The Kastler Brossel Laboratory
A joint research unit of the École normale supérieure, Sorbonne University, Collège de France and the Centre national de la recherche scientifique (CNRS), the Kastler Brossel Laboratory (LKB) is a major player in the field of quantum physics. It covers a wide range of topics, from fundamental quantum physics tests to applications. Its expertise is internationally recognized, as evidenced by the three Nobel Prizes it has won in its 65 year history.
The laboratory's activities are traditionally linked to atomic physics and optics, with particular emphasis on the fundamental questions of light-matter interaction, quantum states of light and precision spectroscopy. An important development in recent decades has been the cooling and trapping of atoms, which has opened up a rich field of studies on quantum gases and liquids, at the frontier between atomic and Quantum Condensed Matter Physics.
Another strong point of the laboratory is the study of the interaction between photons and atoms, with fundamental contributions in the fields of cavity quantum electrodynamics, quantum optics and information, and optomechanics. While these concepts continue to play a central role at the LKB, the laboratory has also diversified its research themes towards nanophotonics, the Casimir effect, imaging in biological and complex media, trapped ions, metrology and tests of fundamental interactions. It is involved in a number of large-scale programs and international collaborations, such as GBAR, Virgo, several space missions and equipment of excellence (Equipex).
Two LKB teams are based at the Collège de France
Bose-Einstein condensates team
The "Bose-Einstein Condensates" research team, associated with the Atoms and Radiation Chair held by Prof. Jean Dalibard, comprises some twenty researchers, postdocs and students, and is led by five permanent members : Jean Dalibard, Jérôme Beugnon (Sorbonne University), Fabrice Gerbier (CNRS), Raphaël Lopes (CNRS), and Sylvain Nascimbene (ENS). The team's main work focuses on the manipulation of atoms by electromagnetic fields. Using laser beams with carefully selected characteristics, we can cool a gas of atoms to an extremely low temperature, on the order of a millionth of a degree above absolute zero. The result is new states of matter, such as Bose-Einstein condensates, whose behavior, entirely governed by quantum mechanics, differs markedly from that of ordinary fluids.
Studies currently underway in the team aim to deepen our understanding of the properties of matter at very low temperatures. Recent results have focused on reduced-dimension physics - planar fluids in particular - the behavior of gases of spinning atoms, i.e. with an internal degree of freedom, and the study of these ultra-cold gases in the presence of a gauge field, in direct connection with the quantum Hall effect known for solid bodies.
