基于腔QED制备W纠缠态

利用一个三能级原子与四个腔场之间相互作用研究双光子四粒子体系W态的制备,通过合适选择原子与腔场之间的相互作用时间可以获得该态的最大保真度以及成功几率     

基于腔QED技术的原子态纠缠纯化方案

基于两能级原子与单模腔场之间的失谐相互作用,我们提出了一个有效的且能够纯化任意未知原子纠缠态的纠缠纯化方案。将量子逻辑门(Phys.Rev.Lett.74,4087(1995))和纠缠纯化(Phys.Rev.Lett.76,722(1996))的理论研究的最新进展相结合提出了一个在实验上可行的纠缠纯化物理方案。     

腔QED制备三原子W态的一般方案

本文提出了一个基于腔QED技术的制备三原子最大W态的一般方案.通过讨论表明三个原子不论是被同时注入腔中还是在不同的时刻被注入腔中我们都能得到三原子最大W态.该方案可以在当前的技术范围内实现并且可以推广到制备n个原子的W态.     

腔场QED与量子点系统激子纠缠态的制备及消纠缠研究

利用量子点与单模腔场共振相互作用模型提出了激子Bell类和W类纠缠态的制备方案.借助于超算符方法和态的保真度考察了所制备的激子纠缠态的消相干特性,结果表明:激子Bell类和W态的纠缠特性非常脆弱,在极短的时间里演变为消纠缠态.基于腔场与两量子点共振相互作用模型设计了一个量子交换门.     

通过原子与腔场共振相互作用制备三原子的W态

提出了一种简单、可行的三原子W态制备方案，它是基于三个二能级原子与一个单模腔场共振相互作用实现的。通过控制原子与腔场相互作用时间和耦合参数，无需对腔场态的探测，就可获得三原子的W态。此外，讨论了在现有实验技术下本方案实现的可能性。     

传送两原子直积态的腔QED方案(英文)

本文提出一个基于原子和腔场共振相互作用传送未知原子直积态的腔QED方案,原子和腔场通过J-C哈密顿量发生共振相互作用.在这个方案里,我们只需要用两个原子接受被传送的原子态以及两个单模腔作为量子通道.该方案既不需要贝尔态测量,也不需要任何操作重构纠缠初态,并且传送成功的概率为100%.这个方案也可以推广到传送n个原子的直积态.     

利用腔QED技术控制传输任意两原子态

我们提出一个利用腔QED技术控制传输任意两原子态的方案.在此方案中,我们选择一个GHZ态和一个EPR对作为量子通道.在控制者的帮助下,发送者可以把量子信息传送给接收者.在传输过程中,两对原子分别与两个全同单模场相互作用,同时两对原子分别由两个全同经典场驱动.该方案对腔衰变和热场不敏感,并且传输成功的几率为1.     

利用超导量子相干装置制备纠缠态的方案(英文)

本文提出用两个超导量子相干装置在一个单模大失谐腔中制备一个最大纠缠态的新方案,在这个方案里,腔场态处于虚激发,在超导量子相干装置和腔场之间没有信息传递,因此对腔的品质要求大大减低.     

利用选择共振作用制备纠缠态

文章提出一个在高品质腔中利用选择性相互作用制备Bell态和W态的方案。该方案通过参数的选择来严格控制囚禁原子和腔场之间的相互作用,在所需要的子空间里实现共振跃迁,而让原子的其它跃迁处于大失谐,从而可以绝热去除。因此,本方案可以有效抑制原子的自发辐射,而且不需要对腔中原子独立寻址,使其在实验上更容易实现。     

基于腔QED的原子纠缠态的辅助克隆

本文提出一种克隆未知两原子纠缠态的方案，这种克隆方案基于腔QED技术，且在原子态制备态（Victor）的帮助下而完成。方案包括了两个步骤：第一步需要用通常的隐形传态方法，运用腔QED技术及纠缠交换实现原子纠缠态从发送者（Alice）到接收者（Bob）的隐形传送；第二步是由Victor完成来之于Alice的两原子态的离散测量，根据Victor的测量信息，Alice能够获得未知初始原子纠缠态的拷贝。     

One-step generation of qutrit entanglement via adiabatic passage in cavity quantum electrodynamics

A scheme is proposed for generating a three-dimensional entangled state for two atoms trapped in a cavity by one step via adiabatic passage. In the scheme, the two atoms are always in ground states and the field mode of the cavity excited is negligible under a certain condition. Therefore, the scheme is very robust against decoherence. Furthermore, it needs neither the exact control of all parameters nor the accurate control of the interaction time. It is shown that qutrit entanglement can be generated with a high fidelity.     

腔量子电动力学系统中耦合三原子的纠缠特性

研究了三个全同二能级原子与单模腔相互作用系统中原子间的三体纠缠特性.考虑原子间存在相互耦合,并且腔场处于弱相干态的情况,通过数值计算给出了纠缠量的演化曲线,讨论了原子间耦合强度和弱相干场强度对三体纠缠的影响.研究结果表明:随弱相干场强度增强,原子间的三体纠缠增强;相反,随原子间耦合系数增大,原子间三体纠缠减弱.     

