arXiv subjects

H. B. van Ommen

Publications and source records attributed to H. B. van Ommen.

3 recordsLinked to original sources

arXiv2026

Two-qubit cryo-CMOS control of a spin register in diamond

Utility-scale quantum technologies will not only require a well-performing quantum platform, but also classical control hardware that is scalable, efficient, and meets the design requirements set by the quantum system of interest. One approach is the application of silicon CMOS technology, a highly scalable and mature technology, to design application-specific integrated circuits (ASIC) that are optimized for the quantum system. In this work, we present two-qubit control of electron and nuclear spins in NV centres in diamond, using a cryogenic CMOS qubit controller integrated with a diamond quantum device in a cryostat. Using Gate Set Tomography (GST) we characterize the performance of the single-qubit gates on both electron- and carbon nuclear spins, and analyze the limiting noise processes. We use dynamical decoupling to engineer a two-qubit gate, and estimate $F_\text{2q,avg} = 95(2)\%$ for the electron-nuclear two-qubit gate fidelity. Our demonstration of cryo-CMOS-driven two-qubit gates is a key step towards highly-integrated quantum devices based on colour centres.

quant-ph↗

arXiv2024

Improved Electron-Nuclear Quantum Gates for Spin Sensing and Control

The ability to sense and control nuclear spins near solid-state defects might enable a range of quantum technologies. Dynamically Decoupled Radio-Frequency (DDRF) control offers a high degree of design flexibility and long electron-spin coherence times. However, previous studies considered simplified models and little is known about optimal gate design and fundamental limits. Here, we develop a generalised DDRF framework that has important implications for spin sensing and control. Our analytical model, which we corroborate by experiments on a single NV center in diamond, reveals the mechanisms that govern the selectivity of gates and their effective Rabi frequencies, and enables flexible detuned gate designs. We apply these insights to numerically show a 60x sensitivity enhancement for detecting weakly coupled spins and study the optimisation of quantum gates in multi-qubit registers. These results advance the understanding for a broad class of gates and provide a toolbox for application-specific design, enabling improved quantum control and sensing.

quant-ph↗

arXiv2024

Universal high-fidelity quantum gates for spin-qubits in diamond

Spins associated to solid-state colour centers are a promising platform for investigating quantum computation and quantum networks. Recent experiments have demonstrated multi-qubit quantum processors, optical interconnects, and basic quantum error correction protocols. One of the key open challenges towards larger-scale systems is to realize high-fidelity universal quantum gates. In this work, we design and demonstrate a complete high-fidelity gate set for the two-qubit system formed by the electron and nuclear spin of a nitrogen-vacancy center in diamond. We use gate set tomography (GST) to systematically optimise the gates and demonstrate single-qubit gate fidelities of up to $99.999(1)\%$ and a two-qubit gate fidelity of $99.93(5) \%$. Our gates are designed to decouple unwanted interactions and can be extended to other electron-nuclear spin systems. The high fidelities demonstrated provide new opportunities towards larger-scale quantum processing with colour-center qubits.

quant-ph↗