The high accuracy is well beyond the fidelity threshold needed to implement error correction codes and the architecture can be deployed in large scale systems too.
Previous work in quantum computing has used transmon qubits. However, more recently, fluxonium qubits have gained popularity since they have longer coherence times when compared to transmons.
Coherence is how long a qubit can un algorithms before all the information is lost. Fluxonium qubits have demonstrated more than a millisecond coherence times, but these are 10 times longer than the transmons. The longer a qubit remains coherent, the greater the fidelity or accuracy of the quantum operation at the gates. A gate is a logical operation performed using one or more qubits.to reduce error rates.
Artist's illustration of FTF architecture with the fluxonium qubits in red and the blue, transmon coupler in between them.In their experiments, the researchers demonstrated 99.99 percent computation accuracy when using a single-qubit gate and 99.9 percent accuracy when using a two-qubit gate. These fidelities are much higher than the threshold for error-correcting codes and can be used in large-scale systems.
The FTF architecture plays a vital role in these scores since it minimizes unwanted interactions in the background during quantum computation. As couplings get more substantial, background noise in the system becomes more persistent and is referred to as ZZ interactions by scientists. The FTF architecture helped in overcoming this problem.
“This work pioneers a new architecture for coupling two fluxonium qubits. The achieved gate fidelities are not only the best on record for fluxonium but also on par with those of transmons, the currently dominating qubit", said Chunqing Deng, head of the experimental quantum team at the Quantum Laboratory of DAMO Academy, Alibaba’s global research institution in the press release.