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BEGIN:VEVENT
UID:1-400@lptms.universite-paris-saclay.fr
DTSTART:20151201T110000Z
DTEND:20151201T120000Z
DTSTAMP:20151124T141619Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm
 s-o-lychkovskiy/
SUMMARY:Séminaire du LPTMS: Oleg Lychkovskiy - LPTMS\, salle 201\, 2ème 
 étage\, Bât 100\, Campus d'Orsay - 1 Déc 15 11:00
DESCRIPTION:Perpetual motion and driven dynamics of a mobile impurity in a 
 quantum fluid.\nOleg Lychkovskiy\, Russian Quantum Center\, Moscow\nWe stu
 dy the dynamics of a mobile impurity in a quantum fluid at zero temperatu
 re. Two related settings are considered. In the first setting\, the impur
 ity is injected in the fluid with some initial velocity v_0 (which is bel
 ow the critical velocity)\, and we enquire about its velocity at infinite
  time\, v_inf. We derive a rigorous upper bound on |v_0 − v_inf|. In the
  limit of vanishing impurity-fluid coupling\, this bound amounts to v_inf
  = v_0\, which is anticipated from the Landau criterion of superfluidity.
  In the case of a finite coupling\, the velocity of the impurity can decr
 ease\, but not to zero\; the bound quantifies the maximal possible decrea
 se.\nIn the second setting\, a small constant force is exerted upon the im
 purity. We argue that two distinct dynamical regimes exist—backscatterin
 g oscillations of the impurity velocity and saturation of the velocity wit
 hout oscillations. Which regime is realized depends on the mass of the imp
 urity. A nonequilibrium quantum phase transition occurs at some critical m
 ass.
CATEGORIES:seminars
LOCATION:LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay\, 15 
 Rue Georges Clemenceau\, Orsay\, 91405\, France
GEO:48.698185;2.181768
X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\,
  Orsay\, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=LPTMS\, salle 201\, 2è
 me étage\, Bât 100\, Campus d'Orsay:geo:48.698185,2.181768
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