共查询到20条相似文献,搜索用时 122 毫秒
1.
This paper reports that a quantum dense coding can be implemented
with ions confined in a linear trap and interacting with laser
beams. The scheme is insensitive to the interaction between the
quantum channel and the environment. The Bell-state measurement is
not involved and the probability of success in our scheme is $1.0$. 相似文献
2.
A scheme for conditional quantum phase gate viabimodal cavity and a Λ-type three-level atom
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We propose a scheme to implement a two-qubit conditional quantum
phase gatefor the intracavity field viaa single three-level
$\Lambda$-type atom driven by two modes in a high-Q cavity. The
quantum information is encoded on the Fock states of the bimodal
cavity. The gate's averaged fidelity is expected to reach $99.8\%$. 相似文献
3.
As a special quantum node in a quantum network, the quantum router plays an important role in storing and transferring quantum information. In this paper, we propose a quantum router scheme based on asymmetric intercavity couplings and a three-level Λ-type atomic system. This scheme implements the quantum routing capability very well. It can perfectly transfer quantum information from one quantum channel to another. Compared with the previous quantum routing scheme, our proposed scheme can achieve the transfer rate of single photons from one quantum channel to another quantum channel reaching 100%, the high transfer rate is located in the almost quadrant regions with negative values of the two variables λ_a and λ_b, and their maximum values T_u~b+T_d~b= 1 emerge in the center point λ_a=λ_b=-1. Therefore, it is possibly feasible to efficiently enhance the routing capability of the single photons between two channels by adjusting the inter-resonator couplings, and the asymmetric intercavity coupling provides a new method for achieving high-fidelity quantum routers. 相似文献
4.
A potential scheme is proposed for generating cluster states of many atoms in cavity quantum electradynamics (QED), in which an unorthodox encoding is employed with the ground state being qubit [0〉 while two closely spaced upper states being qubit |1〉. Throughout the scheme the cavities can be in thermal states but axe only virtually excited. We show how to create the cluster states by performing a two-step hut no single-qubit operation. Discussion is also carried out on the experimental feasibility of our scheme. 相似文献
5.
A potential scheme is proposed for generating cluster states of many
atoms in cavity quantum electradynamics (QED), in which an unorthodox
encoding is employed with the ground state being qubit $\left\vert
0\right\rangle $ while two closely spaced upper states being qubit
$\left\vert 1\right\rangle $. Throughout the scheme the cavities can
be in thermal states but are only virtually excited. We show how to
create the cluster states by performing a two-step but no
single-qubit operation. Discussion is also carried out on the
experimental feasibility of our scheme. 相似文献
6.
Scheme for the implementation of 1→3
optimal phase-covariant quantum cloning in ion-trap systems
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This paper proposes a scheme for the implementation of 1→ 3 optimal phase-covariant quantum cloning with trapped ions. In the present protocol, the required time for the whole procedure is short due to the resonant interaction, which is important in view of decoherence. Furthermore, the scheme is feasible based on current technologies. 相似文献
7.
The general scheme for teleportation of a multi-particle d-level
quantum state is presented when m pairs of partially entangled
particles are utilized as quantum channels. The probabilistic
teleportation can be achieved with a successful probability of $
\prod \limits_{N=0}^{d-1} ({C_0^N})^2/{d^M}$,
which is determined by the smallest coefficients of each entangled channels. 相似文献
8.
Implementing Deutsch-Jozsa Algorithm with?Superconducting Quantum Interference Devices in?Cavity QED
Hong-Fu Wang Shou Zhang Yong-Fang Zhao 《International Journal of Theoretical Physics》2009,48(8):2384-2389
We propose a scheme for implementing the Deutsch-Jozsa (DJ) algorithm with superconducting quantum interference devices (SQUIDs)
in cavity quantum electrodynamics (QED). The required controlled-NOT (CNOT) operations can be easily realized based on the
resonant interaction of SQUIDs with a single-mode high-
cavity. The scheme has the advantages of being simple, scalable and feasible in the experimental realization and further utilization. 相似文献
9.
