Rearranging equation in Dirac-notation for 3 particles (quantumteleportation)

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In summary, the conversation is about rearranging a given state into a different form, but the person is having trouble understanding how to do it. They have attempted to expand the state using a normal method, but it does not seem to be correct. Another person points out the mistake and provides the correct solution.
  • #1
keen23
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Hello all!
I try to follow the computation in my textbook (nielsen, quantum computation) and miss a step.

Homework Statement


They say the following state
[tex]|p\rangle=\frac{1}{2}\big[a (|0\rangle+|1\rangle)(|00\rangle+|11\rangle)+b(|0\rangle-|1\rangle)(|10\rangle+|01\rangle)\big][/tex]
could be rearranged to
[tex]|p\rangle=\frac{1}{2}\big[|00\rangle(a|0\rangle+b |1\rangle)+|01\rangle(a|1\rangle+b|0\rangle)+|10\rangle(a|0\rangle-b|1\rangle)+|11\rangle(a|1\rangle-b|0\rangle)}\big]
[/tex].

But I don't see how.

(The start state comes from combining an arbitrary state a|0>+b|1> with an epr-pair in bell-state, then using CNOT for particles 1 and 2, then Hadamardgate on particle 1, well, I think that's not important for my question).

Homework Equations



The Attempt at a Solution


With normal expansion I get:
[tex]|p\rangle=\frac{1}{2}\big[a|0\rangle|00\rangle+a|0\rangle|11\rangle+a|1\rangle|00\rangle+a|1\rangle|11\rangle+b|0\rangle|10\rangle+b|0\rangle|01\rangle-b|1\rangle|10\rangle-b|1\rangle|01\rangle[/tex]
[tex]
=|00\rangle a(|0\rangle +|1\rangle )+|01\rangle b(|0\rangle -|1\rangle )+|10\rangle b(|0\rangle -|1\rangle )+|11\rangle a(|0\rangle +|1\rangle )
[/tex]

So "normal" expansion seems not to be the right way, but how shall I do it? Even if I think about the physical meaning I don't see what's wrong.
Maybe someone has more experience?
Thanks for your help!
 
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  • #2
I think your mistake is that you're setting |00>|1> and |1>|00> equal -- but surely the first one equals |001> and the second equals |100>, which are different?
 
  • #3
Oh no! Yes, sure. that was my mistake.
Thank you!
 

1. How is Dirac-notation used in quantum teleportation?

Dirac-notation is used in quantum teleportation to represent quantum states of particles and their interactions. It allows for a concise and elegant way to express complex equations and operations in quantum mechanics.

2. What is the purpose of rearranging the equation in Dirac-notation for 3 particles in quantum teleportation?

Rearranging the equation in Dirac-notation for 3 particles in quantum teleportation enables us to better understand the relationships and interactions between the particles involved. It also allows for more efficient calculations and predictions.

3. Can the equation in Dirac-notation for 3 particles in quantum teleportation be simplified?

Yes, the equation in Dirac-notation for 3 particles in quantum teleportation can be simplified by using mathematical operations and simplifying any terms that cancel out or can be combined. This can make the equation easier to understand and work with.

4. How does quantum teleportation work with 3 particles?

In quantum teleportation with 3 particles, the quantum state of one particle (the input particle) is transferred to another particle (the target particle) through the manipulation and measurement of a third particle (the ancilla particle). This process involves entangling the input and ancilla particles, performing measurements on both of them, and then manipulating the target particle based on the measurement outcomes.

5. What are the benefits of using Dirac-notation for rearranging equations in quantum teleportation with 3 particles?

Using Dirac-notation for rearranging equations in quantum teleportation with 3 particles allows for a more compact and elegant representation of the equations involved. It also helps to reveal the underlying symmetries and relationships between the particles and their quantum states, making it easier to analyze and predict quantum teleportation outcomes.

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