Parcourir Sciences Et Techniques thématique/sous thématique "Physique, chimie, mathématiques & sciences de la terre"
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Adiabatic invariants drive rhythmic human motion in variable gravity
01 décembre 2020, CeREF TechniqueArticle scientifiqueVoluntary human movements are stereotyped. When modeled in the framework of classical mechanics they are expected to minimize cost functions that may include energy, a natural candidate from a physiological point of view also. In time-changing environments, however, energy is no longer conserved—regardless of frictional energy dissipation—and it is therefore not the preferred candidate for any cost ... -
Alice et le Pendule : au pays des variables actions-angles
27 octobre 2020, CeREF TechniquePublication d'intérêt général/presseArticle de vulgarisaiton sur le pendule de Foucault -
Anyons in quantum mechanics with a minimal length
15 février 2017, HE Louvain en HainautArticle scientifiqueThe existence of anyons, i.e. quantum states with an arbitrary spin, is a generic feature of standard quantum mechanics in (2+1)-dimensional Minkowski spacetime. Here it is shown that relativistic anyons may exist also in quantum theories where a minimal length is present. The interplay between minimal length and arbitrary spin effects are discussed. -
Compte rendu de : "Mee (Nicholas), Celestial Tapestry : The Warp and Weft of Art and Mathematics"
2022, HE Louvain en HainautRapportIl s'agit du compte rendu du livre : "Mee (Nicholas), Celestial Tapestry : The Warp and Weft of Art and Mathematics. – Ox ford : Oxford University Press, 2020. – 325 p. – 1 vol. broché de 20 × 13 cm. – 16,99 £. – isbn 978-0-19-885195-0". -
Compte rendu de Harry M. Collins : «Gravity's kiss : the detection of gravitational waves»
01 janvier 2018, HE Louvain en HainautRapportCompte rendu de Harry M. Collins : «Gravity's kiss : the detection of gravitational waves» -
Compte rendu de Hermann Weyl : «Philosophie des mathématiques et des sciences de la nature»
01 octobre 2019, HE Louvain en HainautRapportCompte rendu de Hermann Weyl : «Philosophie des mathématiques et des sciences de la nature» -
Compte rendu de Nicolas Beck : «En finir avec les idées reçues sur la vulgarisation scientifique»
01 janvier 2017, HE Louvain en HainautRapportCompte rendu de Nicolas Beck : «En finir avec les idées reçues sur la vulgarisation scientifique» -
Compte rendu de Patrick Tort : «Qu'est-ce que le matérialisme ? Introduction à l'analyse des complexes discursifs»
01 janvier 2017, HE Louvain en HainautAutreCompte rendu de Patrick Tort : «Qu'est-ce que le matérialisme ? Introduction à l'analyse des complexes discursifs» -
Diffusion in Phase Space as a Tool to Assess Variability of Vertical Centre-of-Mass Motion during Long-Range Walking
06 février 2023, CeREF SantéCeREF TechniqueArticle scientifiqueWhen a Hamiltonian system undergoes a stochastic, time-dependent anharmonic perturbation, the values of its adiabatic invariants as a function of time follow a distribution whose shape obeys a Fokker–Planck equation. The effective dynamics of the body’s centre-of-mass during human walking is expected to represent such a stochastically perturbed dynamical system. By studying, in phase space, the ... -
Ergonomic Risk Assessment of Developing Musculoskeletal Disorders in Workers with the Microsoft Kinect: TRACK TMS
19 octobre 2018, CeREF TechniqueArticle scientifiqueCompte rendu de la conférence JETSAN 2017 -
A First-Quantized Model for Unparticles and Gauge Theories around Conformal Window
02 décembre 2021, CeREF TechniqueArticle scientifiqueWe first quantize an action proposed by Casalbuoni and Gomis in 2014 that describes two massless relativistic scalar particles interacting via a conformally invariant potential. The spectrum is a continuum of massive states that may be interpreted as unparticles. We then obtain in a similar way the mass operator for a deformed action in which two terms are introduced that break the conformal symmetry: ... -
