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

Homework Help: Help with solution

  1. Oct 5, 2008 #1
    A simple and famous model of certain magnetic materials is the Ising model in
    which each of N atoms is modeled as a simple spin which can point upwards or
    downwards. The magnetization of the material is proportional to the number of up
    spins minus the number of down spins (each spin has a certain magnetization associated
    with it).
    Let's consider N spins in a row (as shown below). Let the "magnetization" be M,
    where M is the number of up spins minus the number of down spins. Each spin is
    constantly changing its direction from up to down and vice versa according to some
    complex dynamics. Assume the dynamics of one spin are independent of other spins.
    (i) Clearly state a postulate on the spin configurations which will help us calculate
    probabilities of different spin configurations.
    (ii) Using (i), calculate the probability of a certain M value P(M) exactly.
    (iii) Show P(M) is a Gaussian in the large N limit and sketch it.
    (iv) Estimate the probability that M is larger than 0.1% of N when N takes the value of
    Avogadro’s constant, 6x1023
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted