11 votes

Does entanglement allow enhanced communication efficiency?

First, about teleportation, you say that you think quantum communication takes place in the protocol, but it doesn't. They only share an EPR pair they created together, hence the coordination and ...
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  • 2,394
8 votes
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Why does quantum distinguishability ensure no faster-than-light communication?

In the situation described in the book, Alice and Bob share the state $$ |\psi\rangle = \frac{|00\rangle+|11\rangle}{\sqrt{2}}. $$ Using the definition $|\pm\rangle=(|0\rangle\pm|1\rangle)/\sqrt2$ and ...
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  • 14.3k
5 votes
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Does the Lieb-Robinson bound constrain the speed of entanglement information transmission?

Entanglement does not transmit information, as follows from the No-communication theorem. Lieb-Robinson bound is a limit on speed at which perturbation propagates using short-range interactions, for ...
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  • 3,084
5 votes
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Can we teleport a human or send information faster than light using quantum teleportation?

In conclusion, NO and NO, respectively. Quantum teleportation does not mean instantaneous disappearance and reappearance of information at another spatial point. Quantum teleportation in plain ...
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4 votes
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Can joint measurement be achieved in two labs far apart?

TL;DR No. Non-local gates and measurements between causally disconnected observers violate the no-signalling theorem and are therefore impossible. No-signalling theorem The following protocol allows ...
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  • 14.3k
3 votes

Does entanglement allow enhanced communication efficiency?

It sounds like the source of your misunderstanding is the following Bob is able to harness the information of a qubit which contains more information than regular classical bits This statement is ...
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  • 518
3 votes
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Quantum indistinguishability using density operators

The mistake occurs when you compute the reduced state on Alice2's system. For simplicity we'll assume all systems are qubits and in addition $|x\rangle = |0\rangle$. In this setting, Bob2 prepares the ...
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  • 4,192
1 vote

Does entanglement allow enhanced communication efficiency?

In your argument, you are missing the relativistic causality. Bob and Alice simply cannot decide who did the measurement first because their space-time measurement events are connected by the space-...
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