2019-2020 ICFP seminar Program

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Accès rapides

Prochain Séminaire de la FIP :
Accéder au programme

Retrouvez toutes les informations pour vos stages :
Stages L3
Stages M1 ICFP
Stages M2 ICFP

Actualités : Séminaire de Recherche ICFP
du 25 au 29 novembre 2019 :

Retrouvez le programme complet

Emploi du temps :
Emploi du temps L3
Emploi du temps M1 ICFP
Emploi du temps M2 ICFP

Contact - Secrétariat de l’enseignement :
Tél : 01 44 32 35 60
enseignement@phys.ens.fr

The seminar takes place on Tuesday, at 5:15pm in room CONF 4.

 September 24 : M1 interships

Oral defenses of two M1 internships

Grégoire Le Lay
Manchester Centre for Nonlinear Dynamics
Bubble propagation in a Hele–Shaw channel with centred constriction

We study the propagation of air bubbles in an oil-filled Hele—Shaw channel presenting a centred constriction. We show that the bubbles can exhibit a variety of different behaviours, observed both in the experiments and in the numerical simulations. We interpret the transient evolution of the shape and speed of the bubbles using a dynamical systems approach : the bubbles transiently explore weakly unstable steady modes and we are able to understand the evolution of its behaviour using a numerical bifurcation diagram. During this transient evolution, the bubble may break-up into two or more smaller bubbles, changing the topology of the dynamical system.

Ancel Larzul
Stockholm University, Astronomy department
Cosmology from the 21-cm signal through the Alcock-Paczynzski effect

The hyperfine transition at 21-cm of neutral hydrogen constitutes a very promising probe of the epoch of reionization, when the first stars and galaxies lighted up and ionized the surrounding intergalactic medium. The Alcock-Paczynski effect is a geometrical effect that can be used to probe cosmological parameters and that can potentially be seen in the brightness temperature power spectrum of the 21-cm line. However it is not the only line of sight effect to consider when analysing 21-cm data : redshift space distortions (an additional redshift due to the proper motion of the gas that alter our measure of distances) turn out to play an important role in modelling the shape of the observed signal. The aim of this study is to compare the strength of the Alcock-Paczynski effect to redshift space distortions in the context of the 21-cm line and see if the Alcock-Paczynski effect could be detected by SKA1-Low. We simulate a mock observation and interpret it with a wrong cosmology to produce the Alcock-Paczynski effect. We find that even though redshift space distortions dominate the anisotropies in the signal the two line of sight effects are in principle distinguishable. However, it is unlikely that it is possible to separate them in practice since it would require a detailed knowledge of the history of reionization and of the properties of the first galaxies to predict very precisely the brightness temperature power spectrum.

 October 22 : Tristan Briant

Laboratoire Kastler Brossel
From gravitational wave detection to quantum optomechanics

LIGO’s historical first detection of gravitational waves in 2015 opened a new window of astrophysics. Since then a tenth of black hole binaries and one neutron-star binary have been observed. All this results relies on the comprehension of the fundamental limits in high sensitivity interferometric measurements. The enhancement of the sensitivity of the giant gravitational waves detectors will require the implementation of new quantum optics schemes that are now tested on various optomechanical system in our labs.

 November 5 : Preden Roulleau & Carles Altimiras

Service de Physique de l’Etat Condensé, CEA Saclay

Preden Roulleau
Quantum computing is based on the manipulation of quantum bits (qubits) to enhance the efficiency of information processing. In solid-state systems, two approaches have been explored :
1) static qubits, coupled to quantum buses used for manipulation and information transmission,
2) flying qubits which are mobile qubits propagating in quantum circuits for further manipulation.
Flying qubits research led to the recent emergence of the field of electron quantum optics, where electrons play the role of photons in quantum optic like experiments. This has recently led to the development of electronic quantum interferometry as well as single electron sources. As of yet, such experiments have only been successfully implemented in semi-conductor heterostructures cooled at extremely low temperatures.
I will show that it now possible to mimic interference experiments, like electronic mach Zehnder, in graphene. We have demonstrated a record coherence length, confirming that graphene is an ideal material for more advanced quantum operations.

