Adiabatic Approximation

The reaction of a system to a time-dependent perturbation depends in detail on the time scale of the perturbation. 

Consider, for example, an ideal pendulum, with no friction or air resistance, oscillating back and forth in a vertical plane. If we move the support ‘quickly’, the motion of the bob will be wildly chaotic. On the other hand, if we move the support ‘gradually’, the bob will continue to oscillate smoothly, in the same plane (or one parallel to it) and with the same amplitude. 

This gradual change in the external conditions characterizes an adiabatic process. The quick movement which had a chaotic effect is often referred to as sudden. 


To download the file click on the link below:

http://www.rpi.edu/dept/phys/Courses/phys410/lct10.pdf