Classification of four-rebit states

Heiko Dietrich, Willem A. de Graaf, Alessio Marrani +1

We classify states of four rebits, that is, we classify the orbits of the group $\hat{G}(\mathbb{R})=\mathrm{SL}(2,\mathbb{R}{)}^4$ in the space $(\mathbb R^2)^{\otimes…