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How far is the distance between the two is obtained through mutually entangled particles. A far as long as the state of one particle changes, so as the state of the other particle instantaneously change. We present a scheme for hierarchical quantum teleportation via a four-qubit cluster state, where a sender distributes asymmetrically a quantum state to distant agents. This asymmetrically distribution leads to different agents to have different authority to reconstruct the secret quantum information. Furthermore, the hierarchical quantum teleportation of an arbitrary single-qubit state can be realized in cavity quantum electrodynamics (QED) systems.

In this paper, a theoretical scheme for bidirectional quantum teleportation by using a four-qubit GHZ state and two Bell states as a quantum channel is proposed. In this scheme, two arbitrary single-qubit quantum states and an unknown three-qubit state can be mutually transmitted between the two communication participants Alice and Bob. The quantum state information can be transmitted if Alice performs four single-qubit measurement operations on her qubits and Bob carries out a four-qubit joint measurement on his qubits, respectively. Then both Alice and Bob can reconstruct the target quantum state by means of appropriate unitary operations. Then we take comparisons with the other bidirectional quantum teleportation protocols in five aspects of quantum information bits transmitted, necessary operations, consumption of quantum resource, consumption of classical resource and intrinsic efficiency. Furthermore, we use channel authentication method to ensure the channel security and prove that our protocol can withstand four attack scenarios. It is concluded that our scheme has significant advantages of more qubits number transmitted, higher intrinsic efficiency and high security.

We present a scheme that Quantum decoherence problem in quantum teleportation process in two three-level system. Evolution of entanglement of two V-type three-level atom system with time were studied under the vacuum radiation field. When the distance between two atoms is far, that is, the two atoms are independent of each other, at this time, under the action of the vacuum radiation field, the atomic entanglement will suddenly die after a period of time; When the distance between two atoms is very small, the co-operative effect induced by the vacuum radiation field between atoms may appear entangled and suddenly recover after death. We then design the related parameter of entanglement death and entanglement, in order to find out the cause of the entanglement death in order to address them, thereby improving the quality of quantum communication.

In this paper, we show that current two different quantum channels of two three-qubit GHZ states and the six-qubit entangled state can be used for quantum teleportation of an arbitrary two-qubit state deterministically. Moreover, we propose two distinct protocols for quantum teleportation of an arbitrary two-qubit state within a three-qubit, by using a single-qubit measurement under the basis and also using a two-qubit projective measurement under the basis $$\{|+\rangle ,|-\rangle \}$$ , so as to get 16 kinds of possible measured results with equal probability of 1/4. Furthermore, the deterministic quantum teleportation of an arbitrary two-qubit states can be realized in a cavity quantum electrodynamics systems. This is unique, in that a cluster state has a maximal persistence when compared with a entangled state and it is also more robust against decoherence. Furthermore, the schemes are secure against internal and external attacks.

With the advent of the Internet and information and communication technology, quantum teleportation has become an important field in information security and its application areas. This is because quantum teleportation has the ability to attain a timely secret information delivery and offers unconditional security. And as such, the field of quantum teleportation has become a hot research topic in recent years. However, noise has serious effect on the safety of quantum teleportation within the aspects of information fidelity, channel capacity and information transfer. Therefore, the main purpose of this paper is to address these problems of quantum teleportation. Firstly, in order to resist collective noise, we construct a decoherence-free subspace under different noise scenarios to establish a two-dimensional fidelity quantum teleportation models. And also create quantum teleportation of multiple degree of freedom, and these models ensure the accuracy and availability of the exchange of information and in multiple degree of freedom. Secondly, for easy preparation, measurement and implementation, we use super dense coding features to build an entangled quantum secret exchange channel. To improve the channel utilization and capacity, an efficient super dense coding method based on ultra-entanglement exchange is used. Thirdly, continuous variables of the controlled quantum key distribution were designed for quantum teleportation; in addition, we perform Bell-basis measurement under the collective noise and also prepare the storage technology of quantum states to achieve one-bit key by three-photon encoding to improve its security and efficiency. We use these two methods because they conceal information, resist a third party attack and can detect eavesdropping. Our proposed methods, according to the security analysis, are able to solve the problems associated with the quantum teleportation under various noise environments.

In this paper, we present a scheme for quantum dialogue by using a four-qubit cluster state as quantum channel.The scheme has two cases: Case 1, Sender Alice and receiver Bob share information using an orderly sequence of entangled state as quantum channel which was prepared by Alice. This case is achieved as follows: The two sides agreed to encode quantum state information, then Alice perform a bell state measurement for quantum information which has been encoded. This will convey the information to Bob, then Bob measuring his own qubits, through the analysis of the measurement results of Alice and Bob, Bob can obtain quantum information. For case 2, four-qubit cluster state and quantum state information is transmitted to form a total quantum system. In the Case 2 scenario, Alice and Bob perform bell state measurements for part of the qubits, and tell the measurement result to each other through the classical channel. Finally, according to the measurement result, Alice and Bob operate an appropriate unitary transformation, as a result, Alice’s qubit will be renewed upon Bob’s measurements, and also, Bob’s qubit will be renewed upon Alice’s measurements. Thus, a bidirectional quantum dialogue is achieved. After analysis, this scheme has high security by taking certain eavesdropping attacks into account. There is therefore a certain reference value to the realization of quantum dialogue.

In this paper, we proposed a scheme for quantum information splitting of arbitrary two-qubit by using four-qubit cluster state and Bell-state as quantum channel. The splitter (Alice) and two receivers (Bob and Charlie) safely share a four-qubit cluster and Bell-state as quantum channel. Then, the sender Alice first performs Bell-state measurement (BSMs) on her qubit pairs, respectively, and tells the results to the receiver Bob and Charlie via a classical channel. But it is impossible for Bob to reconstruct the original state with local operations without help from Charlie. If Charlie allows Bob to reconstruct the original state information, he also needs to perform BSMs on his qubits and tell Bob the measurement result. Using the measurement results from Alice and Charlie, Bob can reconstruct the original state by applying the appropriate unitary operation. The scheme is tested against various attack scenarios such as eavesdropping attack, eavesdropping in the presence of a malicious attacker and even in the presence of a dishonest agent and found to be secure in all these cases. In addition, the deterministic quantum information splitting of arbitrary two-qubit state in cavity quantum electrodynamics is implemented.

In this paper, we use the idea of quantum Graphic Cascade Coding, information security and quantum random coding to construct an immune noise channel, by using the normal state of pattern tree chart and forest chart, to make large diagonal matrices or blocks, in order to perform quantum coding operations under multiple degrees of freedom. Through calculation and analysis of different concatenated code channel capacity, we get the formula of different noise channels in multi-channel coherence information under the coder multiple degrees of freedom. By this, we can quickly calculate the coherence information of various concatenated codes in the channel, the approximation of the channel capacity and the noise margin of the channel transmission quantum, and analyze the different anti-noise performance of different cascaded codes in different parameter channels. And, thus, we can obtain the security regions where different noise channels can transmit quantum information.

In this paper, we propose a scheme of quantum information splitting arbitrary three-qubit state by using seven-qubit entangled as quantum channel. The sender Alice first performs Bell-state measurements (BSMs) on her qubits pairs respectively and tells her measurement outcome to authorizers Bob to reconstruct the original state, then Charlie should carries out single-qubit measurement (SQM) on his qubits. According to the results from Alice and Charlie, Bob can reconstruct the original state by applying an appropriate unitary operation. After analyzing, the method achieved the desired effect of quantum information splitting (QIS). We also realize the QIS of arbitrary three-qubit state in cavity quantum electrodynamics (QED).