Ross Duncan
@rossquantum.bsky.social
630 followers 370 following 190 posts
Quantum computing lifer. ZX-calculus co-inventor. Quantum compiler compiler and quantum programmer programmer. String diagrammer. Category theoriser. Head of Quantum Software @ Quantinuum (I cannot read DMs on Bluesky)
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rossquantum.bsky.social
In a pub in Cambridge? Maybe not that surprising.
rossquantum.bsky.social
I would wear this t-shirt.
Reposted by Ross Duncan
dangaristo.bsky.social
Interesting bit of sociology: They are really studiously avoiding any mention of quantum computing. First and only mention came in the last few words of the presentation by Johansson.
Reposted by Ross Duncan
Reposted by Ross Duncan
parodypm.bsky.social
This story is now big news all over the world... except in the UK.
rossquantum.bsky.social
HR would not let me make this a firing offence in our company, but I think it should be.
rossquantum.bsky.social
Eh, modernised acid house.
Reposted by Ross Duncan
pigworker.bsky.social
"If the thing you call a 'policy' creates responsibility and accountability for something, without granting resources and authority to achieve that something, then it fails to qualify functionally as a 'policy' and is merely BULLYING."
-- me, far too often in this academic life
Reposted by Ross Duncan
qzoeholmes.bsky.social
We provide evidence of an exponential gap between adaptive & nonadaptive strategies for a quantum recompilation task

Key takeaways:

- Entanglement isn’t always a roadblock: its degree can aid training

- Discrete optimization may be key to finding sweet spots between concentration & surrogation
rossquantum.bsky.social
Wait till you hear about the difference in retraction rates!
Reposted by Ross Duncan
schuckert.org
When you realize the whole yearly budget for Quantum journal is equal to 8 Nature APCs - and they don't even wreck your paper in proof stage because...there is none
rossquantum.bsky.social
FAQs:
1. It's a hybrid position, based in Cambridge UK. If you want a fully remote position this is not for you. You will need to come to the office regularly.
2. We will support a visa application if needed.
3. If you are QEC-curious, this is not for you. I want to see relevant publications.
rossquantum.bsky.social
Agree, but I can only think of abelian and gaussian from the top of my head. I always have to think about whether to capitalise Hamiltonian...
rossquantum.bsky.social
Then I would not donate my labour to this extremely profitable corporation. There are plenty of community run journals which are not in the business of rent-extraction from the public sector.
rossquantum.bsky.social
The point being that whatever the physical layer compiler/transpiler is doing in the FT compilation process, it will not look like compiling algorithms, and will have a very different set of constraints and goals. It needs to be developed in its proper context.
rossquantum.bsky.social
I don't think this is question of "NISQ compilation is a solved problem". More like "NISQ hardware cannot run interesting algorithms". It's not strictly true, but for 95% of applications physical error rates are not good enough, and won't be. Hence the widespread switch to focus on FTQC.
rossquantum.bsky.social
How much do they pay? Do they waive any journal fees for your institution? Does doing this achieve anything positive other than the rentier-shareholders of Springer-Nature?
rossquantum.bsky.social
Meanwhile in Tokyo, the temperature has dropped to the point where wearing clothes at all starts to seem reasonable.
Cityscape of Tokyo, blue skies, fluffy clouds.  Skytree visible in distance.
rossquantum.bsky.social
So congratulations to @mattgirling.com @bencriger.bsky.social and @cristinacirstoiu.bsky.social on this new paper, addressing problems that too many people refuse to even think about.
rossquantum.bsky.social
Lazy people in quantum computing use the term "fault-tolerant" to mean "I don't want to think about errors". Unfortunately for these magical thinkers, QEC will not make error rates zero. Logical operations on logical qubits will have errors, and you'd better understand them. #quantum #quantinuumm
quantinuum.bsky.social
We're focused on de-risking the path to large-scale fault-tolerant quantum computing, and we are doing the work to get there. This work is platform-agnostic — relevant to anyone working on quantum hardware, QEC theory, or benchmarking tools.

🔬: arxiv.org/abs/2508.08188
Characterization of syndrome-dependent logical noise in detector regions
Characterizing how quantum error correction circuits behave under realistic hardware noise is essential for testing the premises that enable scalable fault tolerance. Logical error rates conditioned o...
arxiv.org
Reposted by Ross Duncan
martinescardo.mathstodon.xyz.ap.brid.gy
I am happy to announce that my colleague Paul Blain Levy has won the Alonzo Church Award.

https://siglog.org/winner-of-the-2025-alonzo-church-award/
Winner of the 2025 Alonzo Church Award
The 2025 Alonzo Church Award for Outstanding Contributions to Logic and Computation is presented to **Paul Blain Levy** for his fundamental study of effectful λ-calculi through the Call-by-Push-Value calculus. The awardee book and paper are: > Paul Blain Levy. Call-By-Push-Value: A Functional/Imperative Synthesis. Semantics Structures in Computation 2, Springer 2004, ISBN 1-4020-1730-8 > > Paul Blain Levy. Call-by-Push-Value: Decomposing call-by-value and call-by-name. High.-Order Symb. Comput. 19(4): 377-414 (2006) ## The Contribution Initiated by Alonzo Church, the research programme into the λ-calculus as an abstract model of computation has spurred volumes of fundamental research in logic and computation. By the end of the 20th century, the studies of the λ-calculus in its purely logical form and its applied effectful form bifurcated. In an outstanding contribution, Levy has reunited the many existing research streams into the study of one subsuming calculus: Call-by-Push-Value (CBPV). Levy developed and presented an extraordinarily large body of evidence spanning a cross-section of the semantic theory of the λ-calculus and its application to programming language modelling, including: algebraic datatypes, operational semantics, denotational semantics, and equational theories. To date, CBPV remains a unifying starting point in the study of computational and logical phenomena, including: effects, polarisation, term normalisation, type-isomorphisms, and program transformations. In addition to its scientific contribution, the nominated monograph is a unique access-point into the culmination of decades of logic and programming language semantics.
siglog.org