2007/05/31 by Joachim Brand, Sergej Flach, V. Fleurov +4
Computer Science · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Quantum Information and Cryptography #Quantum many-body systems #cond-mat.other #nlin.PS #quant-ph
paper · pdf · doi:10.1209/0295-5075/83/40002
published as Europhys. Lett., 83 (2008) 40002 · 6 pages, 4 figures; final published version with small changes in response to reviewer comments
openalex publication_date 2008/08/01 · arxiv created 2008/08/05 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
We study the localization of bosonic atoms in an optical lattice, which interact in a spatially confined region. The classical theory predicts that there is no localization below a threshold value for the strength of interaction that is inversely proportional to the number of participating atoms. In a full quantum treatment, however, we find that localized states exist for arbitrarily weak attractive or repulsive interactions for any number (>1) of atoms. We further show, using an explicit solution of the two-particle bound state and an appropriate measure of entanglement, that the entanglement tends to a finite value in the limit of weak interactions. Coupled with the non-existence of localization in an optimized quantum product state, we conclude that the localization exists by virtue of entanglement.