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The Physics Institute

Jean Dalibard
p. 23-25
Cet article est une traduction de :
L’Institut de Physique du Collège de France

Notes de la rédaction

Source: La lettre, no. 38, June 2014

Texte intégral

1The Collège de France’s Physics Institute is a new research centre set up on the historical Marcelin-Berthelot site. Its establishment follows a long tradition that was recently illustrated by that of Louis Leprince-Ringuet’s, Marcel Froissart’s and Pierre-Gilles de Gennes’s laboratories. The Institute is comprised of three physics Chairs and a junior research team incubator, surrounded by efficient technical and administrative services. In total, about one hundred researchers, engineers, technicians, administrative staff and students share the three floors of the entirely renovated building.

2In this institute, the teams of Serge Haroche (Quantum Physics) and Jean Dalibard (Atoms and Radiation) carry out experimental research, manipulating material and photon particles to propose new tools for the quantum treatment of information and to shed light on new phases of ultra-cold matter. Antoine Georges’s team (Physics of Condensed Matter) studies the theoretical aspects of the properties of quantum systems comprised of a large number of particles (electrons or atoms) with strong correlations, in close collaboration with materials physicists and chemists.

Preparation of laser beams for a cold-atom experiment (Prof. Jean Dalibard’s team)

3The junior research team incubator, the fruit of a partnership with the CNRS, will ultimately include five independent research groups. The first call for proposals was launched at the end of 2013, and the first two winning teams were selected. Çalar Girit is carrying out research focused on mesoscopic physics, using graphene and Josephson junctions, and Alexei Ourjoumstev is studying new regimes of light-matter interaction, with applications in quantum information processing and the development of new sensors.

Crystalline structure of cerium fluorosulfide, a red pigment studied in Prof. Antoine Georges’ team. Certain iron-based supraconductors have
an analogous structure.

4The Institute’s scientific activity therefore covers a vast field of research, both theoretical and experimental, which lies at the crossroads between atomic physics, optics, solid-state physics, and materials science. This multidisciplinary research relies on high-tech infrastructures: a mechanical workshop equipped with high precision machine tools, fast computing systems, a helium circuit for cryogenics, and a clean room for sample preparation.

5The Physics Institute is heavily involved in teaching science. Annual lectures linked to the Chairs address a very broad audience interested in “research in the making”. Moreover, most members of the Chairs’ teams and that of junior teams teach at the undergraduate, Master’s or PhD levels. The teaching takes place at the École Normale Supérieure, at the PSL Research University or within other institutions linked to the Physics Institute, such as the Pierre et Marie Curie University and the École Polytechnique.

The Institute’s Physics Chairs

6Prof. Serge Haroche’s research team studies matter-radiation coupling at the threshold where a single atom interacts with a few photons stored in a modern equivalent of Einstein’s famous “photon box”, here developed using superconductive mirrors. This very simple system, which the fundamental premises of quantum physics account for, illustrates the least intuitive quantum behaviours, like the superposition of states or the measurement postulate. It allows for a same photon to be seen multiple times, without being destroyed, and for light’s quantum jumps to be observed. With it, scientists can explore quantitatively the threshold between the strange quantum world that enables Schrödinger’s famous cat to be both dead and alive, and the classical world, the only one that is accessible to our senses, where cats are either dead or alive. Finally, it constitutes the prototype of a system that processes information using these remarkable properties of quantum logic. The research carried out by the physics of condensed matter research team, headed by Prof. Antoine Georges, is primarily concerned with the materials in which electrons strongly interact between themselves, like transition metal oxides. These strong interactions lead to remarkable physical properties (like superconductivity), which endow these materials with functionalities that lend themselves to innovative applications. In this field, strong synergy will develop with the chemistry Chairs and research teams, also located in Building E, particularly with regard to energy materials.

Prof. Serge Haroche (centre), surrounded by his colleagues Michel Brune and Jean-Michel Raimond, and his team

7Prof. Jean Dalibard’s team studies the collective behaviour of atoms cooled to an extremely low temperature (microkelvin and below). This temperature is reached by irradiating the atoms with laser beams at a carefully chosen frequency; the atoms are then trapped in “cages of light”. The properties of these ultra-cold gases are very different from those of regular fluids, due to the important role played by the quantum nature of the atoms' motion. These gases present a superfluid behaviour, that is, they can flow around an obstacle without friction.

