Abstract Ensuring information security in quantum communication often requires a supervisory mechanism to regulate and authenticate information transmission. In this study, we investigate controlled quantum teleportation (CQT) and controlled dense coding (CDC) using parameterized three-particle pure states as quantum channels. We assess the authority of the controlling party through two key metrics: uncontrolled fidelity and minimal control power. Our analysis reveals that for single-parameter three-particle pure states, when no controlling party is involved, the average uncontrolled fidelity exceeds the classical fidelity threshold, rendering them unsuitable as arbitrary single-particle CQT channels. For multi-parameter three-particle pure states, we derive explicit parameter conditions under which non-trivial control power emerges and provide analytical expressions for several representative cases. Additionally, in the context of CDC, we quantify the minimal control power required when employing single-parameter three-particle states as quantum channels. Our findings establish rigorous criteria for controller authority in parameterized quantum communication, offering both theoretical guarantees and practical insights for secure quantum networks. This work lays the foundation for adaptive quantum protocols where control power and fidelity can be dynamically optimized to enhance security and performance in real-world implementations.
Abstract Ensuring information security in quantum communication often requires a supervisory mechanism to regulate and authenticate information transmission. In this study, we investigate controlled quantum teleportation (CQT) and controlled dense coding (CDC) using parameterized three-particle pure states as quantum channels. We assess the authority of the controlling party through two key metrics: uncontrolled fidelity and minimal control power. Our analysis reveals that for single-parameter three-particle pure states, when no controlling party is involved, the average uncontrolled fidelity exceeds the classical fidelity threshold, rendering them unsuitable as arbitrary single-particle CQT channels. For multi-parameter three-particle pure states, we derive explicit parameter conditions under which non-trivial control power emerges and provide analytical expressions for several representative cases. Additionally, in the context of CDC, we quantify the minimal control power required when employing single-parameter three-particle states as quantum channels. Our findings establish rigorous criteria for controller authority in parameterized quantum communication, offering both theoretical guarantees and practical insights for secure quantum networks. This work lays the foundation for adaptive quantum protocols where control power and fidelity can be dynamically optimized to enhance security and performance in real-world implementations.
Quantum teleportation stands as a cornerstone of quantum communication, enabling the transmission of an unknown quantum state—typically a qubit—from a sender to a receiver without the physical transfer of the particle itself. In this study, we explore two novel teleportation protocols within the framework of ternary quantum logic, which extends conventional binary systems by incorporating three distinct quantum states, known as qutrits. This ternary paradigm introduces richer computational possibilities and more nuanced entanglement structures compared to binary logic. Both protocols incorporate a supervisory controller to regulate the transmission. The first proposed scheme utilizes entanglement swapping between two qutrits to achieve the teleportation of a qutrit. This approach demonstrates the feasibility of ternary teleportation using minimal entangled resources. The second scheme builds upon this foundation by employing entanglement swapping among three qutrits, offering enhanced control. In the second scheme, the controller remains actively embedded in the quantum circuit throughout the protocol, with the authority to abort or validate the teleportation either at the beginning of protocol or at the end, thereby introducing dynamic control. Direct entanglement between distant parties like Alice and Bob is often infeasible due to channel noise and losses, but using an intermediary party who shares entangled pairs with each party, enables long-distance entanglement, which is crucial for scalable quantum networks and quantum repeaters. This modular approach not only enhances the security and reliability of quantum communication by managing errors locally but also offers flexibility and practicality in real-world systems by facilitating entanglement through local intermediaries.
Controlled quantum teleportation (CQT) is a key technique that allows quantum information to be transmitted over a quantum network under the control of a network administrator/ firewall. Existing CQT protocols rely on complex entanglement structures or increased number of qubits to enhance the administrator’s ability to block unauthorized communication, referred to as the control level, which poses practical challenges on current quantum hardware due to decoherence and the fragility of quantum states. In contrast, we propose efficient single and dual controller protocols that improve the control level, while using practical and experimentally feasible entanglement resources such as GHZ and GHZ-like states. The proposed protocols adopt quantum hiding to enhance the network’s control level, whether the receiver is compliant or non-compliant with the protocol. The dual-controller design further enables the integration of demilitarized zones (DMZs) into quantum networks, providing isolated intermediate regions jointly governed by two controllers and strengthening security boundaries. Our results demonstrate that the single-controller protocol achieves 87.5% control, reflecting a 75% improvement over the standard CQT scheme, while the dual-controller protocol achieves 98.44% control, corresponding to a 96.88% improvement. This improvement is achieved at a low cost of 2−9% reduction in the rate of successful teleportation when tested in noisy environments. In addition, both protocols maintain high state-averaged teleportation fidelity across randomly generated input states. When benchmarked against existing protocols, the proposed schemes demonstrate superior performance by achieving the highest efficiency while using the least amount of quantum resources.
