Correlated metallic two-particle bound states in quasiperiodic chains
Max-Planck Institute for the Physics of Complex Systems - Nöthnitzer Str. 38, 01187 Dresden, Germany, EU
2 Theory of Oscillations Department, University of Nizhniy Novgorod - Nizhniy Novgorod, Russia
3 Physics Department, Tbilisi State University - Chavchavadze 3, 0128 Tbilisi, Georgia
Accepted: 25 May 2012
Single-particle states in a chain with quasiperiodic potential show a metal-insulator transition upon the change of the potential strength. We consider two particles with local interaction in the single-particle insulating regime. The two-particle states change from being localized to delocalized upon an increase of the interaction strength to a nonperturbative finite value. At even larger interaction strength the states become localized again. This transition of two-particle bound states into correlated metallic ones is due to a resonant mixing of the noninteracting two-particle eigenstates. In the discovered correlated metal states two particles move coherently together through the whole chain.
PACS: 67.85.-d – Ultracold gases, trapped gases / 37.10.Jk – Atoms in optical lattices / 03.65.Ge – Solutions of wave equations: bound states
© EPLA, 2012