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X-ORIGINAL-URL:https://www.lps.u-psud.fr/
X-WR-CALNAME:Laboratoire de physique des Solides
X-WR-CALDESC:
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BEGIN:VEVENT
CLASS:PUBLIC
DTSTART;TZID=Europe/Paris:20240321T110000
DTEND;TZID=Europe/Paris:20240321T120000
DTSTAMP:20240316T082900
UID:MEC-130ea938864f051b9a40c85b6a713306@lps.u-psud.fr
CREATED:20240316
LAST-MODIFIED:20240316
PRIORITY:5
TRANSP:OPAQUE
SUMMARY:L.MESSIO:Overview of the possibilities of high temperature series expansions
DESCRIPTION:\nIn the search for exotic properties of spin lattices, many numerical methods focus on the ground state and on the low-energy excitations of a model. Here, we use the opposite approach, with high temperature series expansions. The coefficients of the free energy, the specific heat or the magnetic susceptibility series are obtained up to 20 (depending on the model complexity). Yet, the convergence radius limits the range of temperature where information can be obtained by simple summation. Thus, alternative methods are required. One of them is the entropy method, that uses some hypothesis on the nature of the ground state to reconstruct thermodynamic quantities over the whole temperature range.\n\nThe entropy method has been used on several compounds to propose exchange parameter values. When a finite temperature phase transition occurs, a singularity forbids to use the entropy method, but then, information about the critical exponents and about the critical temperature can be extracted. I will present a review of these methods and their limitations, together with some applications.\n\n
URL:https://www.lps.u-psud.fr/events/messio-2024/
ORGANIZER;CN=Andrej Mesaros:MAILTO:andrej.mesaros@universite-paris-saclay.fr
CATEGORIES:Séminaire de la Théorie de la Matière Condensée
LOCATION:Moyen amphi (LPS) + ONLINE (Zoom)
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