Quantum teleportation is a cornerstone protocol for future quantum networks and distributed quantum com- puting. However, scaling teleportation to an arbitrary N- qubit state using conventional methods, which require N separate Bell pairs, presents a significant challenge in terms of both quantum and classical resource overhead. This paper introduces a novel and resource-efficient protocol for tele- porting an arbitrary N-qubit state using a single, pre-shared (N+1)-qubit Greenberger-Horne-Zeilinger (GHZ) state. Our approach reduces the required entangled channel qubits and classical communication bits from O(2N) to N+1, offering a substantial improvement in communication efficiency. The protocol mechanism involves a sequence of local and non-local CNOT gates performed by the sender (Alice), followed by local measurements on her N+1 qubits. The N+1 classical measurement outcomes are then transmitted to the receiver (Bob), who recovers the original quantum state by applying a specific corrective unitary transformation U-f, followed by a set of conditional Pauli gates. We provide a high-level proof of the protocol’s correctness and show that the corrective trans- formation U-f can be implemented efficiently using only local operations on the receiver’s side. Recognizing the practical difficulty of implementing non-local quantum gates between spatially separated nodes, we also propose a modified scheme to enhance near-term feasibility. This practical approach re- locates the non-local operations to a co-located preparation phase, thereby trading the formidable challenge of non-local interactions for a high-fidelity quantum memory requirement. This work analyzes the critical trade-offs between communication efficiency and operational complexity, presenting a vi- able alternative for designing scalable and resource-optimized quantum communication systems.
Quantum teleportation is a cornerstone protocol for future quantum networks and distributed quantum com- puting. However, scaling teleportation to an arbitrary N- qubit state using conventional methods, which require N separate Bell pairs, presents a significant challenge in terms of both quantum and classical resource overhead. This paper introduces a novel and resource-efficient protocol for tele- porting an arbitrary N-qubit state using a single, pre-shared (N+1)-qubit Greenberger-Horne-Zeilinger (GHZ) state. Our approach reduces the required entangled channel qubits and classical communication bits from O(2N) to N+1, offering a substantial improvement in communication efficiency. The protocol mechanism involves a sequence of local and non-local CNOT gates performed by the sender (Alice), followed by local measurements on her N+1 qubits. The N+1 classical measurement outcomes are then transmitted to the receiver (Bob), who recovers the original quantum state by applying a specific corrective unitary transformation U-f, followed by a set of conditional Pauli gates. We provide a high-level proof of the protocol’s correctness and show that the corrective trans- formation U-f can be implemented efficiently using only local operations on the receiver’s side. Recognizing the practical difficulty of implementing non-local quantum gates between spatially separated nodes, we also propose a modified scheme to enhance near-term feasibility. This practical approach re- locates the non-local operations to a co-located preparation phase, thereby trading the formidable challenge of non-local interactions for a high-fidelity quantum memory requirement. This work analyzes the critical trade-offs between communication efficiency and operational complexity, presenting a vi- able alternative for designing scalable and resource-optimized quantum communication systems.
Quantum teleportation is important for quantum communication. We propose a protocol that uses a partially entangled Greenberger–Horne–Zeilinger (GHZ) state for single hop teleportation. Quantum teleportation will succeed if the sender makes a Bell state measurement, and the receiver performs the Hadamard gate operation, applies appropriate Pauli operators, introduces an auxiliary particle, and applies the corresponding unitary matrix to recover the transmitted state.We also present a protocol to realize multiple teleportation of partially entangled GHZ state without an auxiliary particle. We show that the success probability of the teleportation is always 0 when the number of teleportations is odd. In order to improve the success probability of a multihop, we introduce the method used in our single hop teleportation, thus proposing a multiple teleportation protocol using auxiliary particles and a unitary matrix. The final success probability is shown to be improved significantly for the method without auxiliary particles for both an odd or even number of teleportations.
A multiparty-controlled teleportation (M-CT) scheme for securely teleporting an arbitrary unknown single-qubit state by using generalised Greenberger-Horne-Zeilinger (GHZ) states is presented in this paper, i.e., a sender, Alice, transmits an arbitrary single-qubit state to a distant receiver, Bob, under approving by all N controllers Charliei(i = 1, 2, …, N) in a quantum communication network. It is proved feasibly and easily to realise by quantum entanglement. The security of proposed scheme is also discussed. We make sure of the security of the quantum channel between the parties by decoy states. This scheme also can be used to share a quantum secret information in quantum secret sharing.
