By making small adjustments to the frequency that the qubits are operating at, it’s possible to avoid these problems. This could be done when the Heron chip is being calibrated before it’s opened for general use.
Individually, the corporate has done a rewrite of the software that controls the system during operations. “After learning from the community, seeing the way to run larger circuits, [we were able to] almost higher define what it needs to be and rewrite the entire stack towards that,” Gambetta said. The result’s a dramatic speed-up. “Something that took 122 hours now’s all the way down to a few hours,” he told Ars.
Since individuals are paying for time on this hardware, that is good for purchasers now. Nonetheless, it could also repay within the longer run, as some errors can occur randomly, so less time spent on a calculation can mean fewer errors.
Deeper computations
Despite all those improvements, errors are still likely during any significant calculations. While it continues to work toward developing error-corrected qubits, IBM is specializing in what it calls error mitigation, which it first detailed last yr. As we described it then:
“The researchers turned to a way where they intentionally amplified after which measured the processor’s noise at different levels. These measurements are used to estimate a function that produces similar output to the actual measurements. That function can then have its noise set to zero to provide an estimate of what the processor would do with none noise in any respect.”
The issue here is that using the function is computationally difficult, and the problem increases with the qubit count. So, while it’s still easier to do error mitigation calculations than simulate the quantum computer’s behavior on the identical hardware, there’s still the danger of it becoming computationally intractable. But IBM has also taken the time to optimize that, too. “They have algorithmic improvements, and the tactic that uses tensor methods 1731913835 uses the GPU,” Gambetta told Ars. “So I believe it’s a mix of each.”
