Timo Hillmann

Timo Hillmann

@timohillmann.bsky.social

PhD student @ Chalmers University of Technology

508 followers173 following43 posts

Timo Hillmann
@timohillmann.bsky.social

Working on LSD was fun! - Our paper on Localized statistics decoding (LSD) for qLDPC codes is now in print. LSD is a highly parallelizable, reliability-guided inversion decoder that exploits the clustering of errors. Think of it as a parallel version of OSD. www.nature.com/articles/s41...

nature.comLocalized statistics decoding for quantum low-density parity-check codes - Nature CommunicationsQuantum low-density parity-check (QLDPC) codes offer lower overhead than topological quantum error-correcting codes, but decoding remains a key challenge for scalable fault-tolerant quantum computing....
Timo Hillmann
@timohillmann.bsky.social

All of this is made possible through a novel parallel matrix factorization strategy, which we call on the-fly elimination, to identify, validate, and solve local decoding regions on the decoding graph.

Timo Hillmann reposted

Arne Semsrott
@arnesemsrott.bsky.social

Der Polizist behält seinen Job, denn: "Aus den Nachrichten ergebe sich noch keine eindeutig verfassungsfeindliche Gesinnung."

Reiko Pinkert@reikopinkert.bsky.social

Während seines Einsatzes als Leibwächter für Charlotte Knobloch, Präsidentin der israelitischen Kultusgemeinde - schrieb er: "Ich scheiß ihr vor die Tür, schön braun, mit Fähnchen". Er wünsche sich, seine Schutzperson würde vergast bzw in ein Konzentrationslager verbracht (…). tinyurl.com/2dp3fa58

tinyurl.com"Fahrziel Auschwitz": Polizist behält Job trotz menschenverachtender Chat-NachrichtenDie Chats eines Polizisten waren fremdenfeindlich, geschmacklos und durchzogen von rechtsradikaler Rhetorik. Nicht genug für eine Suspendierung, meint der VGH München.
Timo Hillmann
@timohillmann.bsky.social

As Gallager already noted, BP is often more art than science, justified “only by the fact that it works.” But it does work in many cases, and I think it’s worth exploring how far we can push it with careful heuristics and structured approaches.

Timo Hillmann
@timohillmann.bsky.social

Since even for surface codes Relay-BP (Fig. 2) competes with matching-based decoders, it would be interesting to see whether Relay-BP outperforms known color code decoders, relevant, for example, to the performance of magic state cultivation.

Timo Hillmann
@timohillmann.bsky.social

While writing my thesis, I revisited a lot of the BP literature and dug into the basics. One thing that stood out is that heuristics for trapping sets are rarely tested under circuit-level noise, even though decoding in that setting is significantly different from code capacity.

Timo Hillmann
@timohillmann.bsky.social

Another thing I noticed: there has been only limited effort to combine different strategies to mitigate trapping sets. I had actually written this down as a future project idea but didn't get to it, so I’m glad to see that the IBM Quantum team has already shown that this direction is viable.

Timo Hillmann reposted

Seok-Hyung Lee
@seokhyung-lee.bsky.social

I recently created a simple Python wrapper for the Tesseract decoder for personal use, but I’ve decided to make it public in case others find it useful. Feel free to let me know if you encounter any issues! github.com/seokhyung-le...

github.comGitHub - seokhyung-lee/tesseract-python: Python Wrapper for Tesseract DecoderPython Wrapper for Tesseract Decoder. Contribute to seokhyung-lee/tesseract-python development by creating an account on GitHub.

Timo Hillmann reposted

Max Czollek
@maxczollek.bsky.social

Ok, heute ARD-Brennpunkt zur AfD, auf einen der Gäste kommt ihr nie. Richtig, Tino Chrupalla. Vor 80 Jahren hätte der zumindest auf der Anklagebank gesessen. Woher diese unbändige Lust, weiter mit Nazis zu reden? Ist es Masochismus? Erinnerungskultur tm? Oder vermisst ihr einfach eure Omas und Opas?

Timo Hillmann reposted

Mark M. Wilde
@markwilde.bsky.social

This past week, I received a second stop work order on one of my grants. This now means that we can no longer spend on *two* of my major grants. Several of my group members will now graduate earlier than expected, I am looking into being a consultant for the summer, and students will do internships

Timo Hillmann reposted

Ingwar Perowanowitsch
@ingwarpero.bsky.social

Dass ausgerechnet die CSU-Politikerin Doro Bär, die noch vor wenigen Jahren den menschengemachten Klimawandel leugnete, jetzt neue Forschungsministerin werden soll - ein Job, bei dem es ganz besonders darauf ankommt, der Kraft der Wissenschaft zu vertrauen, ist m.E. hochproblematisch.

Timo Hillmann
@timohillmann.bsky.social

When we wrote the theory proposal for the dissipatively stabilized squeezed cat qubit, we got into an argument with the copy editors of the journal. I had a strong opinion against calling it „cat state qubit“ (as no one does) which got so far that we almost had to add a disclaimer, see the mail

Alice & Bob @alice-and-bob.bsky.social

What if we could “squeeze” even more performance out of cat qubits? 📝 In our new paper, we show how Squeezing can drastically reduce overall errors, with a 160x increase in bit-flip lifetime while keeping phase-flips constant. 🔗 Link to paper: arxiv.org/pdf/2502.07892 #quantumcomputing #physics

Timo Hillmann reposted

Henrik Wilming
@arrr.de

I think it would be a good time to reinstantiate the mirror network for the # arXiv. It’s an essential piece of the global research community in math, physics, computer-science and adjacent fields. Under the current circumstances it should not only be hosted in the US. #quantum #math #physics #cs

Timo Hillmann reposted

Diego Ruiz
@diego-ruiz.bsky.social

First realization of a dissipatively stabilized squeezed cat qubit (a slight variation that we called a moon cat 🌛 actually), it was super interesting to work on this with experimentalists! arxiv.org/abs/2502.07892 My two key takeaways ⬇️⬇️

arxiv.orgEnhancing dissipative cat qubit protection by squeezingDissipative cat-qubits are a promising architecture for quantum processors due to their built-in quantum error correction. By leveraging two-photon stabilization, they achieve an exponentially suppres...
Timo Hillmann
@timohillmann.bsky.social

I’m super excited to see the experimental realization of a variant of the dissipatively stabilized squeezed cat that we proposed! Congrats to Alice & Bob and everyone else involved Especially great to see that it comes with similar performance gains as promised by the theory arxiv.org/abs/2502.07892

arxiv.orgEnhancing dissipative cat qubit protection by squeezingDissipative cat-qubits are a promising architecture for quantum processors due to their built-in quantum error correction. By leveraging two-photon stabilization, they achieve an exponentially suppres...

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