Massive two-dimensional Dirac Hamiltonian
= Massive two-dimensional Dirac Hamiltonian
{c}
{title2=$H=c(p_x\sigma_x+p_y\sigma_y)+V\sigma_z$}
The two-component model $H=c(p_x\sigma_x+p_y\sigma_y)+V\sigma_z$ has energies $E_s=s\sqrt{c^2p^2+V^2}$. The sign of $V$ changes <eigenstates> and <spin> <polarization> but not the uniform energy dispersion at fixed $|V|$. The <Pauli matrices> may represent actual <spin> or an effective pseudospin, depending on the physical realization.