Zheng-An Wang 《中国物理 B》2022,31(4):40309-040309
We report a metrology scheme which measures the magnetic susceptibility of an atomic spin ensemble along the $x$ and $z$ directions and produces parameter estimation with precision beating the standard quantum limit. The atomic ensemble is initialized via one-axis spin squeezing with optimized squeezing time and parameter $\phi$ (to be estimated) assumed as uniformly distributed between 0 and $2\pi$ while fixed in each estimation. One estimation of $\phi$ can be produced with every two magnetic susceptibility data measured along the two axes respectively, which has an imprecision scaling $({1.43\pm0.02})/N^{0.687\pm0.003}$ with respect to the number $N$ of the atomic spins. The measurement scheme is easy to implement and is robust against the measurement fluctuation caused by environment noise and measurement defects. 相似文献
10.
We propose a scheme for realizing a controlled teleportation of random
$M$-qudit quantum information under the control of $N$ agents. The resource
consumption includes a prearranged $(2M + N + 1)$-qudit entangled quantum
channel and $(2M + N + 1)\log _2 d$-bit classical communication. And the
quantum operations used in the teleportation process are a series of
generalized Bell-state measurements, single-qudit measurements, qudit
$H$-gates, qudit-Pauli gates and qudit phase gates. It is shown that the
original state can be restored by the receiver only on condition that
all the agents work in collaboration with each others.
If one agent does not cooperate with the other, the original
state cannot be fully recovered. 相似文献
11.
This paper proposes a deterministic quantum key distribution scheme based
on Gaussian-modulated continuous variable EPR correlations. This
scheme can implement fast and efficient key distribution. The
security is guaranteed by continuous variable EPR entanglement correlations
produced by nondegenerate optical parametric amplifier. For
general beam splitter eavesdropping strategy, the secret
information rate $\Delta I=I(\alpha,\beta)-I(\alpha,\epsilon)$ is
calculated in view of Shannon information theory. Finally the
security analysis is presented. 相似文献
12.
In this paper, a scheme is proposed for remote state preparation (RSP) with cavity quantum electrodynamics (QED). In our scheme, two observers share two-atom nonmaximally entangled state as quantum channels and can realize remote preparation of state of an atom. We also propose a generalization for remote preparation of N-atom entangled state by (N+1)-atom GHZ-like state (N ≥ 2). By this scheme, one single-atom projective measurement is enough for the RSP of a qubit or N-atom entangled state, and the probability of success for RSP is unity. Furthermore, we have considered the case where observers use W-like state as quantum channels to realize RSP of a qubit. We compare our scheme with existing ones. 相似文献
13.
Economical quantum secure direct communication network with single photons 总被引:1,自引:0,他引:1
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In this paper a scheme for quantum secure direct communication
(QSDC) network is proposed with a sequence of polarized single
photons. The single photons are prepared originally in the same
state $\vert 0\rangle$ by the servers on the network, which will
reduce the difficulty for the legitimate users to check
eavesdropping largely. The users code the information on the single
photons with two unitary operations which do not change their
measuring bases. Some decoy photons, which are produced by operating
the sample photons with a Hadamard, are used for preventing a
potentially dishonest server from eavesdropping the quantum lines
freely. This scheme is an economical one as it is the easiest way
for QSDC network communication securely. 相似文献
14.
Three-party quantum secret sharing of secure direct communication based on χ-type entangled states
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Based on χ-type entangled states and the two-step protocol [Deng F G,Long G L and Liu X S 2003 Phys.Rev.A 68 042317],a quantum secret sharing protocol of secure direct communication based on χ-type entangled states |χ00 3214 is proposed.Using some interesting entanglement properties of this state,the agent entirety can directly obtain the secret message from the message sender only if they collaborate together.The security of the scheme is also discussed. 相似文献
15.
