# Calculate the spin wave dispersion relation for a ferromagnetic heisenberg model

1. Jan 14, 2013

### matt_crouch

1. The problem statement, all variables and given/known data
Calculate the spin wave dispersion relation Ek for the ferromagnetic heisenberg model with jtot = 1/2
Assume a 1d square lattice and interactions of strength J between nearest neighbours and zero elsewhere

2. Relevant equations

H|k> = [E0 +2jtot$\sum J(r)(1-Exp(ik.r)$] |k>

3. The attempt at a solution

Not really sure where to start :/
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution