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UID:0-745@lptms.universite-paris-saclay.fr
DTSTART:20201015T143000Z
DTEND:20201015T173000Z
DTSTAMP:20201008T142231Z
URL:https://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-th
 ese-sebastian-grijalva/
SUMMARY:Soutenance de thèse: Sebastian GRIJALVA - Grand amphi\, bâtiment 
 Pascal n° 530 - 15 Oct 20 14:30
DESCRIPTION:Boundary effects in Quantum Spin Chains and Finite-Size Effects
  in the Toroidal Correlated Percolation model\npar\n\nSebastian Grijalva\n
 Jury:\n\nChristian Hagendorf\, Université catholique de Louvain\, examina
 teur\n\nJacopo De Nardis\, ENS\, invité\n\nNikolai Kitanine\, Institut de
  Mathématiques de Bourgogne\, examinateur\n\nKarol Kozlowski\, ENS de Lyo
 n\, rapporteur\n\nVincent Pasquier\, IPhT\, examinateur\n\nPierre Pujol\, 
 Université Paul Sabatier\, rapporteur\n\nRaoul Santachiara\, LPTMS\, Univ
 ersité Paris Saclay\, co-directeur de thèse\n\nVéronique Terras\, LPTMS
 \, Université Paris Saclay\, directrice de thèse\n\n&nbsp\;\n\nRésumé:
 \nThis thesis is divided in two parts: The first one presents a 2D statist
 ical model of correlated percolation on a toroidal lattice. We present a p
 rotocol to construct long-range correlated surfaces based on fractional Ga
 ussian surfaces and then we relate the level sets to a family of correlate
 d percolation models. The emerging clusters are then numerically studied\,
  and we test their conformal symmetry by verifying that their finite-size 
 corrections follow the predictions of Conformal Field Theory. We also prov
 ide numerical details to produce the results.\nThe second part studies the
  quantum integrable XXZ spin-1/2 chain with open boundary conditions for 
 even and odd number of sites. We concentrate in the anti-ferromagnetic reg
 ime and use the Algebraic Bethe Ansatz to determine the ground state confi
 gurations that arise in terms of the boundary fields. We find the conditio
 ns of existence of quasi-degenerate ground states separated by a gap to th
 e rest of the spectrum. We calculate the boundary magnetization at zero te
 mperature and find that it depends on the field at the opposite edge even 
 in the semi-infinite chain limit. We finally calculate the time auto- corr
 elation function at the boundary and show that in the even-size case it is
  finite for the long-time limit as a result of the quasi-degeneracy.\n\n\n
 \nZOOM Meeting ID: 962 2604 2868\nPassword: 708393
CATEGORIES:seminars
LOCATION:Grand amphi\, bâtiment Pascal n° 530\, rue André Rivière\, Ors
 ay\, 91405\, France
X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Rivière\, Orsay
 \, 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Grand amphi\, bâtiment Pasca
 l n° 530:geo:0,0
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