共查询到20条相似文献,搜索用时 965 毫秒
1.
ZHENGShi-Biao 《理论物理通讯》2002,38(6):663-666
A scheme is suggested for the generation of multi-atom maximally entangled states with a cavity in a thermal state,In this scheme several appropriately prepared two-level atoms are simultaneously sent through the nonresonant cavity.We divide the whole atom-cavity interaction time into two equal parts.At the end of the first part a π pulse is applied to the atome using a classical field.Then the photon-number-dependent shifts on the atomic states are cancelled and the atomic system finally evoloves to a maximally entangled state. 相似文献
2.
LIN Xiu CHEN Mei-Ying LIN Xiu-Min LI Hong-Cai YANG Rong-Can 《理论物理通讯》2007,47(5):816-820
We present a scheme for transferring atomic entangled states via adiabatic passage. In the scheme, we use photons to achieve efficient quantum transmission among spatially distant atoms. The probability of the successful transferring quantum state approaches 1. Meanwhile, the scheme is robust against the effects of atomic spontaneous emission. 相似文献
3.
This paper proposes an efficient scheme for deterministic generation
of entangled coherent states for two atomic samples. In the scheme
two collections of atoms are trapped in an optical cavity and driven
by a classical field. Under certain conditions the two atomic
samples evolve from an coherent state to an entangled coherent
state. During the interaction the cavity mode is always in the
vacuum state and the atoms have no probability of being populated in
the excited state. Thus, the scheme is insensitive to both the
cavity decay and atomic spontaneous emission. 相似文献
4.
YE Liu GUO GuangcanLaboratory of Quantum Communication Quantum Computation University of Science Technology of China Hefei ChinaDepartment of Physics Anhui University Hefei China 《Chinese Journal of Lasers》2002,11(2):96-98
A scheme is proposed for the generation of entangled atomic states and a method is presented to produce entangled photon states. It is shown that entanglement can be swapped from atoms to cavities via atom-cavity interaction. 相似文献
5.
A scheme is proposed for the generation of entangled atomic states and a method is presented to produce entangled photon states. It is shown that entanglement can be swapped from atoms to cavities via atom-cavity interaction. 相似文献
6.
通过对比分立变量量子信息过程和连续变量量子信息过程的差别,利用相干态比较容易获得的这个特点,提出一种方案制备三个腔场的W型纠缠相干态.方案基于Λ型三能级原子与单模腔场的简并Raman 相互作用.三个相同的腔初始分别处于相干态,三个相同的原子初始处于W型纠缠态,通过三个原子分别与三个腔的Raman相互作用、选择适当的相互作用时间并探测作用后的三个原子,三个腔场坍缩为W型纠缠相干态.在原子与腔的相互作用过程中原子不处于高能级,可以忽略原子的自发辐射,系统的相干性能够得到较好的维持.基于当前的腔量子电动力学技术,相信方案能在实验上实现.该方案制备的三个腔场W型纠缠相干态有望在连续变量量子信息过程中有重要的应用价值.文中将方案推广到制备n(n〉3)个腔场的W型纠缠相干态. 相似文献
7.
In this paper, we propose a physical scheme to concentrate non-maximally entangled
atomic pure states by using atomic collision in a far-off-resonant cavity. The most
distinctive advantage of our scheme is that the non-maximally entangled atoms may be
far from or near each other and their degree of entanglement can be maximally
amplified. The photon-number-dependent parts in the effective Hamiltonian are
cancelled with the assistance of a strong classical field, thus the scheme is
insensitive to both the cavity decay and the thermal field. 相似文献
8.
9.
JIANG Chun-Lei FANG Mao-Fa 《理论物理通讯》2007,47(3):557-560
We propose a scheme for generating maximally entangled states for two or more two-level atoms in a thermal cavity. The cavity frequency is large-detuned from the atomic transition frequency, so the Hamiltonian can be expressed as an effective form. The photon-number-dependent parts in the effective Hamiltonian are cancelled with the assistance of a strong classical field, thus the scheme is insensitive to both the cavity decay and the thermal field. The scheme can be used to generate multi-atom Bell-state and Greenberger-Horne-Zeiliner (GHZ) state. 相似文献
10.
提出一种利用绝热过程制备多原子GHZ态的方案.本方案可有效地抑制原子的自发辐射噪声.利用相似的方法可制备腔场GHZ态.制备成功的几率约为1.0. 相似文献
11.
SONG Ke hui 《原子与分子物理学报》2000,17(2):349-352
A scheme for preparing two and four atom entangled states is presented. It is based on atom cavity field interactions. Firatly, the cavity is prepared in the superposition of the number states through the atom undergoing a two photon transition, the secondly, the two or four identical two level atoms, which are all initially in their ground states, are sent through the cavity sequentially and can make resonant single photon transition in the cavity. Then atomic entangled states are created and the cav 相似文献
12.
