Questions tagged [teleportation]

Quantum teleportation is a process by which quantum information (e.g. the exact state of an atom or photon) can be transmitted (exactly, in principle) from one location to another, with the help of classical communication and previously shared quantum entanglement between the sending and receiving location. (Wikipedia)

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Is quantum teleportation fully secure (in principle)?

Suppose two parties Alice and Bob have access to as many EPR pairs as needed, with each one having a qubit of each pair. Now Alice can create a sequence of qubit states $|i_{1}\rangle, |i_{2}\rangle, |...
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How is the grouping of terms done in the calculations for the teleportation circuit?

I have a CS background and am studying quantum computing by myself. Struggling at the moment with the Dirac notation for the teleportation circuit. Here we go: The circuit starts with the EPR pair ...
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How to teleport an entangled state via the two-qubit Heisenberg model?

I saw many articles that talk about entanglement teleportation via the two-qubit Heisenberg model as a quantum channel for example look at this artiles https://arxiv.org/ftp/arxiv/papers/0808/0808....
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Why doesn't reading the ancilla qubit in Quantum Error Correction kill entanglement?

In Quantum Error Correction we have ancilla qubits (in gray) that will be entangled with the pair of bits we want to check. Because we don't want to directly measure the "main" qubits (in ...
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Quantum teleportation transmits the exact qubit even when the state $\alpha\vert 1\rangle+\beta\vert 0\rangle$ has arbitrary $\alpha,\beta$?

I saw the concept of quantum teleportation, and they say you have a pre-shared state between Alice and Bob, such as $\alpha\vert 1\rangle+\beta\vert 0\rangle$, with $\alpha=\beta=\frac{1}{\sqrt{2}}$. ...
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General Proof of the Statement that You Need $1$ Ebit and $2$ Bits to Teleport $1$ Qubit?

I understand from the standard teleportation protocol that 1 ebit is used up in teleporting 1 qubit and thus, cannot be used again -- and thus, we need 1 fresh ebit of shared entanglement between ...
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How Quickly Can We Entangle a Pair of Unentangled Qubits Without Using Pre-existing Entanglement?

The Set-Up Let's say we want to entangle two qubits $\phi_a,\phi_b$ (at locations $a$ and $b$ respectively) that are spatially separated by distance $d$ (in natural units) at a given instance of time. ...
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how to prove quantum teleportation can't be achieved by sending only one classical bit

If Alice and Bob share an entangled state like the EPR state, by sending only two classical bits, Alice can transfer one qubit to Bob by means of quantum teleportation (see also Section 1.3.7 of http:/...
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Can we teleport an arbitrary two-qubit state? [duplicate]

Can we teleport a quantum register $a\left|00\right> + b\left|01\right> + c\left|10\right> + d\left|11\right>$ ? How can I visualize the output for this? I was looking at the https://...
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Gate teleportation between different QEC codes

I've heard people mention that one can teleport a gate from one QEC code into another, but I am trying to better understand operationally what exactly this entails, and whether there are any ...
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are the operation applied in Teleportation circuit fixed?

I implemented teleportation described on this page: Teleporation Circuit diagram is as follows: since we use entanglement for teleportation, as entanglement is done before 1st barrier, just wanted to ...
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What is the logic behind applying $X$ or $Z$ conditionally to the received bits?

I implemented teleportation described on this page: Teleporation Circuit is as follows: Here, as we are trying to teleport the quantum state from Alice (q0) to Bob(q2). Bob, on receiving the bits ...
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What is the time overhead for fault-tolerant gate teleportation?

The gate teleportation protocol (https://arxiv.org/abs/quant-ph/9908010) has a step where it utilizes cat state measurement of transversal operators. Since cat states can not detect phase errors it is ...
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What is a realistic model for simulating physical tampering of a channel? (ex: nearby vibrations)

Somewhat related to this question. Imagine a fully functioning quantum network, where qubits are transported via fiber optic cable. If vibrations were to physically tamper with a channel in such a ...
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Why does gate teleportation allow to implement nonlocal operations via local ones?

In (Gottesman and Chuang 1999), when discussing quantum gate teleportation, they mention how it can be used to implement nonlocal gates such as a CNOT, by only using (classically controlled) local ...
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How does quantum gate teleportation differ from state teleportation?

