Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 25: Correlated Electrons - Low-dimensional Systems: Models

TT 25.9: Vortrag

Dienstag, 8. März 2005, 12:00–12:15, TU H2053

Thermodynamics of a t–J chain with boundary impurities — •Guillaume Palacios and Holger Frahm — Institut für Theoretische Physik, Universität Hannover, D-30167 Hannover, Germany

We consider a supersymmetric t–J chain with integrable boundary impurities. Within the framework of the Quantum Inverse Scattering Method (QISM), these impurities are constructed by the combination of boundary fields with an integrable impurity [1]. The impurity site differs from the bulk chain by allowing double occupancy of the local orbitals. In addition to the boundary fields, that can be either a chemical potential or a magnetic field imposed at the ends of the chain, the model possesses two free parameters which allow to control the coupling between the Anderson-like impurity and the rest of the chain and the on-site interaction on the impurity site. It is of interest to mention that the latter can be tuned continuously without breaking the integrability of the model [2].

Starting from the Bethe Ansatz equations for the chain spectrum, our goal is to evaluate such impurities’ contribution to thermodynamics quantities like magnetic susceptibilities or electronic densities.

[1] G. Bedürftig and H. Frahm, J. Phys A32 (1999) 4585

[2] G. Bedürftig, F. H. L. Essler and H. Frahm, Nucl. Phys. B489 (1997) 697