Supercharges commute with translations
= Supercharges commute with translations
{title2=$[P^\mu,Q_\alpha]=0$}
In the minimal <Super-Poincaré algebra>, <Lorentz covariance> allows $[P^\mu,Q_\alpha]=A\sigma^\mu_{\alpha\dot\beta}\bar Q^{\dot\beta}$. The <graded Jacobi identity> with $P^\mu,Q_\alpha,Q_\beta$ forces $A=0$. Thus each <supercharge> preserves <four-momentum> and its mass Casimir, giving <supersymmetric mass degeneracy> in an unbroken physical <supermultiplet>.