1,628 research outputs found

    Fast quantum information transfer with superconducting flux qubits coupled to a cavity

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    We present a way to realize quantum information transfer with superconducting flux qubits coupled to a cavity. Because only resonant qubit-cavity interaction and resonant qubit-pulse interaction are applied, the information transfer can be performed much faster, when compared with the previous proposals. This proposal does not require adjustment of the qubit level spacings during the operation. Moreover, neither uniformity in the device parameters nor exact placement of qubits in the cavity is needed by this proposal.Comment: 6 pages, 3 figure

    A tunable S-plus L-band continuous-wave single-longitudinal-mode fiber-optical parametric oscillator

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    We demonstrate an all-fiber continuous-wave single-longitudinal-mode fiber-optical parametric oscillator. The output tuning range extends from 1487 to 1541 nm and from 1570 to 1630 nm, which covers the S- and L-bands. Single-longitudinal-mode oscillation with a side-mode suppression ratio greater than 43 dB is achieved while the linewidth of the output is 1.5 kHz. This scheme has the potential to be a useful source in wavelength-division-multiplexing networks and optical communications in the nonconventional wavelength bands. © 2011 IEEE.published_or_final_versio

    Dynamical Properties of a Growing Surface on a Random Substrate

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    The dynamics of the discrete Gaussian model for the surface of a crystal deposited on a disordered substrate is investigated by Monte Carlo simulations. The mobility of the growing surface was studied as a function of a small driving force FF and temperature TT. A continuous transition is found from high-temperature phase characterized by linear response to a low-temperature phase with nonlinear, temperature dependent response. In the simulated regime of driving force the numerical results are in general agreement with recent dynamic renormalization group predictions.Comment: 10 pages, latex, 3 figures, to appear in Phys. Rev. E (RC

    Towards Efficient Sequential Pattern Mining in Temporal Uncertain Databases

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    Uncertain sequence databases are widely used to model data with inaccurate or imprecise timestamps in many real world applications. In this paper, we use uniform distributions to model uncertain timestamps and adopt possible world semantics to interpret temporal uncertain database. We design an incremental approach to manage temporal uncertainty efficiently, which is integrated into the classic pattern-growth SPM algorithm to mine uncertain sequential patterns. Extensive experiments prove that our algorithm performs well in both efficiency and scalability

    Wigner crystallization and metal-insulator transition of two-dimensional holes in GaAs/AlGaAs at B=0

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    We report the transport properties of a low disorder two-dimensional hole system (2DHS) in the GaAs/AlGaAs heterostructure, which has an unprecedentedly high peak mobility of 7×105cm2/Vs7\times 10^5cm^2/Vs, with hole density of 4.8×109cm2<p<3.72×1010cm24.8\times 10^9 cm^{-2}<p<3.72\times 10^{10}cm^{-2} in the temperature range of 50mK<T<1.3K50mK<T<1.3K. From their T, p, and electric field dependences, we find that the metal-insulator transition in zero magnetic field in this exceptionally clean 2DHS occurs at rs=35.1±0.9r_s=35.1\pm0.9, which is in good agreement with the critical rsr_s for Wigner crystallization rsc=37±5{r_s}^c=37\pm 5, predicted by Tanatar and Ceperley for an ideally clean 2D system.Comment: 4 pages, 4 Postscript figure

    Glassy Roughness of a Crystalline Surface Upon a Disordered Substrate

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    The discrete Gaussian model for the surface of a crystal deposited on a disordered substrate is studied by Monte Carlo simulations. A continuous transition is found from a phase with a thermally-induced roughness to a glassy one in which the roughness is driven by the disorder. The behavior of the height-height correlations is consistent with the one-step replica symmetry broken solution of the variational approximation. The results differ from the renormalization group predictions and from recent simulations of a 2D vortex-glass model which belongs to the same universality class.Comment: 12 pages (RevTeX) & 3 figures (PS) uuencode

    Construction of orthonormal wavelet-like bases

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    A general method for constructing wavelet-like bases in a Hilbert space H starting from any orthonormal basis in H and any periodic orthonormal wavelet basis is presented. With this method we can take advantage of the characteristics of both types of bases to obtain orthonormal wavelet-like bases that are suitable to represent functions and operators efficiently.Fil: Morillas, Patricia Mariela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Matemática Aplicada de San Luis; Argentina. Universidad Nacional de San Luis; Argentin

    Diffusion and activation of n-type dopants in germanium

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    The diffusion and activation of nn-type impurities (P and As) implanted into pp-type Ge(100) substrates were examined under various dose and annealing conditions. The secondary ion mass spectrometry profiles of chemical concentrations indicated the existence of a sufficiently high number of impurities with increasing implanted doses. However, spreading resistance probe profiles of electrical concentrations showed electrical concentration saturation in spite of increasing doses and indicated poor activation of As relative to P in Ge. The relationships between the chemical and electrical concentrations of P in Ge and Si were calculated, taking into account the effect of incomplete ionization. The results indicated that the activation of P was almost the same in Ge and Si. The activation ratios obtained experimentally were similar to the calculated values, implying insufficient degeneration of Ge. The profiles of P in Ge substrates with and without damage generated by Ge ion implantation were compared, and it was clarified that the damage that may compensate the activated nn-type dopants has no relationship with the activation of P in Ge.Comment: 6 pages, 4 figure
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