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TZID:Europe/Paris
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BEGIN:VEVENT
UID:1-497@lptms.universite-paris-saclay.fr
DTSTART:20170309T110000Z
DTEND:20170309T120000Z
DTSTAMP:20170301T201557Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-lptms-t
ommaso-comparin-seminaire-exceptionnel/
SUMMARY:Séminaire LPTMS: Tommaso Comparin *** séminaire exceptionnel ***
- LPTMS\, salle 201\, 2ème étage\, Bât 100\, Campus d'Orsay - 9 Mar 17
11:00
DESCRIPTION:Thermodynamics of the unitary Bose gas from first principles\nT
ommaso Comparin (LPS-ENS\, Paris)\nUltracold atomic gases offer access to
a broad class of quantum systems. The strength of interatomic interactions
\, in particular\, may be tuned across a wide range\, through the Feshbach
-resonance technique. In this talk\, I consider a gas of bosonic atoms in
the unitary limit\, where the scattering length is infinite. For three bos
ons\, unitary interactions lead to the Efimov effect\, consisting in an in
finite sequence of scale-invariant three-body bound states. The Efimov sce
nario (predicted in nuclear physics in the 1970s\, and first observed in 2
006 with ultracold atoms) is correctly described through a model with zero
-range two-body interactions and a hard-core three-body repulsion. We use
this model to describe a many-body system of unitary bosons\, which we stu
dy through a dedicated path-integral quantum Monte Carlo algorithm. At the
rmal equilibrium\, the phase diagram of the system includes the normal-gas
phase at high temperature and two low-temperature phases: The Efimov liqu
id and the Bose-Einstein condensate. We determine the critical temperature
for Bose-Einstein condensation\, which is found to be 10% smaller than fo
r non-interacting bosons. We also compute the momentum distribution of the
gas\, and compare it with available experimental results which are part o
f the current effort towards the realization of a degenerate unitary Bose
gas.\n\nReference: T. Comparin and W. Krauth\, Phys. Rev. Lett. 117\, 2253
01 (2016)
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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