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Zoe Holmes

@qzoeholmes.bsky.social

970 followers 790 following 66 posts

Quantum physicist. Assistant Prof at EPFL. Climber.

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Reposted by Zoe Holmes

The Schrodinger cat's Post @schrodcatpost.bsky.social · 16h

A new article introduces a continuous-variable analogue of the Pauli propagation algorithm, called Displacement Propagation. Surprisingly, non-Gaussianity and symplectic coherence can make the system easier to simulate when noise is present.
arxiv.org/abs/2510.07264

When quantum resources backfire: Non-gaussianity and symplectic coherence in noisy bosonic circuits

Analyzing the impact of noise is of fundamental importance to understand the advantages provided by quantum systems. While the classical simulability of noisy discrete-variable systems is increasingly...

Zoe Holmes @qzoeholmes.bsky.social · 1d

Among todays mad arxiv overflow is our preprint:

"When quantum resources backfire: Non-gaussianity and symplectic coherence in noisy bosonic circuits"

We introduce a path propagation classical simulation alg for bosonic circuits

And find a funky interplay between quantum resources and noise

🧵👇

Reposted by Zoe Holmes

Dulwich Quantum Computing @dulwichquantum.bsky.social · 1d

Quantum arXiv today.

Zoe Holmes @qzoeholmes.bsky.social · 7d

Oh yeah. Strange. It was working (for me) earlier but not now.

Thanks for highlighting.

Let‘s try this: arxiv.org/abs/2510.01154

Advantage for Discrete Variational Quantum Algorithms in Circuit Recompilation

The relative power of quantum algorithms, using an adaptive access to quantum devices, versus classical post-processing methods that rely only on an initial quantum data set, remains the subject of ac...

Zoe Holmes @qzoeholmes.bsky.social · 8d

This is the paper: scirate.com/arxiv/2510.0...

Thanks for the fun collaboration Sasha (
@sheffield-qc.bsky.social
) and Chiddy !

Zoe Holmes @qzoeholmes.bsky.social · 8d

FYI, our results here don’t contradict arXiv:2312.09121 which focus on loss estimation, proofs, and continuous protocols

Of these, the most intriguing/significant is the switch to discrete optimization

& maybe the path to adaptive quantum advantage is all about finding those discrete sweet spots 😉

Zoe Holmes @qzoeholmes.bsky.social · 8d

And we have found one… we provide numerical evidence that our problem lives in the Goldilocks zone:

- trainable (no exponential concentration)

- not classically surrogatable (thanks to high entanglement + magic)

Zoe Holmes @qzoeholmes.bsky.social · 8d

Of course, this being quantum, we face two extra demons…

- Exponential concentration (barren plateaus + shot noise)

- Classical surrogation (can classical shadows fake the landscape?)

For a real separation, we need a sweet spot that dodges both.

Zoe Holmes @qzoeholmes.bsky.social · 8d

More concretely, we show that for a range of moderate entangling strengths the landscape is unimodal but non-separable landscapes.

Then numerics show adaptive hill-climbing converges efficiently

But non-adaptive approaches - blow up exponentially.

Zoe Holmes @qzoeholmes.bsky.social · 8d

We translate that logic into a quantum recompilation task

The hidden string = the placement of T-gates between layers of semi-random unitaries

Goal = uncover the T gates positions

As in LeadingOnes, identifying early T-gates helps you make progress, but you can’t optimize each gate independently

Zoe Holmes @qzoeholmes.bsky.social · 8d

This is the canonical “adaptivity pays” task

Its unimodal (no local minima) but non-separable (each bit cannot be trained independently)

- Adaptive strategies can flip one bit at a time, use the feedback, and find the string in O(n) queries.

- Non-adaptive strategies need exponentially many.

Zoe Holmes @qzoeholmes.bsky.social · 8d

Our task is a quantum twist on the classic LeadingOnes-OneMax problem.

In this problem you're trying to learn a hidden bitstring.

Your score = how many leading bits match the target before the first mismatch.

So 1110… matches 1101 better than 1011… even if they have the same Hamming weight.

Zoe Holmes @qzoeholmes.bsky.social · 8d

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

Reposted by Zoe Holmes

Zoe Holmes @qzoeholmes.bsky.social · Jul 24

EPFL are recruiting a tenure track assistant proff working on the theory of condensed matter and interacting quantum matter:

www.epfl.ch/about/workin...

Feel free to reach out if you have any questions about life at EPFL/in Switzerland etc.

Faculty Position in Theory of Condensed Matter and Interacting Quantum Matter

The School of Basic Sciences (Physics, Chemistry and Mathematics) at EPFL seeks to appoint a Tenure Track Assistant Professor in condensed matter theory with a focus on interacting quantum matter. Can...

