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1.
The dependence of fidelity on the squeezing parameter in teleportation of the squeezed coherent states
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This paper investigates an analytical expression of teleportation fidelity in the teleportation scheme of a single mode of electromagnetic field.The fidelity between the original squeezed coherent state and the teleported one is expressed in terms of the squeezing parameter r and the quantum channel parameter(two-mode squeezed state) p.The results of analysis show that the fidelity increases with the increase of the quantum channel parameter p,while the fidelity decreases with the increase of the squeezing parameter r of the squeezed state.Thus the coherent state(r = 0) is the best quantum signal for continuous variable quantum teleportation once the quantum channel is built. 相似文献
2.
Statistical properties of coherent photon-subtracted two-mode squeezed vacuum and its application in quantum teleportation
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We introduce a kind of non-Gaussian entangled state, which can be obtained by operating a non-local coherent photon-subtraction operation on a two-mode squeezed vacuum. It is found that its normalization factor is only related to the Legendre polynomials, which is a compact expression. Its statistical properties are discussed by the negative region Wigner function with the analytical expression. As an application, the quantum teleportation for coherent states is considered by using the non-Gaussian state as an entangled channel. It is found that the teleportation fidelity can be enhanced by this non-Gaussian operation. 相似文献
3.
An optical scheme for probabilistic teleporting entangled squeezed vacuum states (SVS) is proposed. In this scheme, the teieported state is a bipartite entangled SVS, and the quantum channel is a tripartite entangled SVS. The process of the teleportation is achieved by using a 50/50 symmetric beamsplitter and photon detectors with the help of classical information. 相似文献
4.
The dependence of fidelity on the squeezing parameter in teleportation of the squeezed coherent statesvglue4pt
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This paper investigates an analytical expression of teleportation fidelity in the teleportation scheme of a single mode of electromagnetic field. The fidelity between the original squeezed coherent state and the teleported one is expressed in terms of the squeezing parameter r and the quantum channel parameter (two-mode squeezed state) p. The results of analysis show that the fidelity increases with the increase of the quantum channel parameter p, while the fidelity decreases with the increase of the squeezing parameter r of the squeezed state. Thus the coherent state (r=0) is the best quantum signal for continuous variable quantum teleportation once the quantum channel is built. 相似文献
5.
借助于双模压缩真空态在EPR纠缠态表象中的表示,研究了用双模压缩真空态作为量子通道 实现任意的单模和双模量子态的远程传输.
关键词:
量子隐形传态
EPR纠缠态
压缩真空态 相似文献
6.
Effects of photon addition on quantum nonlocality of squeezed entangled coherent states for Bell-inequality tests are studied theoretically. By utilizing the method of photon-parity measurement, it is found that photon addition can always increase the degrees of Bell violations within a certain parameter range. A possible scheme for generating photon-added squeezed entangled coherent states is proposed. 相似文献
7.
We present a realistic scheme for the entanglement swapping of continuous
variable, in which a two-mode squeezed vacuum state serves as a quantum
channel. The position sum and momentum difference of two local modes are
measured. By taking the input entangled state also as a two-mode squeezed
vacuum state, we investigate the average fidelity and the von Neumann
entropy of the output state. The results show that the
perfect teleportation can be
achieved by increasing the squeezing of the quantum channel and that any
nonzero squeezing in both the quantum channel and the input entangled state
is sufficient to swap the entanglement. 相似文献
8.
Preparation of multicomponent motional coherent and squeezed coherent states of a trapped ion 总被引:1,自引:0,他引:1
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In this paper, we present a scheme for preparation of multicomponent motional coherent and squeezed coherent states of the quantized centre of mass of an ion trapped in a one-dimensional harmonic potential and driven by two travelling-wave laser beams tuned to the nth red and blue vibrational sidebands, respectively. In addition, our scheme also provides experimental possibility for quantum state engineering. 相似文献
9.
