共查询到20条相似文献,搜索用时 15 毫秒
1.
We present a new protocol for the quantum secret sharing (QSS) task among multiparties with two-particle entangled states. In our scheme, the secret is split among a number of participatlng partners and the reconstruction requires collaboration of all the authorized partners. Instead of multiparticle Greenberger-Horne-Zeillnger states, only two-particle entangled states are employed in this scheme. By local operations and individual measurements on either of the two entangled particles, each authorized partner obtains a sequence of secret bits shared with other authorized partners. This protocol can be experimentally realized using only linear optical elements and simple entanglement source. It is scalable in practice. 相似文献
2.
Using even and odd coherent states, we define a new state, which is called the spin-type W state. With the spin-type W states, we provide a new scheme for testing fundamental aspects of quantum mechanics and refuting local hidden variable theory without using inequalities. Finally, a scheme for preparing the spin-type W states, and discussion of experimental possibility and the effect of the measurement on physical observables due to a close orthogonality of the two coherent states are given. 相似文献
3.
Unconventional geometric phase gate and multiqubit entanglement for hot ions with a frequency-modulated field 下载免费PDF全文
We present an alternative scheme for implementing the unconventional geometric two-qubit phase gate and prepar-ing multiqubit entanglement by using a frequency-modulated laser field to simultaneously illuminate all ions.Selecting the index of modulation yields selective mechanisms for coupling and decoupling between the internal and the external states of the ions.By the selective mechanisms,we obtain the unconventional geometric two-qubit phase gate,multipar-ticle Greenberger-Horne-Zeilinger states and highly entangled cluster states.Our scheme is insensitive to the thermal motion of the ions. 相似文献
4.
Efficient Scheme for Greenberger-Horne-Zeilinger State and Cluster State with Trapped Ions 下载免费PDF全文
We propose a scheme to generate the Greenberger-Horne-Zeilinger (GHZ) states and the cluster states of many trapped ions. In the scheme, the ion is illuminated by a single laser tuned to the first lower vibrational sideband. The scheme only requires resonant interactions. Thus the scheme is very simple and the quantum dynamics operation can be realized at a high speed, which is important in view of decoherence. 相似文献
5.
X. L. Zhang X. L. Feng C. F. Wu C. H. Oh 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,60(2):411-415
We propose a scheme for implementing two-qubit geometric phase gate via the
adiabatic evolution for trapped ions in thermal motion, leveraging on the
stimulated Raman adiabatic passage with the geometric phase mechanism.
Evolution along a dark state makes our scheme not only immune from decoherence
due to spontaneous emission from excited states, but also rid off the
dynamical phase. Furthermore, due to the opposite detuning of the driving
lasers, the vibrational states of the trapped ions are only virtually excited
during the operations, so our scheme is also insensitive to the occupation
number of the vibrational mode. 相似文献
6.
Shi-Biao Zheng 《Czechoslovak Journal of Physics》2002,52(5):713-718
We propose a method for the generation of motional pair coherent states for the center of mass and relative motional modes
for two trapped ions. The scheme is generalized to prepare pair cat states. The scheme does not require individual ionic laser
addressing. 相似文献
7.
YANG Wen-Xing 《理论物理通讯》2006,46(8)
We propose a scheme to generate a superposition of motional coherent states with arbitrary coefficients on a line in phase space and implement a quantum controlled phase-gate for multiple trapped ions with a single standing-wave laser pulse whose carrier frequency is tuned to the ions transition. In the scheme each ion does not need to be exactly positioned at the node of the standing wave, which is very important from viewpoint of experiment. Furthermore, our scheme may allow the generation of a superposition of coherent states with large mean phonon number for a large number of trapped ions in a fast way by choosing suitable laser intensity. We show that it can also be used to generate maximally entangled states of multiple trapped ions. 相似文献
8.
YANG Wen-Xing 《理论物理通讯》2006,46(2):297-302
We propose a scheme to generate a superposition of motional coherent states with arbitrary coefficients on a line in phase space and implement a quantum controlled phase-gate for multiple trapped ions with a single standing-wave laser pulse whose carrier frequency is tuned to the ions transition. In the scheme each ion does not need to be exactly positioned at the node of the standing wave, which is very important from viewpoint of experiment, Furthermore, our scheme may allow the generation of a superposition of coherent states with large mean phonon number for a large number of trapped ions in a fast way by choosing suitable laser intensity. We show that it can also be used to generate maximally entangled states of multiple trapped ions. 相似文献
9.
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
10.
S. B. Zheng 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(3):715-718
We propose a scheme for the generation of an arbitrary quantum states for multiple trapped ions in the symmetric Dicke subspace.
