Quantum Correlations in a Few-Atom Spin-1 Bose-Hubbard Model
  We study the thermal quantum correlations and entanglement in spin-1 Bose-Hubbard model with two and three particles. While we use negativity to calculate entanglement, more general non-classical correlations are quantified using a new measure based on a necessary and sufficient condition for zero-discord state. We demonstrate that the energy level crossings in the ground state of the system are signalled by both the behavior of thermal quantum correlations and entanglement. 
B. \c{C}akmak, G. Karpat and Z. Gedik
quant-ph cond-mat.stat-mech