Scheme for implementing perfect quantum teleportatior with four-qubit entangled states in cavity quantum electrodynamics

Recently, Peng et al. [2010 Eur. Phys. J. D 58 403] proposed to teleport an arbitrary two-qubit state with a family of four-qubit entangled states, which simultaneously include the tensor product of two Bell states, linear cluster state and Dicke-class state. This paper proposes to implement their scheme in cavity quantum electrodynamics and then presents a new family of four-qubit entangled state ｜Ω/1234. It simultaneously includes all the well-known four-qubit entangled states which can be used to teleport an arbitrary two-qubit state. The distinct advantage of the scheme is that it only needs a single setup to prepare the whole family of four-qubit entangled states, which will be very convenient for experimental realization. After discussing the experimental condition in detail, we show the scheme may be feasible based on present technology in cavity quantum electrodynamics.     

Scheme for implementing perfect quantum teleportation with four-qubit entangled states in cavity quantum electrodynamics

Recently, Peng et al. [2010 Eur. Phys. J. D 58 403] proposed to teleport an arbitrary two-qubit state with a family of four-qubit entangled states, which simultaneously include the tensor product of two Bell states, linear cluster state and Dicke-class state. This paper proposes to implement their scheme in cavity quantum electrodynamics and then presents a new family of four-qubit entangled state |Ω₄>₁₂₃₄. It simultaneously includes all the well-known four-qubit entangled states which can be used to teleport an arbitrary two-qubit state. The distinct advantage of the scheme is that it only needs a single setup to prepare the whole family of four-qubit entangled states, which will be very convenient for experimental realization. After discussing the experimental condition in detail, we show the scheme may be feasible based on present technology in cavity quantum electrodynamics.     

Preparation of steady-state entanglement via a laser-excited resonant interaction

In this paper we propose a scheme in which two-mode entanglement in a steady state is produced by using two lasers to resonantly drive a single four-level atom embedded inside a two-mode optical cavity.In this scheme,atomic coherence induced by a classical laser plays an important role in the process of preparing the entangled state.With the coupling of a strong control field,direct two-photon transition is generated and the relatively weak pump field induces the parametric interaction between two photons,which makes them entangle with each other.By numerical calculation,we find that the degree of entanglement depends strongly on the Rabi frequencies of the classical laser fields and the cavity losses.     

Implementation of n-qubit Deutsch--Jozsa algorithm using resonant interaction in cavity QED

We propose a scheme to implement the n-qubit Deutsch--Jozsa algorithm based on resonant interaction between the atoms and a single-mode cavity. In the scheme, the resonant transitions between two ground states and one excited state of an atom are changed alternately by adjusting the cavity frequency appropriately, and the operations required to complete the algorithm can be significantly simplified following the increment of the number of qubits. The implementation of the scheme in experiment would show the full power of quantum algorithm and would be significative and important for more complicated quantum algorithm in cavity quantum electrodynamics.     

Two simple schemes for implementing Toffoli gate via atom--cavity field interaction in cavity quantum electrodynamics

This paper proposes two schemes for implementing three-qubit Toffoli gate with an atom (as target qubit) sent through a two-mode cavity (as control qubits). The first scheme is based on the large-detuning atom--cavity field interaction and the second scheme is based on the resonant atom-field interaction. Both the situations with and without cavity decay and atomic spontaneous emission are considered. The advantages and the experimental feasibility of these two schemes are discussed.     

Robust generation of qutrit entanglement via adiabatic passage of dark states

We propose a scheme for the deterministic generation of qutrit entanglement for two atoms trapped in an optical cavity. Taking advantage of the adiabatic passage, the operation is immune to atomic spontaneous emission as the atomic excited states are never populated; under certain conditions, the probability that the cavity is excited is negligible. We also study the influences of the dissipation due to the atomic spontaneous emission and cavity decay.     

利用Λ型原子与双模腔场的相互作用进行量子信息处理

利用Λ型三能级原子与一个两模腔场在两光子共振和单光子大失谐条件下的相互作用模型，给出了制备两个和三个远距离的腔场的纠缠态和如何实现一个量子比特的原子态的远距离转移、纠缠态的转移的方案；同时找到了一种不用进行Bell基测量而实现纠缠交换的方法；构造了实现量子交换门的操作.最后对实验的可行性进行了分析. 关键词： 量子信息处理 Λ型原子 双模腔场 相互作用     

陆续通过一个双模腔的两原子之间纠缠的突然产生和调控

通过计算并发度研究了陆续通过一个双模腔的两个原子之间的纠缠动力学特性, 讨论了第一个原子的相干性以及腔场初始纠缠度对两原子之间纠缠的影响. 结果表明系统在一定条件下可以出现两原子之间纠缠突然产生现象, 两原子之间产生纠缠的最大值依赖于双模腔场初始纠缠度; 并且可以通过改变原子的振幅来控制产生纠缠的阈值时间和纠缠的最大值, 理论上提供了一种调控纠缠的方式.