We demonstrate how the quantum teleportation protocol of a single qubit can be understood by designing a simple game that can be played by three participants: Alice, Bob, and Quantum God.
Quantum teleportation with optimum quantum resources and hardware in a quantum network poses a pressing and demanding need. Here, we offer a protocol for asymmetric two-way controlled quantum teleportation via employing a sixteen-qubit entangled state as a resource in a quantum network consisting of five communicating participants Alice, Bob1, Bob2, Bob3and Eve. Our protocol is designed so that a sending party (Alice) transmit its three single information-qubits to three different parties Bob1, Bob2& Bob3, respectively and at the mean time, these three parties (Bob1, Bob2& Bob3) send their Bell-like information-qubits back to the sender (Alice) under the supervision of administrator (Eve) by invoking projective Bell State measurements, GHZ-state measurements and X-basis measurements and local unitary operations. Furthermore, we have analyzed intrinsic efficiency of the protocol and compare our scheme with other competitive protocols.
In this paper, different from the other existing methods that only the special and limited numbers of qubits transmit between Alice and Bob, a general method is proposed to implement Bidirectional Quantum Controlled/uncontrolled Teleportation (BQCT/BQT) that Alice and Bob can transmit each type of arbitrary n and m-qubits to each other, simultaneously. This protocol is based on Controlled-NOT (CNOT) operation, appropriate single-qubit unitary operations and single-qubit measurement in the Z-basis and X-basis. Also, the quantum channel can be created by using Hadamard and CNOT operations. One of the advantages of this method is using the single-qubit measurements which are more efficient than two-qubit measurements.
We explicitly show a protocol in which an arbitrary two qubit state $\ensuremath{\mid}\ensuremath{\phi}⟩=a\ensuremath{\mid}00⟩+b\ensuremath{\mid}01⟩+c\ensuremath{\mid}10⟩+d\ensuremath{\mid}11⟩$ is faithfully and deterministically teleported from Alice to Bob. We construct the 16 orthogonal generalized Bell states that can be used to teleport the two qubits. The local operations Bob must perform on his qubits in order to recover the teleported state are also constructed. They are restricted only to single-qubit gates. This means that a controlled-NOT gate is not necessary to complete the protocol. A generalization where N qubits are teleported is also shown. We define a generalized magic basis, which possesses interesting properties. These properties help us to suggest a generalized concurrence from which we construct a measure of entanglement that has a clear physical interpretation: A multipartite state has maximum entanglement if it is a genuine quantum teleportation channel.
Summary form only given. Characterizing the entanglement of a general bipartite quantum system is a difficult problem. Most measures involve difficult extremizations and their physical motivation is not always clear. In this paper we propose an experimental measure of entanglement based on a modified version of the familiar teleportation protocol of Bennett et al. (1993). Briefly, teleportation traditionally involves two parties, Alice and Bob. Initially, Alice has a qubit in an unknown quantum state which she would like to communicate to Bob and Bob has two qubits in an entangled Einstein-Podolsky-Rosen (EPR) pair. To accomplish this transfer, Bob shares one qubit of his EPR pair with Alice. She then performs a joint measurement or Bell measurement on her two qubits and relays this information back to Bob over a classical channel. Bob then uses the outcome of Alice's Bell measurement to transform his qubit, with a local unitary transformation, into the original quantum state, always with a fidelity of one.