One can manipulate the collective ion transition in a selective symmetric Dicke subspace via the virtual excitation induced
inequidistant energy levels. All the states undergo the same phonon-number-dependent Stark shift and thus the scheme is insensitive
to the thermal motion. Furthermore, the scheme does not require individual addressing of the ions. 相似文献
11.
We propose a scheme for controllably entangling the ground states of five-state W-type atoms confined in a cavity and realizing swap gate and phase gate operations. In this scheme the cavity is only virtually excited and the atomic excited states are almost not occupied, so the produced entangled states and quantum logic operations are very robust against the cavity decay and atomic spontaneous emission. 相似文献
12.
ZHENG Shi-Biao 《理论物理通讯》2007,48(4):626-628
We propose a scheme to produce quantum phase gates for trapped ions. Taking advantage of the adiabatic evolution, the operation is insensitive to small fluctuations of experimental parameters. Furthermore, the spontaneous emission is suppressed since the ions have no probability of being populated in the electronic excited states. 相似文献
13.
The controllability of a quantum system for the modified Pöschl-Teller (MPT) potential with the discrete bound states is investigated. The creation and annihilation operators of this potential are constructed directly from the normalized wave function with the factorization method and associated to an su(2) algebra. It is shown that this quantum system with the nondegenerate discrete bound states can, in principle, be strongly completely controllable, i.e., the system eigenstates can be guided by the external field to approach arbitrarily close to a target state, which could be theoretically realized by the actions of the creation and annihilation operators on the ground state. 相似文献
14.
A potential scheme is proposed for generating cluster states of many trapped ions in thermal motion, in which the effective Hamiltonian does not involve the external degree of freedom and thus the scheme is insensitive to the external state, allowing it to be thermal state. The required experimental techniques of the schemes are within the scope that can be obtained in the ion-trap setup. 相似文献
15.
In the system with two two-level ions confined in a linear trap,
this paper presents a simple scheme to realize the quantum phase
gate (QPG) and the swap gate beyond the Lamb--Dicke (LD) limit.
These two-qubit quantum logic gates only involve the internal states
of two trapped ions. The scheme does not use the vibrational mode as
the data bus and only requires a single resonant interaction of the
ions with the lasers. Neither the LD approximation nor the auxiliary
atomic level is needed in the proposed scheme. Thus the scheme is
simple and the interaction time is very short, which is important in
view of decoherence. The experimental feasibility for achieving this
scheme is also discussed. 相似文献
16.
A scheme is proposed to generate arbitrary, discrete
superpostions of squeezed coherent states of the squeezed center of mass of
$N$ trapped ions along a straight line in phase space.
The scheme is based on a
resonant bichromatic excitation of each trapped ion that generates
displacement and squeezing in the vibrational motion conditioned to each
internal state. In this paper, we also show that such a method can be
used for the engineering of motional quantum states. 相似文献
17.
Implementing remote controlled-NOT gates and entanglement swapping via geometric phase gates in ion-trap systems 下载免费PDF全文
We propose a scheme for the implementation of remote controlled-NOT gates and entanglement swapping via geometric phase gates in ion-trap systems. The proposed scheme uses the two ground states of the A-type ions as memory instead of the vibrational mode. And the system is robust against the spontaneous radiation and the dephasing. 相似文献
18.
We show that the physical system consisting of trapped ions interacting with lasers may undergo a rich variety of quantum phase transitions. By changing the laser intensities and polarizations the dynamics of the internal states of the ions can be controlled, in such a way that an Ising or Heisenberg-like interaction is induced between effective spins. Our scheme allows us to build an analogue quantum simulator of spin systems with trapped ions, and observe and analyze quantum phase transitions with unprecedented opportunities for the measurement and manipulation of spins. 相似文献
19.
Implementing remote controlled-NOT gates and entanglement swapping via geometric phase gates in ion-trap systems 下载免费PDF全文
We propose a scheme for the implementation of remote controlled-NOT
gates and entanglement swapping via geometric phase gates in
ion-trap systems. The proposed scheme uses the two ground states of
the $\Lambda$-type ions as memory instead of the vibrational mode.
And the system is robust against the spontaneous radiation and the
dephasing. 相似文献
20.
We propose a method of generating a four-atom entangled cluster state by considering two kinds of the atoms–cavity field interaction in cavity QED. During the preparation the cavity is only virtually excited no quantum information will be transferred from the atoms to the cavity and thus the scheme is insensitive to the cavity field states and cavity decay. The scheme can also be used to generate the cluster state for the trapped ions. 相似文献