Mémoires de Fin d’Etudes
Etablissement
Université d’Oran1 - Ahmed Ben Bella
Affiliation
Département de Physique
Auteur
SI LAKHAL, Bahia
Directeur de thèse
ABADA A. (Professeur)
Filière
Physique
Diplôme
Doctorat
Titre
Dynamic correlation function in the heisenberg spin-12 antiferromagnetic mode
Mots clés
Quantum groups; XXZ Heisenberg model; Quantum spin chains; Quantum a¢ ne algebra; Dynamic correlation functions; Dynamic structure functions; Four spinon dynamic correlation function; Sum rules for the dynamic structure function.
Résumé
We derive the exact expression of the four-spinon contribution S4 to the dynamic correlation function S (DCF) of the spin-1/2 antiferromagnetic Heisenberg XXZ model using the quantum a¢ ne algebra symmetry present in the model. First, an exact expression for the n-spinon contribution is given in the form of contour integrals. After we display previous known results concerning the two-spinon contribution S2, we specialize the n-spinon formula to the case n = 4. An explicit series representation of this contribution in the isotropic limit is given and shown to be free from divergences.We then go to describe the behavior of the exact isotropic four-spinon DCF S4 as a function of the neutron energy ! and momentum transfer k. For this, Monte Carlo integration methods are used.
Date de soutenance
2006
Cote
TH2226
Pagination
XI-86F.
Format
30CM.
Notes
ABSTRACT.BIBLIOG.81-86F.ANNEXES.
Statut
Soutenue