Ref HAL: hal-03319381_v1
Ref Arxiv: 2107.13328
Ref INSPIRE: 1894553
DOI: 10.1103/PhysRevD.104.096012
Ref. & Cit.: NASA ADS
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We investigate the renormalization group optimized perturbation theory (RGOPT) at the next-to-next-to-leading order (NNLO) for the thermal scalar field theory. From comparing three thus available successive RGOPT orders, we illustrate the efficient resummation and very good apparent convergence properties of the method. In particular, the remnant renormalization scale dependence of thermodynamical quantities is drastically improved as compared to both standard perturbative expansions and other related resummation methods, such as the screened perturbation theory. Our present results thus constitute a useful first NNLO illustration in view of NNLO applications of this approach to the more involved thermal QCD.

Ref HAL: hal-03319142_v1
Ref Arxiv: 2108.04265
DOI: 10.1007/JHEP11(2021)018
Ref. & Cit.: NASA ADS
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Type IIA string theory compactified on a Calabi-Yau threefold has a hypermultiplet moduli space whose metric is known to receive non-perturbative corrections from Euclidean D2-branes wrapped on 3-cycles. These corrections have been computed earlier by making use of mirror symmetry, S-duality and twistorial description of quaternionic geometries. In this paper we compute the leading corrections in each homology class using a direct world-sheet approach without relying on any duality symmetry or supersymmetry. Our results are in perfect agreement with the earlier predictions.

Ref HAL: hal-03297036_v1
DOI: 10.1002/1873-3468.14157
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Munc13-1 is a large banana-shaped soluble protein that is involved in the regulation of synaptic vesicle docking and fusion. Recent studies suggest that multiple copies of Munc13-1 form nanoassemblies in active zones of neurons. However, it is not known if such clustering of Munc13-1 is correlated with multivalent binding to synaptic vesicles or specific plasma membrane domains at docking sites in the active zone. The functional significance of putative Munc13-1 clustering is also unknown. Here we report that nano-clustering is an inherent property of Munc13-1, and is indeed required for vesicle binding to bilayers containing Munc13-1. Purified Munc13-1 protein reconstituted onto supported lipid bilayers assembled into clusters containing from 2 to ~20 copies as revealed by a combination of quantitative TIRF microscopy and step-wise photobleaching. Surprisingly, only clusters containing a minimum of 6 copies of Munc13-1 were capable of efficiently capturing and retaining small unilamellar vesicles. The C-terminal C 2 C domain of Munc13-1 is not required for Munc13-1 clustering, but is required for efficient vesicle capture. This capture is largely due to a combination of electrostatic and hydrophobic interactions between the C 2 C domain and the vesicle membrane.

Ref HAL: hal-03295873_v1
DOI: 10.1021/acsami.1c00625
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Recently, filling zeolites with gaseous hydrocarbons at high pressures in diamond anvil cells has been carried out to synthesize novel polymer-guest/zeolite-host nanocomposites with potential, intriguing applications, although the small amount of materials, 10–7 cm3, severely limited true technological exploitation. Here, liquid phenylacetylene, a much more practical reactant, was polymerized in the 12 Å channels of the aluminophosphate Virginia Polytechnic Institute—Five (VFI) at about 0.8 GPa and 140 °C, with large volumes in the order of 0.6 cm3. The resulting polymer/VFI composite was investigated by synchrotron X-ray diffraction and optical and 1H, 13C, and 27Al nuclear magnetic resonance spectroscopy. The materials, consisting of disordered π-conjugated polyphenylacetylene chains in the pores of VFI, were deposited on quartz crystal microbalances and tested as gas sensors. We obtained promising sensing performances to water and butanol vapors, attributed to the finely tuned nanostructure of the composites. High-pressure synthesis is used here to obtain an otherwise unattainable true technological material.

Ref HAL: hal-03295925_v1
DOI: 10.1103/PhysRevB.103.235418
WoS: WOS:000662302900006
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The nitrogen-vacancy (NV) defect in diamond is an efficient quantum sensor of randomly fluctuating signalsvia relaxometry measurements. In particular, the longitudinal spin relaxation of the NV defect accelerates in thepresence of magnetic noise with a spectral component at its electron spin resonance frequency.We look into thiseffect quantitatively by applying a calibrated and tunable magnetic noise on a single NV defect.We show that anincrease of the longitudinal spin relaxation rate translates into a reduction of the photoluminescence (PL) signalemitted under continuous optical illumination, which can be explained using a simplified three-level model of theNV defect. This PL quenching mechanism offers a simple, all-optical method to detect magnetic noise sourcesat the nanoscale.

Ref HAL: hal-03287898_v1
PMID 34270306
DOI: 10.1103/PhysRevLett.127.018002
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Using x-ray tomography, we experimentally investigate granular packings subject to mechanical tapping for three types of beads with different friction coefficients. We validate the Edwards volume ensemble in these three-dimensional granular systems and establish a granular version of thermodynamic zeroth law. Within the Edwards framework, we also explicitly clarify how friction influences granular statistical mechanics by modifying the density of states, which allows us to determine the entropy as a function of packing fraction and friction. Additionally, we obtain a granular jamming phase diagram based on geometric coordination number and packing fraction.

Ref HAL: hal-03285247_v1
DOI: 10.1016/j.polymer.2021.123987
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Poly[R-3-hydroxybutyrate-co-(R-3-hydroxyvalerate)] (PHBVs) are promising biopolymers, which could substitute petro-based plastics for packaging applications. To anticipate the behavior of PHBVs when transformed using conventional thermo-mechanical shaping processes, it is needed to better understand the effect of processing temperature on their crystallization behavior and final properties. The objectives of the present work were thus (1) to better understand the influence of the processing temperature on the PHBV macromolecular and crystalline structures, depending on its HV content, and (2) to define a processing window guaranteeing optimized mechanical properties of PHBV films. An innovative experimental strategy was proposed, enabling the study of melting and crystallization events, crystalline structure changes, and evolution of mechanical properties of PHBV according to processing temperature, using identical thermal cycles. A comprehensive dynamic monitoring of the studied PHBVs was achieved by coupling differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), step scan DSC (SDSC), observations of isothermal crystallization under polarized optical microscopy (POM), thermo-regulated wide angle X-ray analysis (WAXS), Nuclear Magnetic Resonance (NRM), and finally mechanical tests on PHBV films. The combination of these experiments revealed how inappropriate processing temperatures can result in irreversible changes in PHBVs’ macromolecular and crystalline structures, thermal behavior and mechanical performances. When increasing the HV content of the copolymer, adjusting the processing conditions according to these results revealed to be critical to match the functional properties targeted for a specific use.