Random interactions and random fields in quantum dipolar systems

Anisotropic dipolar systems are ideal for the study of quantum phase transitions, as the weak magnetic dipolar interaction and the moderate anisotropy allow the induction of appreciable quantum fluctuations at applicable transverse magnetic fields. Furthermore, upon dilution, random interactions and effective random fields emerge, allowing the study of their interplay with quantum fluctuations in the ferromagnetic and spin glass phases. Here I will review some of the intriguing phenomena resulting from this interplay and from the uniqueness of the dipolar interaction, including the destruction of spin glass order at infinitesimal transverse field, a new type of Imry-Ma like disordering of the ferromagnetic phase, and recent results showing that an effective three body interaction is needed to account for the anomalous dependence of the critical ferromagnetic temperature on transverse field. Relevance to classical dipolar systems will be discussed.