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Donley EA, Claussen NR, Cornish SL, Roberts JL, Cornell EA, Wieman CE. (2001) Dynamics of collapsing and exploding Bose-Einstein condensates. Nature;412(6844):295-9
"When atoms in a gas are cooled to extremely low temperatures, they will-under the appropriate conditions-condense into a single quantum-mechanical state known as a Bose-Einstein condensate. In such systems, quantum-mechanical behaviour is evident on a macroscopic scale. Here we explore the dynamics of how a Bose-Einstein condensate collapses and subsequently explodes when the balance of forces governing its size and shape is suddenly altered. A condensate's equilibrium size and shape is strongly affected by the interatomic interactions. Our ability to induce a collapse by switching the interactions from repulsive to attractive by tuning an externally applied magnetic field yields detailed information on the violent collapse process. We observe anisotropic atom bursts that explode from the condensate, atoms leaving the condensate in undetected forms, spikes appearing in the condensate wavefunction and oscillating remnant condensates that survive the collapse. All these processes have curious dependences on time, on the strength of the interaction and on the number of condensate atoms. Although the system would seem to be simple and well characterized, our measurements reveal many phenomena that challenge theoretical models."
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MESSAGE EN CAUSE
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Mais c'est qu'il mordrait l'enragé!
Re: J F est un malade mental ! quand il a tort ; il a raison -- Gatti
Posted by Jean-Francois , Dec 10,2001,08:02 Post Reply Forum
"Ce type est un sale connard qui veut toujours avoir raison c’est un comedien car l’article de la revue « SCIENCE » ne dit pas autre chose"
Je ne me souviens pas d'un article sur moi dans Science - a fortiori sur mes talents (?) de comédien -, le délire s'arrange pas. Plutôt que de débiter de nouvelles âneries, il aurait été plus intelligent de donner la bonne référence... A condition, bien sûr que vous l'ayez. Ce n'est pas à radoter "Science, Science, Science" que vous deviendrez crédible.
Olanzapine et au lit! Avec des couches, l'incontinent... Ah, non! Pas de couches... inutile... celle que vous tenez est largement suffisante.
Jean-François
P.S.: A mon avis, ce résumé - par Cornell et Wieman eux-mêmes - contredit à peu près tout ce que le POF affirme (du moins, ce qu'il est possible de tirer de ses divagations... sa clarté d'expression étant ce qu'elle est). Je retiens spécialement le "comportement mécanique-quantique [des condensats qui] est évident à une échelle macroscopique". Pas fort son affaire:
Donley EA, Claussen NR, Cornish SL, Roberts JL, Cornell EA, Wieman CE. (2001) Dynamics of collapsing and exploding Bose-Einstein condensates. Nature;412(6844):295-9
"When atoms in a gas are cooled to extremely low temperatures, they will-under the appropriate conditions-condense into a single quantum-mechanical state known as a Bose-Einstein condensate. In such systems, quantum-mechanical behaviour is evident on a macroscopic scale. Here we explore the dynamics of how a Bose-Einstein condensate collapses and subsequently explodes when the balance of forces governing its size and shape is suddenly altered. A condensate's equilibrium size and shape is strongly affected by the interatomic interactions. Our ability to induce a collapse by switching the interactions from repulsive to attractive by tuning an externally applied magnetic field yields detailed information on the violent collapse process. We observe anisotropic atom bursts that explode from the condensate, atoms leaving the condensate in undetected forms, spikes appearing in the condensate wavefunction and oscillating remnant condensates that survive the collapse. All these processes have curious dependences on time, on the strength of the interaction and on the number of condensate atoms. Although the system would seem to be simple and well characterized, our measurements reveal many phenomena that challenge theoretical models."
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