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51.
For a general quantum ensemble with Hamiltonian fluctuations, this paper proposes a sampling-based two-stage approximate time-optimal control algorithm with momentum terms and achieves a high-fidelity state transition of all member systems to a common target state within an approximate minimum time. The fidelity and the control time are respectively optimized in the two stages. In particular, the introduction of momentum terms greatly improves the convergence rate of the algorithm. Simulation experiments on a two-level quantum ensemble verify the effectiveness of the proposed algorithm. 相似文献
52.
Wen-Yan Tian Xiao-Yu Kuang Mei-Ling Duan Rui-Peng Chai Cai-Xia Zhang 《Physica B: Condensed Matter》2009,404(21):3114-4336
A theoretical method for studying the inter-relation between electronic and molecular structure has been proposed based on the complete energy matrices for a d3 configuration ion in a tetragonal ligand-field. By means of this method, the local structure for Cr3+ ion doped in oxides TiO2 (anatase) and MgO has been determined. The calculated results indicate that the local structure of the (CrO6)9− cluster in TiO2:Cr3+ and MgO:Cr3+ systems exists as a compressed distortion relative to the regular octahedron. Meanwhile, the dependence of the EPR zero-field splitting parameter D on the local structure parameter ΔR (ΔR=R1−R2) has been revealed. In addition, the relation between the EPR g-factors (g,g,Δg) and the orbit reduction factor k has been discussed for the two systems, suggesting that the orbit reduction factor k is very important to understand the EPR g-factors. 相似文献
53.
Four-mode continuous-variables entangled state: generation from beam splitter, a parametric down-conversion and a polarizer 下载免费PDF全文
We introduce a new kind of four-mode continuous variable entangled
state in Fock space. The completeness relation and the partly
nonorthonormal property of such a state are proven. The scheme to
generate this state is presented by combining a symmetrical
beamsplitter, a parametric down-conversion and a polarizer. After
making a single-mode quadrature amplitude measurement, the remaining
three modes are kept in entanglement. And its applications are also
discussed. 相似文献
54.
Belz J Cousins RD Diwan MV Eckhause M Ecklund KM Hancock AD Highland VL Hoff C Hoffmann GW Irwin GM Kane JR Kettell SH Klein JR Kuang Y Lang K Martin R May M McDonough J Molzon WR Riley PJ Ritchie JL Schwartz AJ Trandafir A Ware B Welsh RE White SN Witkowski MT Wojcicki SG Worm S 《Physical review letters》1996,76(18):3277-3280
55.
1引言我们知道,一个可生成L2(R)中的多分辩分析的尺度函数(x)满足双尺度差分方程(1)式的Fourier变换为其中(ω)是函数(x)的Fourier变换,而叫做小波的共轭滤波器(简称滤波器),它满足若将滤波器H(ω)设成则条件(3)成为可形式地写出Daubechies[1]给出了(6)式无穷乘积收敛的条件.她还针对F(z)为多项式情形(此时称滤波器为多项式滤波器),给出了产生紧支小波的方法并给出了正则阶估计[2].在[3]中,作者给出了小波分式滤波器的定义(即(4)式中F(z))是实系数有理… 相似文献
56.
A theoretical investigation is reported of the fine structure levels and the spin-singlet contributions to zero-field-splitting (ZFS) parameters for Cr2+ ion in CdGa2S4 crystals. Firstly, the complete energy matrix including all spin states for a 3d 4 ion in tetrahedral D 2d symmetry is constructed according the double-group chain in the strong-field scheme. Then, by diagonalizing the complete energy of electron–electron interactions, the crystal field and the spin–orbit coupling for the Cr2+ (3d 4) ion in CdGa2S4 crystal, the fine structure levels and the spin-singlet contributions to ZFS parameters a, D and F are calculated. The results show that the spin-singlet contribution to D is negligible, but the contributions to a and F are very important. So, to obtain more accurate ZFS parameters for 3d 4 ions in the tetrahedral crystals, all spin states should be considered. 相似文献
57.
本文给出数值方法解Volterra积分方程的稳定性分析,我们判定可约积分方法的数值稳定性基于如下试验方程其中τ是正常数,p和q是复值的。在上述试验方程的情况下,我们研究θ-方法及可约积分方法的稳定性。 相似文献
58.
This paper focuses on the numerical stability of the block θ-methods adapted to differential equations with a dday argument. For the block θ-methods, an interpolation procedure is introduced which leads to the mumerical processes that satisfy an important asymptotic stability condition related to the class of test problems y' (t)=ay(t)+by(t-r) with a,b∈C, Re(a)<- |b| and τ>0. We prove that the block θ-method is GP-stable if and only if the method is A-stable for ordinary differential equations. Furthermore, it is proved that the P-and GP-stability are equivalent for the block θ-method. 相似文献
59.
Based on the theories of nonlinear continuum mechanics, piezoelectricity and elastic waves in solids, theoretical analysis of Bleustein-Gulyaev surface acoustic wave propagation in a prestressed layered piezoelectric structure are described. Numerical calculations are performed for the case that the layer and the substrate are identical LiNbO(3) except that they are polarized in opposite directions. It is found that an almost linear behavior of the relative change in phase velocity versus the initial stress is obtained for both surface electrically free and shorted cases. Potential applications in the design of acoustic wave devices are suggested. 相似文献
60.
We propose a scheme to engineer a non-local two-qubit
phase gate between two remote quantum-dot spins. Along with
one-qubit local operations, one can in principal perform various
types of distributed quantum information processing. The scheme
employs a photon with linearly polarisation interacting one after
the other with two remote quantum-dot spins in cavities. Due to the
optical spin selection rule, the photon obtains a Faraday rotation
after the interaction process. By measuring the polarisation of the
final output photon, a non-local two-qubit phase gate between the
two remote quantum-dot spins is constituted. Our scheme may has very
important applications in the distributed quantum information
processing. 相似文献