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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.

We propose a scheme for Quantum Information Splitting of Arbitrary Two-qubit State via a Five-qubit Cluster State and a Bell-state as the quantum channels. There exist a sender (Alice) and two receivers (Bob and Charlie), who share a seven-qubit cluster state as the quantum channel. Alice performs a Bell-state measurements (BSMs) on her qubit pairs, Alice reveals the results to Bob and Charlie via a classical channel. If it is impossible without the help from Charlie for Bob to reconstruct the original information. Charlie performs GHZ-state measurements on his particles and informs Bob about the result. Bob will perform unitary operations to reconstruct the original state information. This scheme is tested for different eavesdropping attacks, of which eavesdropping is easy to detect. In addition, we compared the agreement, such as the number of particles in the program itself, the method of measurement and the efficiency of measurement, etc. All of those prove the innovation of the comprehensive measurement method in this experiment. Overall, we can get the conclusion from the comparison that the scheme is more stable and robust in terms of transmission efficiency and security.

Handwritten numeral recognition is a technology for automatic recognition and classification of handwritten numeral input through machine learning model. This is widely used in postal code digital automatic system to sort letters. The classical k-nearest neighbor algorithm is used in the traditional digital recognition training model. The recognized digital image classification is obtained through similarity measure or calculation and K value selection. Nonetheless, as the applied data volume exceeds a certain threshold, the time complexity of the model increases exponentially upon the similarity measure and K value search. This condition makes it hard to apply the model universally. In this paper, we introduce quantum computing, that is where digital image information is stored in the quantum state, and its similarity is calculated in parallel. Also, the most similar K points are obtained through the Grover algorithm. The theoretical analysis of the proposed improved algorithm shows that, handwritten numeral recognition based on quantum k-neighbor algorithm can improved upon time complexity of $$ \mathrm{O}\left(\mathrm{R}\sqrt{kM}\right) $$ of the existing algorithm.

With the rapid development of the Internet, e-commerce plays an important role in people’s lives, and the recommendation system is one of the most critical technologies. However, as the number of users and the scale of goods increase sharply, the traditional collaborative filtering recommendation algorithm has a large computational complexity in the part of calculating the user similarity, which leads to a low recommendation efficiency. In response to the above problems, this paper introduces the concept of quantum computing theory. The user score vector is first prepared into a quantum state, the similarity score is calculated in parallel, then the similarity information is saved into the quantum bit, and finally the similar user is searched by the Grover search algorithm. Compared with the traditional collaborative filtering recommendation algorithm, the time complexity of the collaborative filtering recommendation algorithm based on Grover algorithm can be effectively reduced under certain conditions.

We analyze the properties of immune noise model and propose a noise model that achieves high fidelity and in secure channel. We focuse on four different types of channel properties which include bit-flipping noise, phase-flip or phase-damping noise, depolarization noise, and amplitude-damping noise. Finally, we analyze Alice’s qubit efficiency and all quantum bit efficiency in noise, and further design a high-fidelity immunity noise model based on density matrix. This research article is one of the cores of constructing a unified framework for high-fidelity secure communication channels. we also using decoherence-free subspaces (DFS) immune combined noise characteristics, a generalized entangled states to convert IDs that are initially shared by both the parties into logical quantum states for noise immunity, randomly mixed message sequence and transmitted.

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 present a scheme that solves the entanglement death problem by using a quantum entanglement model. We solved this problem by analyzing the evolutionary properties of entanglement together with the time evolution of the two atomic systems that are independent of each other in space. 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.

The major problem faced by photons propagating through a physical channel is that of collective noise. This collective noise has the ability to reduce the number of quantum bits that are transmitted, thereby reduces the message fidelity. The traditional method of noise immunity is the use of entanglement purification, which consumes a lot of quantum resources in accomplishing the joint probability of noise immunity but does not guarantee accurate quantum dialog. In this paper, we investigate a new approach to quantum dialogue in which quantum information can be faithfully transmitted via a noisy channel. we constructs corresponding Decoherence Free Subspace(DFS), the quantum state after the change is in the maximally entangled state, so as to realize the fidelity of quantum dialogue model that can ensure the accuracy and noise resistance, and secret information exchange.

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 demonstrate how a five-qubit entangled state can be used to realize the deterministic Quantum State Sharing (QSTS) of a single and two-qubit state among three parties by performing von-Neumann measurement and bell-state measurements. In our scheme, any of the two agents has the ability to reconstruct the original state if he/she collaborates with the other agent,otherwise an individual agent does not have enough information to reconstruct the original state. The paper also outlines the various measurements and mathematical framework of the scheme. The security analysis of our scheme against two attacks scenarios prove that the scheme is secure against an eavesdropper attack and a malicious attacks.

Quantum secure communication of dephasing in the presence of noise is a hot spot in research in the field of quantum secure communication. Quantum steganography aims is to transfer secret information in public quantum channel. But because effect of annealing phase noise, quantum states which is need to transfer easily delayed or changed. So, quantum steganography is very meaning apply to transmit secret information covertly in quantum noisy channels. The article introduced dephasing noise impact on the physics of quantum state, through the theoretical research, construct the logic of quantum states to back the phase noise immunity, and construct the decoherence free subspace, It can guarantees fidelity secret information exchange through quantum communication model in a noisy environment.

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.

A scheme is proposed for quantum information splitting of arbitrary three-qubit state by using four-qubit cluster state and GHZ state as quantum channel. In the scenario, assume that the sender is called Alice, the receiver is called Bob and the controller id called Charlie. First of all, Alice performs Bell-state measurements on her qubit paris (A, 1), (B, 3), (C, 5), respectively. And then tells Charlie and Bob measure results via a classical channel. It is impossible for Bob to reconstruct the original state with local operation; if Charlie allows Bob to reconstruct the original states, he needs to perform a single particle measurement on his particle and tells Bob the results. According to the information from Alice and Charlie, Bob can reconstruct the original state with an appropriate unitary operation of his qubits 2, 4, 6.We also consider the problem of security attacks .This protocol is considered to be secure.