In this paper, two conclusive three-party cyclic assisted cloning protocols in amplitude damping (AD) channel are put forward that, respectively clone three arbitrary unknown single-qubit states and single-qutrit states with the help of a state preparer. Each of our protocols includes three consecutive stages: quantum channel preparation, cyclic quantum teleportation (CQT), and multi-party assisted cloning. The first stage of each protocol proposes the detailed processes of sharing a pure entangled quantum state as a component of a quantum channel in AD channel via entanglement compensation. In second stage, a three-party CQT is presented where three unknown single-qubit states (or single-qutrit states) are reconstructed simultaneously in three different places, respectively, by introducing auxiliary qubits and performing appropriate operations. In the third stage, the state preparer Victor performs one multi-qubit measurement (or one unitary transformation and one multi-qutrit measurement) and informs the three communicators of his outcome, three distinct unknown single-qubit states or their orthogonal complement states (or single-qutrit states) are cloned simultaneously and with probability at three separate locations,respectively. Furthermore, we extend the above protocols from two aspects: (i) the extension to the case of [Formula: see text] participants; (ii) extension to the case of d-dimensional unknown single-qudit state cycle-assisted cloning.
In this paper, two conclusive three-party cyclic assisted cloning protocols in amplitude damping (AD) channel are put forward that, respectively clone three arbitrary unknown single-qubit states and single-qutrit states with the help of a state preparer. Each of our protocols includes three consecutive stages: quantum channel preparation, cyclic quantum teleportation (CQT), and multi-party assisted cloning. The first stage of each protocol proposes the detailed processes of sharing a pure entangled quantum state as a component of a quantum channel in AD channel via entanglement compensation. In second stage, a three-party CQT is presented where three unknown single-qubit states (or single-qutrit states) are reconstructed simultaneously in three different places, respectively, by introducing auxiliary qubits and performing appropriate operations. In the third stage, the state preparer Victor performs one multi-qubit measurement (or one unitary transformation and one multi-qutrit measurement) and informs the three communicators of his outcome, three distinct unknown single-qubit states or their orthogonal complement states (or single-qutrit states) are cloned simultaneously and with probability at three separate locations,respectively. Furthermore, we extend the above protocols from two aspects: (i) the extension to the case of [Formula: see text] participants; (ii) extension to the case of d-dimensional unknown single-qudit state cycle-assisted cloning.
Abstract The purpose of this article is to explore a scheme for controlled double-direction cyclic (DDC) assisted cloning of arbitrary unknown single-qubit states. We first present a construction method for a 13-qubit entangled quantum state using Hadamard gates and controlled-NOT gates, and subsequently generalize it to a ( 4 n + 1 ) -qubit entangled quantum state. Using the 13-qubit entangled state we constructed as a quantum channel, we propose a novel theoretical scheme for achieving five-party controlled DDC-assisted cloning. The first stage of the scheme involves a controlled DDC quantum teleportation, where each of the three communicators can simultaneously teleport two distinct unknown single-qubit states to the other two, under the supervisor’s control. This process ensures that controlled cyclic quantum communication occurs synchronously in both clockwise and anticlockwise directions. In the second stage of the scheme, with the help of special multi-qubit projective measurements from the state preparer, perfect copies or orthogonal complement copies of the two original unknown single-qubit states can be simultaneously created at each sender’s location. Furthermore, the above presented five-party scheme for controlled DDC-assisted cloning can be extended to scenarios with ( n + 1 ) (n > 3) parties by using the ( 4 n + 1 ) -qubit maximally entangled state as the quantum channel. Moreover, we have provided the mathematical expressions for the general analysis of both the sender’s operations and the receiver’s transformations in each scheme. The study shows that the intrinsic efficiency, security, feasibility, and control power of our scheme are good.
