Nonclassical correlations in a class of spin chains with longrange interactions and exactly solvable ground states
Abstract
We introduce a class of spin models with longrange interactions—in the sense that they extend significantly beyond their nearest neighbors—whose ground states can be constructed analytically and that have a simple matrix product state representation. This enables the detailed study of ground state properties, such as correlation functions and entanglement, in the thermodynamic limit. The spin models presented here are closely related to lattice gases of strongly interacting polar molecules, or Rydberg atoms that feature an excluded volume or blockade interaction. While entanglement is only present between spins that are separated by no more than a blockade length, we show that nonclassical correlations can extend much further, and we analyze them through quantum discord. We furthermore identify a set of seemingly critical points where the ground state approaches a crystalline state with a filling fraction that is given by the inverse of the blockade length. We analyze the scaling properties in the vicinity of this parameter region and show that the correlation length possesses a nontrivial dependence on the blockade length.
 Publication:

New Journal of Physics
 Pub Date:
 September 2014
 DOI:
 10.1088/13672630/16/9/093053
 arXiv:
 arXiv:1403.2866
 Bibcode:
 2014NJPh...16i3053L
 Keywords:

 Condensed Matter  Strongly Correlated Electrons;
 Physics  Atomic Physics;
 Quantum Physics
 EPrint:
 5 pages, 3 figures