# Spherical Harmonics within QM

1. May 25, 2007

### Brewer

1. The problem statement, all variables and given/known data
The spherical harmonics $$Y^m_l$$ with l=1 are given by
$$Y^{-1}_1 = \sqrt{\frac{3}{8\pi}}\frac{x-iy}{r}, Y^0_1 = \sqrt{\frac{3}{4\pi}}\frac{z}{r}, Y^1_1 = -\sqrt{\frac{3}{8\pi}}\frac{x+iy}{r}$$

and they are functions of $$L^2$$ and $$L_z$$ where L is the angular momentum.

i) From these functions find a new set of three functions $$X^m_1$$ which are now eigenfunctions of $$L^2$$ and $$L_x$$.

2. Relevant equations

3. The attempt at a solution
I'm not 100% sure about this question. Is it asking me to give the spherical harmonics in terms of $$\theta, \phi$$? I think I can do that, but if thats not the question, could someone please explain to me what is being asked of me.

Thanks

Brewer

2. May 25, 2007

### stunner5000pt

i think it would be better if you wrote your spherical harmonics in spherical coords ..

but in any case
if $X_{lm}$ is an eignefunction of L^2 and Lz then
$$\hat{L_{z}} X_{lm} = mX_{lm}$$
and
$$\hat{L^2} X_{lm} = l(l+1) X_{lm}$$
and i think Xlm would b acquired by finding a superposition of the three given eigenfunctions.

3. May 25, 2007

### Brewer

Thats what the question gives, cartesian coords.