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Felix Leditzky 🏳️‍🌈🏳️‍⚧️

@felixleditzky.info
766 followers 584 following 434 posts

Associate Professor in Math at University of Illinois Urbana-Champaign | Quantum information theorist | Vienna native | CHI & STL fan (the cities, but also the sports) | (he/him)

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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 14/10/2026
Reference letter system admins of the world, please make it easy for us to check that we uploaded the right letter for the right job 🙏
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 13/10/2026
"If an expert prompts a result, they take up the mantle of responsibility I describe above [of explaining what you did, what is new vs. well-known, and nurturing the literature]. OpenAI not only refuses to take their responsibility, but they prevent their own customers from doing so." 🎯💯👏
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Nicholas Jackson @njj4.bsky.social · 10/10/2026
It's an academic DoS attack. Also it feels like OpenAI have burst in through the door and said "hey, I finished all those jigsaw puzzles you were doing - you're welcome!"
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Maris Ozols @marisozols.bsky.social · 09/10/2026
You may finally rest easy at night since SICs exist in all dimensions! github.com/marozols/SIC... SICs are d² unit vectors in d complex dimensions with pairwise equal inner products. Their existences in all dimensions d was conjectured by Zauner in 1999. en.wikipedia.org/wiki/SIC-POVM
Diagram illustrating Lean proof of SIC existence
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Robert "The Bobby Yaga" McNees @mcnees.bsky.social · 07/10/2026
Where is the understanding in any of this?
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Phil PlAIt @philplait.bsky.social · 06/10/2026
Congratulations to this year's winner of the Physics Nobel Prize!
Rapper Ice Cube wearing a baseball hat against a red background. Trillions of neutrinos are passing through him (not shown).
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Katie Mack @astrokatie.com · 06/10/2026
What is the IceCube neutrino observatory? Neutrinos are elusive particles that rarely interact, but can create flashes of light when they do. Most neutrino detectors are giant water tanks surrounded by light detectors. IceCube is kilometer-long strings of detectors embedded in the Antarctic ice.
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arXiv @arxiv.bsky.social · 01/10/2026
arXiv has updated our policy on rate limiting for all submitters. This update was made to fairly distribute moderator time & support the arXiv community of staff, volunteers, readers & authors. Please read our announcement to learn more: blog.arxiv.org/2026/10/01/updated-r…
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 01/10/2026
We analyze optimal data hiding schemes based on multipartite Werner states under PPT measurements, using the representation-theoretic framework of mixed Schur-Weyl duality. scirate.com/arxiv/2609.4...
scirate.com
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 01/10/2026
We investigate constructions of exact unitary designs under symmetry constraints that reflect physical limitations in quantum devices. scirate.com/arxiv/2609.4...
scirate.com
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 01/10/2026
We study the compatibility of measurements, quantum channels and quantum instruments using techniques from operator space theory. scirate.com/arxiv/2609.4...
scirate.com
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 01/10/2026
We recast the sample complexity of k-copy quantum state discrimination as a quantum mixing time problem that becomes fully classical under suitable (and natural) symmetries, with applications to e.g. learning phase states and hypergraph states. scirate.com/arxiv/2609.4...
scirate.com
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 01/10/2026
We use representation theory to understand IID depolarizing channels as Gaussian channels in a suitable limit, which yields a substantial improvement on the best lower bound on the quantum capacity threshold of the depolarizing channel. scirate.com/arxiv/2609.3...
scirate.com
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 01/10/2026
Today my group put out 5 new papers in time for the QIP deadline next week! With 221 (!) other papers posted to arXiv.org/quant-ph today, it might be a good idea to try to increase their visibility. I'll mention them sorted alphabetically by title (and might add little blurbs about each later) 🧵
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 01/10/2026
Today my group put out 5 new papers in time for the QIP deadline next week! With 221 (!) other papers posted to arXiv.org/quant-ph today, it might be a good idea to try to increase their visibility. I'll mention them sorted alphabetically by title (and might add little blurbs about each later) 🧵
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 29/09/2026
🐻↘️🦅
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Graeme Smith @graemesmith.bsky.social · 28/09/2026
Shame on @qipconference.bsky.social for using X/twitter. You give our community a bad name.
