This thesis presents an exact theoretical study of dynamical correlation functions in different phases of a two-dimensional quantum spin liquid. By calculating the dynamical spin structure factor and the Raman scattering cross section, this thesis shows that there are salient signatures-qualitative and quantitative-of the Majorana fermions and the gauge fluxes emerging as effective degrees of freedom in the exactly solvable Kitaev honeycomb lattice model. The model is a representative of a class of spin liquids with Majorana fermions coupled to Z2 gauge fields. The qualitative features of the response functions should therefore be characteristic for this broad class of topological states.

This thesis presents an exact theoretical study of dynamical correlation functions in different phases of a two-dimensional quantum spin liquid. By calculating the dynamical spin structure factor and the Raman scattering cross section, this thesis shows that there are salient signatures-qualitative and quantitative-of the Majorana fermions and the gauge fluxes emerging as effective degrees of freedom in the exactly solvable Kitaev honeycomb lattice model. The model is a representative of a class of spin liquids with Majorana fermions coupled to Z2 gauge fields. The qualitative features of the response functions should therefore be characteristic for this broad class of topological states.

Migration is in the news every day. Whether it be the plight of refugees fleeing Syria, or the outbreak of the Zika virus across Latin America, the modern world is fundamentally shaped by movement across borders. Migration, arising from the 2018 Darwin College Lectures, brings together eight leading scholars across the arts, humanities, and sciences to help tackle one of the most important topics of our time. What is migration? How has it changed the world? And how will it shape the future? The authors approach these questions from a variety of perspectives, including history, politics, epidemiology, and art. Chapters related to policy, as well as those written by leading journalists and broadcasters, give perspective on how migration is understood in the media, and engage the public more widely. This interdisciplinary approach provides an original take on migration, providing new insights into the making of the modern world.