Yale Scientists Achieve Quantum Breakthrough: Niobium Cavities with Q Factor Over 3 × 10^9
Scientists at Yale University have made a significant breakthrough in quantum technology. They've developed a precise method to fabricate and characterise high-quality niobium cavities, crucial for quantum applications. The team, led by Takaaki Takenaka, Takayuki Kubo, and Imran Mahoob, has achieved an extraordinary internal quality factor of over 3 × 10^9, accessible at the single-photon level below 20 millikelvin.
The key to this success lies in a novel mid-temperature annealing process. This process creates a stable, low-loss oxide layer on the cavity surface, minimising energy loss. The team demonstrated a 3D niobium coaxial cavity with exceptionally low energy loss, reaching the single-photon level below 20 millikelvin. This breakthrough is a result of exploring the fundamental limits of superconducting radio frequency (SRF) cavities and understanding 'Q disease' and flux penetration mechanisms.
The cavity maintains its performance even after repeated use and exposure to air. Researchers are now exploring the use of alternative materials and optimising surface treatments to further improve superconducting cavity performance.
This advancement paves the way for longer coherence times in quantum circuits. With an internal quality factor exceeding 3 × 10^9 at the single-photon level and millikelvin temperatures, these niobium cavities bring us closer to practical quantum technologies. The team's work continues, aiming to push the boundaries of superconducting cavity performance.