In this work, we consider the following teleportation protocol: There is an arbitrary two-qubit resource state, shared between two spatially separated parties, Alice and Bob. Applying local unitary operators, they transform the resource state into the canonical form. To teleport an unknown qubit, Alice now measures her qubits in the Bell basis. Then, the measurement outcome is communicated by Alice to Bob via noisy classical channel(s). Finally, after receiving the classical message, Bob applies the necessary unitary operator to his qubit. Under this protocol, we find the exact formulae of teleportation fidelity and its deviation. We further find conditions for non-classical fidelity within this protocol. If the classical communication is noiseless in the above protocol then there are resource states which can lead to zero fidelity deviation. However, we show that such states may not lead to zero fidelity deviation when the classical communication is noisy in the same protocol. We also explore the opposite case, i.e., the states, which cannot lead to zero fidelity deviation in the above protocol when the classical communication is noiseless, may lead to zero fidelity deviation when the classical communication is noisy in the same protocol without compromising the non-classical fidelity. Moreover, we exhibit scenarios within the present protocol, where the fidelity deviation increases if the entanglement of the resource state is increased.
Teleporting an unknown qubit state is a paradigmatic quantum information processing task revealing the advantage of quantum communication protocols over their classical counterpart. For a teleportation protocol using a Bell state as quantum channel, the resource has been identified to be the concurrence. However, for mixed multipartite states the lack of computable entanglement measures has made the identification of the quantum resource responsible for this advantage more challenging. Here, by building on previous results showing that localizable concurrence is the necessary resource for controlled quantum teleportation, we show that any teleportation protocol using an arbitrary multipartite state, that includes a Bell measurement, requires a nonvanishing localizable concurrence between two of its parties to perform better than the classical protocol. By first analyzing Greenberger–Horne–Zeilinger (GHZ) channel and GHZ measurement teleportation protocol, in the presence of GHZ-symmetric-preserving noise, we compare different multipartite entanglement measures with the fidelity of teleportation, and we find that the protocol performs better than the classical protocol when all multipartite entanglement measures vanish, except for the localizable concurrence. Finally, we extend our proof to an arbitrary teleportation protocol with an arbitrary multipartite entangled channel.
This study presents a generalized n--bit superdense coding protocol that enables the transmission of n classical bits of information using an entangled n--qubit quantum system and the transmission of n−1 qubits. The protocol involves creating a maximally entangled n--qubit GHZ state, encoding the classical message with Pauli--Z and Pauli--X gates, and then transmitting and decoding the message via quantum communication, quantum operations, and measurements. The key novelty of this work is an explicit, scalable n--bit encoding routine, realized on the GHZ channel with a low--depth encoding layer using only single--qubit Pauli--X and Pauli--Z operations.
The protocol was tested on real quantum hardware using Qiskit 2.0 and the IBM--Fez quantum computer for message lengths of 4, 6, 8, and 10 bits, as a circuit--level proof of concept on a single processor; the physical transmission of qubits between the parties was not implemented. Results show that success rates decrease as message length, transpiled circuit depth and gate count increase; the latter two are set mainly by transpilation rather than by the encoding itself. A mutual information analysis shows that the transmitted information exceeds the classical bound of n−1 bits only for short messages. Strategies to improve performance include sending messages in shorter segments and advances in qubit coherence and gate fidelity. This work offers a practical and easily scalable quantum communication protocol with potential applications in quantum networks and communication systems.
We introduce an efficient and versatile quantum teleportation protocol for specific types of n-qubit entangled states. By employing a partially entangled Greenberger-Horne-Zeilinger (GHZ) state as the quantum channel and an optimal Positive Operator-Valued Measure (POVM) based on an improved reciprocal state formulation, we achieve unambiguous state discrimination. The scheme has been generalized to support various entangled state configurations and demonstrates a notable reduction in classical communication costs for these states compared to standard Bell-basis teleportation. Its capacity for integration with conventional protocols is pivotal, enhancing quantum hop-by-hop communication security by allowing strategic choices in quantum channel and teleportation strategy