# Tag Info

Accepted

### Why is a Bell state involved in quantum teleportation?

The motivation for introducing the Bell state is simple: it gets the job done! This of course raises the question: what properties of the Bell state make it suitable for use as a resource in quantum ...
• 23k
Accepted

### Injecting arbitrary rotations into the surface code

Generally speaking, you would never do a $\pi/2^{10}$ rotation by physical injection and distillation. It would be horrendously expensive. It's far cheaper to use a series of T and H gates to ...
• 38.6k

### How does quantum teleportation not lose information?

Alice doesn't just concatenate her message qubit with her half of the Bell pair, she entangles these qubits in the process of doing the Bell measurement (remember that it involves a CNOT gate before ...
• 9,135
Accepted

### What is the difference between quantum teleportation and quantum entanglement with dense coding?

Both teleportation and (super)dense coding use entanglement as a resource. I like to think that one is dual to the other, as the quantum circuits are, basically, inverses of each other. For example, ...
• 12.8k

### Teleportation of Transversal Hadamard Gate from the $[[8,3,2]]$ to $[[4,2,2]]$ codes

It's going to be easier to explain if we start with one qubit being teleported. I'm also going to use Gottesman-Knill to do the proofs here, and if you're not familiar with it, you should definitely ...
1 vote

### In quantum teleportation, why does measuring entanglement not destroy the whole state?

Good question, to answer it you can (and should) of course describe the system mathematically, but the problem is that the description never specifies what "classical transport" exactly does....
1 vote

### In quantum teleportation, why does measuring entanglement not destroy the whole state?

The measurement doesn't "destroy the whole quantum system", because you're not measuring the whole quantum system. You're only measuring two of the three systems. It's like saying: if you ...
• 25.6k
1 vote

### Can we perform teleported-error-correction with noisy Bell pairs?

Yes. You just prepare, on one side, a logical Bell pair and teleport one half of it through the noisy bell pairs. When you run error correction on it, it effectively corrects the errors that were in ...
• 59.3k
1 vote

### Why does this not break the security of quantum teleportation

It is possible for Eve to do this, but then you don't achieve teleportation. Bob does not recieve the pure state $c|0_B\rangle+d|1_B\rangle$, which was the goal. Bob can measure things that only ...
1 vote

### Quantum teleportation of unknown qubit when the entangled state is not a Bell state

I am assuming that $|j|=1$, i.e. $j$ is just a phase factor. Otherwise, the state would not be normalized (as already mentioned in a comment above) and the state would also not be maximally entangled (...
• 55
1 vote

### 2-Qubit Gate Teleportation with 1 Maximally Entangled State for Distributed Computation

$\newcommand{\ket}[1]{|#1\rangle}$ This paper: arXiv:quant-ph/0005101 shows how a circuit, closely related to the CNOT teleportation from the question, can be generalized to arbitrary controlled 2-...
• 311
1 vote
Accepted

### $CNOT$ teleportation in ZX-calculus: how to simplify my circuit further?

I think I see where you went wrong. In ZX-Calculus, only connectivity matters. So in your final stage, you can connect the middle two phaseless nodes with a vertical line, instead of the cup. Then, ...
1 vote

### Use of maximally entangled states in dense coding and quantum teleportation

Maximally entangled states just work better for these two applications: for superdense coding, you need an orthonormal basis which can be mapped between each other using unitaries that are local to ...
• 59.3k
1 vote
Accepted

### What is the exact mathematical content of the no-teleportation theorem?

Disclaimer: I am just a mathematician that likes to try to understand the math behind quantum things. I am very bad at physics. As far as I understand the link you provide, I think a mathematical ...
• 126

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