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(419) Production(s) de l'année 2017
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Models and algorithms for the next generation of glass transition studies
Auteur(s): Ninarello A. S., Berthier L., Coslovich D.
(Article) Publié:
Physical Review X, vol. 7 p.021039 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01539636_v1
Ref Arxiv: 1704.08864
DOI: 10.1103/PhysRevX.7.021039
WoS: 000402816600002
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
102 Citations
Résumé: Successful computer studies of glass-forming materials need to overcome both the natural tendency to structural ordering and the dramatic increase of relaxation times at low temperatures. We present a comprehensive analysis of eleven glass-forming models to demonstrate that both challenges can be efficiently tackled using carefully designed models of size polydisperse supercooled liquids together with an efficient Monte Carlo algorithm where translational particle displacements are complemented by swaps of particle pairs. We study a broad range of size polydispersities, using both discrete and continuous mixtures, and we systematically investigate the role of particle softness, attractivity and non-additivity of the interactions. Each system is characterized by its robustness against structural ordering and by the efficiency of the swap Monte Carlo algorithm. We show that the combined optimisation of the potential's softness, polydispersity and non-additivity leads to novel computer models with excellent glass-forming ability. For such models, we achieve over ten orders of magnitude gain in the equilibration timescale using the swap Monte Carlo algorithm, thus paving the way to computational studies of static and thermodynamic properties under experimental conditions. In addition, we provide microscopic insights into the performance of the swap algorithm which should help optimizing models and algorithms even further.
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Radiative Heat Transfer between Metallic Gratings Using Adaptive Spatial Resolution
Auteur(s): Guizal B., Messina R., Noto A., Antezza M.
Conférence invité: PIERS : Progress In Electromagnetics Research Symposium (Saint Petersbourg, RU, 2017-05-22)
Ref HAL: hal-01538779_v1
Exporter : BibTex | endNote
Résumé: We calculate the radiative heat transfer between two identical metallic one-dimensional lamellar gratings. To this aim we present and exploit a modification to the widely-used Fourier modal method, known as adaptive spatial resolution, based on a stretch of the coordinate associated to the periodicity of the grating. We first show that this technique dramatically improves the rate of convergence when calculating the heat flux. We then present a study of heat flux as a function of the grating height, highlighting a remarkable amplification of the exchanged energy, ascribed to the appearance of spoof-plasmon modes, whose behavior is also spectrally investigated. Differ- ently from previous works, our method allows us to explore a range of grating heights extending over several orders of magnitude. By comparing our results to recent studies we find a consis- tent quantitative disagreement with some previously obtained results going up to 50%. In some cases, this disagreement is explained in terms of an incorrect connection between the reflection operators of the two gratings.
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Origin of Noncubic Scaling Law in Disordered Granular Packing
Auteur(s): Xia Chengjie, Li Jindong, Kou Binquan, Cao Yixin, Li Zhifeng, Xiao Xianghui, Fu Yanan, Xiao Tiqiao, Hong Liang, Zhang Jie, Kob W., Wang Yujie
(Article) Publié:
Physical Review Letters, vol. 118 p.238002 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01536101_v1
DOI: 10.1103/PhysRevLett.118.238002
WoS: 000402979400019
Exporter : BibTex | endNote
6 Citations
Résumé: Recent diffraction experiments on metallic glasses have unveiled an unexpected non-cubic scaling 14 law between density and average interatomic distance, which lead to the speculations on the presence of 15 fractal glass order. Using X-ray tomography we identify here a similar non-cubic scaling law in 16 disordered granular packing of spherical particles. We find that the scaling law is directly related to the 17 contact neighbors within first nearest neighbor shell, and therefore is closely connected to the 18 phenomenon of jamming. The seemingly universal scaling exponent around 2.5 arises due to the isostatic 19 condition with contact number around 6, and we argue that the exponent should not be universal. .
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Impact of drops and balls : Spread, Bounce or Burst of Soft Matter sheets
Auteur(s): Ligoure C.
(Séminaires)
Laboratoire Matière et Systèmes Complexes UMR 7057 (Paris, FR), 2017-05-15
Résumé: In a first part I will focus on the destabilization of dilute oil-in-water emulsion-based liquid sheets expanding in air. A sheet results from the collision of a single tear on a small solid target ; it disintegrates through the nucleation and growth of holes that perforate the sheet. We have developed an optical technique that allows the determination of the time and space-resolved thickness of the sheet to gain a, understanding of the physical mechanisms f the perforation events This bursting based-liquid sheet destabilization is at the origin of emulsion-based anti-drift formulations are developed for agricultural spray.
In a second part, I will investigate freely expanding sheets formed by ultra soft spherical gel beads of elastic but also liquid droplets with various surface tensions, and simple viscoelastic fluids (Maxwell fluids), produced by impacting them on a silicon wafer covered with a thin layer of liquid nitrogen that suppresses viscous dissipation by an inverse Leidenfrost effect.
The experiments reveal a universal behaviour of the impact dynamics with impact velocity, for both solids and liquids, and even viscoelastic fluids, that we have rationalized .
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Complementarity between Optics and Neutron spectroscopy in the THz domain: An introduction
Auteur(s): Ruffle B.
Conférence invité: Workshop SON2017 (Grenoble, FR, 2017-06-19)
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Robust entanglement with three-dimenstional nonreciprocal photonic topological insulators
Auteur(s): Hassani Gangaraj S. Ali, Hanson George W., Antezza M.
(Article) Publié:
-Physical Review A Atomic, Molecular, And Optical Physics [1990-2015], vol. 95 p.063807 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01533723_v1
DOI: 10.1103/PhysRevA.95.063807
WoS: 000402794000009
Exporter : BibTex | endNote
14 Citations
Résumé: We investigate spontaneous and pumped entanglement of two-level systems in the vicinity of a photonic topological insulator interface, which supports a nonreciprocal (unidirectional), scattering-immune, and topologically protected surface-plasmon polariton in the band gap of the bulk material. To this end, we derive a master equation for qubit interactions in a general three-dimensional, nonreciprocal, inhomogeneous, and lossy environment. The environment is represented exactly, via the photonic Green's function. The resulting entanglement is shown to be extremely robust to defects occurring in the material system, such that strong entanglement is maintained even if the interface exhibits electrically large and geometrically sharp discontinuities. Alternatively, depending on the initial excitation state, using a nonreciprocal environment allows two qubits to remain unentangled even for very close spacing. The topological nature of the material is manifest in the insensitivity of the entanglement to variations in the material parameters that preserve the gap Chern number. Our formulation and results should be useful for both fundamental investigations of quantum dynamics in nonreciprocal environments and technological applications related to entanglement in two-level systems.
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