Efficient online quantum gate set diagnosis by Fast-Bayesian Tomography*

To push the error rate closer to the threshold for fault-tolerate quantum computing, it is critical to characterise the gate error and fix them actively. Harnessed the power of Bayesian approach, Fast Bayesian Tomography (FBT) is a self-consistent process tomography technique, which is experimentally flexible and computationally efficient. In this work, we demonstrate the experimental approach of running the FBT online, which allows the model to be updated as experiment data obtained. Various improvements have been achieved to make the protocol even more efficient and experimentally low-cost. We are also showing the practical diagnosis applications of the FBT protocol on our 2 qubit system based on silicon quantum dots.