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Jeffrey Shallit 🇺🇦 @shallit.bsky.social · 18/09/2026
A new risk for mathematicians: a colleague reports that immediately after they posted an abstract of their upcoming talk online, a student elsewhere used AI to derive proofs of the stated results and then posted it on the arxiv. My colleague hadn't posted to arxiv yet. Scummy. Watch out.
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Katie Mack @astrokatie.com · 23/09/2026
Good morning from @perimeterinstitute.bsky.social ! ☀️
A chalkboard on an outdoor wall next to a reflecting pool, with chairs and a sofa in front of the wall. In chalk, there is a drawing of the institute and the words “Welcome to Perimeter. Discovery starts with curiosity.”
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 15/09/2026
New work "High quantum local differential privacy breaks entanglement" led by my student Sujeet Bhalerao and postdoc Theshani Nuradha! We study the interplay of local differential privacy and entanglement, and implications for learning theory in the private setting. scirate.com/arxiv/2609.1...
scirate.com
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Dmitry Grinko @dmitry-grinko.bsky.social · 08/09/2026
One could try to explain Navier-Stokes drama via hypothesis that Levent or Tristan did not properly turn off data-sharing in ChatGPT. It is not enough to turn off "Improve the model for everyone" in Data controls settings, you need to submit it via "Privacy center". 1/3
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 08/09/2026
Caution should be applied when using LLMs in your research. This story is wild.
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Karthik Ram @karthik.io · 06/09/2026
Today's vibe
A cartoon character tired of Zoom calls, ready to go recharge in nature
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 02/09/2026
arXiv submission statistics for the quant-ph channel for the last 5 years, 2 years, 6 months.
Plot of the arXiv submissions to the quant-ph channels in the last 5 years.Plot of the arXiv submissions to the quant-ph channels in the last 2 years.Plot of the arXiv submissions to the quant-ph channels in the last 6 months.
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 26/08/2026
Great way to honor Dolly Parton: donate.imaginationlibrary.com
donate.imaginationlibrary.com
Home
Make a donation and support Dolly Parton's Imagination Library in communities around the world and help put more books into the hands of more children.
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 26/08/2026
Great way to honor Dolly Parton: donate.imaginationlibrary.com
donate.imaginationlibrary.com
Home
Make a donation and support Dolly Parton's Imagination Library in communities around the world and help put more books into the hands of more children.
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 20/08/2026
Awful news
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 18/08/2026
A brief history of the Four-Color Theorem, eventually proved by Appel and Haken in the late 70s at #UIUC in one of the first (?) computer-assisted proofs. www.ams.org/journals/not...
ams.org
AMS :: Notices of the American Mathematical Society
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Mark M. Wilde @markwilde.bsky.social · 15/08/2026
AI sloppers, they ain't scholars, just faking it Forcing youth away from the truth, they ain't making it The kids of today should defend themselves against GPT Emptying minds with empty lies gotta make you laugh Tech-bro vendors buying true defenders of the math
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 13/08/2026
Is anyone else bothered by the fact that \overset{x}{y} puts x over y and not the other way round? I always think this out loud as "overset x with y", only to find my latex garbled.
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 10/08/2026
Bravo an dieses Wiener Lokal und deren Belegschaft für ein Zeichen gegen Rechts, die Identitären und ihr Ober-Heisl Sellner
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 10/08/2026
Very happy for Joel Hamkins (I think his "Lectures on Infinity" (youtube.com/playlist?lis...) are fantastic), and eager to learn about the other award winners!
youtube.com
Lectures on Infinity - YouTube
Professor Joel David Hamkins guides viewers through the great paradoxes and discoveries about infinity, from Zeno's ancient puzzles to Cantor's revolutionary...
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Claudine Monteil @claudinemonteil.bsky.social · 09/08/2026
In a little more than one month, September 15, my father, French #mathematician Jean-Pierre Serre, Fields medal and Abel Prize, will hopefully speak at the conférence in his honor for his 100th Birthday. Can't wait 🙏🏻
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 08/08/2026
This article is a really good read! Thx for posting @joshuagrochow.bsky.social It's also a reminder that LLMs, when they produce a solid or even exciting mathematical result, don't *actually* do math in the background. That is still us.† †Hopefully including those who now do research this way.
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 02/08/2026
One way to cope with the current situation as a mathematician: understand the mathematics of transformers, the driver of LLMs. arxiv.org/abs/2312.10794
arxiv.org
A mathematical perspective on Transformers
Transformers play a central role in the inner workings of large language models. We develop a mathematical framework for analyzing Transformers based on their interpretation as interacting particle sy...
