It’s been a year since Martin Weides joined Oxford Instruments NanoScience as our Consultant Technical Director. Have a read through our Q&A with Martin about his role at Oxford Instruments NanoScience.

How has your first year been at Oxford Instruments NanoScience?

Being in this position for 12 months now is fantastic. I'm enjoying meeting the highly talented Oxford Instruments NanoScience team members, even though, some of the introductions have been remote. We have hit the ground running on a number of projects, for example, looking at the cryogenic hardware requirements for cryogenic quantum technologies, and how to take steps forward to support their further scale-up. The market for cryogenic quantum technologies is developing rapidly, which means our original and impactful solutions are being proposed. It’s fantastic to see all that cryogenic hardware moving up the technological readiness ladder towards commercial deployment.

What are your main responsibilities at Oxford Instruments NanoScience?

My role here entails advising on new developments in techniques such as dilution refrigeration, propelling our technology, and identifying opportunities in the field to scale the technology. Oxford Instruments has a range of products serving both physical sciences and quantum computing, including a wide range of cryostats as well as dilution refrigerators that can cool samples to a few milli-Kelvin. They all have a range of options for studying samples with magnets or lasers.

What’s the focus of your research group at the University of Glasgow?

We tend to focus on superconductor-based quantum circuits, developing the cryogenic hardware, the nanoelectronic chips and the electronics needed for quantum computers. Therefore, our research covers everything from circuit integration to materials science, and device fabrication. We collaborate with other researchers, start-ups, and small to medium-sized enterprises (SMEs) both in the UK and internationally. For example, we’re involved in the Quantum Computing and Simulation Hub hosted by the University of Oxford, and have four projects with industrial partners that are funded by Innovate UK.

How has your research evolved in the past 12 months?

Our research has expanded with some new projects, and the team has grown by welcoming new members. For example, we are now investigating cryogenic electronics, which is increasingly interesting for the integration of conventional electronic circuits with quantum chips inside the cryostat. The benefits include, for example, less interconnects, shorter latencies, and reduced external noise and heat radiation onto the quantum chip. The challenge, of course, is adjusting the long-established semiconducting electronics to work equally well (or better!) at cryogenic temperatures and managing the heat load within the cryostat. My team is characterising conventional transistors as they are cooled down and providing that data to modelling and design experts to create cryogenic analogue and digital CMOS chips for quantum.

Another exciting development is our new network ‘Empowering Practical Interfacing of Quantum Computing (EPIQC)’ (https://qc-ict.org/), which was started in April 2022 with support from the Engineering and Physical Sciences Research Council. EPIQC brings together academics and industrial partners in quantum computing and information & communication technologies to work on the interface of quantum computing and ICT through the co-creation and networking activities. The collaborators will focus on three key areas of work to help overcome some of the barriers which are currently preventing the field of quantum computing from scaling up to practical applications through ICT: optical interconnects, wireless control and readout, and cryoelectronics. Together we have the expertise and access to facilities which will help us tackle tricky problems. We expect to develop a robust network of collaboration and co-creation which will produce some exciting results and help further develop the roadmap to realising the potential of quantum computing interfaces.

What other expertise do you have that you’ve brought to your role?

Having worked with cryogenic quantum circuits and technologies for nearly two decades, I’ve seen them grow and develop drastically. It involved a fascinating mix of electronics, optics, photonics and, of course, cryogenics. There are lots of exciting new applications, ranging from dark-matter detectors and single-photon cameras to implementations in quantum metrology, quantum simulation and quantum computing. That progress involves advances in materials science, integration concepts and chip design, underpinned by improvements in theoretical models and in supporting hardware, such as electronics and cryogenics. I further support the momentum Oxford Instruments NanoScience is gaining in quantum computing and materials science to ensure we stay at the forefront of innovation.

Can you give some examples of your work?

We recently investigated the long-term stability of individual “fixed-frequency” qubits, similar to those that Google and IBM are using for their quantum processors. It turns out that these quantum circuits aren’t very stable for more than a few hours because their coherence times and resonance frequency are affected by tiny, fluctuating surface defects. Finding ways to reduce these microscopic states is a big challenge, but we’ve been trying out some ideas. Another project has led to a cleaner, wafer-scale process for making tunnel junctions, which are the key component of superconducting quantum circuits. We’ve also been studying the thermal noise introduced by the coaxial wiring to the quantum-computing stage and finding ways to scale up quantum processors.

What, in your opinion, is the biggest challenge for customers working with quantum tech?

Keeping the chips well isolated from infrared radiation running down the coaxial lines or from outside the sample package is a big challenge, as well as keeping it cold when pulsing more and more qubits simultaneously. When it comes to scaling up devices, the integration, filtering and thermalization of high-density coax lines with high signal purity, is paramount to achieving quantum error correction or increasing the quantum volume of a quantum processor.

The quantum scale-up demand goes beyond having more wiring and a bigger fridge, though. Another challenge is the shift from research being funded by government grants to it being funded by companies earning profits from selling products in the area.

How do you work out what customers in quantum tech need?

We work closely with our customers and get involved in activities from sponsoring scientific meetings and conferences, hosting virtual symposiums and publishing technical white papers. We recently announced the LOR Science Prize winner which promotes and recognises the innovative work of early-career scientists in North America who work with low temperatures and/or use high magnetic fields. Oxford Instruments NanoScience also conducts a lot of research and development (R&D) itself, working with partners on our shared mission - the commercialisation of quantum computing.

Is developing the right products in this field exciting?

Yes! In quantum computing we’ve seen huge improvements over the last five years in the number of superconducting qubits you can squeeze on a chip. But other hardware platforms, based on semiconductors, are catching up fast. We’re also seeing traditional, room-temperature-based quantum-computing platforms, such as photonic chips or ion traps, going cryogenic to boost their gate fidelities.

Then there’s the development of more and more hybrid approaches, such as super and semiconducting circuits with optical faces or “cryoCMOS” control chips near the qubit processor. Our Proteox family of dilution refrigerators serves this market, providing customers with extra space to install components and other equipment, while also letting them mount samples more easily to operate devices with lots of qubits.

I’d say that the advent of cryogen-free dilution refrigerators 10–15 years ago has allowed researchers to fully focus on the science and technology of quantum computing circuits. What’s more, larger and more powerful cryostats that can host quantum processors with more than 50 qubits, hundreds of coaxial lines,and plenty of passive and active microwave components have also been recently developed. That’s a dramatic improvement – previous cryostats had a sample volume barely the size of a teacup, whereas now they provide much more space.