In this work, we investigate controlled quantum teleportation in the presence of noisy channels acting on the three-qubit resource state. We employ a series of generalized noisy channels that bridge the dephasing channels and amplitude damping channels while encompassing extensive intermediate scenarios. We provide an in-depth analysis of the degradation of the maximal average fidelity and the optimal average fidelity in controlled quantum teleportation induced by such noisy channels by deriving the analytical expression and examining several special cases. The analytical expression shows that attaining the optimal average fidelity requires Charlie's cooperation in performing a measurement at suitably chosen angles, and is also related to the initial state and the channel parameters. Our analysis reveals that the optimal average fidelity does not always decrease monotonically with the evolution parameter, instead, it first decreases and then increases. This non-monotonic behavior depends on the entanglement of the initial resource state, as well as on the parameters of the channel traversed by the first qubit.
Quantum teleportation (QT) is the principal method of transferring quantum states from one place to another without actually revealing which quantum state is being transferred. This protocol makes use of entangled states shared between the sending and receiving stations, and two bits of classical information. However, in real communication systems which are used to carry the entangled state, a typical noise results in the degradation of the fidelity of teleported states. The protocol of controlled quantum teleportation (CQT) represents an extension to the standard quantum teleportation (SQT) with includes the third entity, so called “controller“, and is based on sharing of a tripartite entangled quantum state. The role of controller is to permit the fidelity of teleported state to be higher than it can be done using only classical resources.
As a typical noise has detrimental effect on the performance of quantum teleportation protocols, In this work, a study of different noisy channels, which can exhibit the Markovian or non-Markovian dynamics is presented. Each noisy channel is characterized by the teleportation fidelity and by the control power.
Abstract The purpose of this paper is to further investigate the correlated and memory effects in 3D-Pauli-like noisy channels for controlled teleportation of an arbitrary unknown single-qutrit state. We first construct a three-qutrit maximally entangled state in a three-dimensional (3D) Hilbert space and subsequently propose a 3D controlled quantum teleportation (CQT) scheme for an arbitrary unknown single-qutrit state using the constructed three-qutrit maximally entangled state as the quantum channel. In this ideal case, through a few simple 3D unitary operations, the two communicating parties can perfectly accomplish the teleportation task under the supervision of the controller. Subsequently, we examine the performance of this CQT scheme under two successive uses of a 3D-Pauli-like noisy channel with memory, where the noise errors are categorized into four types: trit-flip, t-phase-flip, trit-phase-flip, and t-depolarizing. For each noise type, an analytical expression of the average fidelity is derived as a function of both the noise and memory parameters. Specifically, we find that, regardless of the noise strength, memory enhances the average fidelity for trit-flip and t-depolarizing noises, whereas for t-phase-flip and trit-phase-flip noises, memory reduces the average fidelity once the noise intensity exceeds a certain threshold. This indicates that in the first two noisy channels, memory can improve the communication efficiency of CQT, while in the latter two, excessive noise causes memory to diminish the teleportation performance.
We analyze and evaluate perfect controlled teleportation via three-qubit entangled channels from the point of view of the controller. The key idea in controlled teleportation is that the teleportation is performed only with the participation of the controller. We calculate a quantitative measure of the controller's power and establish a lower bound on the control power required for controlled teleportation. We show that the maximally entangled Greenberger-Horne-Zeilinger state is a suitable channel for controlled teleportation of arbitrary single qubits---the controller's power meets the bound and the teleportation fidelity without the controller's permission is no better than the fidelity of a classical channel. We also construct partially entangled channels that exceed the bound for controlled teleportation of a restricted set of states called the equatorial states. We calculate the minimum entanglement required in these channels to exceed the bound. Moreover, we find that in these restricted controlled teleportation schemes, the partially entangled channels can outperform maximally entangled channels with respect to the controller's power. Our results provide an alternative perspective on controlled teleportation schemes and are of practical interest since we propose useful partially entangled channels.