Open source quantum software at FOSDEM 19

W. J. Zeng
2 min readFeb 7, 2019


FOSDEM is one of the largest open source software conferences in the world and last weekend, for the first time, it hosted a track on open source quantum software. The schedule was packed back to back and the organizers of Mark, Tomas, and Peter from the new Quantum Open Source Foundation definitely deserve kudos.

There was a line out the door all day!

The first day included talks from some of the more established projects, including Qiskit (IBM), Forest (Rigetti), D-Wave’s Ocean (D-Wave), PennyLane, Strawberry Fields (Xanadu), QuTiP, and Cirq (Google). A welcome surprise was when Robert Smith open sourced Rigetti’s quantum virtual machine and quilc quantum compiler live in front of the audience!

The second day was the highlight for me. There were talks from emerging community projects with lots of new ideas. The talks ranged from programming environments for quantum networks (SimulaQron) to quantum debuggers (Q-bug) to projects that let you compile from Verilog into quantum circuits (MustangQ).

There were three talks from recipients of Unitary Fund grants:

  • Ryan LaRose spoke about the NISQAI project which is a multi-platform library for quantum machine learning. They were able to connect with Xanadu’s Pennylane project as well.
  • Lucas Saldyt spoke on Curry, a library for functional, probabilistic quantum programming.
  • John van de Wetering showed off how the PyZX compiler beat other benchmarks in lowering the T-count of compiled circuits.

Several talks were from folks who had recently gotten into the field. This is a testament to how open source software and educational tools have made quantum accessible over the last few years.

Talking about quantum computing at a software conference, rather than a specialized academic conference, was also important. One of my favorite questions of the weekend was asked by an audience member who was in their first quantum computing talk: “What’s the equivalent to the cache in a quantum processor?” This is a great question. Right now most quantum processors are just a hunk of quantum memory without a differentiated architecture. But what would something like a cache look like?

Maybe we’ll find out next year.

To follow more on open quantum software check out

The full schedule from the weekend is hosted here:

Videos of the first day of talks are here: with more to be posted.

And of course it wouldn’t be a visit to Brussels without looking for Belgian beer.

A successful quest for Westvleteren 12



W. J. Zeng

Focused on making quantum computers useful asap. $\langle sold|\otimes|worn\rangle+|not sold\rangle\otimes|never worn\rangle/\sqrt{2}$