共查询到20条相似文献,搜索用时 0 毫秒
1.
LU Hong-Xia 《理论物理通讯》2006,46(3):423-428
The generalization of geometric phase from the pure states to the mixed states may have potential applications in constructing geometric quantum gates. We here investigate the mixed state geometric phases and visibilities of the trapped ion system in both non-degenerate and degenerate cases. In the proposed quantum system, the geometric phases are determined by the evolution time, the initial states of trapped ions, and the initial states of photons. Moreover, special periods are gained under which the geometric phases do not change with the initial states changing of photon parts in both non-degenerate and degenerate cases. The high detection efficiency in the ion trap system implies that the mixed state geometric phases proposed here can be easily tested. 相似文献
2.
We describe a scheme for the generation of macroscopic quantum-interference states for a collection of trapped ions by a single geometric phase operation. In the scheme the vibrational mode is displaced along a circle with the radius proportional to the number of ions in a certain ground electronic state. For a given interaction time, the vibrational mode returns to the original state, and the ionic system acquires a geometric phase proportional to the area of the circle, evolving from a coherent state to a superposition of two coherent states. The ions undergo no electronic transitions during the operation. Taking advantage of the inherent fault-tolerant feature of the geometric operation, our scheme is robust against decoherence. 相似文献
3.
This paper presents an alternative scheme to realize the storage of entangled states for multiple trapped ions including W state, Bell states, and GHZ states even with ions which exchange vibrational energy with a heating surrounding. Our scheme requires that the ions be simultaneously excited by two laser beams with different frequencies.In this scheme the vibrational degrees of freedom are only regarded as intermediate states and the ions exchange energy via the mediation of the vibration of the vibrational mode in coupling processes. The scheme is insensitive to both the initial vibrational state and heating if the system remains in the Lamb-Dicke regime. Since the effective Rabi frequency has a small dependence on the vibrational quantum number the heating will have no direct effect on the internal state evolution. 相似文献
4.
YANG Wen-Xing LI Jia-Hua ZHNG An-Shou 《理论物理通讯》2007,47(3):421-426
We propose two schemes to prepare entanglement for the vibronic collective states of multiple trapped ions. The first scheme aims to generating multipartite entanglement for vibrational modes of trapped ions, which only requires a single laser beam tuned to the ionic carrier frequency. Our scheme works in the mediated excitation regime, in which the corresponding Rabi frequency is equal to the trap frequency. Beyond their fundamental importance, these states may be of interest for experimental studies on decoherence since the present scheme operates in a fast way. The second scheme aims to preparing the continuous variable multimode maximal1y Greenberger-Horne-Zeilinger state. The distinct advantage is that the operation time is only limited by the available laser intensity, not by the inherent mechanisms such as off-resonant excitations. This makes it promising to obtain entanglernent of multiple coherent and squeezing states with desired amplitudes in a reasonable time. 相似文献
5.
We propose a scheme for telecloning quantum states with trapped ions. The scheme is based on a single ion interacting with a single laser pulse. In the protocol, an ion is firstly measured to determine whether the telecloning succeeds or not, and then another ion is detected to complete the whole procedure. The required experimental techniques are within the scope of what can be obtained in the ion-trap setup. 相似文献
6.
YANG Rong-Can LI Hong-Cai LIN Xiu HUANG Zhi-Ping 《理论物理通讯》2007,48(5):827-830
We propose a scheme for telecloning quantum states with trapped ions. The scheme is based on a single ion interacting with a single laser pulse. In the protocol, an ion is firstly measured to determine whether the telecloning succeeds or not, and then another ion is detected to complete the whole procedure. The required experimental techniques are within the scope of what can be obtained in the ion-trap setup. 相似文献
7.
A scheme is presented for teleportation of an unknown entangled ionic state between ions kept in two vell separated traps, which is induced by means of two dispersive laser excitations. The scheme is insensitive to the thermal motion and its successful probability can reach 1. 相似文献
8.
A scheme is presented for teleportation of an unknown entangled ionic state between ions kept in two well separated traps, which is induced by means of two dispersive laser excitations. The scheme is insensitive to the thermal motion and its successful probability can reach 1. 相似文献
9.
ZHENG Shi-Biao 《理论物理通讯》2005,44(7)
A scheme is presented for generating W states for three o()four trapped ions in thermal motion. The scheme works in the regime, where the Rabi frequency of the laser field is on the order of the trap frequency, resulting a fast entanglement speed, which is of importance in view of decoherence. 相似文献
10.
