Singapore scientists achieve 95% fidelity in quantum computing breakthrough
Researchers at the National University of Singapore have made a significant breakthrough in quantum computing. A team led by Adrian Copetudo has developed a new method to directly entangle microwave photons, achieving a controlled-phase (CZ) gate with over 95% fidelity. This advance brings practical, fault-tolerant bosonic quantum computing a step closer to reality.
The team engineered a Raman-assisted cross-Kerr interaction between microwave photons inside superconducting cavities. Unlike previous techniques, this approach avoids exciting an ancillary nonlinear element, preserving photon numbers and maintaining coherence. The result is a CZ gate with average infidelity as low as 2.6% and 3%, a marked improvement over earlier methods.
Traditional parametric activation often introduced unwanted dissipation and decoherence, complicating error correction. The new method, however, operates entirely within the bosonic code space, preventing excursions that could disrupt quantum computations. This compatibility with error correction protocols makes it particularly valuable for scalable quantum systems. Parity checks—critical for detecting errors—were implemented using purely bosonic interactions. This innovation paves the way for fully contained bosonic quantum error correction schemes, enhancing the stability of future quantum processors. The breakthrough also expands the capabilities of bosonic circuit electrodynamics, offering a coherence-preserving pathway for photon-photon interactions.
The achievement marks a key step toward advanced quantum information processing. By improving gate fidelity and reducing decoherence, the method strengthens the foundation for robust, fault-tolerant quantum computing. Further development could lead to more efficient and reliable quantum systems in the future.