基于单-双模组合压缩真空态一定范围内能够获得压缩增强的效果,引入单-双模组合压缩热态(DSMST),讨论其纠缠性质.利用Weyl编序算符在相似变换下的不变性,简洁方便地导出了DSMST的纠缠度-负对数值,并给出了当热效应存在时保持纠缠的条件.研究表明:与通常的双模压缩态相比,随着参数的增加,DSMST的纠缠度增加.作为DSMST的应用,利用其实现相干态的量子隐形传输.结果表明:不同于纠缠度随压缩参数增加,保真度获得改善是有条件的,该条件恰好就是一正交分量涨落出现压缩增强的参数区域.此外,解析推导了有效隐形传输保真度(1/2)的条件. 相似文献
10.
11.
From the normally ordered form of the density operator of a squeezed coherent state(SCS),we directly derive the compact expression of the SCS’s photon-number distribution(PND).Besides the known oscillation characteristics,we find that the PND is a periodic function with a period of π and extremely sensitive to phase.If the squeezing is strong enough,and the compound phase which is relevant to the complex squeezing and displacement parameters are assigned appropriate values,different oscillation behaviours in PND for even and odd photon numbers appear,respectively. 相似文献
12.
We present a scheme to prepare cluster-type entangled squeezed vacuum states (CTESVS) by considering the two-photon interaction between a two-level atom and a high-quality cavity, driven by a strong classical field. After the realization of simple atomic measurements, the generation of CTESVS in four separate cavities is accomplished within the cavity decay time. In the case of large atom=cavity detuning, the scheme is immune to the effect of atomic spontaneous emission. 相似文献
13.
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
14.
By applying the bosonic creation operator to squeezed
vacuum states, this paper introduces a new kind of quantum states:
photon-added squeezed vacuum states. It also presents an
experimental approach to prepare these states, and investigates
their quantum statistical properties by the numerical method. The
results indicate that these states reveal some interesting
non-classical properties, such as anti-bunching effects,
squeezing effects and negativities of the relevant Wigner
functions. 相似文献
15.
Squeezed state of light has drawn an enormous attention in information processing and digital communication since it has broken the quantum limit of noise. Here we have analytically investigated the interactions among coherent and vacuum squeezed states of light, interaction among coherent vacuum and squeezed states of light, and that between phase and amplitude squeezed states of light signals. Hence we established the nature of the resulting interaction with the help of photon statistics. 相似文献
16.
Entanglement diversion and quantum teleportation of entangled coherent states 总被引:2,自引:0,他引:2
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The proposals on entanglement diversion and quantum teleportation of
entangled coherent states are presented.In these proposals, the entanglement between two coherent states, $|\alpha\rangle$ and $|-\alpha\rangle$, with the same amplitude but a phase difference
of $\pi$ is utilized as a quantum channel. The processes of the entanglement diversion and the teleportation are achieved by using the 50/50 symmetric beam splitters, the phase shifters and the photodetectors with the help of classical information. 相似文献
17.
Continuous-variable quantum teleportation of even and odd coherent states through varied gain channels
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This paper has investigated quantum teleportation of even and odd coherent states in
terms of the EPR entanglement states for continuous variables. It discusses the
relationship between the fidelity and the entanglement of EPR states, which is
characterized by the degree of squeezing and the gain of classical channels. It
shows that the quality of teleporting quantum states also depends on the
characteristics of the states themselves. The properties of teleporting even and odd
coherent states at different intensities are investigated. The difference of
teleporting two such kinds of quantum states are analysed based on the quantum
distance function. 相似文献
18.
Effects of photon addition on the quantum nonlocality of squeezed entangled-coherent states
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Effects of photon addition on the quantum nonlocality of squeezed entangled coherent states for Bell-inequality tests are studied theoretically. By utilizing the method of photon-parity measurement, it is found that photon addition can always increase the degrees of Bell violations within a certain parameter range. A possible scheme for generating photon-added squeezed entangled coherent states is proposed. 相似文献
19.
20.
We introduce quasiprobabilities based on the so-called squeezed states to represent the density operator of an oscillator. Such representations become especially useful for oscillators designed to display, strong excitation notwithstanding, pronounced quantum features such as squeezing of the quantum fluctuations of certain observables below the limit characteristic of coherent states. 相似文献