We analyse quantum teleportation (QT) and entanglement swapping (ES) for spin systems. If the permitted operations are restricted to the Ising interaction, plus local rotations and spin measurements, high-fidelity teleportation is achievable for quantum states that are close to the maximally weighted spin state. ES is achieved, and is maximized for a combination of entangled states and Bell mea...

Several protocols for controlled teleportation were suggested by Yang, Chu, and Han [PRA 70, 022329 (2004)]. In these protocols, Alice teleports qubits (in an unknown state) to Bob iff a controller allows it. We view this problem in the perspective of secure multi-party quantum computation. We show that the suggested entanglement-efficient protocols for m-qubit controlled teleportation are open...

In this chapter a quantum communication protocol with use of repeaters is presented. The protocol is constructed for qudits i.e. the generalized quantum information units. One-dit teleportation is based on the generalized Pauli-Z (phase-flip) gate’s correction. This approach avoids using Pauli-X and Hadamard gates unlike in other known protocols based on quantum repeaters which were constructed...

It is shown that the information losses due to the limited fidelity of continuous variable quantum teleportation are equivalent to the losses induced by a beam splitter of appropriate reflectivity. Quantum teleportation allows the transmission of an unknown quantum state by combining the nonlocal quantum coherence of entangled states with the transmission of classical information obtained in a ...

Noisy teleportation of nonclassical quantum states via a two-mode squeezed-vacuum state is studied with the completely positive map and the GlauberSudarshan P -function. Using the nonclassical depth as a measure of transmission performance, we compare the teleportation scheme with the direct transmission through a noisy channel. The noise model is based on the coupling to the vacuum field. It i...

We propose and analyze a potential induced random walk and its modification called random teleportation on finite graphs. The transition probability is determined by the gaps between potential values of adjacent and teleportation nodes. We show that the steady state of this process has a number of desirable properties. We present a continuous time analogue of the random walk and teleportation, ...

Faithful teleportation of an unknown state |φ in C d is considered, where a general entangled state ρ is served as the resource. The necessary conditions of mixed states to complete perfect teleportation are proved. Based on these results, the necessary and sufficient conditions of faithful teleportation channel ρ in C m ⊗ C d and C d ⊗ C n are derived. It is shown that for ρ in C m ⊗ C d , ρ m...

An explicit scheme (quantum circuit) is designed for the teleportation of an n-qubit quantum state. It is established that the proposed scheme requires an optimal amount of quantum resources, whereas larger amount of quantum resources has been used in a large number of recently reported teleportation schemes for the quantum states which can be viewed as special cases of the general n-qubit stat...

We present a high-fidelity quantum teleportation experiment over a high-loss free-space channel between two laboratories. We teleported six states of three mutually unbiased bases and obtained an average state fidelity of 0.82(1), well beyond the classical limit of 2/3. With the obtained data, we tomographically reconstructed the process matrices of quantum teleportation. The free-space channel...

Quantum teleportation allows the transmission of an unknown quantum state by combining the nonlocal quantum coherence of entangled states with the transmission of classical information obtained in a joint measurement of the unknown input state and one part of the entangled pair @1#. Ideally, the classical information transmitted contains no information about the input state, and the output stat...