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BEGIN:VEVENT
UID:1-521@lptms.universite-paris-saclay.fr
DTSTART:20170704T140000Z
DTEND:20170704T150000Z
DTSTAMP:20170702T151852Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm
 s-thomas-barthel-2/
SUMMARY:Séminaire du LPTMS: Thomas Barthel - LPTMS\, salle 201\, 2ème ét
 age\, Bât 100\, Campus d'Orsay - 4 Juil 17 14:00
DESCRIPTION:*** ATTENTION: horaire inhabituel -&gt\; 14h ***\nEntanglement 
 and computational complexity for 1D quantum systems at finite T\nThomas Ba
 rthel (Duke University\, USA)\nUsing the replica trick in 1+1 dimensional 
 quantum field theory\, one can show that the cost for the classical simula
 tion of one-dimensional quantum many-body systems at finite temperatures g
 rows only polynomially with the inverse temperature and is system-size ind
 ependent - even for gapless systems. In particular\, I will show that the 
 thermofield double state (TDS)\, a widely used purification of the equilib
 rium density operator\, has a faithful matrix product state (MPS) represen
 tation. The argument is based on the scaling behavior of Rényi entangleme
 nt entropies in the TDS. At finite temperatures\, they obey the area law. 
 For gapless conformally invariant systems\, the Rényi entropies are found
  to grow only logarithmically with inverse temperature.\nThe field-theoret
 ical results are complemented by exact and quasi-exact numerical computati
 ons for integrable as well as non-integrable spin chains\, and the Bose-Hu
 bbard model. This allows us to compare actual matrix product truncation di
 mensions with upper bounds derived from Rényi entropies. Finally\, I will
  highlight some applications\n\n&nbsp\;
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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