Quantum computing presents a challenge for qubit control systems - they must deliver high speed, high accuracy and provide a useable programming system. Many physicists use the Sinara open-source hardware ecosystem running ARTIQ software, a combination that’s been instrumental in moving research forward since 2016. This is a great example of a community coming together for the common good, and moving away from ad-hoc solutions constructed in-house in favour of those with consistent design, reproducibility, testing and documentation. So it’s not surprising that so many physicists have invested time and effort in building experiments using Sinara and ARTIQ.
Thus far experiments have been small and ‘NISQ-y’ (NISQ = noisy intermediate scale quantum) with a focus on controlling a small number of qubits. The next step for many of these labs is to do more complex work, for example to conduct stability experiments to sustain a value across space, and then progress to implementing quantum memory with error correction to sustain a value across time. This means having more complicated circuits that control more qubits. Many physicists we talk to are finding this challenging with their current set up.
So what are physicists to do? Simply ripping out their entire control system built over many years and replacing it with a new more scalable solution is massively disruptive. It makes more sense to go with a hybrid solution that provides a stepping stone to scalability. That’s why we took the decision to integrate our Deltaflow.Control system with Sinara hardware.
With this setup, physicists can continue using their existing Sinara hardware setup for signal generation but at the same time benefit from Deltaflow.Control’s easy to use programming, debugging and simulation tools. Experiments can be written as a program in pure Python, a language that’s already familiar to them, and leverage the Deltaflow.Control library that provides a high-level abstraction to make pulse definition quick and easy – click here to see code examples for rabi oscillation and spin echo experiments (note this will download a zip file to your computer).
The Urukul module is a powerful frequency synthesizer, but its complexity is something that physicists don’t want to struggle with. By using Deltaflow.Control to drive Urukul, we abstract away that complexity into a simple domain-specific and consistent library.
Looking to the longer-term, switching to Deltaflow.Control also gives physicists a path to mid-circuit measurement and fast branching, both of which are needed to implement quantum error correction.
It’s important to also consider how support needs change over time. Crowdsourcing assistance from peer groups is a great way to access tips and tricks to refine experiments in well understood areas, but when research boundaries are pushed, getting help solving new problems becomes more difficult. By switching to this hybrid setup, physicists get support from dedicated control engineers in the Deltaflow.Control team. It's their full-time job to find solutions to these problems, meaning more predictable response times and a defined path to escalation.
The more physicists we talk to, the more we are convinced that this stepping stone approach can provide a low cost, low risk approach to scaling qubit control.