# Landau quantization of cyclotron orbit

I don't know what the speed of light c is doing in the Hamiltonian for the Landau quantization. The term doesn't have dimensions of momentum anymore.

$\hat{H}=\dfrac{\hat{p}^2_x}{2m}+\dfrac{1}{2m}\left(\hat{p}_y-\dfrac{q|\vec{B}|}{c}\hat{x}\right)^2$

Any ideas?

thanks.

Cthugha