共查询到20条相似文献，搜索用时 0 毫秒
1.
In this paper, we propose a physical scheme to realize quantum SWAP gate by using a large-detuned single-mode cavity field and two identical Rydberg atoms. It is shown that the scheme can also be used to create multi-atom cluster state. During the interaction between atom and cavity, the cavity is only virtually excited and thus the scheme is insensitive to the cavity field states and cavity decay. With the help of our scheme it is very simple to prepare the N-atom cluster state with perfect fidelity and probability. The practical feasibility of this method is also discussed. 相似文献
2.
An experimentally realizable physical scheme for preparing multiqubit cluster states from a large detuned atomcavity interaction is proposed. The scheme is free of any type of measurement and insensitive to the cavity decay, and the cavity field is only virtually excited so that there is no information exchanging between atom and cavity. The time required for the gate operations is very short, which is important for decoherence. We also discuss the experimental feasibility of our scheme. 相似文献
3.
This paper proposes a scalable scheme to generate n-atom GHZ states and cluster states by using the basic building block, i.e., a weak coherent optical pulse [α） being reflected successively from a single-atom cavity. In the schemes, coherent state of light is used instead of single photon source, homodyne measurement on coherent light is done kastead of single photon detection, and no need for individually addressing keeps the schemes easy to implement from the experimental point of view. The successful probabilities of our protocols approach unity in the ideal case. 相似文献
4.
We propose a scheme to achieve a kind of nontrivial multipartite pair-wise controlled phase operation in a cavity QED setup. The operation implemented is of geometrical nature and is not sensitive to the thermal state of the cavity. In particular, we have managed to avoid the conventional dispersive coupling so that high speed gate operation is achieved which is very important in view of decoherence. We show that this multipartite pair-wise controlled phase operation makes the generation of two-dimensional cluster states very efficient. 相似文献
5.
This paper proposes schemes for generating multiple-photon and multiple-atom cluster states, respectively. The schemes are based on the cavity input-output process and atomic or photonic states measurement, and the successful probabilities approach unity in the ideal case. The numerical simulations show that the produced multiple-particle cluster states have high fidelity even if the Lamb-Dicke condition is not satisfied. Some practical imperfections, such as atomic spontaneous emission and output coupling inefficiency, only decrease the success probability but exert no influence on the fidelity of generated multiple-particle cluster states. From the experimental point of view, smaller operation number and lack of need for individual addressing keeps the schemes easy to implement. These schemes may offer a promising approach to the generation of a large-scale cluster state. 相似文献
6.
This paper proposes schemes for generating multiple-photon andmultiple-atom cluster states, respectively. The schemes are based onthe cavity input--output process and atomic or photonic statesmeasurement, and the successful probabilities approach unity in theideal case. The numerical simulations show that the producedmultiple-particle cluster states have high fidelity even if theLamb--Dicke condition is not satisfied. Some practical imperfections,such as atomic spontaneous emission and output coupling inefficiency,only decrease the success probability but exert no influence on thefidelity of generated multiple-particle cluster states. From theexperimental point of view, smaller operation number and lack of needfor individual addressing keeps the schemes easy to implement. Theseschemes may offer a promising approach to the generation of alarge-scale cluster state. 相似文献
7.
Schemes are presented for realizing quantum controlled phase gate and preparing an N-qubit W-like state, which are based on the large-detuned interaction among three-state atoms, dual-mode cavity and a classical pulse. In particular, a class of W states that can be used for perfect teleportation and superdense coding is generated by only one step. Compared with the previous schemes, cavity decay is largely suppressed because the cavity is only virtually excited and always in the vacuum state and the atomic spontaneous emission is strongly restrained due to a large atom-field detuning. 相似文献
8.
We propose a scheme for the generation of the cluster states for many atoms in cavity QED. In our scheme,the atoms are sent through nonresonant cavity fields in the vacuum states. The cavity fields are only virtually excited and no quantum information will be transferred from the atoms to the cavity fields. The advantage is that the cavities are suppressed during the procedure. The scheme can also be generalized to the ion trap system. 相似文献
9.
We propose a scheme for preparing four-particleGreenberger--Horne--Zeilinger states using two identical bimodalcavities, each supports two modes with different frequencies. Thisscheme is an alternative to another published work [Christopher CGerry 1996 {it Phys. Rev.} A {bf 53} 4591]. Comparisons betweenthem are discussed. The fidelity and the probability of successinfluenced by cavity decay for the generated states are alsoconsidered. 相似文献
10.
We propose feasible schemes for preparation of all five-atom graph states by cavity quantum electrodynamics （QED）. Our schemes require only the atom-cavity interaction with a large detuning which is available in current experiment so that these schemes are within the reach of the current technology. 相似文献
11.
