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Claude Cohen Tannoudji

Prix Nobel en 1997 pour le ralentissement et le piégeage des atomes par la lumière laser.

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Accueil du site > Vie de l’IFRAF > Publications > A Drop of Quantum Matter

A Drop of Quantum Matter

Publication in Science of Jakob Reichel and al


In a Bose-Einstein condensate (BEC), thousands of atoms share the same quantum state and form a macroscopic, coherent matter wave. With the experimental realization of BECs of neutral atoms in 1995, honored by the 2001 Nobel Prize, the vision of an “atom laser” thus became reality. The analogy with optical lasers is suggestive of applications ; however, BEC experiments as they now exist in research laboratories are much to big and too delicate to be used outside the well-controlled laboratory environment. This is why a group of young researchers from different universities in Germany decided in 2003 to collaborate and realize an atom laser which would be an “instrument” rather than an “experiment” : compact, transportable, and robust enough to function in the real world where shocks, temperature variations and other perturbations are omnipresent.

Their goal was ambitious : produce a BEC in weightlessness while the complete instrument is in free fall inside a “drop tower” which is 146 m tall. To reach this goal, all components had to be miniaturized and ruggedized, including the heart of the setup, which is a magnetic trap containing the atomic sample. Miniaturizing this trap became possible due an “atom chip” developed in the team of Jakob Reichel, who is now a Professor at Université Pierre et Marie Curie and member of the Laboratoire Kastler Brossel. Once they are trapped on this chip, the atoms are cooled down to Bose-Einstein condensation in less than a second, while the apparatus is freely falling in the tower. After condensation, enough free-fall time is left so that the BEC can be released from the trap and its expansion in microgravity observed for more than a second. This is impossible under normal gravity conditions, where the atoms would hit the wall of their container long before reaching this expansion. This impressive technological progress shows that atom lasers are now ready to serve as a tool in new applications. The researchers also hope to use this new device to test the equivalence principle – a cornerstone of relativity theory – with a quantum object.

Reference : « Bose-Einstein Condensation in Microgravity », T. van Zoest et al. (QUANTUS collaboration), Science 328, 1540 (June 18, 2010).

Authors :

T. van Zoest, N. Gaaloul, Y. Singh, H. Ahlers, W. Herr, S. T. Seidel, W. Ertmer, E. Rasel, (Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1,30167 Hannover, Germany).

M. Eckart, E. Kajari, S. Arnold, G. Nandi, W. P. Schleich, ( Institut für Quantenphysik, Universität Ulm, Albert Einstein Allee 11, 89081 Ulm Germany).

R. Walser, (Institut für Angewandte Physik, Technische Universität Darmstadt, Hochschulstrasse 4A, 64289 Darmstadt, Germany).

A. Vogel, K. Sengstock, (Institut für Laser-Physik, Universität Hamburg, 22761 Hamburg, Germany).

K. Bongs, (Midlands Ultracold Atom Research Centre, Birmingham B15 2TT, UK).

W. Lewoczko-Adamczyk, M. Schiemangk, T. Schuldt, A. Peters, (Humboldt-Universität zu Berlin, Hausvogteiplatz 5-7, 10117 Berlin, Germany).

T. Könemann, H. Müntinga, C. Lämmerzahl, H. Dittus, (Center of Applied Space Technology and Microgravity (ZARM), Universität Bremen, Am Fallturm, 28359 Bremen, Germany).

T. Steinmetz, T. W. Hänsch, (Max-Planck-Institut für Quantenoptik and Sektion Physik der Ludwig-Maximilians-Universität, Schellingstrasse 4, 80799 München, Germany).

J. Reichel, (Laboratoire Kastler-Brossel de l’Ecole Normale Supérieure, 24 rue Lhomond, 75231 Paris, France).

Post-scriptum :

© photos ZARM - University of Bremen and QUANTUS Team