FAMU-FSU College of Engineering designs qubit with floating electrons above chip

Researchers at the FAMU-FSU College of Engineering have designed a novel qubit architecture that suspends quantum information using magnetic levitation. The team utilizes superconducting loops to hold tiny neon particles aloft, addressing the problem of electron instability caused by imperfections on qubit surfaces.

“Instead of hoping that the right nanoscale feature appears in the right place, we want to decide where each electron qubit sits,” explains study co-author Wei Guo, a professor at Florida State University, the FAMU-FSU College of Engineering and the National High Magnetic Field Laboratory. Published in PRX Quantum, the research details a path toward building more reliable and scalable quantum computers by engineering qubit placement by design.

Magnetic Levitation Addresses Electron Trapping in Neon Qubit Devices

Superconducting loops now suspend individual neon particles in a novel qubit architecture developed by researchers, directly addressing the issue of electron trapping caused by surface imperfections. This innovative approach moves beyond relying on chance nanoscale features and instead allows for the deliberate placement of electron qubits, a strategy co-author Wei Guo describes as a shift from chance to design. Instead of directly depositing solid neon onto a chip, where inherent surface roughness can disrupt electron behavior, the researchers propose levitating nearly spherical neon microparticles above the chip’s surface.

This levitation is achieved through the application of magnetic fields generated by superconducting loops integrated into the chip design; the chip itself still houses the necessary microwave circuitry for qubit control and readout. “Magnetic levitation gives us a way to place a clean neon carrier above the chip, while the chip still provides the circuitry needed to control and read the qubit,” Guo explained. This method effectively creates a clean environment for electrons, as described by co-author Yinghe Qi of the National High Magnetic Field Laboratory, minimizing interference from surface irregularities.

The core advantage of this design lies in its reproducibility, a critical hurdle in scaling quantum computing technologies. Current electron-on-neon qubits often depend on random nanoscale surface features to confine electrons, leading to unpredictable behavior and limiting the potential for large-scale arrays.

Yiming Xing, an assistant professor in the FAMU-FSU College of Engineering, emphasized that this approach “replaces those random traps with designed, clean neon carriers placed at intended locations on a chip.” This deliberate placement promises to reduce unwanted charge noise and enhance the stability of individual qubits. The researchers demonstrated that the essential components for this architecture, superconducting loops, microwave resonators, and patterned chip structures, are compatible with existing quantum device fabrication techniques.

This compatibility is expected to accelerate the transition from theoretical design to a functional prototype. “We have not built a full quantum computer in this paper, but we showed that the essential ingredients can work together in a realistic design: clean electron confinement, tunable qubit energy levels, strong coupling to microwave circuits and a way for neighboring qubits to communicate,” Guo stated, outlining the key elements successfully integrated in their model. The team is now focused on constructing a working prototype to validate the design and further explore its potential for scalable quantum computation.