Effects of dipole-dipole interaction on entanglement transfer

A system consisting of two different atoms interacting with a two-mode vacuum, where each atom is resonant only with one cavity mode, is considered. The effects of dipole-dipole （dd） interaction between two atoms on the atom-atom entanglement and mode--mode entanglement are investigated. For a weak dd interaction, when the atoms are initially separable, the entanglement between them can be induced by the dd interaction, and the entanglement transfer between the atoms and the modes occurs efficiently; when the atoms are initially entangled, the entanglement transfer is almost not influenced by the dd interaction. However, for a strong dd interaction, it is difficult to transfer the entanglement from the atoms to the modes, but the atom-atom entanglement can be maintained when the atoms are initially entangled.

Entanglement transfer between atoms in two distant cavities via an optical fibre

This paper presents a treatment of the entanglement transfer between atoms in two distant cavities coupled by an optical fibre. If the atoms resonantly and collectively interact with the local single-mode cavity fields and the dipole-dipole interaction between the atoms is neglected, then it shows that a complete transfer of entanglement from one pair of atoms to another can be deterministically realized. Furthermore, it also investigates the effects of dipole-dipole interaction on entanglement transfer on the condition that the interaction between the atoms and the cavity is much weaker than the coupling between the cavity and the fibre.

The influences of dipole-dipole interaction and detuning on the sudden death of entanglement between two atoms in the Tavis-Cummings model

The influences of dipole-dipole interaction and detuning on the entanglement between two atoms with different initial tripartite entangled W-like states in the Tavis Cummings model have been investigated by means of Wootters＇ concurrence, respectively. The results show that the entanglement between the two atoms can be enhanced via appropriately tuning the strength of dipole-dipole interaction of two atoms or the detunings between atom and cavity, and the so-called sudden death effect can he weakened simultaneously.

Dipole–dipole interactions enhance non-Markovianity and protect information against dissipation

Preserving non-Markovianity and quantum entanglement from decoherence effect is of theoretical and practical significance in the quantum information processing technologies.In this context, we study a system S that is initially correlated with an ancilla A, which interacts with the environment E via an amplitude damping channel.We also consider dipole-dipole interactions(DDIs) between the system and ancilla, which are responsible for strong correlations.We investigate the impact of DDIs and detuning on the non-Markovianity and information exchange in different environments.We show that DDIs are not only better than detuning at protecting the information(without destroying the memory effect) but also induce memory by causing a transition from Markovian to non-Markovian dynamics.In contrast, although detuning also protects the information, it causes a transition from non-Markovian to the Markovian dynamics.In addition, we demonstrate that the non-Markovianity grows with increasing DDI strength and diminishes with increasing detuning.We also show that the effects of negative detuning and DDIs can cancel out each other, causing a certain loss of coherence and information.

The entanglement of two dipole-dipole coupled atoms interacting with a thermal field via a two-photon process

This paper studies entanglement between two dipole-dipole coupled atoms interacting with a thermal field via a two-photon process. It shows that the entanglement is dependent on the mean photon number of the thermal field and the dipole-dipole interaction. The results also show that the atom-atom entanglement through the two-photon process is larger than that through the one-photon process and a remarkable amount of entanglement between the atoms still remains at certain times even for a very highly noisy thermal field.

Exact solution of entanglement of the double Jaynes-Cummings model without rotating wave approximation

This paper investigates the influences of atom field coupling and dipole-dipole coupling for atoms on the entanglement between two atoms by means of concurrence, The results show that the sudden death occurs when the atom field coupling is strong enough, and the collapse and the revival appear when the dipole-dipole interaction is strong enough.

Conservation issue of pairwise quantum discord and entanglement of two coupled qubits in a two-mode vacuum cavity

The conservation issues of pairwise quantum discord and entanglement of two qubits coupled to a two-mode vacuum cavity are investigated by considering the dipole^tipole interaction between two qubits. It is found that the sum of the square of the pairwise quantum discords and the sum of the square of the pairwise concurrences are both conserved in the strong dipole-dipole interaction limit. However, in the middle dipole-dipole and weak dipole-dipole interaction limits, the sum of the square of the pairwise concurrences is still conserved while the sum of the square of the pairwise discords is not. The crucial reason for this is that the quantum discords are not equivalent if the measurements are performed on different subsystems in a general situation. So it is very important for quantum computation depending on the quantum discord to select the target performed by the measurements.

Superluminality and Entanglement in an Electromagnetic Quantum-Relativistic Theory

An electromagnetic theory that links quantum and relativistic phenomena in a single context is built. Wave-particle duality is the experimental proof of their common origin. In this context, Quantum Mechanics and Special Relativity are two compatible synergistic theories. The developed theory shows the existence of superluminal effects that suggest an explanation to the entanglement between pairs of particles and photons.

纠缠原子与光场作用体系的压缩特性

研究了Kerr介质中初始处于纠缠态的两二能级原子与相干光场相互作用体系的压缩特性。通过数值计算,讨论了原子偶极间相互作用耦合常数和Kerr介质与单模腔场相互作甩的耦合强度对体系中的双原子偶极压缩和光场压缩的影响。结果发现在弱光场情况下,纠缠态原子偶极间相互作用和Kerr介质与光场作用越强,都使原子偶极振幅压缩现象从压缩状态退缩到无压缩状态;在强光场情况下,纠缠态原子偶极间相互作用越强,光场振幅压缩次数增多、振荡频率变慢; Kerr介质与光场作用越强,光场振幅压缩次数减少、振荡频率变快。

纠缠态原子与压缩真空场Raman相互作用的量子信息保真度

利用全量子理论和数值计算方法研究了两个全同的纠缠二能级原子与压缩真空场Raman相互作用的量子信息保真度.结果表明,系统、原子和场的保真度随初始光场的压缩参数的增加而急剧减小,且与两原子体系的纠缠度和原子间偶极-偶极相互作用强度相关联.

