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1.
We report the experimental realization and the characterization of polarization and momentum hyperentangled two-photon states, generated by a new parametric source of correlated photon pairs. By adoption of these states an "all-versus-nothing" test of quantum mechanics was performed. The two-photon hyperentangled states are expected to find at an increasing rate a widespread application in state engineering and quantum information. 相似文献
2.
Zhi-Wei Sun Rui-Gang Du Dong-Yang Long 《International Journal of Theoretical Physics》2012,51(6):1946-1952
In a quantum secure direct communication protocol, two remote parties can transmit the secret message directly without first
generating a key to encrypt them. A quantum secure direct communication protocol using two-photon four-qubit cluster states
is presented. The presented scheme can achieve a higher efficiency in transmission and source capacity compared with the proposed
quantum secure direct communication protocols with cluster states, and the security of the protocol is also discussed. 相似文献
3.
Cluster states are the fundamental resource for the one-way model of quantum computation. In this paper we show the realization
of a two-photon four-qubit cluster state. The qubits are encoded in the polarization and the linear momentum of the particles.
By using this state we realized two important quantum algorithms, namely the Grover’s search and the Deutsch’s algorithm. 相似文献
4.
In this paper, a quantum authencryption protocol is proposed by using the two-photon entangled states as the quantum resource. Two communicants Alice and Bob share two private keys in advance, which determine the generation of two-photon entangled states. The sender Alice sends the two-photon entangled state sequence encoded with her classical bits to the receiver Bob in the manner of one-step quantum transmission. Upon receiving the encoded quantum state sequence, Bob decodes out Alice’s classical bits with the two-photon joint measurements and authenticates the integrity of Alice’s secret with the help of one-way hash function. The proposed protocol only uses the one-step quantum transmission and needs neither a public discussion nor a trusted third party. As a result, the proposed protocol can be adapted to the case where the receiver is off-line, such as the quantum E-mail systems. Moreover, the proposed protocol provides the message authentication to one bit level with the help of one-way hash function and has an information-theoretical efficiency equal to 100 %. 相似文献
5.
We report an experimental demonstration of a bit-flip error-rejection protocol for error-reduced transfer of quantum information through a noisy quantum channel. In the experiment, an unknown state to be transmitted is encoded into a two-photon entangled state, which is then sent through an engineered noisy quantum channel. At the final stage, the unknown state is decoded by a parity measurement, successfully rejecting the erroneous transmission over the noisy quantum channel. 相似文献
6.
The degenerate two-photon emission process is treated on the basis of quantum theory. Neglecting relaxation mechanisms, solutions in short time approximation are given. Relevant quantities as the mean photon number, second order correlation, field fluctuations and the uncertainty product are analyzed. It is shown, that an initial coherent state does not tend to a two-photon coherent state by two-photon emission as it can be expected from the results given by Yuen. 相似文献
7.
Entropy squeezing of a moving atom and control of noise of the quantum mechanical channel via the two-photon process 下载免费PDF全文
Based on the quantum information theory, we have investigated the
entropy squeezing of a moving two-level atom interacting with the
coherent field via the quantum mechanical channel of the two-photon
process. The results are compared with those of atomic squeezing
based on the Heisenberg uncertainty relation. The influences of the
atomic motion and field-mode structure parameter on the atomic
entropy squeezing and on the control of noise of the quantum
mechanical channel via the two-photon process are examined. Our
results show that the squeezed period, duration of optimal entropy
squeezing of a two-level atom and the noise of the quantum mechanical
channel can be controlled by appropriately choosing the atomic motion
and the field-mode structure parameter, respectively. The quantum
mechanical channel of two-photon process is an ideal channel for
quantum information (atomic quantum state) transmission. Quantum
information entropy is a remarkably accurate measure of the atomic
squeezing. 相似文献
8.
S. A. Podoshvedov 《JETP Letters》2005,82(7):459-462
As demonstrated by E. Knill et al. [Nature 409, 46 (2001)], quantum teleportation and quantum logic gates with a success probability close to one can be implemented using only linear optical elements, additional photons, and post-selection. To do this, it is desirable to have special quantum channels in sight before quantum teleportation performance. Here, we propose an experimental arrangement to generate a two-photon KLM state different from the well-known Bell states. This two-photon KLM state can be used to enhance the success probability of the quantum teleportation of a one-mode quantum qubit from 0.5 up to 2/3. 相似文献
9.
The procedure of measurement followed by the reconstruction of the quantum state of a three-level optical system is implemented for a frequency-and spatially degenerate two-photon field. The method of statistical estimation of the quantum state from a solution to the likelihood equation and the analysis of the statistical properties of the obtained estimators is developed. Using the root method of estimating quantum states, the initial two-photon (qutrit) wave function is reconstructed from the measured fourth-order field moments. 相似文献
10.