Properties of field quantum entropy evolution in the Jaynes--Cummings model with initial squeezed coherent states field
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The properties of the field quantum entropy evolution in a system of
a single-mode squeezed coherent state field interacting with a
two-level atom is studied by utilizing the complete quantum theory,
and we focus our attention on the discussion of the influences of
field squeezing parameter $\gamma $, atomic distribution angle
$\theta $ and coupling strength $g$ between the field and the atom
on the properties of the evolution of field quantum entropy. The
results obtained from numerical calculation indicate that the
amplitude of oscillation of field quantum entropy evolution
decreases with the increasing of squeezing parameter $\gamma $, and
that both atomic distribution angle $\theta $ and coupling strength
$g$ between the field and the atom can influence the periodicity of
field quantum entropy evolution. 相似文献
16.
A multi-proxy quantum group signature scheme with threshold shared verification is proposed. An original signer may authorize a proxy group as his proxy agent. Then only the cooperation of all the signers in the proxy group can generate the proxy signature on behalf of the original signer. In the scheme, any t or more of n receivers can verify the message and any t - 1 or fewer receivers cannot verify the validity of the proxy signature. 相似文献
17.
Generation of unconventional geometric phase gates in ion trap-optical cavity system by squeezed operators
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Based on squeezed operators this paper has implemented an ideal
unconventional geometric quantum gate (GQG) in ion trap-optical
cavity system by radiating the trapped ions with the cavity field of
frequency wc and an external laser field of frequency
wL. It can ensure that the gate time is shorter than
the coherence time for qubits and the decay time of the optical
cavity by appropriately tuning the ionic transition frequency
w0, the frequencies of the cavity mode wc and
the vibrational mode ν. It has also realized the unconventional
GQG under the influence of the cavity decay based on the
squeezed-like operators and found that the present scheme works well
for the smaller cavity decay by investigating the corresponding
fidelity and success probability. 相似文献
18.
Considering the quantum fluctuation effects, the existence and stabilityof solitons in a Bose-Einstein condensate subjected in a $\mathcal{PT}$-symmetric potentialare discussed. Using the variational approach, we investigate how the quantum fluctuationaffects the self-localization and stability of the condensate with attractivetwo-body interactions. The results show that the quantum fluctuation dramaticallyinfluences the shape, width, and chemical potential of the condensate.Analytical variational computation also predicts there exists a positive critical quantumfluctuation strength $q_{c}$ with each fixed attractive two-body interaction $g_{0}$, if thequantum fluctuation strength $q_{0}$ is bigger than $q_{c}$, there is no bright solitonsolution existence. We also study the effects of the quantum fluctuations on the stabilityof solitons using the Vakhitov-Kolokolov (VK) stability criterion. A robust stable brightsoliton will always exist when the quantum fluctuation strength $q_{0}$ belongs tothe parameter regimes $q_{c}\geq q_{0}>0$. 相似文献
19.
A scheme, based on the two two-level atoms resonantly
driven by the classical field separately trapped in two cavities
coupled by an optical fibre, for the implementation of remote
two-qubit gates is investigated. It is found that the quantum
controlled-phase and swap gates can be achieved with the assistance
of the classical field when there are detunings of the coupling quantum
fields. Moreover, the influence of the dissipation of the cavities
and the optical fibre is analysed while the spontaneous emission of
the atoms can be effectively suppressed by introducing Λ-type atoms. 相似文献
20.
An inhomogeneous (1? $+$ ?1)-dimensional model of the quantum gravity is considered. It is found, that this model corresponds to a string propagating in some curved background space. The quantization scheme including the Wheeler–DeWitt equation and the “particle on a sphere” type of the gauge condition is suggested. In the quantization scheme considered, the “problem of time” is resolved by building of the quasi-Heisenberg operators acting in a space of solutions of the Wheeler–DeWitt equation, and the normalization of the wave function corresponds to the Klein–Gordon type. To analyze the physical consequences of the scheme, a (1? $+$ ?1)-dimensional background space is considered for which a classical solution is found and quantized. The obtained estimations show the way to solution of the cosmological constant problem for this model. Such a solution consists in compensation of the zero-point oscillations of the matter fields by the quantum oscillations of the scale factor. Along with such a compensation, a slow global evolution of a background exists that corresponds to an universe expansion. 相似文献