Fast Preparation of W States for Hot Trapped Ions 总被引:1,自引:0,他引:1
ZHENGShi-Biao 《理论物理通讯》2005,44(1):143-145
A scheme is presented for generating W states for three or four trapped ions in thermal motion. The scheme works in the regime, where the Rabi frequency of the laser field is on the order of the trap frequency, resulting a fast entanglement speed, which is of importance in view of decoherence. 相似文献
11.
We propose an adiabatic-passage scheme for the generation of three-qutrit singlet states with two-level trapped ions. Distinctly different from previous proposals, we encode qutrits in Dicke states with two-level ions and use the adiabatic-evolution techniques in order not to exactly control the laser pulses, making the realization of the scheme much easier. Furthermore, the phonon is only virtually excited in the procedure, so the effect of the phonon losses can be reduced. 相似文献
12.
13.
We propose a scheme for the generation of entangled coherent states for the center-of-mass and relative vibrational modes of two trapped ions. In the scheme the ions are simultaneously illuminated by a single standing-wave laser tuned to the carrier. The scheme allows the production of an entangled coherent states with a considerably high speed as long as a laser field of sufficiently high intensity is available. 相似文献
14.
LIN Li-Hua JIANG Yun-Kun YANG Zhen-Biao YE Sai-Yun 《理论物理通讯》2005,44(4):712-714
We propose a scheme for the generation of entangled coherent states for the center-of-mass and relative vibrational modes of two trapped ions. In the scheme the ions are simultaneously illuminated by a single standing-wave laser tuned to the carrier. The scheme allows the production of an entangled coherent states with a considerably high speed as long as a laser field of sufficiently high intensity is available. 相似文献
15.
YANG Wan-Li WEI Hua CHEN Chang-Yong 《理论物理通讯》2008,50(11):1117-1122
We propose a potentially practical scheme for implementing an n-qubit Toffoli gate by elaborately controlling the transport of ultracold ions through stationary laser beams. Conditioned on the uniform ionic transport velocity, the n-qubit Toffoli gate can be realized with high fidelity and high successful probability under current experimental conditions, which depends on a single resonant interaction with n trapped ions and has constant implementation time with the increase of qubits. We show that the increase of the ion number can improve the fidelity and the successful probability of the Toffoli gate. 相似文献
16.
We show that transverse phonons in a set of trapped ions under the action of lasers are described by an interacting boson model whose parameters can be externally adjusted. If the radial trapping frequency is large enough, the system is described by a Bose–Hubbard model, in which hopping of the phonons between different ions is provided by the Coulomb interaction. On the other hand, the non-linear terms in the interaction of the ions with a standing-wave provide us with the phonon–phonon interaction. We investigate the possibility of observing several quantum many—body phenomena, including (quasi)Bose–Einstein Condensation as well as a superfluid-Mott insulator quantum phase transition. 相似文献
17.
We propose a potentially practical scheme for implementing an
n-qubit Toffoli gate by elaborately controlling the transport of
ultracold ions through stationary laser beams. Conditioned on the
uniform ionic transport velocity, the n-qubit Toffoli gate can be realized
with high fidelity and high successful probability under current experimental
conditions, which depends on a single resonant interaction with n trapped
ions and has constant implementation time with the increase of qubits.
We show that the increase of the ion number can improve the fidelity and
the successful probability of the Toffoli gate. 相似文献
18.
We propose a method for generating SU (1, 1) intelligent states for the center of mass and relative motionalmodes for two trapped ions. In our scheme, only three laser beams are employed, and their directions are all the sameas the direction of the two trapped ions‘ alignment. Under certain conditions, our desired states are obtained as thesteady-state solution of the master equation of the system. 相似文献
19.
ZHENG Shi-Biao 《理论物理通讯》2002,38(8)
We propose a scheme to generate various nonclassical vibrational states in the collective motion of twotrapped ions, such as squeezed states, Schrodinger cat states, and SU(2) states. It is based on Raman-type excitations.Two-mode coupling between the center-of-mass and relative vibrational modes can also be realized. 相似文献
20.
FULi-Ping SUNTian-Yu 《理论物理通讯》2003,40(4):486-488
We propose a method for generating SU(1, 1) intelligent states for the center of mass and relative motional modes for two trapped ions. In our scheme, only three laser beams are employed, and their directions are all the same as the direction of the two trapped ions‘ alignment. Under certain conditions, our desired states are obtained as the steady-state solution of the master equation of the system. 相似文献