Two-spin exchange spectrum with unequal signed magnetic moments
= Two-spin exchange spectrum with unequal signed magnetic moments
For $H=(\Delta/4)\boldsymbol\sigma_1\cdot\boldsymbol\sigma_2-(\mu_0B/2)(g_1\sigma_{1z}+g_2\sigma_{2z})$, the parallel-spin energies are $\Delta/4\mp\mu_0B(g_1+g_2)/2$. The zero-projection block has energies $-\Delta/4\pm\sqrt{\Delta^2+[\mu_0B(g_1-g_2)]^2}/2$. Signed moment conventions must be fixed before assigning a physical opposite-charge case.