Emergence and Frustration of Magnetism with Variable-Range Interactions in a Quantum Simulator

Magnetic Frustration The study of magnetic frustration has a long history in solid-state physics, but cold-atom systems now offer the possibility of simulating the problem with exquisite control. Islam et al. (p. 583) study a system of 16 trapped ions, using the Coulomb interactions between the ions to simulate exchange interactions present in magnetic systems. The measured spin correlations provide a window into the behavior of the system, as the effective magnetic field and the range of the interactions are tuned. Coulomb interactions in a system of 16 trapped ions are used to simulate magnetism with varying degrees of frustration. Frustration, or the competition between interacting components of a network, is often responsible for the emergent complexity of many-body systems. For instance, frustrated magnetism is a hallmark of poorly understood systems such as quantum spin liquids, spin glasses, and spin ices, whose ground states can be massively degenerate and carry high degrees of quantum entanglement. Here, we engineer frustrated antiferromagnetic interactions between spins stored in a crystal of up to 16 trapped 171Yb+ atoms. We control the amount of frustration by continuously tuning the range of interaction and directly measure spin correlation functions and their coherent dynamics. This prototypical quantum simulation points the way toward a new probe of frustrated quantum magnetism and perhaps the design of new quantum materials.