In this paper, a scheme for generating various multiatom entangled graph states via resonant interactions is proposed. We investigate the generation of various four-atom graph states first in the ideal case and then in the case in which the cavity decay and atomic spontaneous emission are taken into consideration in the process of interaction. More importantly, we improve the possible distortion of the graph states coming from cavity decay and atomic spontaneous emission by performing appropriate unitary transforms on atoms. The generation of multiatom entangled graph states is very important for constructing quantum one-way computer in a fault-tolerant manner. The resonant interaction time is very short, which is important in the sense of decoherence. Our scheme is easy and feasible within the reach of current experimental technology. 相似文献
13.
ZHENGShi-Biao 《理论物理通讯》2002,37(1):87-90
A method is presented for generating highly squeezed states of a cavity field via the atom-cavity field interaction of the Raman type.In the scheme a sequence of three-level Λ-type atoms interacts with a cavity field,displaced by a classical source,in a Raman manner.Then the atomic states are measured.By this way the cavity field may collapse onto a superposition of several coherent states,which exhibits strong squeezing.The scheme can also be used to prepare superpositions of many two-mode coherent states for two cavity fields.The coherent states in each mode are on a straight line.This is the first way for preparing multi-component entangled coherent states of this type in cavity QED. 相似文献
14.
A scheme for transferring an unknown atomic entangledstate via cavity quantum electrodynamics 下载免费PDF全文
In this paper, we propose a scheme for transferring an unknown atomic entangled
state via cavity quantum electrodynamics (QED). This scheme, which has a successful
probability of 100 percent, does not require Bell-state measurement and performing
any operations to reconstruct an initial state. Meanwhile, the scheme only involves
atom--field interaction with a large detuning and does not require the transfer of
quantum information between the atoms and cavity. Thus the scheme is insensitive to
the cavity field states and cavity decay. This scheme can also be extended to
transfer ring an entangled state of $n$-atom. 相似文献
15.
In this paper a scheme is proposed for the purification of entangled states for two atoms trapped in two distant cavities via cavity decay. In the scheme, the atoms have no probability of being populated in the excited state and thus the atomic spontaneous emission is suppressed. This scheme is valid no matter when the cavity decay rate is larger or smaller than the effective atom-cavity coupling strength. The fidelity of the final state is not affected by the imperfection of the photodetectors. 相似文献
16.
We propose and analyze a scheme for generating entangled atomic beams out of a Bose-Einstein condensate using spin-exchanging collisions. In particular, we show how to create both atomic squeezed states and entangled states of pairs of atoms. 相似文献
17.
18.
基于低Q腔中单光子的输入与输出关系,提出了利用偏振光Faraday旋转分别遥远制备单原子态和两原子纠缠态的可行方案.研究结果表明,当初始原子态的系数为实数时,通过选择合适的偏振光、腔场与原子相互作用系统的参数,单原子态与两原子纠缠态的远程制备均可确定性地得以实现.与以前的原子态远程制备方案相比,本文方案采用光子作为飞行比特来传递量子信息,故原则上可实现原子态的真正长距离制备.由于原子态的信息编码在耗散单边腔囚禁的Λ型三能级原子的两个基态能级,且原子仅虚激发,因此本文方案对腔衰减和原子自发辐射不敏感.此外,本文所提出的两种方案不需要两体或多体正交测量,仅涉及单体直积态测量,而且两种方案都工作在低Q腔,不需要原子与光腔的强耦合,从而有效降低了实验难度. 相似文献
19.
A scheme is presented for generating entangled states of multiple
atoms in a cavity. In the scheme the atoms simultaneously interact
with a cavity mode, with the first atom driven by two classical
fields and the other atoms driven by a classical field. Our scheme
is valid even if the cavity decay rate is larger than the effective
coupling strength, which is important for experiment. The generation
of entangled states is conditional on the detection of a photon
decaying from the cavity and thus the fidelity of the entangled
state is insensitive to the detection inefficiency. Furthermore, the
scheme can be applied to the case with any number of atoms in
principle. 相似文献
20.
Based on the idea of adiabatic evolution, we propose two
probabilistic but simple schemes for generating maximally entangled
states for two distant atoms and concentrating unknown atomic
entangled states. Taking advantage of adiabatic passage, the atoms
have no probability of being excited and thus the atomic spontaneous
emission is suppressed. Furthermore, in the two schemes accurate
adjustment of the interaction time is not required. 相似文献