We report the first lattice QCD calculation of the glue spin in the nucleon. The lattice calculation is carried out with valence overlap fermions on 2+1 flavor domain-wall fermion gauge configurations on four lattice spacings and four volumes including an ensemble with physical values for the quark masses. The glue spin S_{G} in the Coulomb gauge in the modified minimal subtraction (MS[over ¯]) scheme is obtained with one-loop perturbative matching. We find the results fairly insensitive to lattice spacing and quark masses. We also find that the proton momentum dependence of S_{G} in the range 0≤|p[over →]|<1.5 GeV is very mild, and we determine it in the large-momentum limit to be S_{G}=0.251(47)(16) at the physical pion mass in the MS[over ¯] scheme at μ^{2}=10 GeV^{2}. If the matching procedure in large-momentum effective theory is neglected, S_{G} is equal to the glue helicity measured in high-energy scattering experiments.
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http://dx.doi.org/10.1103/PhysRevLett.118.102001 | DOI Listing |
J Chem Theory Comput
November 2024
Departamento de Física y Química Teórica, Facultad de Química, UNAM, Mexico City 04510, Mexico.
A gradual but steady tide in theoretical chemistry is favoring the exploration of atomic and molecular interactions through the dynamical forces perceived and exerted by the particles of a system. By integrating the quantum mechanical force operator over all the spin and all but one of the spatial coordinates of the electrons, the Ehrenfest force density field reveals these forces directly and is separable into a classical term, related to the electric field, and a quantum mechanical correction, which we introduce and analyze for various atoms and molecules in this work. This exchange-correlation Ehrenfest force density field, (), excludes the dominant nuclear components that shape the full Ehrenfest field, revealing information about electron sharing, pairing, and delocalization.
View Article and Find Full Text PDFInt J Biol Macromol
October 2024
Taizhou Hospital of Zhejiang Province affiliated to Wenzhou Medical University, Taizhou, Zhejiang 317099, China. Electronic address:
Spiders spin high performance silks with diverse mechanical properties for specific biological functions. Of these spider silk types, pyriform silk stands out as a unique combination of wet glue and dry fibers. Investigation of self-assembly process of spider silk proteins is necessary for elucidating the silk formation mechanism.
View Article and Find Full Text PDFActa Biomater
July 2024
Division of Invertebrate Zoology and Institute for Comparative Genomics, American Museum of Natural History, New York, NY, USA.
Although descended from orb weavers, spiders in the family Theridiidae spin cobwebs whose sticky prey capture gumfoot lines extend from a silk tangle to a surface below. When a crawling insect contacts glue droplets at the bottom of a gumfoot line, the line's weak pyriform anchor releases, causing the taut line to contract, pulling the insect from the surface and making its struggles to escape ineffective. To determine if this change in prey capture biomechanics was accompanied by a change in the material properties of theridiid glue, we characterized the elastic modulus and toughness of the glue droplet proteins of four theridiid species at 20-90 % relative humidity and compared their properties with those of 13 orb weaving species in the families Tetragnathidae and Araneidae.
View Article and Find Full Text PDFNat Commun
December 2023
Department of Physics and Arnold Sommerfeld Center for Theoretical Physics (ASC), Ludwig-Maximilians-Universität München, Theresienstr. 37, München, D-80333, Germany.
A key step in unraveling the mysteries of materials exhibiting unconventional superconductivity is to understand the underlying pairing mechanism. While it is widely agreed upon that the pairing glue in many of these systems originates from antiferromagnetic spin correlations, a microscopic description of pairs of charge carriers remains lacking. Here we use state-of-the art numerical methods to probe the internal structure and dynamical properties of pairs of charge carriers in quantum antiferromagnets in four-legged cylinders.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2023
Department of Applied Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8527, Japan.
Precise structural design of large hetero-multinuclear metal-oxo clusters is crucial for controlling their large spin ground states and multielectron redox properties for application as a single-molecule magnet (SMM), molecular magnetic refrigeration, and efficient redox catalyst. However, it is difficult to synthesize large hetero-multinuclear metal oxo clusters as designed because the final structures are unpredictable when employing conventional one-step condensation reaction of metal cations and ligands. Herein, we report a "cationic metal glue strategy" for increasing the size and nuclearity of hetero-multinuclear metal-oxo clusters by using lacunary-type anionic molecular metal oxides (polyoxometalates, POMs) as rigid multidentate ligands.
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