211 research outputs found

    O(D,D)\mathbf{O}(D,D) Covariant Noether Currents and Global Charges in Double Field Theory

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    Double field theory is an approach for massless modes of string theory, unifying and geometrizing all gauge invariance in manifest O(D,D)\mathbf{O}(D,D) covariant manner. In this approach, we derive off-shell conserved Noether current and corresponding Noether potential associated with unified gauge invariance. We add Wald-type counter two-form to the Noether potential and define conserved global charges as surface integral. We check our O(D,D)\mathbf{O}(D,D) covariant formula against various string backgrounds, both geometric and non-geometric. In all cases we examined, we find perfect agreements with previous results. Our formula facilitates to evaluate momenta along not only ordinary spacetime directions but also dual spacetime directions on equal footing. From this, we confirm recent assertion that null wave in doubled spacetime is the same as macroscopic fundamental string in ordinary spacetime.Comment: v2) 1+42 pages, Refs added, minor changes. To appear in JHE

    RIDESOURCING IN MANUFACTURING SITES: A FRAMEWORK AND CASE STUDY

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    With the recent innovations in transportation, ridesourcing services have been proliferating in many countries. There are increasing attempts to apply ridesourcing in the corporate context. Manufacturing companies now install the Industrial Internet of Things (IIOT) sensors to vehicles to obtain real-time data on the movement of goods and materials. Despite the massive amount of data accumulated, little attention has been paid to exploiting the data for vehicle fleet management (FM). This paper proposes an analytical framework to solve two FM problems: how to group organizational units for vehicle sharing and where to deploy the groups. The framework is then validated with a case study of a Korean shipbuilder. The results indicate that grouping departments with similar spatial patterns can reduce the current fleet

    Josephson Parametric Amplifier in Axion Experiments

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    The axion is a hypothetical particle, a promising candidate for dark matter, and a solution to the strong CP problem. Axion haloscope search experiments deal with a signal power comparable to noise uncertainty at millikelvin temperature. We use a flux-driven Josephson parametric amplifier (JPA) with the aim of approaching a noise level near the theoretically allowed limit of half quanta. In our measurements to characterize the JPA we have found the added noise to the system with a JPA as the first-stage amplifier to be lower than 110 mK at the frequencies from 0.938 GHz to 0.963 GHz.Comment: to be published in JPS Conference Proceedings (LT29

    Singular Hall response from a correlated ferromagnetic flat nodal-line semimetal

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    Topological quantum phases have been largely understood in weakly correlated systems, which have identified various quantum phenomena such as spin Hall effect, protected transport of helical fermions, and topological superconductivity. Robust ferromagnetic order in correlated topological materials particularly attracts attention, as it can provide a versatile platform for novel quantum devices. Here, we report singular Hall response arising from a unique band structure of flat topological nodal lines in combination with electron correlation in an itinerant, van der Waals ferromagnetic semimetal, Fe3GaTe2, with a high Curie temperature of Tc=360 K. High anomalous Hall conductivity violating the conventional scaling, resistivity upturn at low temperature, and a large Sommerfeld coefficient are observed in Fe3GaTe2, which implies heavy fermion features in this ferromagnetic topological material. Our circular dichroism in angle-resolved photoemission spectroscopy and theoretical calculations support the original electronic features in the material. Thus, low-dimensional Fe3GaTe2 with electronic correlation, topology, and room-temperature ferromagnetic order appears to be a promising candidate for robust quantum devices

    JaxPruner: A concise library for sparsity research

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    This paper introduces JaxPruner, an open-source JAX-based pruning and sparse training library for machine learning research. JaxPruner aims to accelerate research on sparse neural networks by providing concise implementations of popular pruning and sparse training algorithms with minimal memory and latency overhead. Algorithms implemented in JaxPruner use a common API and work seamlessly with the popular optimization library Optax, which, in turn, enables easy integration with existing JAX based libraries. We demonstrate this ease of integration by providing examples in four different codebases: Scenic, t5x, Dopamine and FedJAX and provide baseline experiments on popular benchmarks.Comment: Jaxpruner is hosted at http://github.com/google-research/jaxprune

    Search for the Sagittarius Tidal Stream of Axion Dark Matter around 4.55 μ\mueV

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    We report the first search for the Sagittarius tidal stream of axion dark matter around 4.55 μ\mueV using CAPP-12TB haloscope data acquired in March of 2022. Our result excluded the Sagittarius tidal stream of Dine-Fischler-Srednicki-Zhitnitskii and Kim-Shifman-Vainshtein-Zakharov axion dark matter densities of ρa0.184\rho_a\gtrsim0.184 and 0.025\gtrsim0.025 GeV/cm3^{3}, respectively, over a mass range from 4.51 to 4.59 μ\mueV at a 90% confidence level.Comment: 6 pages, 7 Figures, PRD Letter accepte
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