# Groupe de Physique Statistique

## Equipe 106, Institut Jean Lamour

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### Séminaire de groupe

 Modified Bethe Ansatz for models without $U(1)$ symmetry Samuel Belliard Equipe 106, Institut Jean Lamour jeudi 14 décembre 2017 , 10h25 Salle de séminaire du groupe de Physique Statistique We present a modified version of the algebraic Bethe ansatz (MABA) that allows to characterize the eigenvalues and the eigenstates of spins chains without $U(1)$ symmetry. In the case of the XXX Heisenberg spin chain on the circle with a twisted boundary condition, the Bethe vectors and associated eigenvalues will be constructed and for some special cases, the scalar product of these Bethe vectors will be conjectured [Belliard, Pimenta (2013)].