# Difference between revisions of "Spherical harmonics"

The spherical harmonics $Y_l^m (\theta,\phi)$ are the angular portion of the solution to Laplace's equation in spherical coordinates. They are given by

$Y_l^m (\theta,\phi) = (-1)^m \sqrt{\frac{2n+1}{4\pi}\frac{(n-m)!}{(n+m)!}} P^m_n(\cos\theta) e^{i m \phi},$

where $P^m_n$ is the associated Legendre function.

The first few spherical harmonics are given by:

$Y_0^0 (\theta,\phi) = \frac{1}{2} \frac{1}{\sqrt{\pi}}$
$Y_1^{-1} (\theta,\phi) = \frac{1}{2} \sqrt{\frac{3}{2\pi}} \sin \theta e^{-i\phi}$
$Y_1^0 (\theta,\phi) = \frac{1}{2} \sqrt{\frac{3}{\pi}} \cos \theta$
$Y_1^1 (\theta,\phi) = -\frac{1}{2} \sqrt{\frac{3}{2\pi}} \sin \theta e^{i\phi}$