2 novembre 2022
Collège de France
Fuseau horaire Europe/Paris
Young physicists (Master students, PhD students and postdoctoral researchers), you are all invited to this free event. Come and bring your friends!

Liste des Contributions

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  1. Denis Werth (Sorbonne University -- IAP)
    02/11/2022 09:00
    Oral presentation

    We welcome all the young physicists to this 2022 edition of the RJP!

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  2. Louis Waquier (Laboratoire MPQ - Université Paris Cité - CNRS)
    02/11/2022 09:15

    We demonstrate the effectiveness of optomechanical devices for the measurement of individual nanoparticles. A semiconductor optomechanical disk resonator is optically driven and detected under ambient conditions, as nebulized nanoparticles land on it. Multiple mechanical and optical resonant signals of the disk are tracked simultaneously, providing access to several pieces of physical...

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  3. Mlle Camille Aracheloff (PMMH (ESPCI) ISYEB (MNHN))
    02/11/2022 09:30

    Odonata (dragonfly and damselfly) exhibit impressive flight ability. They are able to perform many different maneuvers such as zigzag, linear motion back and forth, sharp turn, quick acceleration. These trajectories are the result of complex fluid-structure interactions. Wing morphology has a main role in this interaction as shown in previous studies.
    Insect wings, including dragonfly wings,...

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  4. M. Constant Bourdeloux (Institut Langevin, ESPCI Paris, Université PSL, CNRS, 75005 Paris, France)
    02/11/2022 09:45

    The cocktail party effect is the capability to focus one's auditory attention on particular audio sources while ignoring other audio sources. We propose an experimental setup reproducing the cocktail party effect by designing a time dependent metasurface composed of independent active mirrors. Each active mirror is a programmable acoustical unit cell capable of hearing, computing and emitting...

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  5. Maria Ruiz Ortega
    02/11/2022 10:00

    Adaptive immunity’s success relies on the extraordinary diversity of protein receptors on B and T cell membranes. Despite this diversity, the existence of public receptors shared by many individuals gives hope for developing population wide vaccines and therapeutics. Yet many of these public receptors are shared by chance. We present a statistical approach, defined in terms of a probabilis tic...

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  6. M. Amaury Barral (CEA)
    02/11/2022 10:15

    A great challenge in numerical simulations of geophysical systems (such as in climate models) is the important range of relevant scales. In particular in fluid dynamics, it is impossible to do Direct Numerical Simulations of the whole system, and one has to resort to a variety of numerical tricks.

    We present a new method, “Logarithmic Lattices”, which aims at simulating very important...

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  7. Leïla Godinaud (CEA Saclay / IRFU / AIM)
    02/11/2022 11:00

    In November 1572, a nearby star exploded in a supernova and was observed at the time by Tycho Brahe. Exactly 450 years later, we can study its remnant, the huge cloud made of all the matter of the star ejected at high speeds. The ejected material is heated to tens of millions Kelvin and radiates most of its energy in the X-ray (0.1-10 keV) band.

    Currently, the Chandra X-ray telescope...

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  8. Aurélien LE BAIL (CEA-Saclay)
    02/11/2022 11:15

    Nearly a year ago, the most expensive space telescope ever built was launched into space. After traveling for 6 months, it began to explore the infra-red universe in June. In 4 months, JWST's extraordinary spatial resolution already allowed groundbreaking discoveries in the field of galaxy formation and evolution. From the first detection of extremely old galaxies (back when the universe was...

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  9. Natalie Hogg (IPhT CEA-Saclay)
    02/11/2022 11:30

    Strong lensing -- the effect of light being bent by massive objects such as galaxies and forming circular ring-like images -- is one of the most striking phenomena in observational cosmology. If multiple images are observed, they be used to measure cosmological distances and the expansion rate of the Universe. However, strong lensing images are often distorted by other nearby galaxies or...

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  10. Pierre Granger (CEA/Irfu)
    02/11/2022 11:45

    After the recent discovery of the massive nature of neutrinos, through the observation of their oscillations, we now enter an era of precision measurement of the oscillation parameters. The next long-baseline neutrino accelerator experiments will be crucial for these precision measurements and will need to feature innovative detector technologies that offer high target mass (to acquire large...

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  11. Andrea Saccardi (GEPI, Observatoire de Paris, Université PSL, CNRS)
    02/11/2022 12:00

    Gamma-ray bursts (GRBs) are an amazing class of transient phenomena in the Universe. GRBs are detected from space by satellites thanks to the flash of gamma-ray photons released within an ultra-relativistic jet. The jet is thought to be produced by a new-born accreting black hole formed after the collapse of a massive star, Long-GRBs (LGRBs), or the merger of two compact objects, Short-GRBs...