We propose a scheme to generate two-atom maximally entangled state in cavity quantum electrodynamies （QED）. The scheme can 5e extended to generation of entangled multi-atom Dicke states if we control the interaction time of atoms with cavity modes. We use adiabatically state evolution under large atom-cavity detuning, so the scheme is insensitive to atomic spontaneous decay. The influence of cavity decay on fidelity and success probability is discussed. 相似文献
12.
邵瑞 《原子与分子物理学报》2008,25(6):1352-1356
我们提出一个方案通过极化光子的干涉来制备囚禁在相距很远的腔中的n原子GHZ类态。在该方案中,原子腔耦合强度小于腔衰减率。因此对腔的品质因子的要求大大降低了,而且,该方案的保真度不受探测器效率和原子自发衰变的影响。中文关键词：纠缠制备;GHZ类态;腔QED 相似文献
13.
Efficient scheme for preparation of the multi-atom W state via cavity quantum electrodynamics 
下载免费PDF全文
下载免费PDF全文 We present an efficient scheme for preparation of the multi-atom W state via cavity quantum electrodynamics. Involved in this scheme are n identical two-level atoms and a single-mode cavity field. Discussion indicates that this scheme can be realized easily by current technologies. 相似文献
14.
We propose an experimentally feasible scheme for preparing a four-atom cluster statein a thermal cavity. In the scheme, the cavity field is only virtually excited andthe photon-number-dependent part in the effective Hamiltonian is cancelled so thatthe system is insensitive to the cavity decay and the thermal field. At the sametime, the scheme can be generalized to prepare n-atom cluster states with thesuccess probability 100%. In addition, using the four-atom cluster state, we alsopropose a simpler scheme for implementing a remote--controlled not gate (CNOT)without the Bell states measurement. 相似文献
15.
ZHAN Zhi-Ming 《理论物理通讯》2007,48(1):83-86
We propose a scheme for the generation of the cluster states for many atoms in cavity QED. In our scheme, the atoms are sent through nonresonant cavity fields in the vacuum states. The cavity fields are only virtually excited and no quantum information will be transferred from the atoms to the cavity fields. The advantage is that the cavities are suppressed during the procedure. The scheme can also be generalized to the ion trap system. 相似文献
16.
Based on the coupling of two distant three-level atoms in two separate optical cavities connected with two optical fibres, schemes on the generation of several two-qubit logic gates are discussed under the conditions of Δ = δ - 2ν cos πk/2 >> g/2 and ν ~ g. Discussion and analysis of the fidelity, gate time and experimental setups show that our schemes are feasible with current optical cavity, atomic trap and optical fibre techniques. Moreover, the atom-cavity- fibre coupling can be used to generate an N-qubit nonlocal entanglement and transfer quantum information among N distant atoms by arranging N atom-cavity assemblages in a line and connecting each two adjacent cavities with two optical fibres. 相似文献
17.
A scheme is presented for realizing quantum logic gates for twoatoms localized in two distant optical cavities. Our scheme works ina regime in which the atom--cavity coupling strength is smallerthan the cavity decay rate. Thus the requirement on the qualityfactor of the cavities is greatly relaxed. Furthermore, the fidelityof our scheme is not affected by detection inefficiency andatomic decay. These advantages are important in view of experiment. 相似文献
18.
CHEN Chang-Yong 《理论物理通讯》2008,49(4):871-876
We propose a potentially practical scheme to implement an approximate three-qubit Toffoli gate by a single resonant interaction in dissipative cavity QED in which the cavity mode decay and atomic spontaneous emission are considered. The scheme does not require two-qubit controlled-NOT gates but uses a three-qubit phase gate and two Hadamard gates, where the approximate phase gate can be implemented by only a single dissipative resonant interaction of atoms with the cavity mode. Discussions are made for the advantages and the experimental feasibility of our scheme. 相似文献
19.
Using a system of cavity quantum electrodynamics(QED) we present two schemes for multipartite entanglement generation. In the first scheme, a three-level atom is interacting with three cavities successively. In the second one, two three-level atoms are interacted with a coherent optical cavity. These protocols allow us to generate the six classes of tripartite entanglement(GHZ, W, A-B-C, AB-C, C-AB, and B-AC class states) by controling the interaction time between atoms and cavities. Moreover, they allow us to generate entanglement between the cavity fields degrees of freedom(from the first scheme), and a mixed entanglement between the cavity field degrees of freedom and the atomic degrees of freedom. 相似文献
20.
Assisted by multipartite entanglement, Quantum information may be split so that the original qubit can be reconstructed if and only if the recipients cooperate. This paper proposes an experimentally feasible scheme for splitting quantum information via W-type entangled states in cavity QED systems, where three-level Rydberg atoms interact with nonresonant cavities. Since W-type states are used as the quantum channel and the cavities are only virtually excited, the scheme is easy to implement and robust against decoherence, and the dependence on the quality factor of the cavities is greatly reduced. 相似文献