8 These assemblies of cold atoms make it possible to simulate the behaviour of other systems that are still poorly understood, like certain classes of superconductor materials or astrophysical objects such as neutron stars. Cold atoms also have many applications in metrology, with the development of new clocks and high-precision sensors (gravimetry and accelerometry).

9Serge Haroche’s and Jean Dalibard’s groups are Kastler Brossel Laboratory research teams, of which the Collège de France is a trustee, alongside the École Normale Supérieure, the Pierre and Marie Curie University, and the CNRS. Antoine Georges’ team is affiliated to the École Polytechnique’s Theoretical Physics Centre.

Physics and chemistry at the Collège de France within PSL and in the Île-de-France research network

10The Fondation Paris Science et Lettres (PSL), of which the Collège de France is a founding member, plays an active role in reinforcing scientific synergies between its members’ physics, chemistry and biology teams. In particular, it enables research groups to circulate easily from one institution to another, and affords special access to the technological resources available in each of them. The Initiative d’Excellence endowment, awarded to PSL, provides the funding for new transdisciplinary research projects and the creation of international Chairs.

11The Physics Institute as a whole naturally has special relations with the physics department of the École Normale Supérieure, in both research and the pooling of scientific equipment. Moreover, together the École Normale Supérieure and the Collège de France’s Physics Institute have authority to contribute to second-year Master’s teaching and to high-level PhD supervision. In particular, researchers residing at the research-team incubator are encouraged to take an active part in teaching at the École Normale Supérieure.

12The Collège de France’s ties with the Pierre and Marie Curie University are reinforced by its welcoming teams from the Kastler Brossel Laboratory, the Laboratory of Condensed Matter Chemistry of Paris and the Laboratory of Chemistry of Biological Processes. The research of Antoine Georges and his group directly involves the École Polytechnique. Finally, the Laboratory of Chemistry of Biological Processes actively collaborates with the École Normale Supérieure and the CEA.

The Physics Institute provides a particularly favourable scientific and technical environment for hosting the Junior Research Team Incubator headed by Michel Brune, a member of the Kastler Brossel Laboratory who collaborates with Serge Haroche. The Physics Institute’s Junior Research Team Incubator is the fruit of an alliance between the Collège de France and the CNRS (USR 3573, the “Jeunes équipes de l’Institut de physique du Collège de France”).

Each team’s project leader defines their research theme entirely independently from the Chair teams. Themes may cover the full spectrum of current research in physics, and in particular explore overlaps with chemistry, biology and materials science.

Teams are recruited through calls for projects, which are open to researchers having defended their thesis less than ten years prior to applying, with significant post-doctoral experience and a detailed research project.

These teams benefit from laboratory and office space, as well as material and administrative support. The four-year contract may be renewed for an additional period of the same duration if the teams’ scientific output so justifies and funding for further research can be found. In the long term, the incubator may host up to five groups of independent researchers.

The aim is for the incubator to provide project leaders with an ideal material and intellectual environment to foster innovative research projects to emerge and develop to maturity, when they will be able to obtain a permanent position in another institution.

Winners of the 2013 call for projects

Çalar Girit and his team will be conducting research on mesoscopic physics, using graphene and Josephson junctions. Alexei Ourjoumtsev’s team will be studying new forms of interaction between light and matter, with applications in quantum computing and new sensors.

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Table des illustrations

Légende Preparation of laser beams for a cold-atom experiment (Prof. Jean Dalibard’s team)
Fichier image/png, 23M
Légende Crystalline structure of cerium fluorosulfide, a red pigment studied in Prof. Antoine Georges’ team. Certain iron-based supraconductors have an analogous structure.
Fichier image/png, 287k
Légende Prof. Serge Haroche (centre), surrounded by his colleagues Michel Brune and Jean-Michel Raimond, and his team
Fichier image/png, 14M
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Référence électronique

Jean Dalibard, « The Physics Institute », La lettre du Collège de France [En ligne], 9 | 2015, mis en ligne le 29 septembre 2015, consulté le 26 mars 2017. URL :

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