25,249 research outputs found

    Deterministic Dense Coding and Faithful Teleportation with Multipartite Graph States

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    We proposed novel schemes to perform the deterministic dense coding and faithful teleportation with multipartite graph states. We also find the sufficient and necessary condition of a viable graph state for the proposed scheme. That is, for the associated graph, the reduced adjacency matrix of the Tanner-type subgraph between senders and receivers should be invertible.Comment: 10 pages, 1 figure;v2. discussions improve

    Observation of a push force on the end face of a nm fiber taper exerted by outgoing light

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    There are two different proposals for the momentum of light in a transparent dielectric of refractive index n: Minkowski's version nE/c and Abrahm's version E/(nc), where E and c are the energy and vacuum speed of light, respectively. Despite many tests and debates over nearly a century, momentum of light in a transparent dielectric remains controversial. In this Letter, we report a direct observation of the inward push force on the end face of a free nm fiber taper exerted by the outgoing light. Our results clearly support Abraham momentum. Our experiment also indicates an inward surface pressure on a dielectric exerted by the incident light, different from the commonly recognized pressure due to the specular reflection. Such an inward surface pressure by the incident light may be useful for precise design of the laser-induced inertially-confined fusion.Comment: 9 pages, 3 figures;Accepted for publication as a Letter in Physical Review Letters(CODE: LP11093

    Multipartite Entanglement Measures and Quantum Criticality from Matrix and Tensor Product States

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    We compute the multipartite entanglement measures such as the global entanglement of various one- and two-dimensional quantum systems to probe the quantum criticality based on the matrix and tensor product states (MPSs/TPSs). We use infinite time-evolving block decimation (iTEBD) method to find the ground states numerically in the form of MPSs/TPSs, and then evaluate their entanglement measures by the method of tensor renormalization group (TRG). We find these entanglement measures can characterize the quantum phase transitions by their derivative discontinuity right at the critical points in all models considered here. We also comment on the scaling behaviors of the entanglement measures by the ideas of quantum state renormalization group transformations.Comment: 22 pages, 11 figure

    Green supply management and performance: a resource-based view

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    This study develops and empirically tests, from the resource-based perspective, a conceptual framework linking green supply management and performance. The proposed model is tested using data from a sample of 126 automotive manufactures in China. The results suggest that both green purchasing personnel and green supplier selection have a significant positive effect on green supplier collaboration, and that building green collaboration with suppliers is significantly and positively related to both environmental and operational performance. Accordingly, knowledge and skill development of the purchasing function can be recognised as an important resource in building green supply capabilities and performance

    Quantum size effects on the perpendicular upper critical field in ultra-thin lead films

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    We report the thickness-dependent (in terms of atomic layers) oscillation behavior of the perpendicular upper critical field Hc2⊥H_{c2\perp} in the ultra-thin lead films at the reduced temperature (t=T/Tct=T/T_c). Distinct oscillations of the normal-state resistivity as a function of film thickness have also been observed. Compared with the TcT_c oscillation, the Hc2⊥H_{c2\perp} shows a considerable large oscillation amplitude and a π\pi phase shift. The oscillatory mean free path caused by quantum size effect plays a role in Hc2⊥H_{c2\perp} oscillation.Comment: 4 pages, 4 figure

    Multi-output programmable quantum processor

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    By combining telecloning and programmable quantum gate array presented by Nielsen and Chuang [Phys.Rev.Lett. 79 :321(1997)], we propose a programmable quantum processor which can be programmed to implement restricted set of operations with several identical data outputs. The outputs are approximately-transformed versions of input data. The processor successes with certain probability.Comment: 5 pages and 2 PDF figure
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