Zero-temperature Kosterlitz-Thouless transition in a two-dimensional   quantum system
  We construct a local interacting quantum dimer model on the square lattice, whose zero-temperature phase diagram is characterized by a line of critical points separating two ordered phases of the valence bond crystal type. On one side, the line of critical points terminates in a quantum transition inherited from a Kosterlitz-Thouless transition in an associated classical model. We also discuss the effect of a longer-range dimer interactions that can be used to suppress the line of critical points by gradually shrinking it to a single point. Finally, we propose a way to generalize the quantum Hamiltonian to a dilute dimer model in presence of monomers and we qualitatively discuss the phase diagram. 
Claudio Castelnovo (1), Claudio Chamon (1), Christopher Mudry (2), and   Pierre Pujol (3). ((1) Boston University, (2) Paul ...