title: The spin-partitioned total position-spread tensor: An application to Heisenberg spin chains.
abstract: The spin partition of the Total Position-Spread (TPS) tensor has been performed for one-dimensional Heisenberg chains with open boundary conditions. Both the cases of a ferromagnetic (high-spin) and an anti-ferromagnetic (low-spin) ground-state have been considered. In the case of a low-spin ground-state, the use of alternating magnetic couplings allowed to investigate the effect of spin-pairing. The behavior of the spin-partitioned TPS (SP-TPS) tensor as a function of the number of sites turned to be closely related to the presence of an energy gap between the ground-state and the first excited-state at the thermodynamic limit. Indeed, a gapped energy spectrum is associated to a linear growth of the SP-TPS tensor with the number of sites. On the other hand, in gapless situations, the spread presents a faster-than-linear growth, resulting in the divergence of its per-site value. Finally, for the case of a high-spin wave function, an analytical expression of the dependence of the SP-TPS on the number of sites n and the total spin-projection Sz has been derived.
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Fertitta
authors.affiliation: Laboratoire de Chimie et Physique Quantiques-LCPQ/IRSAMC, Université de Toulouse (UPS) et CNRS (UMR-5626), 118 Route de Narbonne, Toulouse Cedex 31062, France.
authors.forename: Muammar
authors.initials: M
authors.lastname: El Khatib
authors.affiliation: Dipartimento di Chimica Industriale "Toso Montanari," Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy.
authors.forename: Gian Luigi
authors.initials: GL
authors.lastname: Bendazzoli
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany.
authors.forename: Beate
authors.initials: B
authors.lastname: Paulus
authors.affiliation: Laboratoire de Chimie et Physique Quantiques-LCPQ/IRSAMC, Université de Toulouse (UPS) et CNRS (UMR-5626), 118 Route de Narbonne, Toulouse Cedex 31062, France.
authors.forename: Stefano
authors.initials: S
authors.lastname: Evangelisti
authors.affiliation: Laboratoire de Chimie et Physique Quantiques-LCPQ/IRSAMC, Université de Toulouse (UPS) et CNRS (UMR-5626), 118 Route de Narbonne, Toulouse Cedex 31062, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Leininger