snag

Snag is a repository for simulating the Hubbard model.

The Hubbard model is defined as

$$ \hat{H} = -\sum_{ij}\sum_\sigma t_{ij} c_{i\sigma}^\dagger c_{j\sigma} + U \sum_{i}n_{i\uparrow} n_{i\downarrow} $$

where $c_{i\sigma}^\dagger$ is the creation operator for site $i$ and spin $\sigma$, $t_{ij}$ is the hopping term between sites $i$ and $j$, $U$ is the interaction strength and $n_{i\sigma}=c_{i\sigma}^\dagger c_{i\sigma}$.