Robust Spin Polarization by Adiabatic Dynamical Decoupling

TL;DR

This paper demonstrates a robust adiabatic pulsed nuclear spin polarization method in diamond, improving efficiency and tolerance over traditional protocols, with potential benefits for quantum sensing and memory.

Contribution

The authors introduce an adiabatic pulsed DNP protocol that enhances polarization efficiency and robustness in diamond-based quantum systems, overcoming limitations of diabatic methods.

Findings

Achieved room-temperature adiabatic nuclear spin polarization in diamond.

Enhanced polarization efficiency and broader resonance window.

Improved robustness to hyperfine coupling uncertainties.

Abstract

High-fidelity multi-qubit initialization is vital for quantum simulation, quantum information processing (QIP), and quantum sensing. In diamond platforms, nuclear spin registers can be initialized through polarization transfer from a nearby electronic spin whose high gyromagnetic ratio enables efficient dynamical nuclear polarization (DNP). These hybrid systems are typically controlled using diabatic spin rotations, which require precise knowledge of all system parameters. Adiabatic DNP protocols on the other hand have less strict requirements and could enable robust and high fidelity spin transfer. However, due to the slow adiabatic sweeps and limited electron spin coherence times, this approach has remained inaccessible. Here, we demonstrate adiabatic pulsed nuclear spin polarization at room temperature in diamond. We achieve enhanced polarization efficiency, a broad resonance window, and improved tolerance to hyperfine coupling uncertainties relative to conventional diabatic pulsed protocols. We also show how this approach can benefit the initialization of spin clusters. These results set the scene for enhanced qubit initialization in solid state through adiabatic pulsed driving, with applications in solid-state quantum sensor and quantum memory technologies.