Alexis Morvan
@amorvan.bsky.social
Quantum Research Scientist at Google Quantum AI
Another experiment with my son (4yo)! We use this baby nasal aspirator to show the Venturi effect! Blowing air through the horizontal tube creates a low-pressure zone at the T-junction, sucking the liquid right up the vertical tube. Coloring the water is the trick to get my son to pay attention
I cannot decide what's my favorite slop: The single qubit CNOT gate or the tentative to make a graph for a bell pair or maybe the new notation ∣0^2 and ∣1 ^1 . Source: a linked in post I saw while scrolling out of boredom
Google Deep Mind in collaboration with Google Quantum put on arxiv their new decoder AlphaQubit 2. They show high accurancy and fast ML decoding on surface code and Colo(u)r code! Its exciting to start seeing high accuracy and fast decoder for the color code! arxiv.org/abs/2512.07737
A scalable and real-time neural decoder for topological quantum codes
Fault-tolerant quantum computing will require error rates far below those achievable with physical qubits. Quantum error correction (QEC) bridges this gap, but depends on decoders being simultaneously...
arxiv.org
We taught a quantum computer to learn from its own mistakes-- without stopping. Our RL framework repurposes QEC detection events as learning signals to stabilize the system. Result: Improved Logical Error Rates for both Surface and Color codes on Willow! see arxiv: arxiv.org/abs/2511.08493
Great work worth a read if you work on superconducting circuit with flux control!
Andreas Wallraff@andreasateth.bsky.social · 9mo agoDo you find it challenging to accurately control the transition frequency of your superconducting #qubit by applying magnetic flux? Frequently, the frequency dependence of the response function of the electronics, the wiring, and the flux-bias circuitry must be compensated for to accurately .. [1/7]
This weekend I tried another home experiment for my toddler. This one was suggested to me by none other than Michel Devoret! It’s pretty cool. But I was more excited than the kid 😅
Are you a computer scientist and don't know what an OTOC is, but want to understand the problem solved in the recent Nature paper by Google Quantum AI? We wrote a 2-page note that explains the motivation and presents a simplified version of the problem for any input size. scirate.com/arxiv/2510.1...
The same quantum tunneling honored by this year’s #NobelPrize is driving #URochesterResearch @machielblok.bsky.social is building quantum systems that do what classical computers can’t—inspired by the same fundamental questions uofr.us/48o7I0K #QuantumPhysics #QuantumComputing
Quantum tunneling: URochester physicist explains a Nobel Prize–winning discovery
Machiel Blok’s research in superconducting circuits builds on the quantum tunneling effects recognized by the 2025 Nobel Prize in Physics.
uofr.us
Well, so much for my post about learning something new this Nobel week! The Physics prize went to J. Clarke, M. Devoret, and J. Martinis, the pioneers of my own field, superconducting circuits. An absolutely foundational work, and so well-deserved. www.nobelprize.org/prizes/physi...
Nobel Prize in Physics 2025
The Nobel Prize in Physics 2025 was awarded jointly to John Clarke, Michel H. Devoret and John M. Martinis "for the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an...
nobelprize.org
Alexis Morvan@amorvan.bsky.social · 10mo agoNobel Prize week is almost here. I enjoy the predictions, but the real highlight for me is the forced exposure to science outside my field. It’s the one week I get a proper dive into research I’d otherwise miss.
Nobel Prize week is almost here. I enjoy the predictions, but the real highlight for me is the forced exposure to science outside my field. It’s the one week I get a proper dive into research I’d otherwise miss.
With my son, we played with vegetal oil, baking powder and vinegar colored in blue. The effect was really cool!
scottaaronson.blog?p=9170 Scott Aaronson on the recent « quantum advantage » claim. My favorite quote from his comment: « When they simulate the noiseless quantum computation classically, the advantage disappears? WTF? »
HSBC unleashes yet another “qombie”: a zombie claim of quantum advantage that isn’t
Today, I got email after email asking me to comment on a new paper from HSBC—yes, the bank—together with IBM. The paper claims to use a quantum computer to get a 34% advantage in predic…
scottaaronson.blog
Blog post: "Actually, you can't test if quantum uses complex numbers" algassert.com/post/2501 I doom the concept of that 2021 Nature paper by showing how to compile any distributed quantum protocol into real-only gates while preserving locality.
This work started w/ my struggle to understand fault-tolerant cluster states, and in particular why they always magically implement the same QEC problem as non-MBQC circuits. Understanding this correspondence as chain complex equivalence finally solved it for me, and I hope for other people too :)
Been awhile since I wrote a blog post. Anyways... why haven't quantum computers factored 21 yet? algassert.com/post/2500
Why haven't quantum computers factored 21 yet?
