Topological defect formation and spontaneous symmetry breaking in ion Coulomb crystals

Symmetry breaking phase transitions play an important role in nature. When a system traverses such a transition at a finite rate, its causally disconnected regions choose the new broken symmetry state independently. Where such local choices are incompatible, topological defects can form. The Kibble–Zurek mechanism predicts the defect densities to follow a power law that scales with the rate of the transition. Owing to its ubiquitous nature, this theory finds application in a wide field of systems ranging from cosmology to condensed matter. Here we present the successful creation of defects in ion Coulomb crystals by a controlled quench of the confining potential, and observe an enhanced power law scaling in accordance with numerical simulations and recent predictions. This simple system with well-defined critical exponents opens up ways to investigate the physics of non-equilibrium dynamics from the classical to the quantum regime. The Kibble–Zurek mechanism describes the formation of topological defects in systems undergoing continuous phase transitions, and predicts a power law for their density. Pyka et al . create defects in ion coulomb crystals and observe their scaling behaviour in the context of the Kibble–Zurek theory.