Long-Range Interactions

Locality is essential for our understanding of causality. The most striking consequence is that perturbations exhibit a maximum speed of propagation—this velocity defines a “light-cone” outside of which two regions of a system remain independent. However, long-range interactions are ubiquitous in nature; examples include the Coulomb force between electrons and the magnetic dipolar interaction between spins. Such interactions fundamentally alter how fast a perturbation can propagate and thus modify the shape of the light-cone. Furthermore, the faster growth of correlations across space suggests a path toward the efficient preparation of strongly-entangled quantum states. I am interested in understanding the structure of entanglement generated by long-range interactions and how this connects to the complexity of the underlying quantum dynamics.