27,193 research outputs found

    A large-scale one-way quantum computer in an array of coupled cavities

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    We propose an efficient method to realize a large-scale one-way quantum computer in a two-dimensional (2D) array of coupled cavities, based on coherent displacements of an arbitrary state of cavity fields in a closed phase space. Due to the nontrivial geometric phase shifts accumulating only between the qubits in nearest-neighbor cavities, a large-scale 2D cluster state can be created within a short time. We discuss the feasibility of our method for scale solid-state quantum computationComment: 5 pages, 3 figure

    A modelling study of beta-amyloid induced change in hippocampal theta rhythm

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    Many dementia cases, such as Alzheimer’s disease (AD), are characterized by an increase in low frequency field potential oscillations. However, a definitive understanding of the effects of the beta-Amyloid peptide, which is a main marker of AD, on the low frequency theta rhythm (4-7Hz) is still unavailable. In this work, we investigate the neural mechanisms associated with beta-Amyloid toxicity using a conductance-based neuronal network model of the hippocampus CA1 region. We simulate the effects of beta-Amyloid on the A-type fast inactivating K+ channel by modulating the maximum conductance of the current in pyramidal cells, denoted by gA. Our simulation results demonstrate that as gA decreases (through A[beta]
blockage), the theta band power first increases then decreases. Thus there exists a value of gA that maximizes the theta band power. The neuronal and network mechanism underlying the change in theta rhythm is systematically analyzed. We show that the increase in theta power is due to the improved synchronization of pyramidal neurons, and the theta decrease is induced by the faster depolarisation of pyramidal neurons

    The meson-exchange model for the ΛΛˉ\Lambda\bar{\Lambda} interaction

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    In the present work, we apply the one-boson-exchange potential (OBEP) model to investigate the possibility of Y(2175) and η(2225)\eta(2225) as bound states of ΛΛˉ(3S1)\Lambda\bar{\Lambda}(^3S_1) and ΛΛˉ(1S0)\Lambda\bar{\Lambda}(^1S_0) respectively. We consider the effective potential from the pseudoscalar η\eta-exchange and η′\eta^{'}-exchange, the scalar σ\sigma-exchange, and the vector ω\omega-exchange and ϕ\phi-exchange. The η\eta and η′\eta^{'} meson exchange potential is repulsive force for the state 1S0^1S_0 and attractive for 3S1^3S_1. The results depend very sensitively on the cutoff parameter of the ω\omega-exchange (Λω\Lambda_{\omega}) and least sensitively on that of the ϕ\phi-exchange (Λϕ\Lambda_{\phi}). Our result suggests the possible interpretation of Y(2175) and η(2225)\eta(2225) as the bound states of ΛΛˉ(3S1)\Lambda\bar{\Lambda}(^3S_1) and ΛΛˉ(1S0)\Lambda\bar{\Lambda}(^1S_0) respectively
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