The nonrelativistic Hamiltonian for an electron in a magnetic field

, where

is vector potential, is given by

,

where

and

are the mass and charge of the electron, respectively. We also make use of the Coulomb gauge condition

.

For a constant field in the

direction,

, it is convenient to work in cylindrical coordinates,

. With a convenient choice of gauge, the vector potential can be represented by

,

.

.

The Schrödinger equation for

is given by

.

The equation is separable in cylindrical coordinates, and we can write

,

for definite values of the angular and linear momenta. We consider only angular momentum anticlockwise about the

axis. We set

and consider only motion in a plane perpendicular to the magnetic field. Introducing atomic units

, the radial equation reduces to

.

The solution with the correct boundary conditions as

is given by

,

where

is an associated Laguerre polynomial. The corresponding energy eigenvalues are

.

These are the well-known Landau levels, which are equivalent to the levels of a two-dimensional harmonic oscillator with

.

is the cyclotron frequency for an electron in a magnetic field.

[1] L. D. Landau and E. M. Lifshitz,

*Quantum Mechanics: Non-relativistic Theory*, 2nd ed., Oxford: Pergamon Press, 1965, pp. 424ff.

[2] D. ter Haar (ed. and tr.),

*Problems in Quantum Mechanics*, 3rd ed., London: Pion, 1975 pp. 38, 254ff.