title: Quantum spin glass and the dipolar interaction.
abstract: Anisotropic dipolar systems are considered. Such systems in an external magnetic field are expected to be a good experimental realization of the transverse field Ising model. With random interactions, this model yields a spin glass to paramagnet phase transition as a function of the transverse field. We show that the off-diagonal dipolar interaction, although effectively reduced, induces a finite correlation length and thus destroys the spin-glass order at any finite transverse field. We thus explain the behavior of the nonlinear susceptibility in the experiments on LiHo(x)Y(1-x)F(4), and argue that a crossover to the paramagnetic phase, and not quantum criticality, is observed.
authors.affiliation: Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, V6T 1Z1.
authors.forename: Moshe
authors.initials: M
authors.lastname: Schechter
authors.forename: Nicolas
authors.initials: N
authors.lastname: Laflorencie