22 votes
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Can't quantum teleportation be superluminal some percentage of times?

This is really a subtle point. You are right that in 25% of the cases, Bob will randomly chose the "correct" measurement basis and thus get the correct value. However, there is no way for Bob to ...
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12 votes
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Is High-Fidelity Quantum-Entanglement Data-Transfer Real?

The paper is about quantum teleportation, which is a process enabled by entanglement. However, it does not provide faster-than-light communication. The complete process of teleportation always needs a ...
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7 votes
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How is quantum teleportation any better than regular transfer of information?

There are several reasons quantum teleportation is a useful way to move qubits, even if you already have a normal quantum channel. Latency reduction. Suppose the quantum channel has decent bandwidth ...
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  • 5,924
6 votes
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What is the 3 dB limit of standard parametric squeezing techniques?

As often in continuous variable quantum physics, it is a case where the “limit” is not a hard one (like “no information faster than $c$” in relativity), but a value at which interesting things occurs, ...
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6 votes
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In quantum teleportation, how do the measurement & reconstruction steps work mathematically?

There are two ways to do this. There's the easy, intuitive way, and the complicated, mathematically-rigorous way. Here I'll go over the latter: The Density Operator The density operator is an ...
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  • 263
6 votes
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How does the quantum teleportation protocol not violate the no-cloning theorem?

You could think that quantum teleportation violates the no-cloning theorem, but it is actually not the case. Indeed, the original state $|\psi\rangle$ has not been duplicated, since after the ...
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  • 576
5 votes
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What's wrong with my teleporter?

Your error is in assuming that if D1 does not measure a photon, it will necessarily be measured by D2. But that is not true! If you're sending half the probability amplitude to D1, and half to D2, ...
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5 votes

University of Delft results regarding quantum teleportation of information

I haven't read the links in any detail, but it might help you to understand that teleportation also requires classical communication to work. (Sorry if you already understood this.) In order to ...
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5 votes

How is quantum teleportation any better than regular transfer of information?

The key aspect that sets quantum teleportation apart from the regular classical transfer of information is that it enables Alice to send information that even she does not have access to. The ...
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5 votes
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Quantum teleportation with moving Alice and Bob

The relativity of simultaneity ensures that for non-causal events, the order in which they happen can depend on the reference frame you choose. However, in the case of teleportation, if Bob chooses ...
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  • 1,146
5 votes
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Why is quantum teleportation needed to transmit a state?

If all you want to do is recreate a single quantum state somewhere else, and you have the ability to create exactly this state as many times as you want, and you don't care about exact recreation ...
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4 votes
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Quantum teleportation and macroscopic objects

Quantum teleportation is a concept of transferring quantum states of matter. Not teleporting matter itself. To "clone" an object to the destination, you need to have the same material as the object ...
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4 votes

What's wrong with my teleporter?

The issue is your first assumption. While it's true that the photon can have an amplitude to be in multiple places at once, it can only be measured to be in one place. For example, suppose we split ...
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4 votes
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How can information be communicated with entanglement?

You are right. Bob can only determine the state of his particle (without measuring it) once he receives information from Alice about the outcome of her measurement - and this information can be ...
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  • 35.6k
4 votes

If there's a small probability particles may teleport anywhere in an infinite Universe, shouldn't stars pop up in existence close to us ever so often?

No, an infinite universe does not make this likely. As the distance from earth increases (on cosmological scales) the number of atoms increases with the square of the distance. So, in order for the ...
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3 votes

Speed of Quantum Teleportation?

Quantum teleportation requires sending classical information. So you can't do it faster than the speed of light. Quantum Teleportation (simplified) Alice and Bob have a pair of qubits, $A$ and $B$. $...
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  • 5,924
3 votes

Can't quantum teleportation be superluminal some percentage of times?

If you are happy with Bob being right only in some percentage of the cases, there is a much easier protocol which does not even require entanglement: Just let Bob guess Alice's bits. He will be right ...
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3 votes
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Quantum teleportation and no-communication theorem

Quantum teleportation requires a "classical channel" of information to be communicated between the two experimenters, so it doesn't violate the no-communication theorem because that theorem only rules ...
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  • 6,050
3 votes

What does it mean that quantum teleportation can be classically simulated?

I don't really know what answer you expect here. As you have found out yourself, the Gottesman-Knill theorem tells you that stabilizer circuits can be efficiently simulated by a classical computer. ...
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2 votes

Quantum computing records (entangled qubits)

This link at the Institute for Quantum Computing, Waterloo website mentions that the current world record is shared by IQC and MIT for 12 qubits. The link mentioned in the question talks about 14 ...
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2 votes

Quantum teleportation of a macroscopic object

Even without sending classical infotmation - the state was completley teleported. Unfortunatley, by teleportation identity - after teleporting state $ |\psi\rangle$ at A you get a state $U^{\mu \...
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2 votes
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Can a non-entangled qubit be teleported by entangling it?

Quantum teleportation works on any qubit. It isn't restricted to only working on entangled qubits. It works on unentangled qubits. Quantum teleportation does require the sender and receiver to have ...
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  • 5,924
2 votes

Can a non-entangled qubit be teleported by entangling it?

Take a pair of qubits in a maximally entangled state $\phi=A\otimes B+B\otimes A$. (Here $A$ and $B$ are a basis for the state space of a single qubit.) One stays with you, the other resides at the ...
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2 votes

What's wrong with my teleporter?

This fails the "is there something quantum mechanical about this test setup" basic requirement for asking if quantum teleportation allows superluminal transport of information. Your setup could be ...
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  • 35.2k
2 votes

On what qubit does Bob perform Pauli Correction in Quantum teleportation protocol?

I think your lecture notes are not so clear - I would instead just look at Wikipedia. 1) You are correct that the 'Pauli correction' is to apply a correction operator (either $X$, $Z$, or some ...
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  • 1,356
2 votes
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How do 3 physically entangled particles work?

"Say a particle split into 3 particles that are all entangled to each other, ... if I'm to measure only one of them can I thus predict the quantum states of the other two?" Well it depends on how ...
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  • 12.4k
2 votes

Patent for full body teleportation system using wormholes

To answer your first question, anyone can patent anything, it does not have to work even in theory, if you have some data behind it you can patent it To answer your second question... I cannot ...
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2 votes

Teleportation without classical channel

If Alice observes an electron from a maximally entangled EPR pair, the expectation value of the spin is always $$\langle \vec S \rangle = 0,$$ not the cosine indicated by the OP. It's because the EPR ...
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2 votes

China quantum telecom

I believe the best possible answer to your question is given in this Nature News article. As the article explains in detail, this type of technology has been established before, and indeed it doesn't ...
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