As described e.g. in this post, quantum gate teleportation can be framed as a variation of quantum state teleportation where a gate is applied beforehand on the receiver, and this results in the final ...
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Why do we use the Bell state $|00\rangle+|11\rangle$ for quantum teleportation?

In the quantum teleportation protocol we use the Bell state given by $$\frac{1}{\sqrt{2}} \left( |00\rangle + |11\rangle\right). $$ My intuition tells me this works is because we can transform this ...
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Quantum Teleportation Algorithm Always Ends in State $|0\rangle$

I'm trying to put together a demo using the Quantum Teleportation example provided by qiskit. The quantum circuit runs as intended when it's initialized to the state $|0\rangle$, and the measured ...
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How to simulate the state of a system after partial measurement?

Based on the answers at here and here, I have a quantum simulator which implements the operations described in the classic Teleporting an Unknown Quantum State. Careful comparison of circuits with the ...
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Why do unitaries act on maximally entangled states as $(U\otimes I)|\phi\rangle=(I\otimes U^T)|\phi\rangle$?

I was reading about teleportation which had the following Bell counterpart in $N$ dimensions $|{\phi}\rangle=\sum_{i=0}^{N-1}|i\rangle\otimes|i\rangle$. The next line was $$(U\otimes I)|\phi\rangle=\...
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Getting different sets of plots for the teleportation algorithm in Composer and Lab

I tried recreating the quantum teleportation circuit (in the Qiskit Foundation Youtube Playlist) both in Lab and Composer and getting different plots for each. Here is circuit and histogram from ...
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Decompose bell measurement gate into combination of controlled-not gates and one-qubit gates

OPENQASM2.0 has only one two-qubit gate: controlled not. For a teleportation experiment, I need to perform a measurement in the Bell basis. That is, I need a two-qubit gate with matrix representation $...
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Why doesn't this simpler teleportation idea work?

This circuit: The first (upper) qubit is the one we want to teleport, so could start it any state, call $\alpha|0\rangle+\beta|1\rangle$. Our goal is to teleport it to the third (bottom) bit. After ...
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Is it possible to have Quantum Teleportation Protocol without using classical channel?

I'm still learning Quantum Information right now, especially with Quantum Teleportation (QT). I have found an interesting article suggesting a Simplified Protocol of QT that doesn't need classical ...
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Does the teleportation protocol work for any dimension? [duplicate]

Suppose Alice and Bob share a maximally entangled state in $d$ dimensions i.e $$\vert\phi\rangle = \frac{1}{\sqrt{d}}\sum_{i=1}^d \vert i\rangle\vert i\rangle$$ Given a state $d$ dimensional $\rho$, ...
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Strange behaviour of IdentityGate IGate in IBM Q Composer

Can anyone explain the strange impact of the IGate in the enclosed quantum teleportation setup in view of the computational basis states? Any help is welcome!
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Generalizing the circuit for quantum teleportation for $n$-qubit states?

So the usual quantum circuit I know for quantum teleportation allows for the teleportation of the state on a single qubit, in the following way: How easy is to generalize this algorithm to allow for ...
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What is the name of this "ancilla based" process to implement gates

I just want to know if there is a specific name for the implementation of a gate on the top qubit with the help of the bottom qubit, represented on this image: It looks like gate teleportation but it ...
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Can we actually do quantum teleportation in IBM quantum computers?

I am going through a course in Quantum computation by NPTEL-IBM, which is designed to introduce Qiskit. In one lecture they describe the concept of quantum teleportation, and point out that since IBMQ ...
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Is it possible to use the mitigation process on a teleportation circuit?

Is it possible to use the mitigation process on a teleportation circuit? Sorry, i'm still starting, if someone can get me out of this doubt, I would appreciate it. The circuit I'm trying to make this ...
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What is the difference between having a single-qubit state and knowing a result of a measurement you want to perform on it?

In the quantum teleportation protocol Alice can send Bob an unknown quantum state $|\psi\rangle$. If the only thing Bob does with $|\psi\rangle$ is to measure it in some basis, I guess it would be ...
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What it means that the quantum teleportation involves projection onto a maximally entangled state?

