共查询到20条相似文献,搜索用时 15 毫秒
1.
We propose a scheme for cloning an unknown single qutrit state with assistance. The scheme includes a qutrit-state teleportation at the cloner's site. During this process different states (i.e., the maximally entangled or non-maximally entangled two-qutrit states) as quantum channel are taken into account. After the teleportation, to help the cloner Alice to reestablish the unknown state, the state preparer Victor should perform a single-qutrit measurement and tell her the outcome. In this scheme, the success probability of cloning the original state is determined by the used quantum channel. 相似文献
2.
Bogdanov YI Chekhova MV Kulik SP Maslennikov GA Zhukov AA Oh CH Tey MK 《Physical review letters》2004,93(23):230503
The novel experimental realization of three-level optical quantum systems is presented. We use the polarization state of biphotons to generate a specific sequence of states that are used in the extended version of four-state QKD protocol quantum key distribution protocol. We experimentally verify the orthogonality of the basic states and demonstrate the ability to easily switch between them. The tomography procedure is employed to reconstruct the density matrices of generated states. 相似文献
3.
Z. Y. Zhang Y. M. Liu W. Zhang Z. J. Zhang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,64(2-3):539-548
Teleportation of a qutrit state with two different non-maximally entangled qutrit states as quantum channels linking three nodes of an intending quantum network is studied via an ancilla method. With this method a global accumulation approach (GAA) different from the usual node progression approach (NPA) is proposed. Comparisons between two approaches from the four aspects of quantum resource consumption, operation complexity, success probability and efficiency indicate that the GAA is much better than the NPA overall. The average fidelities in both methods are calculated and compared, it is shown that the average fidelity in the GAA is higher than that in the NPA. The error self-correction in the GAA is confirmed and its efficiency relative to the channel-state coefficients is explicitly given. 相似文献
4.
C. Braig P. Zarda C. Kurtsiefer H. Weinfurter 《Applied physics. B, Lasers and optics》2003,76(2):113-116
We demonstrate the principle of complementarity in quantum mechanics in a single-photon interference experiment. Single photons
are provided by isolated, optically pumped nitrogen-vacancy centers in diamond, which can be easily addressed by confocal
microscopy. In order to observe the particle-like behavior of photons, we perform an elementary Welcher-Weg measurement, detecting
photons behind a beam splitter. In contrast, if we dispense with this Welcher-Weg information, we observe interference fringes
with a visibility of about 96%, revealing the wave nature of the photon.
Received: 29 August 2002 / Revised version: 12 December 2002 / Published online: 26 February 2003
RID="*"
ID="*"Corresponding author. Fax +49-89/2180-5032, E-mail: Harald.Weinfurter@physik.uni-muenchen.de 相似文献
5.
We investigate the optimal trade-off between information gained about an unknown coherent state and the state disturbance caused by the measurement process. We propose several optical schemes that can enable this task, and we implement one of them, a scheme that relies on only linear optics and homodyne detection. Experimentally we reach near optimal performance, limited only by detection inefficiencies. In addition, we show that such a scheme can be used to enhance the transmission fidelity of a class of noisy channels. 相似文献
6.
In this Letter we experimentally implement a single photon Bell test based on the ideas of S. Tan et al. [Phys. Rev. Lett. 66, 252 (1991)]] and L. Hardy [Phys. Rev. Lett. 73, 2279 (1994)]]. A double homodyne measurement is used to measure correlations in the Fock space spanned by zero and one photons. Local oscillators used in the correlation measurement are distributed to two observers by copropagating it in an orthogonal polarization mode. This method eliminates the need for interferometrical stability in the setup, consequently making it a robust and scalable method. 相似文献
7.
A three-level system based an a three-level atom interacting with a detuned cavity is considered. Because of the fact that the three-level atom defines a total normalized state composed of superposition of three different single-level states, it is assumed that such a system implements a qutrit. In order to achieve a quantum NOT gate for a single qutrit, the respective Schrödinger equation is solved numerically within a two-photon rotating wave approximation. For small values of one-photon detuning, there appear decoherence effects. Meanwhile, for large values of one-photon detuning, an ideal quantum NOT gate for a single qutrit is achieved. An expression for the execution time of the quantum NOT gate for a single qutrit as a function of the one-photon detuning is found. 相似文献
8.
We have measured the phase structure of a glass wedge with single photons and biphotons in a Mach-Zehnder interferometer using parametric downconverted light from a Hong-Ou-Mandel particle interferometer as the source. By scanning the wedge through the focus of a microscope objective we find a doubling of the period of the interference pattern in the coincidence counts for biphotons compared to the single-photon experiment. We compare our measurement setup with classical ones and discuss some of the problems of superresolution in quantum lithography. 相似文献
9.
Passive decoy state quantum key distribution(PDS-QKD) has advantages in high-speed scenarios.We propose a modified model to simulate the PDS-QKD with a weak coherent light source based on Curty’s theory [Opt.Lett.34 3238(2009)].The modified model can provide better performance in a practical PDS-QKD system.Moreover,we report an experimental demonstration of the PDS-QKD of over 22.0-dB channel loss. 相似文献
10.
