Quantinuum Sets a New Record for Quantum Volume

Chart Showing Quantinuum's Progress in Improving Its Quantum Volume Metric. Credit: Quantinuum

Quantinuum has increased their previous Quantum Volume (QV) record of 8,192 by a factor of 4 and now has demonstrated a QV of 32,768 (215) on their H1-1 ion trap quantum processor. This would represent a quantum circuit of 15 qubits with a gate depth of 15. The QV measure was developed by IBM to come up with a quantum processor metric that combines not only qubit count, but also qubit quality and other factors. Although it is not the only metric out that has been proposed to measure the goodness of a processor, it is thoroughly specific and would be hard to game by creating special software or hardware specifically to look good on this metric.

The Quantinuum team has continued to improve the performance of their H1 processor for a few years. The limiter is not the number of total qubits available, but rather the quality of those qubits as measured by factors such as single qubit fidelity, two qubit gate fidelity, and state preparation and measurement (SPAM) fidelity. These latest improvements came about due to reduction in the phase noise of the lasers as well as improvements in memory error rates and the calibration process. This requires a lot of attention to detail across all levels of the system. At the same time, along with the improvements in quantum volume, Quantinuum also reported excellent fidelity measurements including 99.9955(8)% for single qubit gate fidelity, 99.795(7)% for two-qubit gate fidelity and 99.69(4)% for SPAM.

The Quantinuum team will continue to work on additional improvements on the H1 processors and hopes to achieve QV measures of 65,536 (216) and possibly even 131,072 (217) later this year. The chip in the H1 can contain up to 20 qubits so a QV exceeding 1,000,000 (220) might be possible if noise and gate errors were not a constraint. However, these probably will be issues with the H1, but we should remind you Quantinuum has also been working on a more advanced H2 processor which may allow them to continue making progress once the H1 processor hits its technical limits.

For more about Quantinuum's new QV record, you can see the a news release posted on their website here and a more detailed blog posting that discusses it here.

February 23, 2023