Rewrite state in new basis - Quantum Mechanics

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12x4
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Homework Statement


Rewrite the state |ψ⟩ = √(1/2)(|0> + |1>) in the new basis.

|3⟩ = √(1/3)|0⟩ + √(2/3)|1⟩

|4⟩ = √(2/3)|0⟩ − √(1/3)|1⟩


You may assume that |0⟩ and |1⟩ are orthonormal.

Homework Equations



The Attempt at a Solution


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I have a similar example in my notes however there is a step that I has stumped me. Annoyingly its the first one.

In my notes I have:

"""If we want to work in the basis |+⟩ and |−⟩ instead of | ↑⟩ and |↓⟩, with,

|+⟩ = (1/√2)(| ↑⟩ + | ↓⟩) & |−⟩ = (1/√ 2)(| ↑⟩ − | ↓⟩)

how would |ψ⟩ and I be written in the new basis?

Let us rearrange as:

| ↑⟩ = 1/(√2)(|+⟩ + |−⟩) & | ↓⟩ = (1/√2)(|+⟩ − |−⟩)"""

After rearranging I think that I should be able to complete the question but as it stands I can't see how to rearrange them to get |0> & |1>. Any advice would be much appreciated as really struggling with Dirac notation at the moment. Thanks 12x4
 
on Phys.org
You're probably just getting confused by the new notation. Consider the ordinary algebraic equations
\begin{align*}
u &= \frac{1}{\sqrt 2} x + \frac{1}{\sqrt 2} y \\
v &= \frac{1}{\sqrt 2} x - \frac{1}{\sqrt 2} y
\end{align*} How would you solve for ##x## in terms of ##u## and ##v##? You can essentially do the same thing.
 
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thanks vela, I just managed to do it with your advice.