Amping up quantum computing technologies

Quantum computing can process information more rapidly than traditional methods, but these technologies cannot currently scale up to process higher loads of information in a cost-efficient and simple manner. Tholén et al. developed a highly parallel, all-digital microwave instrument that significantly improved the throughput and fidelity of a superconducting quantum processor.

The instrument is called Presto after the very fast musical rhythm. It employs the latest developments in Radio Frequency System on a Chip (RFSoC) for Software Defined Radio (SDR) to execute synchronized measurements and control qubits on 16 independent channels – a high channel density that enables quantum processing to scale. The team demonstrated that Presto achieves very high fidelity for single-shot qubit readout and single-qubit gate operations.

“We have shown how to adapt RFSoC and SDR technology for controlling and reading out quantum states of superconducting circuits,” co-author David Haviland said. “We achieved this through the development of a flexible Application Programming Interface in the Python language, making the instrument easily adaptable to a wide variety of quantum measurement and control applications.”

These digital means also enabled the team to simplify their system compared to traditional counterparts. The authors replaced analog mixers, which degrade the performance of standard qubit systems through signal distortion and crosstalk, with digital signal processing methods that directly process microwave bands.

The team hopes to extend their results to larger qubit systems.

“We demonstrated that Presto does not introduce errors in a two-qubit circuit. But the power of our instrument lies in its high density of channels that will enable more accurate control of larger, multi-qubit circuits,” Haviland said. “This next level of demonstration is work for the future.”

Source: “Measurement and control of a superconducting quantum processor with a fully-integrated radio-frequency system on a chip,” by Mats O. Tholén, Riccardo Borgani, Giuseppe Ruggero Di Carlo, Andreas Bengtsson, Christian Križan, Marina Kudra, Giovanna Tancredi, Jonas Bylander, Per Delsing, Simone Gasparinetti, and David B. Haviland, Review of Scientific Instruments (2022). The article can be accessed at https://doi.org/10.1063/5.0101398 .