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TZID:Europe/Paris
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UID:0-908@lptms.universite-paris-saclay.fr
DTSTART;TZID=Europe/Paris:20231219T110000
DTEND;TZID=Europe/Paris:20231219T120000
DTSTAMP:20231211T082325Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm
 s-olivier-gauthe-epfl/
SUMMARY:Séminaire du LPTMS : Olivier Gauthé (EPFL Lausanne) - Salle des s
 éminaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 19 Déc 23 11:0
 0
DESCRIPTION:Tensor network methods for frustrated magnets at finite tempera
 tureOlivier Gauthé (EPFL Lausanne)\nWithin strongly correlated systems\, 
 frustrated magnetism is the field that study magnetic insulators when diff
 erent microscopic magnetic interactions favor incompatible orders and no c
 lassical spin configuration can fulfill all of them. This realm offers a f
 ertile ground for experimental and fundamental exploration\, giving rise t
 o unconventional phenomena such as order by disorder or the enigmatic quan
 tum spin liquid phase. Nevertheless\, its study poses challenges due to th
 e presence of competing interactions of comparable magnitude\, confounding
  perturbation theory. On the numerical side\, frustration usually prevents
  the use of quantum Monte Carlo algorithms.\n\nOver the last decades\, ten
 sor network methods have emerged as the one of the most powerful numerical
  approach to tackle the many-body problem in both classical and quantum ph
 ysics. In this talk\, we will review the core principles of tensor network
  and their applications in condensed matter physics. We will focus on stro
 ngly correlated systems in two dimensions and discuss the simulation of fr
 ustrated quantum magnets at thermal equilibrium using Projected Entangled 
 Pair States (PEPS).\n\nTo illustrate this approach\, we will address the s
 pin-1/2 Heisenberg model on the square lattice with nearest-neighbor coupl
 ing J1 and next-nearest coupling J2 (J1-J2 model) at finite temperature [1
 ]. We will consider both antiferromagnetic (J1 > 0) and ferromagnetic (J1 
 < 0) cases. We will expose the first unambiguous and direct evidence of an
  Ising transition associated with the spontaneous breaking of the C_4v sym
 metry within the collinear antiferromagnet region of the phase diagram.\n\
 n[1] O. Gauthé & F. Mila\, PRL\, 128\, 227202 (2022) 
CATEGORIES:seminars
LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53
 0\, rue André Riviere\, Orsay\, 91405\, France
X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\
 , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST 
 et du LPTMS\, bâtiment Pascal n°530:geo:0,0
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DTSTART:20231029T020000
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