Schemes for generation and protocols for network teleportation of multimode entangled cat-states are proposed. Explicit expressions for probability of successful teleportation are derived for both symmetric and asymmetric networks.
We present a scheme of quantum repeater that uses entangled multimode coherent states that are obtained by electro-optic modulation of symmetric and antisymmetric Schr\"odinger cat states. Part of the generated entangled frequency modes is sent to a symmetric beam splitter at the central node, while the remaining modes are stored locally in quantum memories. The entangled coherent states between remote quantum memories are conditionally prepared by photon-counting measurements at the output channels of the beam splitter. We study how the effects of decoherence in the quantum channel affect statistics of photocounts and, for the heralding outcomes determined by the parity of photocounts, evaluate the probability of success and the fidelity of the prepared entanglement depending on the symmetry of input cat states. It is demonstrated that the generated entanglement can be employed for teleportation of the phase information from the modulated states that are utilized in quantum key distributions with subcarrier wave encoding.
Abstract We investigate bidirectional teleportation that works in a fair and efficient manner. Two explicit protocols are proposed to realize bidirectional teleportation with a controller. One is a symmetric protocol for two-qubit states. The other is an asymmetric protocol for single- and two-qubit states. We then devise a universal protocol for arbitrary n 1 - and n 2 -qubit states via a (2 n 1 + 2 n 2 + 1)-qubit entangled state, where n 1 ≤ n 2 . The receiver only needs to perform the single-qubit recovery operation, which is derived by a general expression. Moreover, a (2 n 1 + 1)-bit classical communication cost can be saved within the controller’s broadcast channel by the use of network coding technology.
This study advances economical Quantum Teleportation (QT) schemes for cat states across arbitrary dimensional Hilbert spaces. First, we develop a protocol for teleporting an unknown two-dimensional cat state using a three-dimensional maximally entangled three-qutrit quantum channel. The approach involves constructing a complete orthogonal nonsymmetric measurement basis, where the sender performs joint measurements on three particles. The receiver then applies dimension-specific unitary operations conditioned on measurement outcomes to reconstruct the target state. Subsequently, we extend this protocol by replacing the maximally entangled channel with a nonmaximally entangled three-qutrit state. Through auxiliary qubit introduction and optimized operations, the two-qubit cat state is probabilistically recovered. We derive the success probability for both protocols, demonstrating that the nonmaximally entangled case generalizes the former scheme. Further generalization is achieved through two nonsymmetric basis constructions: (i) Scaling quantum channel dimension from 3 to [Formula: see text] dimensions; (ii) Extending transmitted cat states from 2 to [Formula: see text] dimensions [Formula: see text]. These dual-dimensional generalizations establish distinct economical advantages over existing QT schemes.