Quantum Technology User Meeting 2022 in Munich

Quantum technology progresses towards real-world applications at a tremendous pace, with different technological platforms and approaches being explored. The joint QT User Meeting of Zurich Instruments and Rohde & Schwarz brought together researchers in quantum technologies who may work in different areas and face distinct challenges but share core competencies and important know-how.

During the three days in Munich, 45 quantum technologists mingled with Application Scientists from Zurich Instruments and Trainers from Rohde & Schwarz to enjoy:

• High-level scientific keynotes from Natalia Ares (University of Oxford), Andreas Wallraff (ETH Zurich) and Stefan Filipp (TUM & WMI, Munich);
• Detailed tutorials on how to make the most out of our instrumentation by sharing best practices, tips and tricks;
• An open poster session, instrumentation exhibition and a round table discussion on future challenges and opportunities in the field.

Keynote presentations

We were very happy to welcome internationally acclaimed keynote speakers presenting the latest scientific results, from automated spin qubit tune-up through high fidelity single and multi-qubit gates to fully fledged quantum error correction with superconducting qubits. Their presentations, summarized below, were also streamed and recorded. We are very grateful to Natalia, Andreas and Stefan for sharing their results and hope we can meet them again at future user meetings.

You can watch all the recordings here. 

Natalia Ares (University of Oxford): Machine Learning Based Control of Quantum Devices

Natalia Ares joined us remotely from Oxford and shared her work on using machine learning for tune-up of semiconductor quantum devices. In her experiments, fast and high fidelity readout of the state of the quantum devices is a crucial ingredient to generating the large datasets needed to train the AI agents. Already now, machine learning improves the speed and reliability of tuning up semiconductor quantum dots, and enables faster and more reliable qubit experiments in this platform.

You can watch the recording here.

Andreas Wallraff (ETH Zurich): Quantum Error Correction with Superconducting Circuits

Andreas Wallraff from the Quantum Device Lab at ETH Zurich presented recent results on realizing error correction in a distance 3 surface code using superconducting qubits. In these experiments, where a 17 qubit chip is continuously controlled and monitored, the high quality and fast qubit state readout with the UHFQA Quantum Analyzer was crucial to achieve their ground breaking results. Looking forward to even more results on even bigger logical qubits with next generation hardware.

You can watch the recording here.

Stefan Filipp (TUM and WMI): Control of Superconducting Qubits

Stefan Filipp from the Walter Meißner Institute was co-hosting the User Meeting with us. Apart from delivering a keynote talk, he also enabled the participants to visit his labs. In his presentation on control of superconducting qubits, Stefan highlighted the need for fast, high fidelity single and multi-qubit gates when aiming at large scale quantum chips. He shared results on using optimal control to achieve record short single qubit gates and an outlook for two and three-qubit gates using tuneable couplers in their superconducting qubit architecture.

You can watch the recording here.

Tutorials

At the heart of the QT User Meeting were four tutorial sessions, where Application Scientists from Zurich Instruments and Trainers from the Rohde & Schwarz Academy shared their detailed application knowledge on how to set up, generate and run quantum computing experiments with the Zurich Instruments QCCS Quantum Computing Control Software supported by Rohde & Schwarz signal generation and analysis hardware.

Tutorial: Using the QCCS Software with a Training on R&S Oscilloscopes

When setting up a qubit experiment, scientists worry about individual instrument settings, their synchronization, sampling rates and how to best generate and upload all waveforms. Florian, our Application Scientist, lead a tutorial on how to use the LabOne QCCS Software for high-level pulse sequencing of the QCCS, from single instruments to large scale systems. The participants also looked at the pulses generated with an oscilloscope, and the advanced feature sets of Rohde & Schwarz RTO and RTP line instruments.

Tutorial: Multiplexed Qubit Readout with an Introduction to R&S Spectrum Analyzers

In the second tutorial, we looked at how to optimize qubit readout fidelity, and use a single drive line to read out multiple qubits at the same time. Chunyan, our Application Scientist, shared how to set up the experiments, optimize the integration weights and set up readout thresholds. The high spectral purity and low phase noise of our instruments will be a major asset for the quantum computing experiments. The participants also looked at the Rohde & Schwarz FSW Spectrum Analyzer that has the best sensitivity on the market.

Tutorial: Pulse-level Sequencing with an Introduction to R&S Vector Signal Generators

In the next tutorial, we looked at how to reduce the number of waveforms uploaded to an AWG when calibrating the qubit pulses and how to increase the experiment duty cycle. Our Application Scientist Mark lead the hands on session on pulse-level sequencing, where he shared tricks and tips on how to have the next randomized benchmarking experiment run in seconds. For the qubits that work at higher frequencies, we looked at the R&S SGS RF sources together with the SGU frequency extension unit, which can directly convert the baseband IQ signals to frequencies up to 40 GHz, with high signal quality and small form factor.

Tutorial: Towards Quantum Error Correction

Quantum error correction requires not only fast and high fidelity stabilizer readout but also fast feedback, where the results of stabilizer measurements can be used to apply correction pulses to faulty data qubits in the code. In this tutorial, Andrea introduced the basic principles on how to use our QCCS system for feedback and demonstrated how to efficiently execute active qubit reset, repeat until success and how to stabilize a two-qubit Bell state.

The Python notebooks shown during the first three tutorials can be downloaded here. If this whetted your appetite, contact our Applications Scientists directly or write us at info@zhinst.com. The fourth tutorial (Towards Quantum Error Correction) currently requires functionality that is yet unreleased, but will soon be publicly available. Contact us for more details if you are interested in how to realize feedback in your setup already today.

Panel Discussion

The afternoon of the second day featured a high-level panel discussion on the topic "Challenges when going towards 1000 qubits". The panel was moderated by Sadik Hafizovic from Zurich Instruments and joined by a diverse set of panel members working with superconducting, spin and photonic qubits: Anna Stockklauser (Rigetti), Jan Götz (IQM), Stefan Filipp (WMI & TUM), Natalia Ares (University of Oxford) and Michael Förtsch (Q.Ant). The panelists discussed shortcomings, bottlenecks and advantages of their respective platforms, as well as the possible ways to benchmark different qubit architectures against each other and how much this even makes sense in the current situation. Lastly, the panelists shared their outlook at the roadmap for the coming five years. 

To summarize the discussion, here are some take away messages:

• The community is facing similar challenges, a collaborative approach between all parties will be beneficial.
• Focus on solving real-world problems may be more important than reporting the number of qubits.

You can watch the recordings here.

Networking

The QT User Meeting offered plenty of opportunities for networking, during the coffee breaks, the poster sessions, the social diner or by discussing the latest experiments with our Application Scientists and Trainers from R&S in an in-depth demo sessions on the last day.

Besides the keynote speakers, we would like to thank the speakers of the contributed talks for their big contribution, as well as the members of the WMI for giving our attendees the opportunity to visit their lab!

Please share with us your feedback & impressions from the workshop.

Stay tuned for the next edition of the QT User Meeting, possibly in a city near you!