It is experimentally demonstrated that an arbitrary quantum state of a single spin 1/2, a| upward arrow+b| downward arrow, can be converted into a superposition of the two ferromagnetic states of a spin cluster: a| upward arrow upward arrow... upward arrow upward arrow+b| downward arrow downward arrow... downward arrow downward arrow. The physical system is a cluster of seven dipolar-coupled nuclear spins of single-labeled 13C-benzene molecules in a liquid-crystalline matrix. In this complex system, the pseudopure ground state and the required controlled unitary transformations have been implemented. The experimental scheme can be considered as an explicit model of quantum measurement. 相似文献
11.
12.
We experimentally demonstrate a miniaturized zoom lens with a single moving element based on the concepts and analysis described in Opt. Express 17, 6118 (2009). We show that the implementation of either a cubic or a generalized cubic phase-modulation function makes miniaturization possible in addition to providing extended-depth-of-field imaging. We present recovered images for zoom lenses employing both phase-modulation functions and conclude that the generalized-cubic-phase function yields higher image quality without the artifacts present for the pure-cubic-phase function. 相似文献
13.
Experimental demonstration of a fast calibration method for integrated photonic circuits with cascaded phase shifters 下载免费PDF全文
Junqin Cao 《中国物理 B》2022,31(11):114204-114204
With the development of research on integrated photonic quantum information processing, the integration level of the integrated quantum photonic circuits has been increasing continuously, which makes the calibration of the phase shifters on the chip increasingly difficult. For the calibration of multiple cascaded phase shifters that is not easy to be decoupled, the resources consumed by conventional brute force methods increase exponentially with the number of phase shifters, making it impossible to calibrate a relatively large number of cascaded phase shifters. In this work, we experimentally validate an efficient method for calibrating cascaded phase shifters that achieves an exponential increase in calibration efficiency compared to the conventional method, thus solving the calibration problem for multiple cascaded phase shifters. Specifically, we experimentally calibrate an integrated quantum photonic circuit with nine cascaded phase shifters and achieve a high-precision calibration with an average fidelity of 99.26%. 相似文献
14.
Eichler C Bozyigit D Lang C Steffen L Fink J Wallraff A 《Physical review letters》2011,106(22):220503
A wide range of experiments studying microwave photons localized in superconducting cavities have made important contributions to our understanding of the quantum properties of radiation. Propagating microwave photons, however, have so far been studied much less intensely. Here we present measurements in which we reconstruct the quantum state of itinerant single photon Fock states and their superposition with the vacuum by analyzing moments of the measured amplitude distribution up to fourth order. Using linear amplifiers and quadrature amplitude detectors, we have developed efficient methods to separate the detected single photon signal from the noise added by the amplifier. From our measurement data we have also reconstructed the corresponding Wigner function. 相似文献
15.
It is shown that coherence between nondegenerate sublevels of an atomic ground state is efficiently induced by means of a short resonant light pulse. The free precession of the coherence causes beats in forward stattering of a probe beam, which can sensitively be detected by a polarization technique. Zeeman beats on the 4f6 6s27 F1-4f6 6s6p 7F0 transition of samarium were observed. In sodium vapor transient ground state coherence was detected in a single-shot measurement. 相似文献
16.
简易楞次定律演示仪的改进 总被引:1,自引:1,他引:0
介绍了对楞次定律演示仪的几次改进情况,并分析了改进中存在的利弊,提出了直接用铜丝绕制成线圈代替原演示装置中的铝环,可有效地解决涡流现象带来的问题. 该实验的改进过程可提高师生的动手能力,体验创新过程带来的喜悦心情,激发和培养学生的创新能力,同时也可弥补条件欠缺的地区没有楞次定律演示仪的缺陷. 相似文献
17.
H. Okamoto K. Yamaguchi M. Haraguchi T. Okamoto 《Applied physics. B, Lasers and optics》2012,108(1):149-152
We fabricated and investigated a plasmonic racetrack resonator with a trench structure. Trench channel plasmon polaritons excited by end-fire coupling at a wavelength of 633 nm are observed in the fabricated racetrack resonator. The racetrack resonator also worked as a plasmonic racetrack resonator. The experimental and simulation results of the electric field distributions are in good agreement. 相似文献
18.
We present experimental demonstration of an end-pumping scheme based on splicing the multimode pump and single-mode signal fibers directly to a double-clad fiber with a tailored cross section. The method is used to pump a double-clad, erbium- and ytterbium-doped, fiber ring laser. The efficiency of the end-pumping method is tested by determining the slope efficiencies of the fiber ring laser and the fiber laser in a Fabry-Perot configuration. Comparable slope efficiencies are found when both laser configurations have similar output coupler ratios. The developed pumping scheme and double-clad fiber can find applications in cost-effective power fiber amplifiers and lasers. 相似文献
19.
Ticoş CM Wang Z Wurden GA Kline JL Montgomery DS Dorf LA Shukla PK 《Physical review letters》2008,100(15):155002
Simultaneous acceleration of hundreds of dust particles to hypervelocities by collimated plasma flows ejected from a coaxial gun is demonstrated. Graphite and diamond grains with radii between 5 and 30 microm, and flying at speeds up to 3.7 km/s, have been recorded with a high-speed camera. The observations agree well with a model for plasma-drag acceleration of microparticles much larger than the plasma screening length. 相似文献
20.