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  12. Lucas Teinturier (LESIA/LMD)
    02/11/2022 12:15

    Understanding the atmospheric circulation, radiative transfer and atmo-
    spheric chemistry of exoplanets is crucial for our understanding of these objects.
    In particular, Hot Jupiters are among the most observed type of exoplanets and
    have no equivalent in our Solar System. During the last decade, observational
    and modelling efforts have been made to begin the atmospheric...

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  13. Emma David (ISMO, Université Paris-Saclay)
    02/11/2022 14:30

    The strongly correlated material $VO_2$ displays a metal-to-insulator (MIT) transition when going below $T_{MIT}=280K$. Alongside this electronic transition, the material undergoes a structural transition from a rutile structure in the metallic phase to a monoclinic structure in the insulating phase. These simultaneous transitions have created a long-lasting debate within the community: is the...

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  14. M. Ye Mou (Institut des NanoSciences de Paris - Sorbonne Université)
    02/11/2022 14:45

    The inverse Faraday effect (IFE) allows the generation of stationary magnetic fields through optical excitation only [1,2]. This light−matter interaction in metals results from the creation of drift currents via nonlinear forces that light applies to the conduction electrons [1]. The IFE was believed, until now, to be a symmetrical phenomenon, meaning that a right-handed circularly polarized...

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  15. Eva Desgué (THALES Research & Technology)
    02/11/2022 15:00

    PtSe2 is a promising 2D material for high frequency IR optoelectronics [1], its bandgap varying from 1.2 eV (monolayer) to 0.2 eV (bilayer) [2]. We have grown 2D PtSe2 films on sapphire(0001) substrates by molecular beam epitaxy. In particular, we used sapphire substrates with a 0.25° miscut to generate, after high temperature (1135°C) annealing, stepped structures. Indeed, we demonstrated...

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  16. Xavier Ballu (Laboratoire de Physique des Solides, Université Paris-Saclay, CNRS)
    02/11/2022 15:15

    WTe2, a transition metal dichalcogenide, is predicted to have striking topological properties that combine the characters of type II Weyl semimetal and second-order 3D topological insulator (SOTI). SOTIs are characterized by topologically protected helical 1D states at their hinges. 1D states located at certain edges of multilayer WTe2 have indeed been demonstrated in Josephson interferometry...

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  17. Kahina Vertchik (Laboratoire de Physique des Solides d'Orsay)
    02/11/2022 15:30

    DNA toroids are complex liquid crystalline objects that form spontaneously in vitro by condensation of DNA, a general behaviour of semi-flexible polyelectrolytes. These structures have intrigued biophysicists and physicists, both experimental and theoretical, because of the intrinsic beauty of these toroidal objects, and because they provide models for understanding the packaging of DNA in...

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  18. Sebastian Lahs (Laboratoire Aimé Cotton)
    02/11/2022 15:45

    To explain the open questions in the fundaments of physics, new theories that reach beyond the standard model of particle physics are needed. A great number of these indirectly predict electric dipole moments (EDM) of fundamental particles in ranges that are just within reach for modern atomic and molecular physics experiments. While measurements in atomic and molecular beams provided the most...

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  19. Adrien BOUSCAL (Laboratoire Kastler Brossel, Sorbonne Université)
    02/11/2022 16:30

    Trapping cold neutral atoms in close proximity to nanostructures has raised a large interest in recent years, pushing the frontiers of cavity-QED and boosting the emergence of the waveguide-QED field of research. Such platforms interfacing trapped cold atoms and guided light in nanoscale waveguides are a promising route to achieve a regime of strong coupling between light and atoms, and...

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  20. Simon Metayer (LPTHE - Laboratoire de Physique Théorique et Hautes Energies)
    02/11/2022 16:45

    Quantum field theory (QFT) was developed in the 1940s as a theoretical framework for particle physics by combining classical field theory, special relativity and quantum mechanics. In the context of elementary particle physics, QFT provides various tools to accurately determine multiple physical quantities. The most used are essentially perturbative calculations via Feynman diagrams, as well...

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  21. Emile Emery (CEA)
    02/11/2022 17:00

    Quantum gravity is one of the biggest riddle of our time. One approach to it is the Causal Set Theory (CST) that aims to unify the framework of General Relativity and Quantum Mechanics by the concept of proto-causality. We will explore how the classical spacetime continuum can emerge from the discrete structure of a network of fundamental elements, and how reasoning at this smallest scale of...

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  22. Vaios Ziogas (École Polytechnique)
    02/11/2022 17:15

    One of the main goals of physical theories is to provide a useful, universal, effective description of many-body quantum systems at macroscopic scales, regardless of the complicated microscopic dynamics. This is achieved in the context of hydrodynamic effective field theories at finite temperature, by focussing on the dynamics of conserved charges, corresponding to symmetries of the theory,...

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