I am very happy to see our work on non-Clifford gates with 2D non-Abelian topological phases published in PRX journals.aps.org/prx/abstract.... This is definitely among the most exciting projects I have worked on.

Universal Fault-Tolerant Quantum Computation in 2D without Getting Tied in Knots

Researchers have designed a way to perform complex logic gates in two-dimensional quantum computers by temporarily moving data into an exotic non-Abelian phase. This method provides a path toward larg...

journals.aps.org

This never happened to me before, but this week it happened twice - I got cold two emails asking me for an arXiv endorsement. Anyone else seen this? Is it a scam? I don't see what anyone gets out of it other than an opportunity to spam the arXiv.

"My concern is mostly about scope and relative impact. The decoder feels quite tied to the BB-code setting.” -An excerpt of the referee report from the QEC workshop for a paper titled "A matching decoder for bivariate bicycle codes"

Two papers out today: a double feature introducing the dynamic compass code arxiv.org/abs/2604.14296 arxiv.org/abs/2604.14299 We find novel measurement schedule for the heavy-hex code to find a 2D code that has a threshold against circuit noise and is readily implemented on the heavy-hex lattice.

Some time ago @domwilliamson.bsky.social and I wrote a paper on decoding fracton codes. This gave us the idea to try to extend MWPM decoding to all codes. We didn't get there yet but work led by @kaavyasahay.bsky.social has made great progress showing a matching decoder for bivariate bicycle codes.

Our team at IBM is looking for interns! If you are interested in researching fault-tolerant quantum algorithms, please apply here: ibmglobal.avature.net/en_US/career...

Intern 2026: Fault-tolerant quantum algorithms

ibmglobal.avature.net

Are you a graduate student looking for experience working on the theoretical problems we need to solve to build a quantum computer? We are currently accepting applications for internship positions in the quantum computing theory team at IBM for summer 2026. ibmglobal.avature.net/en_US/career...

Intern 2026: Quantum Computing Theory

ibmglobal.avature.net

New work just published journals.aps.org/prl/abstract... I was sat on this result for a couple of years but as you can see in the acknowledgements sometimes I need to be told three times to get things done (and sometimes I need to be asked more than three times, sorry @kenbrownquantum.bsky.social)

Excited to share our first major result from our IARPA Entangled Logical Qubits team! arxiv.org/abs/2504.07258 @benbrown.bsky.social @universal-soup.bsky.social @evanhockings.bsky.social @georgianixon.bsky.social

Are you a fan of fault-tolerant non-Clifford gates on the 2D surface code? Have you been wondering what was really going on in the protocols by Bombín and Brown? We have a new work for you: arxiv.org/abs/2503.15751

Universal fault tolerant quantum computation in 2D without getting tied in knots

We show how to perform scalable fault-tolerant non-Clifford gates in two dimensions by introducing domain walls between the surface code and a non-Abelian topological code whose codespace is stabilize...

arxiv.org

Logic gates can often be understood in terms of topological phases, so I often felt it was a shortcoming of my work on a 2D CCZ gate that I did not see the analogous physical picture. So I am pleased to share our work arxiv.org/abs/2503.15751 where we show the gate was a non-Abelian phase all along!

Universal fault tolerant quantum computation in 2D without getting tied in knots

We show how to perform scalable fault-tolerant non-Clifford gates in two dimensions by introducing domain walls between the surface code and a non-Abelian topological code whose codespace is stabilized by Clifford operators. We formulate a path integral framework which provides both a macroscopic picture for different logical gates as well as a way to derive the associated microscopic circuits. We also show an equivalence between our approach and prior proposals where a 2D array of qubits reproduces the action of a transversal gate in a 3D stabilizer code over time, thus, establishing a new connection between 3D codes and 2D non-Abelian topological phases. We prove a threshold theorem for our protocols under local stochastic circuit noise using a just-in-time decoder to correct the non-Abelian code.

arxiv.org

Post selection in QEC is not cheating 🤣, but can be scalable and significantly reduce your resources overheads! Check out our newly published paper in @commsphys.bsky.social rdcu.be/d1LuM, a great collab with Sam Smith and @benbrown.bsky.social @sydneyphysics.bsky.social

Mitigating errors in logical qubits

Communications Physics - Quantum error correction produces an enormous amount of data about the quantum system, including information about whether an uncorrectable error is likely. In this work...

rdcu.be

Our work, led by Riddhi Gupta, was just published in Nature nature.com/articles/s41... Thanks to my co-authors for all their hard work.

Encoding a magic state with beyond break-even fidelity - Nature

A scheme to prepare a magic state, an important ingredient for quantum computers, on a superconducting qubit array using error correction is proposed that produces better magic states than those that ...

nature.com