Quantum magnets have occupied the fertile ground between many-body theory and low-temperature experiments on real materials since the early days of quantum mechanics. However, our understanding of ...even deceptively simple systems of interacting spins-1/2 is far from complete. The quantum square-lattice Heisenberg antiferromagnet (QSLHAF), for example, exhibits a striking anomaly of hitherto unknown origin in its magnetic excitation spectrum. This quantum effect manifests itself for excitations propagating with the specific wave vector (
, 0). We use polarized neutron spectroscopy to fully characterize the magnetic fluctuations in the metal-organic compound CFTD, a known realization of the QSLHAF model. Our experiments reveal an isotropic excitation continuum at the anomaly, which we analyse theoretically using Gutzwiller-projected trial wavefunctions. The excitation continuum is accounted for by the existence of spatially-extended pairs of fractional
=1/2 quasiparticles, 2D analogues of 1D spinons. Away from the anomalous wave vector, these fractional excitations are bound and form conventional magnons. Our results establish the existence of fractional quasiparticles in the high-energy spectrum of a quasi-two-dimensional antiferromagnet, even in the absence of frustration.
The inclusive hadroproduction of two heavy quarks, featuring a large separation in rapidity, is proposed as a novel probe channel of the Balitsky–Fadin–Kuraev–Lipatov (BFKL) approach. In a ...theoretical setup which includes full resummation of leading logarithms in the center-of-mass energy and partial resummation of the next-to-leading ones, predictions for the cross section and azimuthal coefficients are presented for kinematic configurations typical of current and possible future experimental analyses at the LHC.
We show that applying feedback and weak measurements to a quantum system induces phase transitions beyond the dissipative ones. Feedback enables controlling essentially quantum properties of the ...transition, i.e., its critical exponent, as it is driven by the fundamental quantum fluctuations due to measurement. Feedback provides the non-Markovianity and nonlinearity to the hybrid quantum-classical system, and enables simulating effects similar to spin-bath problems and Floquet time crystals with tunable long-range (long-memory) interactions.
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We study, within QCD collinear factorization and including BFKL resummation at the next-to-leading order, the production of Mueller–Navelet jets at LHC with center-of-mass energy of 7 TeV. The ...adopted jet vertices are calculated in the approximation of a small aperture of the jet cone in the pseudorapidity-azimuthal angle plane. We consider several representations of the dijet cross section, differing only beyond the next-to-leading order, to calculate a few observables related with this process. We use various methods of optimization to fix the energy scales entering the perturbative calculation and compare our results with the experimental data from the CMS collaboration.
A methodology has been developed to ensure airworthiness by improving the reliability of structural elements of aviation and airfield equipment, which differs from the currently available ones by ...using new effective non-deformational technologies based on pulsating subsonic gas flows during all types of maintenance and repair. New technologies have been developed to improve the mechanical and operational properties of aircraft structural elements, applicable in the production of aviation equip-ment, in the process of its maintenance and repair, characterized by the ability to increase them in a complex, without deterioration of any parameters. The nature of the impact of unsteady subsonic gas flows on the structure and properties of aircraft structural elements made of metal and polymer materials, the stress states of products, and the corresponding physical model has been created. It is proposed to implement measures for the use of new non-deformational technologies for restoring operational properties, as well as improving the reliability and extending the life cycle of elements, parts and assemblies of aircraft, airfield equipment by transport companies that exceed the currently used efficiency, efficiency and envi-ronmental friendliness, making appropriate changes to the maintenance and repair regulations. The direction of improving the methodology for forecasting the technical condition of aircraft structural elements is indicated, which differs from the existing ones by taking into account data on the density of crystal structure defects in surface layers.
The accumulation of cesium-137 by the cap and stalk of fruiting bodies of
Leccinum aurantiacum
(Bull.) Gray from the podzolic soil of an aspen forest 30-35 years old was compared with spruce ...undergrowth, which resumes after felling and damage to the litter. The average specific activity of caesium-137 for dry caps is 1589±85 Bq/kg and for stems 879±72 Bq/kg. It has been established that the specific activity of cesium-137 does not exceed the allowable values. The coefficients of accumulation of cesium-137 by parts of fruiting bodies from the soil vary in the following range: for caps from 5.4 to 6.8, and for legs from 1.2 to 2.8. The maximum specific activity of caesium-137 was found in the forest litter 461±54 Bq/kg. With increasing depth, it naturally decreases.
We study cross sections for the exclusive diffractive leptoproduction of
ρ
-mesons,
γ
∗
p
→
ρ
p
, within the framework of high-energy factorization. Cross sections for longitudinally and ...transversally polarized mesons are shown. We employ a wide variety of unintegrated gluon distributions available in the literature and compare to HERA data. The resulting cross sections strongly depend on the choice of unintegrated gluon distribution. We also present predictions for the proton target in the kinematics of the Brookhaven EIC.
•d-Serine is formed by serine racemase and is vital for synapse development, synaptic plasticity and for cognition.•In physiological conditions, d-serine is formed principally in neurons but not in ...glia in the adult brain.•Pathogenic inflammation makes d-serine coming from reactive astrocytes.•Glia supports the metabolism and function of d-serine through the serine shuttle.
d-Serine is now recognized as the main co-agonist for NMDA receptors. For years it was thought to be exclusively produced by astrocytes and was thus viewed as the archetype of gliotransmitters. Recent research have challenged this long cherished and appealing view by showing that in physiological conditions d-erine would rather originate from neurons but not from glia. In the present review and in the light of the emerging serine shuttle model, we ambition to offer a new reading direction of the glia-neuron cross-talk in shaping the metabolism and the functions of d-serine in cerebral communication in normal and pathological conditions by re-interpretating some seminal findings.
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