微波场作用下的溶质扩散通量

微波场协同溶质扩散机理是强化传质研究的重要内容,由于微波热效应的干扰,微波场协同极性分子扩散的实验研究尚未取得大的进展.基于液体扩散机制,利用微波场对偶极分子的作用以及分子间相互作用能的影响,建立了微波场协同溶质分子扩散的关系式,得出了微波协同极性分子扩散是通过改变分子间的相互作用能来增强溶质分子扩散的结论.微波场的协同作用依赖分子的电偶极矩。温度较高时,电偶极矩越大强化效果越明显。微波场还可以通过削弱分子间动态氢链来增大扩散通量.该结论可为微波强化传质的理论和实验研究提供参考.

偶极相互作用对T-C模型中原子纠缠突然死亡的影响

求出了初态为x态时Tavis-Cummings模型中两个有偶极相互作用原子的共生纠缠度,分析了偶极相互作用对纠缠的时间演化和纠缠突然死亡(ESD)的影响,以及共生纠缠度与原子间相互作用能的关系。结果表明,偶极相互作用对原子间的纠缠和ESD有显著的影响,会改变纠缠度的振荡周期和振幅,使出现ESD的时间间隔和次数减少。原子间的共生纠缠度与原子间相互作用能有着明显的对应关系,且与原子的初态有关。

T-C模型中纠缠原子与相干态光场相互作用的量子态保真度

利用全量子理论研究了两个全同的纠缠二能级原子与相干态光场相互作用的量子信息保真度。结果表明:系统、原子和场的保真度随平均光子数的增加而急剧减小;系统和原子的保真度随原子间偶极—偶极相互作用增加而变大且趋于同步,但原子的保真度增大更为明显:原子初始纠缠度对三体系保真度影响并不大。

偶极-偶极相互作用的探讨(Ⅰ)

：The coherent potential approalmation (CPA) is used in the calculation of thevibrational spectra for absorbed 12CN- /13CN- mixtures on gold. The theoretical resultsare compared with the surface IR-spectra of 12CN-/13CN- ndture absorbed on roughAu-electrod. The results show that in the systems consisting of isotopic drixtures of CN-on Au(100), molecules interact mainly through their dipole fields.

用腔场QED技术隐形传送未知原子态(英文)

提出一种方案用于隐形传送未知原子态,方案基于两个耦合双能级原子与一个单模腔场的非共振相互作用。方案要求腔场处于相干态,这使得方案容易实现。原子与相干腔场相互作用以后,腔场仍然处于相干态,通过探测原子的状态,即可将一个未知原子态隐形传送。方案也可以用于隐形传送未知原子纠缠态。

少体里德堡原子中的稳态激发和量子纠缠

与独立原子不同,里德堡原子间长程的偶极-偶极相互作用能够产生量子纠缠。在偶极阻塞和反阻塞机制下研究稳态激发和量子纠缠行为,发现量子纠缠行为与里德堡激发密切相关。进一步通过改变系统的参数可以实现对量子纠缠的相干操控。

偶极-偶极相互作用的探讨(Ⅱ)

The coherent potential approximation (CPA) was used in the calculation of the vibrational spectra for absorbed 12CO/13CO thextures on platinum. The theoretical results were compared with the surface IR-spectra of 12CO/13CO mixture absorbed on Pt-electrode. The results show that in the systems consisting of isotopic Anxtures of CO on Pt(001), molecules interact mainly through their dipole fields.

偶极相互作用对量子纠缠信息传递与保持的影响

依据全量子理论原理,采用时间演化算符的方法,详细探讨了等同双能级原子与单模光场在偶极共振相互作用过程中系统的时间演化特性,分析了偶极相互作用对量子纠缠信息传递或保持的影响。计算和分析表明:量子信息的传递或保持过程与原子的初态有强烈的关联,即偶极-偶极作用对W型原子,当偶极相互作用强度满足一定条件时,才能使初始原子纠缠态或光子纠缠态完全保持,不同条件下,部分保持或部分交换传递,同时出现一些混合纠缠态;而对于GHZ型原子纠缠态的传递或保持没有影响。

Ca_8Mg(SiO_4)_4Cl_2:Ce^(3+),Eu^(2+)的光致发光特性

对Ca8Mg（SiO4）4Cl2:Ce3+，Eu2+系列荧光粉进行合成与测试，探讨Ca8Mg（SiO4）4Cl2：Ce3+，Eu2+中Ce3和Eu2+之间的相互作用，初步判断Ca8Mg（SiO4）4Cl2：Ce3+，Eu2+中Ce3+→Eu2+的能量传递主要是电偶极-偶极相互作用的结果.

T-C模型中纠缠原子与相干态光场相互作用的场熵演化特性

利用全量子理论,研究了一对纠缠原子与相干态光场相互作用中场熵的演化特性.讨论了原子间偶极-偶极相互作用、光场强度与2原子纠缠度对场熵演化特性的影响.结果表明:原子间偶极-偶极相互作用强度增加使场熵的演化周期增大;初始光场强度增加,场熵平均值先增大后减小,振荡周期变大;场熵平均值随初始纠缠度增大反而减小,但振荡幅度随初始纠缠度增大而增大.