Quantitative expression of the spin gap via bosonization for a dimerized spin-1/2 chain

Edmond Orignac (1)

1 LPTENS - Laboratoire de Physique Théorique de l'ENS [École Normale Supérieure]

Using results on the mass gap in the sine-Gordon model combined withthe exact amplitudes in the bosonized representation of the Heisenbergspin-1/2 chain and one-loop renormalization group, we derive aquantitative expression for the gap in a dimerized spin-1/2chain. This expression is shown to be in good agreement with recentnumerical estimates when a marginallyirrelevant perturbation is taken into account.

Mots clés: Gap de spin; échange alterné; sine-Gordon; bosonisation

Domaines: Electrons fortement corrélés [cond-mat.str-el]; Mécanique statistique [cond-mat.stat-mech]

Edmond Orignac. Quantitative expression of the spin gap via bosonization for a dimerized spin-1/2 chain. The European Physical Journal B: Condensed Matter and Complex Systems, 2004, 39, pp.335. ⟨10.1140/epjb/e2004-00198-5⟩. ⟨hal-00001248v2⟩