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UID:0-671@lptms.universite-paris-saclay.fr
DTSTART;TZID=Europe/Paris:20190416T110000
DTEND;TZID=Europe/Paris:20190416T120000
DTSTAMP:20190404T130008Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm
 s-gregory-astrakharchik/
SUMMARY:Séminaire du LPTMS: Gregory Astrakharchik - LPTMS\, salle 201\, 2
 ème étage\, Bât 100\, Campus d'Orsay - 16 Avr 19 11:00
DESCRIPTION:Andreev-Bashkin Effect in quantum gases\nGregory Astrakharchik 
 (UPC\, Barcelona)\nWe study a mixture of two superfluids with density–de
 nsity and current–current (Andreev–Bashkin) interspecies interactions.
  The Andreev–Bashkin coupling gives rise to a dissipationless drag (or e
 ntrainment) between the two superfluids. Within the quantum hydrodynamics 
 approximation\, we study the relations between speeds of sound\, susceptib
 ilities and static structure factors\, in a generic model in which the den
 sity and spin dynamics decouple. Due to translational invariance\, the den
 sity channel does not feel the drag. The spin channel\, instead\, does not
  satisfy the usual Bijl–Feynman relation\, since the f-sum rule is not e
 xhausted by the spin phonons. The very same effect on one dimensional Bose
  mixtures and their Luttinger liquid description is analysed within pertur
 bation theory. Using diffusion quantum Monte Carlo simulations of a system
  of dipolar gases in a double layer configuration\, we confirm the general
  results. Given the recent advances in measuring the counterflow instabili
 ty\, we also study the effect of the entrainment on the dynamical stabilit
 y of a superfluid mixture with non-zero relative velocity. We quantify the
  non-dissipative drag effect\, resulting from the Andreev-Bashkin current-
 current interaction between the two components of the gas\, and we show th
 at in the regime of strong coupling it causes a significant suppression of
  the spin-wave velocity.\n\n[1] L. Parisi\, G. E. Astrakharchik\, and S. G
 iorgini\,\nSpin Dynamics and Andreev-Bashkin Effect in Mixtures of One-Dim
 ensional Bose Gases\,\nPhys. Rev. Lett. 121\, 025302 (2018)\n\n[2] Jacopo 
 Nespolo\, Grigori E. Astrakharchik\, Alessio Recati\,\nAndreev-Bashkin eff
 ect in superfluid cold gases mixture\,\nNew J. Phys. 19\, 125005 (2017)
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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