Controlled Dense Coding with Symmetric State

Two schemes, introducing the projective operator and the auxiliary qubit respectively, for controlled dense coding are investigated by using a three-qubit symmetric state with entanglement, where the supervisor (Cliff) can control an average amount of information transmitted from the sender (Alice) to the receiver (Bob) by adjusting the measurement angle θ. We show that the results for the average amounts of information are unique from the different two schemes. The schemes may be extended to many-qubit systems.     

Scheme for Implementing Controlled Dense Coding with Six-Atom Cluster State in Cavity QED

We propose an experimentally feasible protocol for implementing controlled dense coding with a six-atom cluster state in cavity QED. In the scheme, we investigate that the atoms interact simultaneously with the highly detuned single-mode cavity and the strong classical driving field, and thus our scheme is not sensitive to both the cavity decay and the thermal field. In addition, the four-atom entangled states can be exactly distinguished by performing the single-atom measurements in cavity QED, therefore our scheme might be implemented in a simple way.     

Quantum Dense Coding Without Joint Measurement

We propose two schemes for quantum dense coding without Bell states measurement. One is deterministic, the other is probabilistic. In the deterministic scheme, the initial entangled state will be not destructed. In the proba-bilistic scheme, the initial unknown nonmaximal entangled state will be transformed into a maximal entangled one. Our schemes require two auxiliary particles and perform single-qubit measurements on them. Thus our schemes are simple and economic.     

Quantum Dense Coding Without Joint Measurement

We propose two schemes for quantum dense coding without Bell states measurement. One is deterministic, the other is probabilistic. In the deterministic scheme, the initial entangled state will be not destructed. In the probabilistic scheme, the initial unknown nonmaximal entangled state will be transformed into a maximalentangled one. Our schemes require two auxiliary particles and perform single-qubit measurements on them. Thus our schemes are simple and economic.     

Scheme for Controlled Dense Coding via Cavity Decay

A scheme for controlled dense coding via cavity decay is proposed. In the scheme, two degenerate ground states of six-level atoms are used as the storage qubits and the leaky photons act as flying qubits. The system is robust against atomic spontaneous emissions and decoherence of cavity field. And the successful probability is nearly 1 with quantum nondemolition parity detectors and photon detectors, The scheme may be realized based on current technologies.     

Scheme for Controlled Dense Coding via Cavity Decay

A scheme for controlled dense coding via cavity decay is proposed. In the scheme, two degenerate ground states of six-level atoms are used as the storage qubits and the leaky photons act as flying qubits. The system is robust against atomic spontaneous emissions and decoherence of cavity field. And the successful probability is nearly 1 with quantum nondemolition parity detectors and photon detectors. The scheme may be realized based on current technologies.     

Quantum Teleportation and Dense Coding in Multiple Bosonic Reservoirs

The effect of a reservoir on quantum communication depends on its spectral density. The efficiency of quantum teleportation and dense coding is explored when each one of the channel qubits is coupled simultaneously to multiple bosonic reservoirs. It is shown that the non-Markovianity triggered by increasing the reservoir number can induce revivals of quantum advantages of the two protocols after their disappearance. However, the backflow of information to the system that signifies non-Markovianity does not always induce immediate revivals of the quantum advantages. There may be a delayed effect for some initial states, and only as the backflow of information accumulates to a certain extent can the revivals of quantum advantages be triggered.     

用三比特海森堡XXZ模型实现量子稠密编码

本文主要研究利用各向异性三比特海森堡XXZ模型实现量子稠密编码的理论可行性问题并讨论在有限温度下,xy平面上的耦合常数J,z方向的耦合常数Jz,以及外加磁场对稠密编码信道容量的影响。结果表明,耦合常数J对量子稠密编码信道容量起到积极作用。尽管耦合常数Jz,外加磁场B及温度T均抑制量子稠密编码的信道容量,但是在一定范围内J总可以抵消这些参数的消极作用并提高信道容量。     

Efficient Scheme for Dense Coding in Cavity QED and Ion Trap Systems

We propose a scheme for realizing dense coding in cavity QED. The scheme is based on the resonant interaction of two atoms with a cavity mode. The scheme may be realizable with presently available techniques in the microwave cavity QED setup. The idea can also be generalized to the ion trap system.     

Scheme for Quantum Dense Coding with Secret Sharing in Cavity QED

Quantum dense coding （QDC） is a process originally proposed to send two classical bits information from a sender to a receiver by sending only one qubit. Our scheme of QDC is proposed following some ideas on secret sharing with entanglement in cavity QED. Based on the theory of secret sharing the QDC process can be more secure.     

