484,842 research outputs found

    Massive Domain Wall Fermions on Four-dimensional Anisotropic Lattices

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    We formulate the massive domain wall fermions on anisotropic lattices. For the massive domain wall fermion, we find that the dispersion relation assumes the usual form in the low momentum region when the bare parameters are properly tuned. The quark self-energy and the quark field renormalization constants are calculated to one-loop in bare lattice perturbation theory. For light domain wall fermions, we verified that the chiral mode is stable against quantum fluctuations on anisotropic lattices. This calculation serves as a guidance for the tuning of the parameters in the quark action in future numerical simulations.Comment: 36 pages, 14 figures, references adde

    Towards Accurate and High-Speed Spiking Neuromorphic Systems with Data Quantization-Aware Deep Networks

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    Deep Neural Networks (DNNs) have gained immense success in cognitive applications and greatly pushed today's artificial intelligence forward. The biggest challenge in executing DNNs is their extremely data-extensive computations. The computing efficiency in speed and energy is constrained when traditional computing platforms are employed in such computational hungry executions. Spiking neuromorphic computing (SNC) has been widely investigated in deep networks implementation own to their high efficiency in computation and communication. However, weights and signals of DNNs are required to be quantized when deploying the DNNs on the SNC, which results in unacceptable accuracy loss. %However, the system accuracy is limited by quantizing data directly in deep networks deployment. Previous works mainly focus on weights discretize while inter-layer signals are mainly neglected. In this work, we propose to represent DNNs with fixed integer inter-layer signals and fixed-point weights while holding good accuracy. We implement the proposed DNNs on the memristor-based SNC system as a deployment example. With 4-bit data representation, our results show that the accuracy loss can be controlled within 0.02% (2.3%) on MNIST (CIFAR-10). Compared with the 8-bit dynamic fixed-point DNNs, our system can achieve more than 9.8x speedup, 89.1% energy saving, and 30% area saving.Comment: 6 pages, 4 figure

    A Numerical Study of Improved Quark Actions on Anisotropic Lattices

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    Tadpole improved Wilson quark actions with clover terms on anisotropic lattices are studied numerically. Using asymmetric lattice volumes, the pseudo-scalar meson dispersion relations are measured for 8 lowest lattice momentum modes with quark mass values ranging from the strange to the charm quark with various values of the gauge coupling β\beta and 3 different values of the bare speed of light parameter ν\nu. These results can be utilized to extrapolate or interpolate to obtain the optimal value for the bare speed of light parameter νopt(m)\nu_{opt}(m) at a given gauge coupling for all bare quark mass values mm. In particular, the optimal values of ν\nu at the physical strange and charm quark mass are given for various gauge couplings. The lattice action with these optimized parameters can then be used to study physical properties of hadrons involving either light or heavy quarks.Comment: 22 pages, 7 figures, 2 tables. Analysis greatly modified compared with previous versio

    Representations and classification of traveling wave solutions to Sinh-G{\"o}rdon equation

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    Two concepts named atom solution and combinatory solution are defined. The classification of all single traveling wave atom solutions to Sinh-G{\"o}rdon equation is obtained, and qualitative properties of solutions are discussed. In particular, we point out that some qualitative properties derived intuitively from dynamic system method aren't true. In final, we prove that our solutions to Sinh-G{\"o}rdon equation include all solutions obtained in the paper[Fu Z T et al, Commu. in Theor. Phys.(Beijing) 2006 45 55]. Through an example, we show how to give some new identities on Jacobian elliptic functions.Comment: 12 pages. accepted by Communications in theoretical physics (Beijing

    Overall properties of the Gaia DR1 reference frame

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    We compare quasar positions of the auxiliary quasar solution with ICRF2 sources using different samples and evaluate the influence on the {\it Gaia} DR1 reference frame owing to the Galactic aberration effect over the J2000.0-J20015.0 period. Then we estimate the global rotation between TGAS with {\it Tycho}-2 proper motion systems to investigate the property of the {\it Gaia} DR1 reference frame. Finally, the Galactic kinematics analysis using the K-M giant proper motions is performed to understand the property of {\it Gaia} DR1 reference frame. The positional comparison between the auxiliary quasar solution and ICRF2 shows negligible orientation and validates the declination bias of \sim0.1-0.1\mas~in {\it Gaia} quasar positions with respect to ICRF2. Galactic aberration effect is thought to cause an offset \sim0.010.01\mas~of the ZZ axis direction of {\it Gaia} DR1 reference frame. The global rotation between TGAS and {\it Tycho}-2 proper motion systems, obtained by different samples, shows a much smaller value than the claimed value 0.240.24\masyr. For the Galactic kinematics analysis of the TGAS K-M giants, we find possible non-zero Galactic rotation components beyond the classical Oort constants: the rigid part ωYG=0.38±0.15\omega_{Y_G} = -0.38 \pm 0.15\masyr~and the differential part ωYG=0.29±0.19\omega^\prime_{Y_G} = -0.29 \pm 0.19\masyr~around the YGY_G axis of Galactic coordinates, which indicates possible residual rotation in {\it Gaia} DR1 reference frame or problems in the current Galactic kinematical model.Comment: 6 pages, 1 figure. Accepted for publication in A&

    LGS AO Science Impact: Present and Future Perspectives

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    The recent advent of laser guide star adaptive optics (LGS AO) on the largest ground-based telescopes has enabled a wide range of high angular resolution science, previously infeasible from ground-based and/or space-based observatories. As a result, scientific productivity with LGS has seen enormous growth in the last few years, with a factor of ~10 leap in publication rate compared to the first decade of operation. Of the 54 refereed science papers to date from LGS AO, half have been published in the last ~2 years, and these LGS results have already made a significant impact in a number of areas. At the same time, science with LGS AO can be considered in its infancy, as astronomers and instrumentalists are only beginning to understand its efficacy for measurements such as photometry, astrometry, companion detection, and quantitative morphology. We examine the science impact of LGS AO in the last few years of operations, largely due to the new system on the Keck II 10-meter telescope. We review currently achieved data quality, including results from our own ongoing brown dwarf survey with Keck LGS. We assess current and near-future performance with a critical eye to LGS AO's capabilities and deficiencies. From both qualitative and quantitative considerations, it is clear that the era of regular and important science from LGS AO has arrived.Comment: Invited review for Proc of the SPIE, "Astronomical Telescopes and Instrumentation" (Marseilles, France, June 2008). Minor typos fixed, upgrade to Figure 3, and addition of new Gemini LGS wor
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