Reposted by Zoe Holmes

James Wootton @decodoku.bsky.social · 24d

Tenure track assistant prof job up for grabs in Basel. It's quantum computing theory, based in computer science, and part of the NCCR SPIN.

Whoever gets this job will probably have to collaborate with me. Whether you see that as a pro or con is up to you.

jobs.unibas.ch/offene-stell...

Universität Basel: Tenure-track Assistant Professorship in Theoretical Quantum Computing

The University of Basel, Switzerland, invites applications for a professorship in theoretical quantum computing. The University of Basel is the home institution of the Swiss National Center of Compete...

Zoe Holmes @qzoeholmes.bsky.social · 28d

Also, sharing for friends:

Anyone fancy a (minimal teaching load) tenure track position on quantum computing on a sunny island 🌤️ 🏝️? The Cyprus Institute are also hiring a tenure track assistant proff on quantum algorithms.

onlinerecruitment.exelsyslive.com?c=6E7274A2-8...

(Deadline next week)

Exelsys - Online Job Application

onlinerecruitment.exelsyslive.com

Zoe Holmes @qzoeholmes.bsky.social · 28d

Fancy being (academic) neighbours?

The University of Basel are hiring a tenure-track assistant professor in theoretical quantum computing:

jobs.unibas.ch/offene-stell...

Universität Basel: Tenure-track Assistant Professorship in Theoretical Quantum Computing

The University of Basel, Switzerland, invites applications for a professorship in theoretical quantum computing. The University of Basel is the home institution of the Swiss National Center of Compete...

Reposted by Zoe Holmes

Marco Cerezo @mvscerezo.bsky.social · Aug 26

I am so, so happy to see this article published as a perspective in Nature Communications:

www.nature.com/articles/s41...

More than the paper itself, I thoroughly enjoyed chatting with all my co-authors on the implications of the absence of BPs ~ classical simulability connection

Does provable absence of barren plateaus imply classical simulability? - Nature Communications

There has been growing evidence that strategies to circumvent the barren plateau problem in variational quantum computing might also kill potential quantum advantages. In this Perspective, the authors...

Zoe Holmes @qzoeholmes.bsky.social · Aug 19

@joachimfavre.bsky.social also has a bunch of cool projects being written up - and is currently looking for a PhD - so I recommend following him :)

Zoe Holmes @qzoeholmes.bsky.social · Aug 19

I highly recommend @joachimfavre.bsky.social’s typed lecture notes for my quantum info course and on (quantum) computer science more generally 👇

(To give credit where it’s due my quantum info lectures built in turn on @davidbjennings.bsky.social’s brilliant quantum info lecture notes)

Joachim Favre @joachimfavre.bsky.social · Aug 18

I recently published the LaTeX notes I took in three amazing classes this semester:
- Computational quantum physics (Prof. @gppcarleo.bsky.social)
- Quantum information theory (Prof. @qzoeholmes.bsky.social)
- Sublinear algorithms for big data analysis (Prof. Michael Kapralov)
Link below👇

Two-panel drake meme, titled "Morris' algorithm be like".
Top panel: Drake looks away, disapprovingly, next to the legend "Counting to n in O(log n) space".
Bottom panel: Drake points approvingly at the legend "Counting to n in O(loglog n) space.

Zoe Holmes @qzoeholmes.bsky.social · Aug 6

Hey! We've put out a paper discussing some pitfalls in attempts to avoid barren plateaus/exponential concentration in variational quantum algortithms and QML.

🧵👇

Zoe Holmes @qzoeholmes.bsky.social · Jul 24

EPFL are recruiting a tenure track assistant proff working on the theory of condensed matter and interacting quantum matter:

www.epfl.ch/about/workin...

Feel free to reach out if you have any questions about life at EPFL/in Switzerland etc.

Faculty Position in Theory of Condensed Matter and Interacting Quantum Matter

The School of Basic Sciences (Physics, Chemistry and Mathematics) at EPFL seeks to appoint a Tenure Track Assistant Professor in condensed matter theory with a focus on interacting quantum matter. Can...

Zoe Holmes @qzoeholmes.bsky.social · Jul 24

thanks! very helpful - will add.

Zoe Holmes @qzoeholmes.bsky.social · Jul 22

We thank the reviewer for bringing this citation to our attention...

Zoe Holmes @qzoeholmes.bsky.social · Jul 22

( And finally finally - if there are any citations you think we've missed - observations that are somewhat analogous to ours hidden in older papers/appendices please do shout! )