Quantinuum has demonstrated an important breakthrough toward building scalable, fault-tolerant quantum computers. Quantum machines are normally extremely error-prone because their qubits are highly unstable, producing frequent mistakes that limit their usefulness. To overcome this, researchers use quantum error correction, where many physical qubits work together to form one more reliable “logical” qubit. A universal quantum computer must perform both Clifford and non-Clifford gates, but the latter require special “magic states,” which were previously very costly to create. Using their trapped-ion H1-1 processor, Quantinuum researchers efficiently produced two high-fidelity magic states using only eight physical qubits and successfully executed a non-Clifford gate with a logical error rate ten times lower than the physical error rate. This is the first time a universal quantum circuit has performed better with encoding than without it. Simulations indicate that future improvements could reduce error rates to as low as a few mistakes per trillion operations. In a separate experiment with the 56-qubit H2-1 processor, the team also demonstrated “code switching,” shifting between different error-correcting codes to take advantage of each code’s strengths. Together, these advances show promising progress toward a practical, large-scale quantum computer by 2029.
Read more-https://spectrum.ieee.org/quantinuum-fault-tolerant-quantum-computing