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1.
We study the dynamics of various branched spin chain systems. In such systems entanglement can be generated and distributed, providing an essential resource for teleportation or distributed quantum processing. We show in detail how simple operations can be employed at chosen times to change the subsequent dynamics of the branched spin chains, rendering the distributed entanglement more accessible. 相似文献
2.
Min-Cang Zhang 《Physics letters. A》2010,374(5):704-3811
A spherically harmonic oscillatory ring-shaped potential is proposed and its exactly complete solutions are presented by the Nikiforov-Uvarov method. The effect of the angle-dependent part on the radial solutions is discussed. 相似文献
3.
Nguyen Ba An 《Physics letters. A》2009,373(20):1701-1707
Three novel probabilistic yet conclusive schemes are proposed to teleport a general two-mode coherent-state superposition via attenuated quantum channels with ideal and/or threshold detectors. The calculated total success probability is highest (lowest) when only ideal (threshold) detectors are used. 相似文献
4.
Yang Xiang Bo Zhou Xianjie Wang Yu Sui Zhe Lü 《Journal of magnetism and magnetic materials》2009,321(9):1188-1191
Mn4+-rich perovskite manganites (nominal composition: Pr0.1Ca0.9MnO3) were synthesized by using a citric acid method and sintered at different temperatures (800, 900, 1000, and 1300 °C) to adjust the concentration of charge carrier. All the samples are found to be in the cluster glass state at low temperature, as indicated by dc and ac magnetization. With the increase of sintering temperature, the ferromagnetic component in samples increases at first, and attains a maximum at 1000 °C, then decreases again at 1300 °C, which could be well interpreted by the change of charge carrier concentration induced by nonstoichiometry, consistent with the trend on the phase diagram. However, nonstoichiometry breaks long-range Mn-O-Mn interaction, resulting in the variance from the phase diagram. 相似文献
5.
D. Shulyatev N. Kozlovskaya A. Pestun Ya. Mukovskii L. Elochina R. Zainullina 《Journal of Crystal Growth》2009,311(16):4142-4145
Single crystals of La0.75Y0.05Sr0.2 MnO3 have been grown by the floating zone technique. The yttrium distribution in the radial and axial directions in the crystals was studied for different growth rates. The sample grown at high rate showed inhomogeneity in the yttrium content in the growth direction, while the sample grown at relatively low rate was homogeneous in the growth direction, but demonstrated compositional separation between the Y-poor central part and Y-enriched peripheral part in the perpendicular plane. The compositional separation led to magnetic inhomogeneity. 相似文献
6.
Kohei M. Itoh 《Solid State Communications》2005,133(11):747-752
An updated version of our all-silicon quantum computing scheme [T.D. Ladd, J.R. Goldman, F. Yamaguchi, Y. Yamamoto, E. Abe, K.M. Itoh, Phys. Rev. Lett. 89 (2002) 017901. [3]] and the experimental progress towards its realization are discussed. We emphasize the importance of revisiting a wide range of isotope effects which have been explored over the past several decades for the construction of solid-state silicon quantum computers. Using RF decoupling techniques [T.D. Ladd, D. Maryenko, Y. Yamamoto, E. Abe, K.M. Itoh, Phys. Rev. B. 71 (2005) 014401] phase decoherence times T2=25 s of 29Si nuclear spins in single-crystal Si have been obtained at room temperature. We show that a linear chain of 29Si stable isotopes with nuclear spin I=1/2 embedded in a spin free 28Si stable isotope matrix can form an ideal building block for solid-state quantum information processors, especially, in the form of a quantum memory which requires a large number of operations within T2 for the continuous error correction. 相似文献
7.
B.M Nagabhushana R.P. Sreekanth Chakradhar C. Shivakumara 《Solid State Communications》2005,136(7):427-432
Nanocrystalline La1−xBaxMnO3 (0.0≤x≤0.3) manganites have been prepared by a simple and instantaneous solution combustion method, which is a low temperature initiated synthetic route to obtain fine-grained powders with relatively high surface area. The phase purity and crystal structure of the combustion products are carried out by powder X-ray diffraction. The as-made nanopowders are in cubic phase. On calcination to 900 °C, barium doped manganites retain cubic phase, whereas barium free manganite transformed to rhombohedral phase. The scanning electron microscope (SEM) results revealed that the combustion-derived compounds are agglomerated with fine primary particles. The doped manganites have surface area in the range 24-44 m2/g. The surface area of the manganites increases with barium content, whereas it decreases on calcination. Both undoped and doped lanthanum manganites show two active IR vibrational modes at 400 and 600 cm−1. The low temperature resistivity measurements have been carried out by four-probe method down to 77 K. All the samples exhibit metal-insulator behaviour and metal-insulator transition temperature (TM-I) in the range 184-228 K and it is interesting to note that, as the barium content increases the TM-I shifts to lower temperature side. The maximum TM-I of 228 K is observed for La0.9Ba0.1MnO3 sample. 相似文献
8.
A. Surzhykov U. D. Jentschura T. Stöhlker S. Fritzsche 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(1):27-36
We apply the density matrix theory to re-investigate the radiative
electron capture into heavy ions with one valence electron. Attention
has been paid particularly to the magnetic sublevel population of the
residual ions, as described in terms of alignment parameters. Simple
method, based on an independent particle model, which takes
into account the Pauli principle, is proposed for evaluating the
alignment of the excited ionic states. By making use of this method,
detailed calculations are performed for electron capture into (initially) hydrogen-like and lithium-like europium, gold and
uranium ions, and are compared with the results of the multiconfiguration Dirac-Fock approach.As seen from the calculations
and from the comparison with available experimental results, the independent particle model provides a good estimate for the
alignment parameters of few-electron heavy ions. Therefore, our simple model may help to understand the basic properties of
the X-ray emission from heavy, few-electron ions without the need for invoking sophisticated MCDF calculations. 相似文献
9.
Quantum computers hold the promise of solving certain computational tasks much more efficiently than classical computers. We review recent experimental advances towards a quantum computer with trapped ions. In particular, various implementations of qubits, quantum gates and some key experiments are discussed. Furthermore, we review some implementations of quantum algorithms such as a deterministic teleportation of quantum information and an error correction scheme. 相似文献
10.
A new polarized-light-controlled holographic recording based on the optical enhancement/restraint of self-diffraction has
been demonstrated in an azobenzene-doped polymer film. It is found that a continuous variation of the polarization status
as well as of the intensity of the pumping light results in a continuous variation of self-diffraction efficiency. The mechanism
originates from the photo-induced anisotropy and polarization-dependent absorption. Both positive and negative replicas of
an incident image were presented in real time by means of this incoherent–coherent optical conversion technique.
Received: 30 March 2000 / Revised version: 28 September 2000 / Published online: 27 April 2001 相似文献