Ref HAL: hal-02379667_v1
DOI: 10.1103/PhysRevLett.123.063601
WoS: WOS:000479005200002
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10 Citations
Résumé:

We report on the realization and verification of quantum entanglement between a nitrogen-vacancy electron spin qubit and a telecom-band photonic qubit. First we generate entanglement between the spin qubit and a 637 nm photonic time-bin qubit, followed by photonic quantum frequency conversion that transfers the entanglement to a 1588 nm photon. We characterize the resulting state by correlation measurements in different bases and find a lower bound to the Bell state fidelity of ≥ 0.77± 0.03. This result presents an important step towards extending quantum networks via optical fiber infrastructure.

Ref HAL: hal-02374362_v1
Ref Arxiv: 1812.06484
DOI: 10.1039/c9sm01172b
WoS: WOS:000493519700010
Ref. & Cit.: NASA ADS
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1 Citation
Résumé:

Cells and tissues have the remarkable ability to actively generate the forces required to change theirshape. This active mechanical behavior is largely mediated by the actin cytoskeleton, a crosslinkednetwork of actin filaments that is contracted by myosin motors. Experiments and active gel theorieshave established that the length scale over which gel contraction occurs is governed by a balancebetween molecular motor activity and crosslink density. By contrast, the dynamics that govern thecontractile activity of the cytoskeleton remain poorly understood. Here we investigate the microscopicdynamics of reconstituted actin–myosin networks using simultaneous real-space video microscopy andFourier-space dynamic light scattering. Light scattering reveals different regimes of microscopicdynamics as a function of sample age. We uncover two dynamical precursors that precede macroscopicgel contraction. One is characterized by a progressive acceleration of stress-induced rearrangements,while the other consists of sudden, heterogeneous rearrangements. Intriguingly, our findings suggest aqualitative analogy between self-driven rupture and collapse of active gels and the delayed rupture ofpassive gels observed in earlier studies of colloidal gels under external loads.

Ref HAL: hal-02373559_v1
DOI: 10.1039/c9nr03853a
WoS: WOS:000483691300033
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1 Citation
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A search for new relatively easy physicochemical methods for structural identification of carbon nanotubes represents a key challenge. Here, analyzing the experimental data on double-walled carbon nanotubes (DWCNTs) obtained by us and taken from literature, we have expressed the magnitude of elastic coupling between two tubular walls forming a DWCNT as a simple function dependent not only on DWCNT diameters but also on the difference between the chirality angles of the constituent nanotubes. To get this quite unexpected result, which allows us to relate more precisely the structural parameters of a DWCNT with frequencies of its radial breathing-like modes (RBLM), we have developed a new model for the RBLM dynamics that takes into account a possible deposition of water molecules from ambient air onto the DWCNT surface. The comparison between theoretical and experimental RBLM frequencies allows the evaluation of the handedness-dependent contribution in elastic coupling between the layers suggesting that, in the formation of DWCNTs, the layers with the same handedness are privilegeted. Application of the results for identification of DWCNTs is also considered.

Ref HAL: hal-02367687_v1
DOI: 10.1007/s10971-019-04952-1
WoS: WOS:000466160600014
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Résumé:

Silica-wollastonite xerogel composites (xerocomposites) with different wollastonite filler content were obtained after classical drying of silica-wollastonite gels. Two different silica precursors were used, TEOS and colloidal LUDOX, for composites named TW and LW, respectively. We utilized SAXS experiments, N2 adsorption-desorption, and SEM techniques to determine the textural and structural properties of these porous materials. For both the TW and LW composites, it was shown that a macroporosity and a mesoporosity coexist. We argue that the proportion of macroporosity directly depends on the proportion of wollastonite fillers in the composite. We propose a unique two-stage drying mechanism to explain the formation of macropores. We additionally found that the surface of wollastonite fillers was covered by a dense multilayer packing of silica colloids in LUDOX LW xerocomposites. We believe that these surface-modified wollastonite fillers could improve the carbonation kinetics of wollastonite when used as a precursor for aqueous mineral carbonation, a promising route for safe and durable carbon sequestration.

Ref HAL: hal-02358674_v1
PMID 31704936
DOI: 10.1038/s41467-019-13010-x
WoS: 000495393400002
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6 Citations

Ref HAL: hal-02358763_v1
Ref Arxiv: 1903.09108
DOI: 10.1103/PhysRevLett.123.175501
WoS: WOS:000491998300008
Ref. & Cit.: NASA ADS
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1 Citation
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Ultrastable vapor-deposited glasses display uncommon material properties. Most remarkably, upon heating they are believed to melt via a liquid front that originates at the free surface and propagates over a mesoscopic crossover length, before crossing over to bulk melting. We combine swap Monte Carlo with molecular dynamics simulations to prepare and melt isotropic amorphous films of unprecedendtly high kinetic stability. We are able to directly observe both bulk and front melting, and the crossover between them. We measure the front velocity over a broad range of conditions, and a crossover length scale that grows to nearly $400$ particle diameters in the regime accessible to simulations. Our results disentangle the relative roles of kinetic stability and vapor deposition in the physical properties of stable glasses.

Commentaires: 7 pages, 6 figures; accepted for publication in Phys. Rev. Lett. Réf Journal: Phys. Rev. Lett. 123, 175501 (2019)

Ref HAL: hal-02355677_v1
PMID 30806422
DOI: 10.1039/c8sm02592d
WoS: 000465292200018
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3 Citations