The Formulations of Classical Mechanics with Foucault’s Pendulum
01 octobre 2020, CERDECAMArticle scientifiqueSince the pioneering works of Newton (1643–1727), Mechanics has been constantly reinventing itself: reformulated in particular by Lagrange (1736–1813) then Hamilton (1805–1865), it now offers powerful conceptual and mathematical tools for the exploration of dynamical systems, essentially via the action-angle variables formulation and more generally through the theory of canonical transformations. ... -
Gravitating Bubbles of Gluon Plasma above Deconfinement Temperature
13 octobre 2020, CeREF TechniqueArticle scientifiqueThe equation of state of SU(3) Yang–Mills theory can be modelled by an effective Z3− symmetric potential depending on the temperature and on a complex scalar field ϕ . Allowing ϕ to be dynamical opens the way to the study of spatially localized classical configurations of the scalar field. We first show that spherically symmetric static Q-balls exist in the range (1−1.21)×Tc , Tc being the ... -
Hadrons, Charmé et Beauté
04 mai 2021, CeREF TechniqueAutreSéminaire donné le 4 mai 2021 pour le département de Physique (UMONS) -
Higher-derivative harmonic oscillators: stability of classical dynamics and adiabatic invariants
06 janvier 2019, CERISICArticle scientifiquehe status of classical stability in higher-deriv- ative systems is still subject to discussions. In this note, we argue that, contrary to general belief, many higher-derivative systems are classically stable. The main tool to see this prop- erty are Nekhoroshev’s estimates relying on the action-angle formulation of classical mechanics. The latter formulation can be reached provided the Hamiltonian ... -
Le Boson de Brout-Englert-Higgs
25 mars 2014, CeREF TechniqueAutreConférence présentée à l'Université de Mons (UMONS dans le cadre du cycle Univers 2014-2015, par Fabien Buisseret (Haute Ecole Louvain en Hainaut et Service de Physique nucléaire et subnucléaire, UMONS) et Evelyne Daubie (Service de Physique nucléaire et subnucléaire, UMONS) « Presque cinquante ans après avoir été postulée, l’existence du boson de Brout-Englert-Higgs est maintenant avérée. Quel ... -
Low-Cost Sensors and Biological Signals
21 février 2021, CeREF TechniqueArticle scientifiqueEditorial of the Special issue Low-Cost sensors and Biological signals https://www.mdpi.com/journal/sensors/special_issues/LCSBS -
Many-Quark Interactions: Large-N Scaling and Contribution to Baryon Masses
31 mai 2022, CeREF TechniqueArticle scientifiqueStarting from an effective Hamiltonian modeling, of a baryon made of N identical quarks in the large-N approach of QCD, we obtain analytical formulas, allowing to estimate the contributions of multiquark interactions to the baryon mass. The cases of vanishing (mass spectrum) and nonvanishing (baryon melting) temperatures are treated. -
Motor strategies and adiabatic invariants: The case of rhythmic motion in parabolic flights
05 août 2021, CeREF TechniqueArticle scientifiqueThe role of gravity in human motor control is at the same time obvious and difficult to isolate. It can be assessed by performing experiments in variable gravity. We propose that adiabatic invariant theory may be used to reveal nearly conserved quantities in human voluntary rhythmic motion, an individual being seen as a complex time-dependent dynamical system with bounded motion in phase space. ... -
Q-balls and charged Q-balls in a two-scalar field theory with generalized Henon-Heiles potential
30 avril 2024, CeREF TechniqueArticle scientifiqueWe construct Q-ball solutions from a model consisting of one massive scalar field ξ and one massive complex scalar field ϕ interacting via the cubic couplings g1ξϕ ϕ þ g2ξ3, typical of Henon-Heiles-like potentials. Although being formally simple, these couplings allow for Q-balls. In one spatial dimension, analytical solutions exist, either with vanishing or nonvanishing ϕ. In three spatial ...