Cyclicity of interaction frame transformations

TL;DR

This paper uncovers a cyclic property of rotation sequences in three dimensions, showing that certain sequences return to their original state after multiple transformations, unifying various quantum control methods.

Contribution

It introduces a new cyclicity property of interaction frame transformations, linking quantum control sequences across different technologies and connecting to polyhedral symmetry models.

Findings

Sequences with $eta=2 ext{pi}/m$ return to original after m transformations.

Duality between narrowband and broadband $ ext{pi}$-element sequences.

New sequences derived for spin control and decoupling applications.

Abstract

We identify a cyclic property of rotation sequences involving piecewise displacements $\beta$ about arbitrary axes in three dimensions. Specifically, when transformation to the toggling frame is applied successively $m$ times, for $\beta=2\pi/m$ the original sequence returns. This main result unites several families of rotation sequences used for error-tuned control across quantum technologies, from NMR and MRI to atomic clocks and atom-scale computing. For the widest class of cycle, $m=2$, we highlight sequence duality where every narrowband $\pi$-element sequence has a broadband $\pi$-element counterpart, and vice-versa. Higher cycles ($m>2$) connect to polyhedral models for error-tolerant sequence design, characterized by vertex axes with $m$-fold rotational symmetry. We derive original sequences and outline their applications to spin control and spin decoupling.