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Ben Brown

@benbrown.bsky.social
380 followers 78 following 31 posts

Research scientist at IBM Quantum

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Ben Brown @benbrown.bsky.social · 27/07/2026
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.
journals.aps.org
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...
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Ben Brown @benbrown.bsky.social · 12/06/2026
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.
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Ben Brown @benbrown.bsky.social · 25/04/2026
"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"
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Ben Brown @benbrown.bsky.social · 17/04/2026
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.
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Ben Brown @benbrown.bsky.social · 28/02/2026
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.
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Reposted by Ben Brown
Anirban Chowdhury @anchowdhury.bsky.social · 12/11/2025
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...
ibmglobal.avature.net
Intern 2026: Fault-tolerant quantum algorithms
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Ben Brown @benbrown.bsky.social · 14/10/2025
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...
ibmglobal.avature.net
Intern 2026: Quantum Computing Theory
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Ben Brown @benbrown.bsky.social · 15/08/2025
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)
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Reposted by Ben Brown
Stephen Bartlett @bartlettquantum.bsky.social · 11/04/2025
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
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Reposted by Ben Brown
Dom Williamson @domwilliamson.bsky.social · 21/03/2025
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
arxiv.org
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...
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Ben Brown @benbrown.bsky.social · 21/03/2025
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!
arxiv.org
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.
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Reposted by Ben Brown
Stephen Bartlett @bartlettquantum.bsky.social · 29/11/2024
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
rdcu.be
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...
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Ben Brown @benbrown.bsky.social · 10/01/2024
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.
nature.com
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 ...
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