I am familiar with the quantum teleportation protocol to some extent. However, I do not understand what it means when we say that "the teleportation relies on the projection of two qubits onto ...
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Is there some nice physical intuition to get for quantum teleportation

I know the quantum teleportation protocol: using an EPR pair you can "teleport" the data of one qubit on one of the qubit composing the EPR pair by doing appropriate measurement in the Bell ...
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Applying $R^{'\dagger}_{xz}$ in gate teleportation

In figure 4 of the paper Quantum Teleportation is a Universal Computational Primitive, the authors show a circuit for applying a unitary $U$ fault-tolerantly via teleportation. I'll paste the figure ...
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What is the right way to teleport qubits on a real quantum computer?

I've been using the teleportation protocol to teleport qubits and then using Qiskit state tomography for reconstructing my qubits. Using this circuit using open qasm I regularly obtain fidelity 0.9. ...
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Optimality of teleportation for entanglement-assisted quantum channel coding

Setting: Consider a quantum channel $N_{A\rightarrow B}$ between Alice and Bob. Let Alice and Bob also share arbitrary amounts of entanglement assistance through the state $\phi_{A_EB_E}$ (these can ...
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What happens to the Bell state qubits after the Quantum Teleportation?

I'm reading on the Quantum Teleportation and I couldn't find anywhere what happens to the bell state qubits after the Quantum Teleportation.
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Quantum teleportation of a mixed state through a pure state?

Let's assume we have a register of qubits present in a mixed state $$\rho = \sum_i^n p_i|\psi_i\rangle \langle \psi_i|$$ and we want to teleport $\rho$ through a random pure state $|\phi\rangle$. What ...
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What do we mean by teleporting state $|\psi\rangle$ through state $|\phi\rangle$?

What does it mean to teleport a state through another state? According to most of the online sources, we use a bell state for teleportation. What would be the outcome if we use any other possible ...
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In quantum teleportation, Is it possible for bob to just see the state vector after receiving it from Alice without measuring it?

I was reading about quantum teleportation using Qiskit. Alice wants to teleport some quantum state to Bob. My question is Is it possible for bob just to see the state vector after receiving it from ...
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Can someone elaborate how to use Qutrits to do teleportation? And the unitary operation Bob needs to do? [duplicate]

I can understand doing teleportation by using qubits, however, I am stuck there when it comes to qutrits and the operation Bob needs to perform. Suppose Alice and Bob are sharing the most entangled ...
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Can I keep data into qubit and teleport?

I was reading about teleportation I have some question about it. Can I keep normalized data (some customized data) on probability amplitudes (which are complex numbers) of a qubit (Alice's side)? ...
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In quantum teleportation, does Bob's qubit depend on Alice's $\alpha$ and $\beta$ coefficients?

Does applying an operation to one half of an entangled pair affect the other? As in the case of quantum teleportation when Alice applies CNOT to her half of the pair and the qubit she wants to send ($\...
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How to fix an error : " QiskitBackendNotFoundError: 'No backend matches the criteria' "

I am trying to run the Quantum Teleportation Algorithm using Qiskit on Jupyter Notebook. Here is my code below where I am finding an error - ...
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What can gate teleportation be used for in practice?

I was quite fascinated when I learned about gate teleportation, but I am struggling with understanding what it may be used for. Sure, one can use ancillae bits to teleport gates into various parts of ...
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Why do quantum networks matter?

I'm very new to quantum computing, sorry if this is a dumb question. I was reading in some lecture notes I found online that a quantum network could be created by using teleportation multiple times to ...
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Quantum teleportaion seems to occuring without entanglement in circuit (what's wrong)

Please, pardon the caption. No intention of making new theories. I am a bit confused about the quantum teleportation. I missed a hadamard gate before CNOT gate for creating the EPR pair. But the ...
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Can I teleport a string of 0s and 1s?

I have recently started with quantum computing and created a quantum teleportation circuit to transmit a qubit state from q_0 to ...
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Teleportation followed by measurement: Lowering communication cost

Suppose Alice and Bob have access to shared entanglement and a classical channel and wish to simulate the following quantum protocol. Alice sends over to Bob an $n$-qubit state which is not known to ...
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Quantum teleportation and the reality of quantum states

This question is perhaps philosophical but it's been confusing me. Suppose Alice is teleporting some qubit state $|\phi\rangle$ to Bob via the quantum teleportation protocol. After Alice applies the ...
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