Quantum Computing Stack Exchange
Quantum Computing Stack Exchange

Questions tagged [entanglement-swapping]

the procedure of entangling particles that do not share a common past, i.e. without any direct interaction

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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. We are allowed to use additional qubits to get…
FreeAssange
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Problem involving entanglement swapping

I'm trying to solve a problem. I have my own approach to it, as the one in the textbook seems overly complicated. I tried using my own approach, but I'm not sure if what I found was a coincidence or not. Here's the problem (it's in French, I did my…
Skyris
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Swaps in a uniform superposition

Starting from a state $|00\rangle|01\rangle|10\rangle$ (from $0$ to $n$ without repetitions), I want to reach an state in which all possible combinations of swaps are in a uniform superposition. I…
Roberto Campos
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Problem about entanglement swapping

I have been learning about the concept of entanglement swapping and found an equation mentioned in the textbook, Mathematics Of Quantum Computing: An Introduction written by Wolfgang Scherer. At section 4.13, equation…
黑傑克
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Problem with Fidelity output in Qiskit with noisy gates for entanglement swap

I'm performing an entanglement swap using 4 qubits in Qiskit. I make my own noisy gates and insert noise in the circuit. I want to create two noisy input Bell pairs of various two different fidelities and, after performing the swap, find the…
Travis
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Inner product in terms of Hadamard and controlled SWAP gates

On p. 7 of this paper (https://arxiv.org/abs/2112.04958) it is claimed that: "For any two states $|φ\rangle$ and $|ψ\rangle$ with the same dimensions, the fidelity $F(|φ\rangle, |ψ\rangle)$ can be measured as the output of an ancillary qubit…
pll04
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What it means to say that SWAP gate has maximum operator entanglement entropy?

In this paper (arXiv), just below equation 14, it says The SWAP operator has the maximum operator entanglement entropy... The operator entanglement entropy, denoted by $E(U)$ for an operator $U$, is such that $E(u_A \otimes u_B) = 0$, which makes…
User101
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Can pairwise entanglement be converted into tripartite correlations?

Suppose Alice shares $m$ pairs of maximally entangled states with Bob and $n$ pairs of maximally entangled states with Charlie. It is clear that by measuring their states, Alice can generate correlations with Bob and Alice can also generate…
user1936752
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Why we do SWAP operations for applying a mode N function in Shor algorithms and How we do this swapping?

I am working on implementing shor algorithm for finding prime factors of N = 15. I am trying to understand a code of qiskit, but i am confused how and why the code editor is using swap codes to define mode function. Here is the code: def c_amod15(a,…
Tayyab Yahya
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How to project on the $\phi^+$ basis when performing entanglement swapping?

I am working on entanglement swapping. Where there are three nodes, a source node, repeater node and a target node. Qubits 1 and 2 are entangled and are distributed between source node and repeater node. Qubits 3 and 4 are entangled and are…
Ganesh M
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What would be the procedure if I wish to code entanglement swapping?

Most of the methods that I have seen in various papers all take single examples and then proceed to manually perform swapping by re-writing the states on a different basis and then performing a measurement to swap entanglement. Examples:…
2Shabby
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Clarification of a theorem mentioned in a paper on RED

I am reading a paper "A study of Teleportation and Super Dense Coding capacity in Remote Entangled Distribution" (arXiv:1210.1312). In this paper Relations on two-qubit pure states are mentioned. Consider a resource entangled in 2 $\otimes $ 2…
Ganesh M
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Entanglement and teleportation transmission costs

Let say we have a product state $$|\phi^+\rangle_{12}|\phi^+\rangle_{34}$$ with particles (1,4) belong to $A$ and (2,3) belong to $B$. Where $A$ and $B$ are say at distance of $L$ from each other. When particle $A$ measures his qubits $(1,4)$ in the…
Upstart
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Entanglement Swapping Circuit

I implemented 2 versions of the entanglement swapping circuit in IBM Q. One is using classical measurement to control X, Z gates. Another is just us C-NOT and Controlled-Z. They should be equivalent. The 1st and 2nd bits were entangled. After…
Dragon123
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Distributing entanglement using entanglement swapping

I've read papers that consider the problem of sharing entanglement between A and C with an intermediate B. A and B share an entangled state and so do B and C. Then, entanglement swapping is used to create entanglement between A and C. Now, in the…
user401163
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