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BEGIN:VEVENT
UID:1-203@lptms.universite-paris-saclay.fr
DTSTART:20140204T110000Z
DTEND:20140204T120000Z
DTSTAMP:20140116T115502Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm
 s-zoran-ristivojevic/
SUMMARY:Séminaire du LPTMS: Zoran Ristivojevic - LPTMS\, salle 201\, 2ème
  étage\, Bât 100\, Campus d'Orsay - 4 Fév 14 11:00
DESCRIPTION:Decay of excitations in interacting one-dimensional Bose gases\
 nZoran Ristivojevic (CPhT\, Ecole Polytechnique\, Palaiseau)\nExcitation s
 pectrum in weakly-interacting systems of bosons have the Bogoliubov form. 
 In three dimensions\, those excitations are unstable due to residual weak 
 interactions. The resulting process is known as Beliaev decay [1\,2] and h
 as been experimentally observed [3]. The related problem of decay of excit
 ations in one-dimensional Bose gases is a fundamental long-standing proble
 m. In this talk I will present its solution [4]. As a result of the conser
 vation laws in one dimension\, at zero temperature the leading mechanism o
 f decay of a quasiparticle excitation is its disintegration into three oth
 ers. We find that a phonon excitation has a decay rate proportional to the
  seventh power of momentum. In the integrable case of contact interaction 
 between the bosons\, the decay rate vanishes. Our theory is based on study
 ing the anharmonic effects produced by the leading integrability breaking 
 perturbations to the Lieb-Liniger model. It is not limited to the decay of
  lowest momentum phonon excitations and can describe full crossover as mom
 entum increases and the excitation spectrum approaches its quadratic form.
 \n[1] S. T. Beliaev\, Sov. Phys. JETP 7\, 299 (1958). [2] L. D. Landau and
  E. M. Lifshitz\, Statistical Physics\, Part 2 (Pergamon Press\, Oxford\, 
 1980). [3]  N. Katz\, J. Steinhauer\, R. Ozeri\, and N. Davidson\, Phys. 
 Rev. Lett. 89\, 220401 (2002). [4] Z. Ristivojevic and K. A. Matveev\, arx
 iv:1312.5322 (2013).
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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