Two-body bound and edge states in the extended SSH Bose-Hubbard model

Year: 2017

Authors: Di Liberto M., Recati A., Carusotto I., Menotti C.

Autors Affiliation: Univ Trento, INO CNR BEC Ctr, I-38123 Povo, Italy; Univ Trento, Dipartimento Fis, I-38123 Povo, Italy; Ludwig Maximilians Univ Munchen, Arnold Sommerfeld Ctr Theoret Phys, D-80333 Munich, Germany

Abstract: We study the bosonic two-body problem in a Su-Schrieffer-Heeger dimerized chain with on-site and nearest-neighbor interactions. We find two classes of bound states. The first, similar to the one induced by on-site interactions, has its center of mass on the strong link, whereas the second, existing only thanks to nearest-neighbor interactions, is centered on the weak link. We identify energy crossings between these states and analyse them using exact diagonalization and perturbation theory. In the presence of open boundary conditions, novel strongly-localized edge-bound states appear in the spectrum as a consequence of the interplay between lattice geometry, on-site and nearest-neighbor interactions. Contrary to the case of purely on-site interactions, such EBS persist even in the strongly interacting regime.

Journal/Review: EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS

Volume: 226 (12)      Pages from: 2751  to: 2762

More Information: A.R. acknowledges support from the Alexander von Humboldt foundation and W. Zwerger for the kind hospitality at the TUM. This work was supported by the EU-FET Proactive grant AQuS, Project No. 640800 and by Provincia Autonoma di Trento, partly through the project SiQuro.
KeyWords: SSH Model, Few Body Physics, Topological states
DOI: 10.1140/epjst/e2016-60388-y

Citations: 18
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