Scheme for Implementing Quantum Dense Coding and Teleportation with Tripartite Entangled State in Cavity QED

In this paper, we present a peculiar tripartite entangled state that is inequivalent to both the GHZ state and the W state, and then propose to implement efficient quantum information processing such as quantum dense coding and teleportation with this entangled state in cavity QED. In this scheme the atoms interact with a highly detuned cavity field with the assistance of a strong classical driven field. It does not require the transfer of quantum information between the atomic system and the cavity, and then our scheme is insensitive to both the cavity decay and the thermal field.     

Scheme for Implementing Quantum Dense Coding and Teleportation with Tripartite Entangled State in Cavity QED

In this paper, we present a peculiar tripartite entangled state that is inequivalent to both the GHZ state and the W state, and then propose to implement efficient quantum information processing such as quantum dense coding and teleportation with this entangled state in cavity QED. In this scheme the atoms interact with a highly detuned cavity field with the assistance of a strong classical driven field. It does not require the transfer of quantum information between the atomic system and the cavity, and then our scheme is insensitive to both the cavity decay and the thermal field.     

Controlled Dense Coding with Four-Particle Entangled State

Two schemes, via generalized measurement and entanglement concentration respectively, for dense coding are investigated by using a four-particle entangled state, in which the supervisor can control the average amount of information transmitted from the sender to the receiver by adjusting the local measurement angle. It is shown that the results for the average amounts of information are unique from the different two schemes.     

Controlled Dense Coding with Four-Qubit Entangled State

Two schemes, via generalized measurement and with entanglement concentration respectively, for controlled dense coding with a four-qubit entangled state are investigated in detail. In the two schemes, the supervisor (Cliff) can control the average amount of information transmitted from the sender (Alice) to the receiver (Bob) by adjusting the local measurement angle θ. It is shown that the results for the average amounts of information are unique from the different two schemes.     

Quantum Teleportation and Superdense Coding via W-Class States

Abstract According to the protocol of Agrawal et al., we propose a cavity QED scheme for realization of teleportation and dense coding. Instead of using EPR states and GHZ states, our scheme is more insensitive to the loss of one particle by using a W-class state as a quantum channel. Besides, our scheme is immune to thermal field, and does not require the cavity to remain in the vacuum state throughout the procedure.     

一种三粒子一般态的远程控制传送方案

基于七粒子纠缠态信道,提出一种三粒子一般态的远程控制传送方案.发送者进行投影测量后,发布测量结果.在控制者的控制下,接受者根据发送者的测量结果对所在处的粒子进行适当的幺正操作从而重构原始态.此方案可用来实现控制量子通信.     

一种三粒子一般态的远程控制传送方案

基于七粒子纠缠态信道,提出一种三粒子一般态的远程控制传送方案.发送者进行投影测量后,发布测量结果.在控制者的控制下,接受者根据发送者的测量结果对所在处的粒子进行适当的幺正操作从而重构原始态.此方案可用来实现控制量子通信.     

基于字典学习的稠密光场重建算法

相机阵列是获取空间中目标光场信息的重要手段,采用大规模密集相机阵列获取高角度分辨率光场的方法增加了采样难度和设备成本,同时产生的大量数据的同步和传输需求也限制了光场采样规模.为了实现稀疏光场采样的稠密重建,本文基于稀疏光场数据,分析同一场景多视角图像的空间、角度信息的关联性和冗余性,建立有效的光场字典学习和稀疏编码数学模型,并根据稀疏编码元素间的约束关系,建立虚拟角度图像稀疏编码恢复模型,提出变换域稀疏编码恢复方法,并结合多场景稠密重建实验,验证提出方法的有效性.实验结果表明,本文方法能够对场景中的遮挡、阴影以及复杂的光影变化信息进行高质量恢复,可以用于复杂场景的稀疏光场稠密重建.本研究实现了线性采集稀疏光场的稠密重建,未来将针对非线性采集稀疏光场的稠密重建进行研究,以推进光场成像在实际工程中的应用.     

Quantum Key Distribution Scheme Based on Dense Encoding in Entangled States

A quantum key distribution protocol, based on the quantum dense encoding in entangled states, is presented. In this protocol, we introduce an encoding process to encode two classical bits information into one of the four one-qubit unitary operations implemented by Alice and the Bell states measurement implemented by Bob in stead of direct measuring the previously shared Einstein-Podolsky-Rosen pairs by both of the distant parties, Alice and Bob. Considering the practical application we can get the conclusion that our protocol has some advantages. It not only simplifies the measurement which may induce potential errors, but also improves the effectively transmitted rate of the generated qubits by the raw key. Here we also discuss eavesdropping attacks against the scheme and the channel loss.