Dresden 2003 – scientific programme

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TT: Tiefe Temperaturen

TT 22: Metall-Isolator-Überg
änge in Quantensystemen II

TT 22.5: Talk

Friday, March 28, 2003, 11:15–11:30, HSZ301

Multiple umklapp scattering driven instabilities in one-dimensional systems — •Peter Schmitteckert and Ralph Werner — Institut für Theorie der Kondensierten Materie, Universität Karlsruhe, 76128 Karlsruhe, Germany

The relevance of umklapp scattering terms in one-dimensional systems with commensurate filling has long been established. The ground state of those systems is ordered with an excitation gap above the ground state.

We show that the concept of umklapp scattering driven instabilities in one-dimensional systems can be generalized to arbitrary multiple umklapp scattering processes at commensurate fillings given that the system has sufficiently longer ranged interactions. Field theoretical approaches have to be extended to include lattice effects in order to describe the instabilities correctly.

To this end we study the fundamental model system, namely interacting spinless Fermions on an one-dimensional lattice, using the density matrix renormalization group approach. The instabilities are investigated using a new approach allowing to calculate the ground state curvature with high accuracy.