Craig Gidney's computer science blog
algassert.com
The QEC25 conference hosted by @yaleqi.bsky.social was really excellent, and videos of all talks are available. So much recent progress on quantum error correction! qec25.yalepages.org
QEC25
qec25.yalepages.org
Color code decoding with some big claim: arxiv.org/abs/2508.15743 I wish they could try to benchmark this decoder against the experimental color code data from arxiv.org/pdf/2412.14256 zenodo.org/records/1423... We are releasing experimental data so people can try out their decoding algorithms!
Colour Codes Reach Surface Code Performance using Vibe Decoding
Two-dimensional quantum colour codes hold significant promise for quantum error correction, offering advantages such as planar connectivity and low overhead logical gates. Despite their theoretical ap...
arxiv.org
The recording of my talk on the Implementing the surface code using dynamic circuits at QEC2025 is available online! yale.hosted.panopto.com/Panopto/Page...
QED25 - Int'l Quantum Conf; Day 1, Recording 2
yale.hosted.panopto.com
Nvidia is releasing their open source tensor network decoder! As a small bonus they used experimental data from the google surface code experiemnt of 2023. I wonder how it would perform on more recent datasets developer.nvidia.com/blog/streaml...
Streamlining Quantum Error Correction and Application Development with CUDA-QX 0.4 | NVIDIA Technical Blog
As quantum processor unit (QPU) builders and algorithm developers work to create large-scale, commercially viable quantum supercomputers, they are increasingly concentrating on quantum error…
developer.nvidia.com
Looks like 3-coupler / hex implementation of the surface code can now tolerate dropout! www.arxiv.org/abs/2508.08116
Handling fabrication defects in hex-grid surface codes
Recent work has shown that a hexagonal grid qubit layout, with only three couplers per qubit, is sufficient to implement the surface code with performance comparable to that of a traditional four-coup...
arxiv.org
I will be at the #QEC25 conference at Yale this week! I will be giving a talk on our work on dynamic implementation of the surface code on Monday
I'm often asked if I'll redo the 2019 quantum factoring estimate. Denser storage by yokes, smaller magic factories by cultivation, slimmer approx arithmetic by Chevignard et al… surely the cost is lower now? Yes, it's lower now. security.googleblog.com/2025/05/trac... arxiv.org/abs/2505.15917
Pretty cool work on qudit encoded in GKP. I think this is also the first experimental demo of a Error Corrected Qudit www.nature.com/articles/s41...
Quantum error correction of qudits beyond break-even - Nature
Quantum error correction of a logical qutrit and ququart were experimentally realized beyond the break-even point with the Gottesman–Kitaev–Preskill bosonic code.
nature.com
Let’s be honest. It’s hard to beat the Surface code!
Craig Gidney@craiggidney.bsky.social · last yr.Mike finally paid for the "pro" version of sketchup, so we owned the 3d models attached to the paper, meaning the yoked surface codes paper is now published! www.nature.com/articles/s41... The message of this paper is: anytime someone says they're 10x better than surface codes, actually it's 4x.
My guess as to why the 3-coupler wasn't discovered before is that it shifts around the flavor of the stabilizers. If you look at the stabilizer at the end of the cycles, for a given measurement qubit in the bulk, the color changes every other round. The 'ear' of the surface code patch shifts a bit.
Craig Gidney@craiggidney.bsky.social · last yr.A diagram of the 3 coupler surface code cycle (from arxiv.org/abs/2412.14360). It's interesting people missed it for so long. I'd have sworn it was impossible before we found it. I think it was hard to find because it oscillates between two surface codes. Probably lots of stuff like that out there.
Tomorrow I'm giving a zoom talk on magic state cultivation at the Simons quantum Colloquium. Apr 8, 10am PST, see simons.berkeley.edu/programs-eve... Cultivation is the (current) culmination of a decade of work ending the reign of T gates as the dominant cost in fault tolerant quantum computation.
Largest factorization done on a quantum computer. Joke aside. That is an extremely instructive work!
Craig Gidney@craiggidney.bsky.social · last yr.For sigbovik, I factored all 8 bit ints (up to 255) with a quantum computer github.com/strilanc/fal... I did it as legit as I possibly could. I ran a correct circuit with no optimization shenanigans. I did correct pre/postprocessing. It took 121 quantum samples to finish the entire task. But...
In 1h (9am PST or 5pm CET) I will give a talk at the QASAR seminar hosted by @vasmer.bsky.social and @christophe.vuillot.info . I will present our work on implementing 3coupler, walking and iSWAP surface codes!
I really enjoyed the MM session on early history of quantum information. It was really uplifting to listen to. I really love old lab notes, notes and written mails communications from these days. Look way more fun than emails and chat messages we have these days
