Dynamic locking of an interacting spin system via periodic driving

TL;DR

This paper demonstrates how detuning and pulse structuring in periodic driving can dynamically lock interacting spin systems, enabling advanced control methods for quantum sensing and energy transfer.

Contribution

It introduces offset-induced dynamic locking in dipolar spin ensembles, supported by a semi-analytical framework, experiments, and AI-assisted sequence design, extending control beyond traditional methods.

Findings

Offset and pulse structure generate a structured effective Rabi field.

Reversible interconversion of Zeeman and dipolar order achieved.

AI-assisted sequences enable control in regimes where average Hamiltonian theory fails.

Abstract

Periodic driving plays a central role in quantum control, but its application in interacting spin systems is often restricted to near-resonant conditions, where standard averaging techniques remain valid. Here we investigate how detuning from resonance can be used to dynamically spin-lock a dipolar-coupled ensemble. We show that the combination of offset and pulse structure generates an effective Rabi field with sharply structured amplitude and tilt. This behavior - supported by a semi-analytical framework, numerical simulations and experiment - enables new approaches to many-body system control, here exemplified via offset-induced reversible interconversion of Zeeman and dipolar order, and heterospin polarization transfer away from rf-field matching conditions. Further, we leverage artificial-intelligence-assisted sequence design to explore regimes with long control cycles - where average Hamiltonian theory breaks down, but effective locking persists - opening pathways to rich offset-dependent responses. These findings position offset-enabled dynamic locking as a promising tool for quantum sensing, energy transfer, and spin-order manipulation beyond traditional approaches.