Coherent control, state preparation, and readout have been achieved with a fully connected triangular exchange-only semiconductor triple quantum dot device using SpinQICK, an open-source spin qubit-control package built on Xilinx RFSoC technology. SpinQICK is an affordable and flexible system for controlling qubits, introducing a new dynamical decoupling sequence designed to characterise electrical noise from the control electronics. These advances provide a pathway towards hardware optimisation through detailed analysis of qubit behaviour.

An open-source software package, SpinQICK, allows greater precision when controlling tiny quantum components called triple quantum dots; these structures represent potential building blocks for future computers. SpinQICK uses affordable technology by utilising Xilinx RFSoC hardware alongside the Quantum Instrumentation Control Kit.

This system provides tools to identify and reduce errors within devices, aiding in the creation of stable and scalable quantum technologies through accessible software and improved diagnostics. Like bits in a regular computer, but instead of being ‘on’ or ‘off’, spin qubits exist in a combination of both states simultaneously, these tiny elements require sophisticated control systems.

To achieve this, the team used Xilinx RFSoC technology, essentially a powerful audio interface handling extremely fast signals, alongside existing Quantum Instrumentation Control Kit tools. A key innovation is a new method for shielding delicate quantum information from disruptive electrical interference, functioning much like noise-cancelling headphones. This establishes an affordable and flexible platform for controlling these devices, opening avenues to optimise hardware through detailed analysis of qubit behaviour; but can this system truly unlock scalable quantum technologies given the inherent challenges of maintaining coherence.

Extended Coherence Enables Precise Quantum Dot Control Across Multiple Axes

This breakthrough unlocks precise manipulation of electron spins within semiconductor triple quantum dots, a key requirement for scalable quantum computers previously hindered by inflexible control systems. Using SpinQICK, an open-source qubit control package built on Xilinx Radio Frequency System-on-Chip technology, researchers achieved these extended coherent exchange oscillations along the J13 axis at 74.8MHz.

Precise manipulation relies upon dynamical decoupling (DD) sequences like NZM1; this sequence fully decouples hyperfine noise while retaining sensitivity to low frequency charge fluctuations, enabling detailed characterisation of voltage noise from control electronics.

Combining measurements using both NZ1 and NZM1 DD techniques allowed quantification of high-frequency white noise alongside drift within the experimental setup. The drive to build practical quantum computers demands new qubit designs *and* tools to control them, with semiconductor triple-quantum dots offering a promising route towards scalability despite long-standing limitations in accessible hardware. SpinQICK directly addresses these limitations by leveraging readily available Xilinx technology, though reliance on existing Quantum Instrumentation Control Kit tools may introduce bottlenecks as systems grow more complex.

Acknowledging potential scaling issues is sensible; building increasingly complex quantum processors will demand further optimisation for larger architectures. Nevertheless, this system represents a step forward, providing an adaptable platform for researchers working with semiconductor triple-quantum dots and their promise of scalable qubits. This open-source approach lowers barriers to entry and enables rapid prototyping of new designs. The development of SpinQICK provides a novel means to manipulate electron spins within semiconductor triple quantum dots, structures considered promising building blocks for future quantum computers. Detailed characterisation of noise at the qubit level becomes possible through its use, opening avenues towards targeted hardware improvements and optimisation beyond achieving extended coherence times via introduction of a dynamical decoupling sequence that actively shields qubits from electrical interference originating in control electronics themselves.

This research demonstrated coherent control and readout of a triangular exchange-only device using an accessible, open-source spin qubit-control package called SpinQICK built on Xilinx technology. This system enables precise voltage control needed to manipulate electron spins within semiconductor triple-quantum dots, materials being explored as scalable components for potential quantum computing architectures.

The researchers also introduced a new method for characterizing electrical noise affecting the qubits by leveraging unique properties of their triangular design and implementing a specific dynamical decoupling sequence (NZM1). These results establish SpinQICK as a flexible platform that allows detailed analysis of hardware limitations at the qubit level, informing future optimization efforts.

👉 More information
🗞 Demonstrating RFSoC-based Control of a Fully Connected Exchange-Only Qubit
✍️ Joseph D. Broz, Alen Senanian and Andrew E. Oriani (Affiliation: HRL Laboratories); Abigail L. Wessels and M. Garrett Bimstefer
🧠 ArXiv: https://arxiv.org/abs/2610.31998

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