Scientists Build a Three-Qubit Quantum Register Using Graphene-Based Molecules
Scientists at RWTH Aachen University have engineered a molecule that mimics a three-qubit quantum register. The breakthrough involves rearranging radical components within a graphene-based structure called aza-triangulene. Their findings, published in Nature Chemistry in 2025, could pave the way for scalable quantum computing technologies.
The research team, led by Nikos Chouaib, included David Zsolt Verli and Manuel A. Mosquera Loira among others. Their work focuses on modifying graphene nanoribbons to exhibit unique magnetic and electronic properties.
The project began with chemical reactions in solution, followed by on-surface dehydrogenation to form extended aza-triangulene platforms. By introducing nitrogen atoms into the graphene structure, the team altered its electronic properties and induced magnetism. This modification revealed magnetic ground states and the potential for spin-polarised arrangements.
To confirm the formation of aza-triangulene, the researchers used advanced microscopy techniques. Low-bias tunnelling spectroscopy then helped investigate the molecule’s magnetic behaviour. Under applied magnetic fields, measurements showed a spin-1/2 ground state, while electron density maps demonstrated a delocalised Kondo effect across the entire molecular platform.
The molecule itself is a frustrated antiferromagnetic triradical, featuring weakly coupled spins. These properties make it a promising candidate for future quantum technologies. The team also employed density functional theory and multireference configuration interaction to model electron behaviour within the material.
By extending a single-radical molecule with anthene units, the scientists induced a transition to a correlated spin system. This reconfiguration resulted in a unique magnetic arrangement, resembling a three-qubit quantum register. Such structures could serve as molecular analogues of multi-qubit quantum registers, offering a scalable path for quantum computing applications.
The study provides a detailed method for creating and analysing aza-triangulene-based quantum structures. The molecule’s spin properties and magnetic configuration open possibilities for developing advanced quantum technologies. The findings mark a step toward practical, scalable quantum computing systems using graphene-derived materials.
