2,691 research outputs found

    Multipartite entangled states with two bosonic modes and qubits

    Full text link
    We theoretically investigate the role of different phases of coupling constants in the dynamics of atoms and two cavity modes, observing deterministic generation of prototype or hybrid Bell, W, GHZ, and cluster states. Commonly induced dipole-dipole interactions (far-off resonance) are inhibited between particular pairs of qubits under suitable choice of those phases. We evaluate the generation fidelities when imperfections such as dissipative environments and time precision errors are considered. We show violation of local realism for the generated cluster state under such imperfections, even when approaching the weak coupling regime.Comment: 10 pages, 5 figures, REVTeX 4.1, BibTeX, final versio

    NUMERICAL STUDY OF COOLING BY TANGENTIAL SYNTHETIC JET

    Get PDF
    Modern electronics are becoming more compact and with higher processing power, which translates into a demand for higher heat dissipation. Current electronic "coolers," which are based on the combination of fans and heat sinks, are becoming unable to provide sufficient heat dissipation since they rely primarily on generating large volumetric flowrates of air to achieve their results. As an alternative, synthetic jets are under consideration due to their known property to enhance turbulence and heat transfer. Synthetic jets are produced by the oscillation of a membrane in a sealed cavity equipped with an orifice. For this study, a numerical model of channel mounted with a heating element on one surface and a synthetic jet directed to blow along the wall was constructed on ANSYS CFX. Heat dissipation provided by the synthetic jet was analyzed with respect to changes in Reynolds number, pulsing frequency and placement of the heated element. Results were compared to a conventional technique represented by a steady channel flow of equivalent mass flow rate to the average flow induced by the synthetic jet. Results showed that the synthetic jet formed a thin layer of intense vorticity along the targeted surface with cooling greatly outperforming conventional techniques. Synthetic jet cooling was also determined to be most affected by jet velocity and Reynolds number while pulsing frequency and placement of the heated element were not as influential

    Spontaneous emission and teleportation in cavity QED

    Full text link
    In this work, we consider atomic spontaneous emission in a system consisting of two identical two-level atoms interacting dispersively with the quantized electromagnetic field in a high-Q cavity. We investigate the destructive effect of the atomic decay on the generation of maximally entangled states, following the proposal by Zheng S B and Guo G C (2000 Phys. Rev. Lett. 85 2392). In particular, we analyze the fidelity of teleportation performed using such a noisy channel and calculatethe maximum spontaneous decay rate we may have in order to realize teleportation.Comment: 11 pages, 6 figures, LaTe

    Bipartite quantum channels using multipartite cluster-type entangled coherent states

    Get PDF
    We propose a particular encoding for bipartite entangled states derived from multipartite cluster-type entangled coherent states (CTECSs). We investigate the effects of amplitude damping on the entanglement content of this bipartite state, as well as its usefulness as a quantum channel for teleportation. We find interesting relationships among the amplitude of the coherent states constituting the CTECSs, the number of subsystems forming the logical qubits (redundancy), and the extent to which amplitude damping affects the entanglement of the channel. For instance, in the sense of sudden death of entanglement, given a fixed value of the initial coherent state amplitude, the entanglement life span is shortened if redundancy is increased.Comment: 6 pages, 3 figures, REVTeX 4.1, BibTe

    Comparação entre a concentração atmosférica de Phl p5 e as contagens polínicas de gramíneas

    Get PDF
    A exposição a alergenos de gramíneas é actualmente calculada a partir de contagens polínicas dos respectivos tipos polínicos, efectuadas em amostras de ar atmosférico segundo uma metodologia normalizada e assente em equipamentos tipo HIRST. Não existe ainda suficiente evidência de que tais contagens representem uma boa estimativa da exposição aos aeroalergenos deste tipo polínico pelo que, neste estudo, se procurou analisar a relação entre tais contagens e a concentração de um dos alergenos polínicos mais importantes
    corecore