New study achieves major advance towards fault-tolerant quantum computing

A study, “Enhanced Majorana stability in a three-site Kitaev chain,” published in Nature Nanotechnology demonstrates significantly enhanced stability of Majorana zero modes (MZMs) in engineered quantum systems.

This research, conducted by a team from the University of Oxford, Delft University of Technology, Eindhoven University of Technology, and Quantum Machines, represents a major step towards fault-tolerant quantum computing.

Majorana zero modes (MZMs) are exotic quasiparticles that are theoretically immune to environmental disturbances that cause decoherence in conventional qubits. This inherent stability makes them promising candidates for building robust quantum computers. However, achieving sufficiently stable MZMs has been a persistent challenge due to imperfections in traditional materials.

The research team addressed this challenge by constructing a three-site Kitaev chain, a stepping stone towards topological superconductors. They used quantum dots coupled by superconducting segments in hybrid semiconductor-superconductor nanowires, allowing precise control of quantum states.

This three-site design provides a “sweet spot” where the MZMs are more spatially separated, reducing their interactions and enhancing their stability, which is a key advancement.

Dr. Greg Mazur (Department of Materials, University of Oxford), lead author of the study and formerly a quantum engineer at QuTech during the research period, stated, “Our findings are a key advancement, proving that scaling Kitaev chains not only preserves but enhances Majorana stability.

“I look forward to advancing this approach with my newly established research group at Oxford, aiming towards even more scalable quantum-dot platforms. The focus of my work at the Department of Materials will be to create artificial quantum matter through advanced nanodevices.”

The team anticipates that extending the chains will exponentially enhance stability, as the MZMs at the ends become increasingly isolated from environmental noise. This strongly motivates future explorations of larger quantum-dot arrays, crucial for practical quantum computing. This approach opens the door to creating entirely new materials with tailored quantum properties through precise device engineering.