Coupled-dimer magnets: Systematic expansions, quantum criticality, and disorder

Abstract: Coupled-dimer magnets have become model systems in the study of quantum phase transitions. After an introduction to quantum criticality, the talk will discuss various theoretical approaches to describe coupled-dimer magnets, using both field-theoretic and microscopic techniques, and link the results to experimental observations. In particular, a novel expansion in 1/d will be presented where d is spatial dimensionality. In addition, interesting phenomena arising from quenched disorder in coupled-dimer magnets will be highlighted, both for dilute and dense concentrations of defects.