Sunday, February 22, 2015

Time Evolution Preliminary results

I've got a workable form of the time evolution simulation. Below are the 40 frame gif results of two different trials. The first was generated using 2,000 time steps of hbar/I units each, and the second was generated using 200,000 time steps of hbar/(100*I) units each. In both cases I was set to 1 eV, the initial wave was localized to well 500, and the initial matrix and vector was of size 1000. I'm thinking I must have made a mistake in how I treated the the second one though, as it looks drastically different from the first. My thought was that if I reduce the time interval by a factor of 100, then I should increase the number of intervals to be even. Is that idea incorrect?




6 comments:

  1. The well size actually isn't even taken into account. This is just the absolute squared amplitude of the wave vector.

    ReplyDelete
  2. I have an idea as to how to calculate an expectation value related to the spatial extent of the wave-function. sum over:
    \(|c_n|^2 (n-500)^2\) and then take the square root of that. Would that work? Have you tried that?

    ReplyDelete
    Replies
    1. Not yet. I was considering just taking the standard deviation of the absolute squared amplitudes. Is there a reason that might not work?

      Delete
    2. I am not sure. I guess what you really want is the square root of the expectation value of n^2 minus the (expectation value of n) squared.

      Delete
  3. Nice simulation Christopher! Just want to make sure I'm on the right page: This simulation illustrates what George talked about in his post; that the particle becomes less localized as time proceed?

    ReplyDelete
    Replies
    1. That would be correct. Over the course of some number of time intervals a particle that starts completely localized to one well disperses out to the wells surrounding it.

      Delete