Abstract The purpose of this article is to further investigate the assisted cloning of a d-dimensional arbitrary unknown state by utilizing quantum teleportation (QT) and remote state preparation (RST) techniques. We first propose a scheme for cloning an arbitrary unknown single-qudit state with assistance from a state preparer. In this scheme, the maximally and non-maximally bipartite d-dimensional states are used as quantum channels, respectively. In the first stage of scheme requires usual QT and in the second stage, the state preparer disentangles the left over entangled states by introducing one auxiliary qudit and performing a generalized CNOT, a single-qudit positive operator-valued measurement (POVM) and a single-qudit projective measurement process and conveys some classical messages to different parties so that a copy is produced probabilistically with the unit fidelity.Then by replacing the maximally or non-maximally bipartite d-dimensional entangled channel with a sequence of maximally or non-maximally bipartite d-dimensional entangled states as quantum channel, we can extend the above scheme to the case of cloning a d-dimensional arbitrary unknown m-qudit state with the unit fidelity and a certain probability in the help of the state preparer. PACS numbers 03.67.Hk, 03.67.-a, 03.65.Bz
In this paper, two conclusive multiparty quantum operation sharing (QOS) schemes in amplitude damping channel are proposed to respectively share partially unknown single-qubit unitary operations and single-qutrit unitary operations from the different restricted sets. To reach this target, the detail procedures of using entanglement compensation in amplitude damped channel to share pure entangled quantum states is first proposed. Then, using the pure entangled quantum state shared between the two sender and their two agents as a quantum channel, the dealer’s secret quantum operation, i.e. partially unknown single-qubit unitary operation (or partially unknown single-qutrit unitary operation) can be remotely implemented by the dealer at any one of the locations of all the agents in such way that the unknown quantum state after being acted on by this quantum operation can be probabilistically reconstructed through introducing an auxiliary qubit and performing appropriate local operations provided that two agents collaborate together. Subsequently, the above two schemes are generalized from 2 agents to the scenario of [Formula: see text] ([Formula: see text]) agents. In addition, through our analysis, we have found that in both single-qubit and single-qutrit QOS schemes, the probability of successful recovery of the target state by the receiver after the quantum operation is solely determined by the smaller of the absolute values of the coefficients that characterize the quantum channel. This proves that, under the same amplitude damping strength, the conclusive multiparty single-qutrit QOS has a higher success probability than the single-qubit QOS.
In this paper, two conclusive bidirectional quantum teleportation (BQT) schemes in an amplitude damping channel are put forward. These schemes, respectively, exchange two arbitrary single-qubit states and two arbitrary single-qutrit states between two users, where both users act as senders and receivers. To achieve this, the detailed procedures for using entanglement compensation in an amplitude damped channel to share pure entangled quantum states between two users are first proposed. Then, using the pure entangled four-qubit (or four-qutrit) state shared between the users as a quantum channel, the secret quantum information of each user, i.e. the single-qubit state (or single-qutrit state), is teleported to the other user. This teleportation is designed in such a way that the information can be probabilistically reconstructed by introducing an auxiliary qubit (or qutrit) and executing proper unitary transformations by the receiver. The research results indicate that, whether in single-qubit or single-qutrit state BQT schemes, the success probability of the receiver restoring secret quantum information is determined only by the smaller absolute value of the coefficients characterizing the quantum channel. Additionally, regardless of the noise intensity in the amplitude damping channel, the fidelity of each quantum state transmitted in our BQT schemes can reach 1, which is unattainable in existing BQT schemes based on noisy environments.
In this paper, we propose a scheme that one can realize quantum cloning of an unknown multi-qudit state with assistance offered by a state preparer. Our scheme includes two parties: teleportation and assisted cloning. In order to complete the purpose, one multi-qudit state teleportation at the cloner's site via k entangled pairs as the quantum channel. After the teleportation, the state preparer Victor performs one unitary transformation and one multi-qudit measurement and informs Alice of his outcome to copy the original state. Compared with existing ones in the literature, our scheme generalize assisted cloning scheme to the case of arbitrary multi-qudit state, in the meantime, we also ensure high security of our scheme.
We first propose a novel protocol to realize quantum cloning of an arbitrary unknown shared state with assistance offered by a state preparer. The initial phase of this protocol involves the utilization of quantum teleportation (QT), enabling the transfer of quantum information from an arbitrary number of senders to another arbitrary number of receivers through a maximally entangled GHZ-type state serving as a network channel, without centralizing the information at any specific location. In the second stage of this protocol, the state preparer performs a special single-qubit projective measurement and multiple Z-basis measurements and then communicates a number of classical bits corresponding to measurement results, the perfect copy or orthogonal-complementing copy of an unknown shared state can be produced at senders hands. Then, using a non-maximally entangled GHZ-type state instead of the aforementioned quantum channel, we extend the proposed protocol from three perspectives: projective measurement, positive operator-value measurement (POVM), and a single generalized Bell-state measurement. Our schemes can relay quantum information over a network without requiring fully trusted central or intermediate nodes, and none of participants can fully access the information.