Universal Finite Temperature Properties of a Three Dimensional Quantum   Antiferromagnet in the Vicinity of a Quantum Critical Point
  We consider a 3-dimensional quantum antiferromagnet which can be driven through a quantum critical point (QCP) by varying a tuning parameter g. Starting from the magnetically ordered phase, the N{\'e}el temperature will decrease to zero as the QCP is approached. From a generic quantum field theory, together with numerical results from a specific microscopic Heisenberg spin model, we demonstrate the existence of universal behaviour near the QCP. We compare our results with available data for TlCuCl_3 
J. Oitmaa, Y. Kulik, and O. P. Sushkov
cond-mat.str-el