Group velocity
= Group velocity
{wiki}
Group velocity is the gradient of angular frequency with respect to wavevector, $\mathbf c_g=\nabla_{\mathbf k}\omega$. It gives the leading propagation velocity of a narrow wave packet.
= Group velocity
{wiki}
Group velocity is the gradient of angular frequency with respect to wavevector, $\mathbf c_g=\nabla_{\mathbf k}\omega$. It gives the leading propagation velocity of a narrow wave packet.