Quantum thermalization and Floquet engineering in a spin ensemble with a clock transition

Abstract

Platforms that enable the study and control of quantum many-body interactions are fundamentally important in quantum science and related emerging technologies. Optically addressable solid-state spins offer scalability to a large Hilbert space but suffer from large on-site disorder and undesired couplings to the environment. Here we investigated a strongly interacting ensemble of millions of optically addressable ytterbium-171 ions in a crystal. This platform features a clock transition that is first-order insensitive to magnetic fluctuations, thus exhibiting superior coherence and small disorder. Notably, the clock transition also gives rise to pure spin-exchange interactions, realizing the dipolar XY model, which is difficult to access in other solid-state spin systems. We exploited this feature to investigate quantum thermalization by varying the relative ratio of interaction strength to disorder, dynamically engineering the XY model into other many-body Hamiltonian models and realizing a time-crystalline phase of matter through periodic driving. Our results demonstrated that an ensemble of rare earth ions serves as a versatile test bed for many-body physics and developing quantum technologies.