双光子拉曼过程是一种有效制备和控制原子内态的方法, 在原子内态操控和基于原子的量子信息处理中具有重要意义. 研制用于特定原子的拉曼激光是实现该过程的重要一步. 报道了利用光纤波导相位调制器及滤波器等实现用于铯原子内态操控的拉曼激光的方法, 并成功用于单个铯原子的内态精密操控. 通过4.6 GHz的微波信号源直接驱动波导相位调制器高效地获得光场的调制边带, 并利用自由光谱区为9.19 GHz的法布里-珀罗腔将载波及二阶边带滤掉, 获得了频率精确、相差9.19 GHz的拉曼激光. 经过基于光纤振幅调制器的功率稳定系统, 最终可以获得总功率为73 μupW、长时间内波动为2.2%的拉曼激光束, 并将此光束用于激发单个铯原子, 实现了|6S1/2, F=4, mF=0和|6S1/2, F=3, mF=0 之间的可控拉比操作. 相似文献
11.
The geometrical optics in Fresnel quantum holography for quantum entangled two-photon source and classical thermal light source based on the second-order correlation measurement has been discussed. We theoretically prove that the Fresnel quantum hologram of the detected object can be obtained through second-order correlation measurement and the optical reconstruction process can be accomplished by making use of a point light source. 相似文献
12.
13.
We propose a probabilistic scheme for realizing teleportation of bipartite photonic states using linear optical elements where only requires a two-photon Bell state used as quantum channel. It reduces the requirement of the entanglement of quantum channel, but requires an additional photon and an auxiliary maximally entangled photon pair locally. 相似文献
14.
DONG Ping LIN Ji-Cheng YANG Ming CAO Zhuo-Liang 《理论物理通讯》2006,46(4):627-630
We propose a probabilistic scheme for realizing teleportation of bipartite photonic states using linear optical elements where only requires a two-photon Bell state used as quantum channel. It reduces the requirement of the entanglement of quantum channel, but requires an additional photon and an auxiliary maximally entangled photon pair locally. 相似文献
15.
Practical non-orthogonal decoy state quantum key distribution with heralded single photon source 下载免费PDF全文
Recently the performance of the quantum key distribution (QKD) is substantially improved by the decoy state method and the non-orthogonal encoding protocol, separately. In this paper, a practical non-orthogonal decoy state protocol with a heralded single photon source (HSPS) for QKD is presented. The protocol is based on 4 states with different intensities. i.e. one signal state and three decoy states. The signal state is for generating keys; the decoy states are for detecting the eavesdropping and estimating the fraction of single-photon and two-photon pulses. We have discussed three cases of this protocol, i.e. the general case, the optimal case and the special case. Moreover, the final key rate over transmission distance is simulated. For the low dark count of the HSPS and the utilization of the two-photon pulses, our protocol has a higher key rate and a longer transmission distance than any other decoy state protocol. 相似文献
16.
It is shown that colloidal semiconductor nanocrystals (quantum dots), which are promising fluorophores for multiphoton fluorescence
microscopy, exhibit a two-photon absorption saturation effect at moderate powers (not exceeding 10 mW) of femtosecond pumping
radiation. An analytical expression for the power of two-photon fluorescence of quantum dots as a function of the average
pumping power is obtained. With this expression, the deviation of the found dependence from the quadratic law is explained
by two factors, i.e., a large two-photon absorption cross section of quantum dots and their slow (compared to the typical
pumping pulse-repetition period) relaxation to an unexcited state. Using an LSM 510 Carl Zeiss laser scanning microscope equipped
with a Ti:Sa tunable femtosecond laser, a series of model experiments is performed to reveal the saturation effect in a solution
of commercially available quantum dots. Good agreement is obtained between the measured dependence of the power of two-photon
fluorescence on the average pump power and the theoretical calculation results. It is also experimentally demonstrated that,
under fluorescence saturation conditions, the spatial resolution of the method of multiphoton fluorescence microscopy is lost;
this effect is analyzed numerically. 相似文献
17.
Pairs of pulses from an incoherent source are used to investigate the time-resolved four-wave mixing response of atomic rubidium when a two-photon resonance is involved in the nonlinear process. By varying the relative polarization of the pulse pairs, we are able to select the quantum pathways and clearly distinguish optical and quantum interferences. 相似文献
18.
基于弱非线性及线性光学元件提出非破坏性测量两光子Bell态及三光子 Greenberger-Horne-Zeilinger (GHZ)态方案. 方案中, 首先应用光束分束器及交叉克尔非线性介质对两光子Bell态进行对称性分析, 进而结合控制非门提出三光子分析方案实现对八个三光子GHZ态完全且非破坏性区分.
关键词:
Bell态测量
Greenberger-Horne-Zeilinger态测量
弱非线性
量子非破坏性测量 相似文献
19.
The spatiotemporal two-photon probability amplitude that describes light in a two-photon entangled state obeys equations identical to the Wolf equations, which are satisfied by the mutual coherence function for light in any quantum state. Both functions therefore propagate similarly through optical systems. A generalized van Cittert-Zernike theorem explains the predicted enhancement in resolution for entangled-photon microscopy and quantum lithography. The Wolf equations provide a particularly powerful analytical tool for studying three-dimensional imaging and lithography since they describe propagation in continuous inhomogeneous media. 相似文献
20.
In this letter we propose a scheme using a two-photon process to teleport an entangled field state of a bimodal cavity to another one without Bell-state measurement. The quantum information is stored in a zero- and two-photon entangled state. This scheme requires two three-level atoms in a ladder configuration, two bimodal cavities, and selective atomic detectors. The fidelity and success probability do not depend on the coefficients of the state to be teleported. For convenient choices of interaction times, the teleportation occurs with fidelity close to the unity. 相似文献