Question on spin 1/2 states in arbitrary direction

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Shivy G
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Homework Statement



Screenshot of an online homework problem showing part a: the unnormalized spin state written as (1+i)|+> - (1+i√3)|->, with answer boxes for gamma = -1/2 and beta = 3/2 and boxes for the normalized vector components n_x, n_y, n_z.


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
  • Handwritten working on lined paper deriving spin-1/2 state coefficients: decomposition of |psi> into |n;+> and |n;-> with alpha = 2 and beta = sqrt(2), then theta = 2pi/3 and phi = 3pi/2, ending with the note 'These are wrong through.'
    image1 (1).JPG
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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.