Question on spin 1/2 states in arbitrary direction

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
2 replies · 2K views
Shivy G
Messages
13
Reaction score
0

Homework Statement



upload_2016-2-29_18-55-54.png


The problem is given above. I am struggling on the first two parts, where I am tasked with finding gamma and beta.

Homework Equations



For spin one half states in arbitrary directions, I know that psi = a*|n;+> + b*|n;-> .

|n;+> = cos(theta/2)|+> +sin(theta/2)*ei*phi|->

|n;-> = -sin(theta/2)e-i*phi|+> + cos(theta/2)|->

The Attempt at a Solution



I have attached my attempt at a solution. I am not sure what I am doing wrong at this point. Any help for the problem would be greatly appreciated :)
 

Attachments

  • image1 (1).JPG
    image1 (1).JPG
    55.7 KB · Views: 481
Physics news on Phys.org
There are multiple mistakes in your calculation. I would suggest that you start over again from the first step by first normalizing the given ##|\psi\rangle##.
 
I ended up getting the solution. I was making a mistake by splitting it up into |n;+> and |n;->. Instead, I factored out a phase and then normalized the whole thing. The answer came fairly quickly from there. Thanks.