LHC searches for heavy resonances predicted by the composite Higgs paradigm has so far been performed under the simplified assumptions of a single composite state present beyond the SM particle content. However, the lack of new physics at the LHC forces us to reconsider this assumptions. After reviewing standard strategies and future prospects for composite resonant searches, I will highlight the presence of exotic decay mode can affect the reach of the LHC

Nous allons passer en revue les progrès récents dans le développement de dispositifs terahertz

(THz) à base de graphène. La première partie portera sur les hétérostructure de van der Waals
(vdW) contenant deux couches de graphène. Les transitions tunnels inter-couches de graphène assistée par l’émission ou l’absorption de photons seront discutées ainsi que la réalisation d’émetteurs et détecteurs THz. Les premiers résultats expérimentaux montrant l’observation de l'émission et de la détection THz dans ces structures seront également présentés. La deuxième partie portera sur des structures plasmoniques à base de graphène conçues avec une deux grilles en forme peigne avec des doigts inter-digités (DGG). La génération et les instabilités de plasmons induit par un courant courant seront discutées. Il sera montré que les spectres d'absorption THz dans ces dispositifs plasmonique présentent des pics résonants, ajustable avec la longueur et la tension de la grille, ces résonances étant associé à l'excitation des plasmons dans la structure. De plus, le courant continu le long du canal induit un décalage vers le rouge des fréquences avec une réduction significative du coefficient d'absorption. Un régime de transparence est aussi observé dans lequel l’absorption s’annule complètement suivi d'une amplification du rayonnement THz incident et d'un décalage vers le bleu des résonances. Cette dynamique induite par le courant dans la structure plasmonique est expliquée par l'apparition d'instabilités plasmon. Cette découverte ouvre de nouvelles voies vers de nouveaux dispositifs THz à base de graphène.

The most challenging hurdle to the construction of UV complete composite Higgs models without fundamental scalars is the generation of Yukawa couplings for the Standard Model fermions. This problem may be successfully addressed if some spin-1/2 operator of the new strong dynamics has scaling dimension close to 2.5 within the conformal window. We discuss this proposal in general, and then focus on a candidate model based on a SU(3) gauge theory with light Dirac flavors.

La découverte du graphène en 2004 a déterminé l’émergence d’un nouveau domaine de recherche - l’étude des matériaux bidimensionnels - qui peut impacter profondément le futur de l’électronique. Actuellement, le grand défi est d’identifier et de caractériser les matériaux 2D aux propriétés les plus remarquables.

Dans la première partie de ce séminaire, je présenterai mon activité dans le domaine des matériaux 2D. Je commencerai par des études sur les propriétés du graphène sous très fort dopage. Ensuite, je présenterai l’influence des défauts sur les propriétés électroniques et photoniques du graphène et MoS2. La partie finale contiendra une courte introduction au phosphorène et les phases électroniques exotiques qu’il peut engendrer (TI/Supra/TS) à l’aide d’un seul levier, le dopage électrostatique sélectif.

The main advantage of effective theories in statistical mechanics is their simple (polynomial) structure that allows for an analytical treatment and suggests that large length-scales physics is insensitive to microscopic details. In general, however, their predictions are quantitatively wrong, except close to a critical point, where universality ensures that all systems behave in the same way. On the contrary, when there is no genuine critical point there is no guarantee that they are appropriate to describe a given system. This problem is becoming particularly pressing since recent advances have shown that a dynamical effective theory of supercooled liquids display a rich phenomenology, namely: i) dynamical crossover from power-law to exponential relaxation, ii) dynamical heterogeneities iii) decreasing dynamical correlation lengths. A partial answer to these problems comes from the existence of a number of academic models that are exactly described by the dynamical effective theory. Thus it can be viewed, at worst, as a toy model of supercooled liquids. For a given realistic system, instead, the problem cannot be decided a priori but one can devise a certain number of tests to determine whether the system under consideration should be described by the effective theory in the glass crossover region.

If the Physics Beyond the Standard Model (BSM) is decoupled at higher energies, the Standard Model as an effective field theory (SM EFT) is a pertinent framework for phenomenology. The BSM effects on observables are parametrized by the Wilson coefficients of dimension-6 operators, and bounds on their values can be placed from experimental measurements. Integrating out heavy particles at one-loop to obtain expressions for the Wilson coefficients is now also simplified by the use of our universal one-loop effective action. We show how the one-loop effective action obtained from the path integral Covariant Derivative Expansion method can be written in a universal closed form. This result has general applicability beyond the SM EFT and can be used for integrating out any UV theory to obtain a low-energy EFT. We illustrate the relationship of our results to the Standard Model EFT, using as an example the supersymmetric stop and sbottom squark Lagrangian and extracting from our universal expression the Wilson coefficients of dimension-six operators composed of SM fields.
We will also cover the alternative scenario where the New Physics is also directly produced at the LHC by analyzing a selection of interesting direct searches of BSM particles.

We compressed a 2D binary crystal into a glass in simulation. It exhibits a drastic structural change, in contrast to the conventional glass transition from a supercooled liquid where the structure changes little.
We identified the boundary between polycrystal and glass from various mechanical, structural, dynamic, and thermodynamic features. In addition, we identified Hall-Petch and inverse-Hall-Petch regimes in 2D polcrystals and three glass regimes. In the second part, we experimentally studied the relaxations of 2D bidispersed colloidal glasses near its surface during and after the vapor deposition. We observed the surface mobile layer at the single-particle level, and further discovered a middle layer which relaxes via large and anisotropic cooperative motions. It released free volumes towards the surface, leaving a more compact bulk glass. This novel relaxation mode in the middle layer cast light on the ultrastable glasses formed by vapor deposition.

Metabolism is the set of enzymatic reactions that cells use to generate energy and biomass. Interestingly, recent studies suggest that many metabolic enzymes assemble into large clusters, often in response to environmental conditions. Theoretically, we find that large-scale enzyme clusters, with no internal spatial ordering of enzymes, offer many of the same advantages as direct substrate channeling: accelerating intermediate processing, protecting intermediates from degradation/cross-reactions, and protecting the cell from toxic intermediates. The model predicts the separation and size of coclusters that maximize metabolic efficiency. For direct validation, we study a metabolic branch point in Escherichia coli and experimentally confirm the model predictions. Our studies establish a quantitative framework to understand coclustering-mediated metabolic channeling and its application to both efficiency improvement and metabolic regulation.