Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Probability of staying in same state after time-dep perturbation?

  1. Apr 2, 2008 #1
    Let's say that you've got a time-dependent perturbation to your potential (say, the particle-in-a-box to make things simple). Say you start in energy eigenstate #3. What's the probability that the particle will stay in eigenstate 3 after time T?

    This is not a homework problem. I'm not understanding the equation for the probability which seems to give a number larger than 1.
  2. jcsd
  3. Apr 3, 2008 #2
    I take you're staring at Fermi's Golden Rule. That rule is a first order time dependent perturbation result, and so will not give the correct answer at large times or for large perturbations.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook