19,453 research outputs found

    Anticipating Daily Intention using On-Wrist Motion Triggered Sensing

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    Anticipating human intention by observing one's actions has many applications. For instance, picking up a cellphone, then a charger (actions) implies that one wants to charge the cellphone (intention). By anticipating the intention, an intelligent system can guide the user to the closest power outlet. We propose an on-wrist motion triggered sensing system for anticipating daily intentions, where the on-wrist sensors help us to persistently observe one's actions. The core of the system is a novel Recurrent Neural Network (RNN) and Policy Network (PN), where the RNN encodes visual and motion observation to anticipate intention, and the PN parsimoniously triggers the process of visual observation to reduce computation requirement. We jointly trained the whole network using policy gradient and cross-entropy loss. To evaluate, we collect the first daily "intention" dataset consisting of 2379 videos with 34 intentions and 164 unique action sequences. Our method achieves 92.68%, 90.85%, 97.56% accuracy on three users while processing only 29% of the visual observation on average

    Decoherence suppression of open quantum systems through a strong coupling to non-Markovian reservoirs

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    In this paper, we provide a mechanism of decoherence suppression for open quantum systems in general, and that for "Schrodinger cat-like" state in particular, through the strong couplings to non-Markovian reservoirs. Different from the usual strategies of suppressing decoherence by decoupling the system from the environment in the literatures, here the decoherence suppression employs the strong back-reaction from non-Markovian reservoirs. The mechanism relies on the existence of the singularities (bound states) of the nonequilibrium retarded Green function which completely determines the dissipation and decoherence dynamics of open systems. As an application, we examine the decoherence dynamics of a photonic crystal nanocavity that is coupled to a waveguide. The strong non-Markovian suppression of decoherence for the optical cat state is attained.Comment: 5 pages, 4 figure

    Cluster X-ray line at 3.5keV3.5\,{\rm keV} from axion-like dark matter

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    The recently reported X-ray line signal at Eγ3.5keVE_\gamma \simeq 3.5\, {\rm keV} from a stacked spectrum of various galaxy clusters and the Andromeda galaxy may be originating from a decaying dark matter particle of the mass 2Eγ2 E_\gamma. A light axion-like scalar is suggested as a natural candidate for dark matter and its production mechanisms are closely examined. We show that the right amount of axion relic density with the preferred parameters, ma7keVm_a \simeq 7 \,{\rm keV} and fa4×1014GeVf_a \simeq 4\times 10^{14}\, {\rm GeV}, can be naturally obtainable from the decay of inflaton. If the axions were produced from the saxion decay, it could not have constituted the total relic density due to the bound from structure formation. Nonetheless, the saxion decay is an interesting possibility, because the 3.5keV3.5\, {\rm keV} line and dark radiation can be addressed simultaneously, being consistent with the Planck data. Small misalignment angles of the axion, ranging between θa104101\theta_a\sim 10^{-4} -10^{-1} depending on the reheating temperature, can also be the source of axion production. The model with axion misalignment can satisfy the constraints for structure formation and iso-curvature perturbation.Comment: 14 pages, significant changes in the form, matched to the journal versio

    Stop and Sbottom LSP with R-parity Violation

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    Considering a third-generation squark as the lightest supersymmetric particle (LSP), we investigate R-parity violating collider signatures with bilinear LH or trilinear LQD operators that may contribute to observed neutrino masses and mixings. Reinterpreting the LHC 7+8 TeV results of SUSY and leptoquark searches, we find that third-generation squark LSPs decaying to first- or second-generation leptons are generally excluded up to at least about 660 GeV at 95%C.L.. One notable feature of many models is that sbottoms can decay to top quarks and charged leptons that lead to a broader invariant mass spectrum and weaker collider constraints. More dedicated searches with bb-taggings or top reconstructions are thus encouraged. Finally, we discuss that the recently observed excesses in the CMS leptoquark search can be accommodated by the decay of sbottom LSPs in the LQD113+131_{113+131} model.Comment: 17 pages, v2: figure 5 is corrected and more references are cite
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