In classical nonlinear systems, chaotic behavior is characterized by extreme sensitivity to initial conditions, leading to exponential divergence between systems starting from nearly identical states. In contrast, quantum systems typically exhibit quasiperiodic behavior due to the discrete nature of quantum mechanics. However, it is predicted that quantum systems with chaotic classical counterparts will also exhibit chaotic features.

Studying the emergence of chaotic behavior in quantum systems offers insights into the boundary between the quantum and classical realms. Moreover, quantum chaos is thought to play a significant role in fundamental physics topics such as decoherence [Paz1994] and the thermalization of isolated quantum systems [Deutsch1991]. Despite its importance, experimental studies of quantum chaos remain [Hensinger2001, Steck2001, Chaudhurry2009, Manai2015, Neill2016], with no experiments to date observing a single quantum-mechanical degree of freedom in real time.

We plan to use the 7/2 nuclear spin of a single antimony donor in silicon to implement a quantum-mechanical analogue of a classically chaotic system, known as the driven top [Mourik2017]. By utilizing the recently developed infrastructure for full control over the 7/2 antimony spin system [Assad2020, Fuentes2024, Yu2024], we aim to conduct the first experimental study of quantum chaos in a single quantum system. The antimony nucleus's long coherence times will enable us to explore these dynamics over unprecedented timescales.