897

displaymath899

Note: tex2html_wrap_inline901 .

   figure328
Figure 4: Position of Wave Packet

a) Using the method of stationary phase, determine tex2html_wrap_inline903 , the location of the first part of the wave packet tex2html_wrap_inline905 at time t. Sketch the path followed by the first packet tex2html_wrap_inline909 on Figure 4. Give the trajectory both for times t;SPMgt;0 and times t;SPMlt;0.
Hint: After deriving your final result, use the definition tex2html_wrap_inline915 to simplify your result.

b) Using the method of stationary phase, determine tex2html_wrap_inline917 , the location of the second part of wave packet tex2html_wrap_inline905 at time t. Sketch the path followed by the second packet tex2html_wrap_inline923 on Figure 4. Give the trajectory both for times t;SPMgt;0 and times t;SPMlt;0.
Hint: After deriving your final result, use the definition tex2html_wrap_inline915 to simplify your result.

c) Keeping in mind that by definition, tex2html_wrap_inline931 for x;SPMgt;0 for all t, so that the wave packet may never be centered around positions x;SPMgt;0, describe in a short sentence the classical behavior of a particle described by the total wave packet tex2html_wrap_inline939 .



Prof. Tomas Alberto Arias
Sat Mar 8 16:29:07 EST 1997