Alexis Morvan
@amorvan.bsky.social
Quantum Research Scientist at Google Quantum AI
Pinned
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
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
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
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
November 12, 2025 at 4:44 AM
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
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!
Do 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]
[1/7]
November 8, 2025 at 4:52 PM
Great work worth a read if you work on superconducting circuit with flux control!
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 😅
It’s pretty cool. But I was more excited than the kid 😅
November 3, 2025 at 1:32 AM
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 😅
It’s pretty cool. But I was more excited than the kid 😅
Reposted by Alexis Morvan
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...
scirate.com/arxiv/2510.1...
October 23, 2025 at 2:58 AM
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...
scirate.com/arxiv/2510.1...
Reposted by Alexis Morvan
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
@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
October 9, 2025 at 1:44 PM
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
@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
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...
www.nobelprize.org/prizes/physi...
October 7, 2025 at 3:46 PM
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...
www.nobelprize.org/prizes/physi...
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.
October 5, 2025 at 8:55 PM
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!
September 28, 2025 at 10:08 PM
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? »
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
September 27, 2025 at 9:34 PM
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? »
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? »
Reposted by Alexis Morvan
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.
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.
September 15, 2025 at 4:20 AM
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.
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.
Reposted by Alexis Morvan
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 :)
September 13, 2025 at 11:05 AM
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 :)
Reposted by Alexis Morvan
Been awhile since I wrote a blog post.
Anyways... why haven't quantum computers factored 21 yet?
algassert.com/post/2500
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
August 31, 2025 at 12:21 AM
Been awhile since I wrote a blog post.
Anyways... why haven't quantum computers factored 21 yet?
algassert.com/post/2500
Anyways... why haven't quantum computers factored 21 yet?
algassert.com/post/2500
Reposted by Alexis Morvan
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.yalepages.org
QEC25
qec25.yalepages.org
August 17, 2025 at 5:32 PM
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.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!
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
August 22, 2025 at 11:41 PM
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!
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!
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...
yale.hosted.panopto.com/Panopto/Page...
QED25 - Int'l Quantum Conf; Day 1, Recording 2
yale.hosted.panopto.com
August 18, 2025 at 3:33 AM
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...
yale.hosted.panopto.com/Panopto/Page...
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
August 14, 2025 at 3:40 PM
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...
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...
www.arxiv.org
August 12, 2025 at 3:53 AM
Looks like 3-coupler / hex implementation of the surface code can now tolerate dropout! www.arxiv.org/abs/2508.08116
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
August 10, 2025 at 3:26 PM
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
Reposted by Alexis Morvan
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
Yes, it's lower now.
security.googleblog.com/2025/05/trac...
arxiv.org/abs/2505.15917
May 23, 2025 at 1:25 PM
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
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...
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.
www.nature.com
May 16, 2025 at 1:57 AM
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...
I think this is also the first experimental demo of a Error Corrected Qudit
www.nature.com/articles/s41...
Let’s be honest. It’s hard to beat the Surface code!
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.
The message of this paper is: anytime someone says they're 10x better than surface codes, actually it's 4x.
May 15, 2025 at 1:29 AM
Let’s be honest. It’s hard to beat the Surface code!
Detecting region with ZX calculus!
Hector Bombin, Daniel Litinski, Naomi Nickerson, Fernando Pastawski, Sam Roberts
Unifying flavors of fault tolerance with the ZX calculus
https://arxiv.org/abs/2303.08829
Unifying flavors of fault tolerance with the ZX calculus
https://arxiv.org/abs/2303.08829
May 4, 2025 at 8:11 PM
Detecting region with ZX calculus!
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.
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.
April 25, 2025 at 5:03 AM
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.
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.
Reposted by Alexis Morvan
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.
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.
April 7, 2025 at 5:30 PM
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.
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!
Joke aside. That is an extremely instructive work!
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...
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...
April 2, 2025 at 2:23 AM
Largest factorization done on a quantum computer.
Joke aside. That is an extremely instructive work!
Joke aside. That is an extremely instructive work!