Carles Altimiras
Owing to the probabilistic character of discrete charge transfers through a quantum conductor, such as quantum point contacts or Josephson junctions, a dc bias produces quantum current fluctuations which couple to the electromagnetic environment of the conductor. Our group investigates the resulting dynamics in its many facets : The emitted microwave radiation naturally conveys information on charge transport in ns timescales otherwise hardly accessible. Moreover, being emitted by a quantum source, this radiation displays quantum correlations as well. Not the least, the electrodynamic coupling can be engineered in order to provide a strong measurement backaction on the transport properties of the conductor itself, where the equivalent of the fine structure constant is of order 1. Such regime is totally unparallled by usual quantum electrodynamics. Beyond aiming at providing a unified quantum description of electrical transport and electromagnetic radiation, this activity brings the oportunity to develop new quantum devices.

 November 26 : (postponed to 14/01)

 December 10 : Jean-François Rupprecht & Hervé Rouault

Centre Physique Théorique (Université Aix-Marseille, Luminy campus)
postponed to January

 December 17 : Marco Saitta & Carlo Sirtori

Laboratoire de physique de l’ENS
Condensed Matter and Advanced Technology

In this presentation we will first present the large extent of modern condensed matter physics, and the great theoretical and experimental challenges at the frontiers of research in this vast field. In the second part, we will introduce the strong and growing interface between fundamental condensed matter physics and advanced technologies, particularly quantum technologies, nanosciences, and new materials.

 January 14 : Bernard Plaçais

Laboratoire de physique de l’ENS
A small tour in graphene flatland

 February 11 : François Levrier

Laboratoire de radioastronomie
École Normale Supérieure
La physico-chimie d’un nuage moléculaire géant

Les étoiles ne naissent pas complètement au hasard dans les galaxies, mais au sein de grandes concentrations de gaz et de poussières interstellaires, les nuages moléculaires géants (Giant Molecular Clouds, GMC). La compréhension des processus amenant à la formation des étoiles dans ces GMC met en jeu une large gamme de domaines de la physique, de la mécanique à l’électromagnétisme et à la thermodynamique, en passant par la physique quantique. Nos connaissances en ce domaine progressent en grande partie grâce à des observations de plus en plus détaillées et sensibles, qui permettent de contraindre les modèles théoriques de la machinerie interstellaire. Je présenterai un exemple de telles observations, menées sur le nuage moléculaire d’Orion avec le radiotélescope de l’Institut de Radio Astronomie Millimétrique (IRAM), et les méthodes d’analyse employées pour exploiter ces données.

 February 25 : Raphael Lopes

LKB
École Normale Supérieure
Probing universality with cold atomic gases

In this talk, I will briefly introduce the concept of cold atoms experiments and discuss their bottom-up approach to simulate a vaste scope of complex systems, ranging from condensed-matter to cosmology. In particular, I will focus on recent experiments aiming at probing Universality in- and out-of-equilibrium.

 March 10 : Massimo Vergassola

LPENS
TBA

 March 24 : Hilton Barbosa de Aguiar

École Normale Supérieure
TBA

 May 5 :

TBA

 May 19 : Benoit Semin

TBA

 June 2 :

TBA

 June 16 :

TBA

Accès rapides

Prochain Séminaire de la FIP :
Accéder au programme

Retrouvez toutes les informations pour vos stages :
Stages L3
Stages M1 ICFP
Stages M2 ICFP

Actualités : Séminaire de Recherche ICFP
du 25 au 29 novembre 2019 :

Retrouvez le programme complet

Emploi du temps :
Emploi du temps L3
Emploi du temps M1 ICFP
Emploi du temps M2 ICFP

Contact - Secrétariat de l’enseignement :
Tél : 01 44 32 35 60
enseignement@phys.ens.fr