Quantum bright solitons in the Bose-Hubbard model with site-dependent repulsive interactions

Year: 2014

Authors: Barbiero L., Malomed BA., Salasnich L.

Autors Affiliation: Univ Padua, Dipartimento Fis & Astron Galileo Galilei, I-35131 Padua, Italy; Univ Padua, CNISM, I-35131 Padua, Italy; Tel Aviv Univ, Fac Engn, Sch Elect Engn, Dept Phys Elect, IL-69978 Tel Aviv, Israel; CNR, Ist Nazl Ott, Sez Sesto Fiorentino, I-50019 Sesto Fiorentino, Italy.

Abstract: We introduce a one-dimensional spatially inhomogeneous Bose-Hubbard model (BHM) with the strength of the onsite repulsive interactions growing, with the discrete coordinate z(j), as vertical bar z(j)vertical bar(alpha) with alpha > 0. Recently, the analysis of the mean-field (MF) counterpart of this system has demonstrated self-trapping of robust unstaggered discrete solitons, under the condition alpha > 1. By using the numerically implemented method of the density matrix renormalization group, we demonstrate that, in a certain range of the interaction, the BHM also features self-trapping of the ground state into a soliton-like configuration, at alpha > 1, and remains weakly localized at alpha < 1. An essential quantum feature found in the BHM is a residual quasi-constant density of the background surrounding the soliton-like peak in the ground state, while in theMF limit the finite-density background is absent. Very strong onsite repulsion eventually destroys soliton-like states, driving the system, at integer densities, into the Mott phase with a spatially uniform density. Journal/Review: PHYSICAL REVIEW A

Volume: 90 (6)      Pages from: 63611-1  to: 63611-6

More Information: The authors acknowledge partial support from the Universita a di Padova (Grant No. CPDA118083), the Cariparo Foundation (Eccellenza Grant 11/12), MIUR (PRIN Grant No. 2010LLKJBX). The visit of B.A.M. to the Universita di Padova was supported by the Erasmus Mundus EDEN Grant No. 2012-2626/001-001-EMA2. We thank M. Dalmonte for useful discussions.
KeyWords: Superfluid; Insulator; Gas
DOI: 10.1103/PhysRevA.90.063611

ImpactFactor: 2.808
Citations: 8
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