211 research outputs found
Covariant Noether Currents and Global Charges in Double Field Theory
Double field theory is an approach for massless modes of string theory,
unifying and geometrizing all gauge invariance in manifest
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
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
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
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
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
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Optical dispersion control in surfactant-free DNA thin films by vitamin B2 doping
A new route to systematically control the optical dispersion properties of surfactant-free deoxyribonucleic acid (DNA) thin solid films was developed by doping them with vitamin B2, also known as riboflavin. Surfactant-free DNA solid films of high optical quality were successfully deposited on various types of substrates by spin coating of aqueous solutions without additional chemical processes, with thicknesses ranging from 18 to 100 nm. Optical properties of the DNA films were investigated by measuring UV-visible-NIR transmission, and their refractive indices were measured using variable-angle spectroscopic ellipsometry. By doping DNA solid films with riboflavin, the refractive index was consistently increased with an index difference Δn ≥ 0.015 in the spectral range from 500 to 900 nm, which is sufficiently large to make an all-DNA optical waveguide. Detailed correlation between the optical dispersion and riboflavin concentration was experimentally investigated and thermo-optic coefficients of the DNA-riboflavin thin solid films were also experimentally measured in the temperature range from 20 to 85 °C, opening the potential to new bio-thermal sensing applications
JaxPruner: A concise library for sparsity research
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 eV
We report the first search for the Sagittarius tidal stream of axion dark
matter around 4.55 eV 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 and GeV/cm,
respectively, over a mass range from 4.51 to 4.59 eV at a 90% confidence
level.Comment: 6 pages, 7 Figures, PRD Letter accepte
Correction to: Channel-mediated astrocytic glutamate modulates hippocampal synaptic plasticity by activating postsynaptic NMDA receptors
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