Why is minus sine in definition of hamiltonian(adsbygoogle = window.adsbygoogle || []).push({});

[tex]H=-\sum_{i,j}J_{i,j}(S_{i}^+S_{j}^-+S_i^zS_j^z)[/tex]

Why not?

[tex]H=\sum_{i,j}J_{i,j}(S_{i}^+S_{j}^-+S_i^zS_j^z)[/tex]

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Heisenberg hamiltonian

**Physics Forums | Science Articles, Homework Help, Discussion**