Jimmy Castillo (Universidad Simon Bolivar, Caracas)

travaille sur la synthèse de nanoparticules métalliques (argent, or, fer, cuivre) obtenues par méthodes chimiques, pour des applications en adsorption. Il s'intéresse également à des structures cœur-coquilles, ayant un noyau métallique recouvert d'un oxyde de silicium. Enfin, il développe une méthodologie pour préparer des nanoparticules d’oxyde de silicium à partir de déchets agricoles, elles sont ensuite dopées avec du fer, du cuivre du cobalt ou d'autres métaux afin de les utiliser dans le domaine agricole comme nano-nutriment et dans le domaine pétrolier comme nano-catalyseur supporté.

Tunnelling is almost as old as quantum mechanics. Eddi et al. [2] reported unpredictable tunnelling when a walking droplet encounters a submerged wall corresponding to an energy barrier. These experimental results have then been confirmed by the numerical simulations of Nachbin et al. [3], proving that tunnelling is a shared trait between quantum particles and walking droplets. The walking droplets are a macroscopic system with deterministic, sometimes chaotic, behaviour. Here we address the seemingly simple question: What are the origins of the unpredictability in walker tunnelling?
We here focus on the fast dynamics of the bouncing droplet, the resolution of which should allow us to recover deterministic behaviour. The apparent stochastic tunnelling is thus directly linked to the time resolution of the fast dynamics of the droplets as was also shown to be of primary importance in the stochastic interaction of two walkers [4]. These studies raise the following: could the zitterbewegung frequency suggested by de Broglie set the fast time scale of a quantum particle account for the stochasticity of quantum mechanics?

Keywords: bouncing droplets, quantum analog, fluid mechanics, tunnelling

References:
[1] Couder, Y., Protiere, S., Fort, E., & Boudaoud, A. (2005). Dynamical phenomena: Walking and orbiting droplets. Nature, 437(7056), 208.
[2] Eddi, A., Fort, E., Moisy, F., & Couder, Y. (2009). Unpredictable tun- neling of a classical wave-particle association. Physical review letters, 102(24), 240401.
[3] Nachbin, A., Milewski, P. A., & Bush, J. W. (2017). Tunneling with a hydrodynamic pilot-wave model. Physical Review Fluids, 2(3), 034801.
[4] Tadrist, L., Sampara N., Schlagheck, P. & Gilet, T. Interaction of two walkers: perturbed vertical dynamics as a source of chaos. 2018, in press in Chaos .

I describe a class of two-dimensional sigma-models with complex homogeneous target spaces, whose equations of motion admit zero-curvature representations. I point out the relation to models with Z_m-graded target spaces and to the so-called eta-deformed models.

Gauge-gravity duality allows for the reformulation of certain strongly coupled quantum field theories in terms of higher-dimensional gravity. In these lectures, aimed at the graduate level, we will introduce the general set-up of the correspondence, and describe the dictionary that maps between the observables on the field theory and gravity sides of the duality. We will cover topics such as how, by making use of the gravity dual description, one can compute correlation functions in strongly coupled theories, how to extract the spectrum of composite states, the relation between renormalization group flow and the geometry of the gravity dual, as well as how linear confinement can be modelled on the gravity side. Once the general framework has been introduced, we will discuss some applications to scenarios for strongly coupled physics beyond the Standard Model.

Gauge-gravity duality allows for the reformulation of certain strongly coupled quantum field theories in terms of higher-dimensional gravity. In these lectures, aimed at the graduate level, we will introduce the general set-up of the correspondence, and describe the dictionary that maps between the observables on the field theory and gravity sides of the duality. We will cover topics such as how, by making use of the gravity dual description, one can compute correlation functions in strongly coupled theories, how to extract the spectrum of composite states, the relation between renormalization group flow and the geometry of the gravity dual, as well as how linear confinement can be modelled on the gravity side. Once the general framework has been introduced, we will discuss some applications to scenarios for strongly coupled physics beyond the Standard Model.

Not many ingredients are needed for a quantum system to turn complex, with the helium atom as the arguably most elementary example. Much as for classically chaotic systems, accurate predictions of the long-time dynamics, or an exhaustive description of the very structure of such a system’s state turns quickly prohibitive as the size of state space is increased. This has been a concern of theory for long, and recently receives renewed interest as also quantum optics labs turn “complex”, where a stunning level of control over elementary constituents now makes contact with the exponential proliferation of alternative transition amplitudes. To characterise and to certify such systems, let alone to actively control them, we need to identify robust, coarse-grained quantifiers which allow to discriminate their distinctive features, on the basis of experimentally accessible and scalable, yet necessarily incomplete information. We will have a closer look at some exemplary certification problems, with a special emphasis on indistinguishability as a specific source of complexity in many-particle quantum dynamics.

Gauge-gravity duality allows for the reformulation of certain strongly coupled quantum field theories in terms of higher-dimensional gravity. In these lectures, aimed at the graduate level, we will introduce the general set-up of the correspondence, and describe the dictionary that maps between the observables on the field theory and gravity sides of the duality. We will cover topics such as how, by making use of the gravity dual description, one can compute correlation functions in strongly coupled theories, how to extract the spectrum of composite states, the relation between renormalization group flow and the geometry of the gravity dual, as well as how linear confinement can be modelled on the gravity side. Once the general framework has been introduced, we will discuss some applications to scenarios for strongly coupled physics beyond the Standard Model.