Asymmetric bidirectional quantum teleportation via six-qubit partially entangled state

In this paper, an asymmetric bidirectional controlled quantum teleportation via a six-qubit partially entangled state is given, in which Alice wants to transmit a two-qubit entangled state to Bob and Bob wants to transmit a single-qubit state to Alice on the same time. Although the six-qubit state as quantum channel is partially entangled, the teleportation is implemented deterministically. Furthermore, only Bell-state measurements, single-qubit measurements and some unitary operations are needed in the scheme.

Cyclic quantum teleportation via GHZ-like state

Following the work of Chen et al. [Quantum Inf. Process. 16, 201 (2017)] and Zhang [Mod. Phys. Lett. A 34, 1950290 (2019)], we propose a scheme for cyclic quantum teleportation (CYQT) in which three participants Alice, Bob and Charlie can teleport three arbitrary single-qubit information states cyclically among themselves by using GHZ-like states. Chen et al. and Zhang proposed schemes for CYQT and bidirectional quantum teleportation (BQT) involving three participants, respectively. In the scheme of Chen et al., the quantum teleportation (QT) can be realized successfully between any two participants without the help of third participants and in Zhang’s scheme, two unknown single-qubit states are teleported bidirectionally between two participants with the help of a third participant. On the other hand, in our proposed scheme, all the three participants are controller as well as sender and receiver. The teleportation processes Alice [Formula: see text] Bob, Bob [Formula: see text] Charlie and Charlie [Formula: see text] Alice are controlled by Charlie, Alice and Bob, respectively, and hence the CYQT could not be realized successfully without the cooperation of all three participants. If any one participant denies to cooperate with other two participants, then the CYQT cannot be realized successfully.

Bidirectional quantum teleportation and cyclic quantum teleportation of multi-qubit entangled states via G-state

We propose a novel scheme for faithful bidirectional quantum teleportation (BQT) in which Alice can transmit an unknown N-qubit entangled state to Bob and at the same time Bob can transmit an unknown M-qubit entangled state to Alice by using a four-qubit entangled G-state as a quantum channel. We also propose a new scheme for cyclic QT of multi-qubit entangled states by using two G-states as a quantum channel. The advantage of our schemes is that it seems to be much simpler and requires reduced number of qubits in quantum channel as compared with the other proposed schemes.