OLIVITRAN Nathalie
Organisme : CNRS
Chargé de Recherche
(HDR)
Nathalie.OliviTran
umontpellier.fr
Bureau: 46.0, Etg: 1, Bât: 21  Site : Campus Triolet
Domaines de Recherche:  Physique/Matière Condensée/Science des matériaux
 Physique/Physique des Hautes Energies  Théorie
 Physique/Astrophysique/Cosmologie et astrophysique extragalactique [astroph.CO]
 Physique/Physique Quantique
 Physique/Relativité Générale et Cosmologie Quantique

Dernieres productions scientifiques :


Theoretical approach in real space to the masses of protons and neutrons
Auteur(s): OliviTran N.
(Article) Publié:
Nuclear And Particle Physics Proceedings, vol. 312317C p.7881 (2021)
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Résumé: We make the hypothesis that our universe is threedimensional and curved, hence our universe may be embedded in a fourdimensional Euclidean space where the four dimensions are (x, y, z, t). The fourth dimension is time t which is treated like a spatial dimension. Straightforwardly, this Euclidean space has an underlying hypersquare array for which the edges have a width of one Planck length. The eigenfunctions of each edge of this array are √ 2exp(ix i) where x_i = x, y, z or t. As previously published, the quarks are threedimensional in real space. The quark up has a mass of 2^ 21 eV/c 2 and the quark down 2^22 eV/c 2 (the quark down is an excited state of the quark up). Because the quark up is threedimensional (like the apex of a tetrahedron), each edge of the quark has an eigenvalue of 2 ^7 eV/c 2. Let us consider that the color charge of the gluons are in fact the coordinates in real space (x: red; y:blue; z: green). The gluons have no mass so they have no temporal dimension. Each pair of quarks, share one gluon (the gluons interfere with the quarks edges).Gluons are bosons and quarks are fermions so for each edge of the underlying array (except the temporal edges) we calculate the ground states. In one proton or in one neutron, there are 3 gluons and 3 quarks; as only the temporal edges of the 3 quarks are not in the ground states and because the protons and neutrons obey the Schrödinger equation, the masses of the proton or neutron are equal to 2^ 30 / ln(π)eV/c 2 = 937MeV/c 2. The difference between the masses of the proton and neutron comes from the difference between the experimental masses and the theoretical masses of quarks up and down. Straightforwardly, we found theoretical values of the masses of protons and neutrons within 2% of the experimental values of the masses of protons and neutrons.



Drying of a colloidal suspension deposited on a substrate: experimental and numerical studies
Auteur(s): OliviTran N., Bonnet L., Etienne P.
(Article) Publié:
Crystals, vol. 11 p.829 (2021)
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Ref HAL: hal03320786_v1
DOI: 10.3390/cryst11070829
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Résumé: We studied a colloidal suspension of polystyrene beads deposited on a glass substrate. The glass substrate contained either straight rough areas on the borders of an open channel or only straight rough areas. The drying of the suspension was observed with an optical microscope which light bulb acted as an energy source to evaporate the suspension. Moreover, the light bulb of the microscope provided optical pressure due to light. We observed that the colloidal particles where trapped on the rough areas of the substrate and not in the open channel, at the end of the drying process. In order to understand the experimental results, we modelled numerically the drying of the suspension by a Molecular Dynamics program. The forces acting on the substrate by the particles are their weight, the optical pressure due to the light bulb of the optical microscope, the attractive Van der Waals force and the repulsive diffuse layer force. The forces acting between two particles are the attractive Van der Waals forces, the repulsive diffuse layer force, the capillary force. The Gaussian random force (linked to the Brownian motion), the particle liquid viscous drag force (also linked to the Brownian motion) are horizontal and applied on one particle. The relation between the normal forces N (forces acting by the particles on the substrate) and the horizontal forces F is Amontons' third law for friction F ≤ µ k N ; in rough areas of the substrate µ k is larger than in smooth areas. This explains that particles are trapped in the large roughness areas.



Theoretical calculations of the masses of the elementary fermions
Auteur(s): OliviTran N.
Chapître d'ouvrage: Accelerators And Colliders, vol. p. (2020)
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Résumé: Our universe is threedimensional and curved (with a positive curvature) and thus may be embedded in a fourdimensional Euclidean space with coordinates x, y, z, t where the fourth dimension time t is treated as a regular dimension. One can set in this spacetime a fourdimensional underlying array of small hypercubes of one Planck length edge. With this array all elementary particles can be classified following that they are two, three or fourdimensional. The elementary wavefunctions of this underlying array are equal to √ 2exp ix i for x i = x, y, z or to √ 2exp it for t. Hence, the masses of the fermions of the first family are equal to 2 n (in eV/c 2) where n is an integer. The other families of fermions are excited states of the fermions of the first family and thus have masses equal to 2 n .p 2 /2 where n and p are two integers. Theoretical and experimental masses fit within 10%.



Modeling of deep indentation in brittle materials
Auteur(s): OliviTran N., Despetis F., Faivre A.
(Article) Publié:
Materials Research Express, vol. 7 p.035201 (2020)
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DOI: 10.1088/20531591/ab7b29
WoS: 000521374800001
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Résumé: We modelled deep indentation in brittle materials via a tensorial approach in three dimensions. Experimentally, we performed deep indentation in base catalyzed aerogels. When deep indentation is performed in these materials, it appears a Hertzian cone crack for both experimental and numerical results. The cone angle (angle between the surface and the boundaries of the Hertzian cone) depends on the material in which indentation is performed. The Young moduli of the materials has no effect on these angles. The tendency is that materials with increasing Poisson ratios have a decreasing value of the Hertzian cone angle.



Theoretical approach to the masses of the elementary fermions
Auteur(s): OliviTran N.
(Article) Publié:
Nuclear And Particle Physics Proceedings, vol. 309311C p.7376 (2020)
Texte intégral en Openaccess :
Ref HAL: hal02322855_v1
DOI: 10.1016/j.nuclphysbps.2019.11.013
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Résumé: We made the hypothesis that, if spacetime is composed of small hypercubes of one Planck length edge, it exists elementary wavefunctions which are equal to √ 2 exp(ix j) if it corresponds to a space dimension or equal to √ 2 exp(it) if it corresponds to a time dimension. The masses of fermions belonging to the first family of fermions are equal to integer powers of 2 (in eV/c 2) [1]. We make the hypothesis that the fermions of the 2nd and 3rd families are excited states of the fermions of the 1st family. Indeed, the fermions of the 2nd and 3rd families have masses equal to 2 n .(p 2)/2 where n is an integer [1] calculated for the first family of fermions and p is another integer. p is an integer which corresponds to the excited states of the elementary wavefunctions (the energy of the excited elementary wave functions are equal to p 2 /2; using normalized units).
Commentaires: Talk given at 19th International Conference in Quantum Chromodynamics (QCD 19), 2 july – 5 july 2019, Montpellier – FR.

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