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Ciara Torres-Spelliscy @profciara.bsky.social · 31/07/2026
To go from Pee-Wee’s Playhouse to the Matrix should give everyone hope that your career can improve. Today’s job is not your identity.
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Rod Van Meter @rdvquantum.bsky.social · 30/07/2026
I personally know these people, this is legit. A small org for continuing financial, organizational and legal support for making some of the independent quantum conferences run.
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International Association for Quantum Information @iaqi.bsky.social · 30/07/2026
Let's have a community discussion about the impact of LLMs on quantum information research, and how to react to it as a research community! 👩‍🔬⚛️🤖 🏛️ Head over to the IAQI forum 👇 discuss.iaqi.org/t/quantum-in... 🦋 Please share widely!
discuss.iaqi.org
Quantum Information Processing research in the age of AI
Dear colleagues, Over the past weeks there have been more and more results in which AI models played a crucial role, not only in mathematics and theoretical computer science, but right at the heart o...
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 30/07/2026
Film you've watched more than six times with a gif. Hard mode: no Star Trek, Star Wars, LOTR, Marvel, Disney, or Ghibli.
static.klipy.com
Jack Black's Crazy Dance in High Fidelity
Alt: Jack Black's Crazy Dance in High Fidelity
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Alexander Stottmeister @stotti-alex.bsky.social · 28/07/2026
I tend to agree with Tobias. It will be interesting to see near-term changes in the valuation of certain aspects of research. An important problem I see is who can afford access to frontier models and how the scientific community should address this. tjoresearchnotes.wordpress.com/2026/07/28/p...
tjoresearchnotes.wordpress.com
Proof inflation
I have been thinking a lot about how social dynamics are going to shift in the new era of cognitive abundance. I don’t pretend to have any kind of crystal ball, but there are numerous histori…
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 28/07/2026
Some good personal news in these strange and turbulent times: I was just promoted to Associate Professor on indefinite Tenure, effective Aug 16 🥲 Immensely grateful to everyone who helped me get here - I won't list them since they know who they are 😊
static.klipy.com
Michael Scott's Dancinha Dance
ALT: Michael Scott's Dancinha Dance
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Clément Canonne @ccanonne.github.io · 26/07/2026
There may be, and there is, a debate to have about the use of AI in research, in maths, in society. Using it as "an oracle to put words in the mouth of dead people" is not part of that, and is (IMO) absolutely insane to use one's platform to the community for that.
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 24/07/2026
Elvis actually never existed.
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 23/07/2026
2026 Fields Medalists: Yu Deng (University of Chicago) John Pardon (State University of New York Stony Brook) Jacob Tsimerman (University of Toronto) Hong Wang (New York University and IHES) www.mathunion.org/imu-awards/f...
mathunion.org
Fields Medals 2026 | International Mathematical Union (IMU)
For his work in partial differential equations, including the rigorous derivation of the Boltzmann equation from hard-sphere dynamics for rarefied gases, the derivation of wave kinetic equations from nonlinear dispersive systems, and probabilistic approaches to nonlinear Schrodinger dynamics.
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 23/07/2026
I do not think that relegating research work to an LLM is the same as giving a research idea to a student. The latter involves mentoring, which is an integral part of our work as advisors. (I've heard this argument a lot in discussions with colleagues about the use of LLMs in research.)
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 22/07/2026
Another aspect of this is that certain academic institutions with the necessary resources are making LLMs freely accessible for their staff and students, which will further aggravate the existing inequality in the academic landscape.
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Felix Leditzky 🏳️‍🌈🏳️‍⚧️ @felixleditzky.info · 21/07/2026
In recent times far too many colleagues start discussions about LLMs and the future of math and related fields. I've always taken the stance that mathematical research is more than just a giant list of open problems to be solved.* @amkasprzyk.bsky.social finds a great way of framing this 👇
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Alexander Kasprzyk @amkasprzyk.bsky.social · 21/07/2026
I’m not disagreeing with you Pieter, but we don’t need an LLM to tell us that the dim >= 3 case wasn’t well studied. The people doing the work have already written this. The real “problem” (if it is one) is that as a community we make a huge fuss over these questions, raising them to mythical…
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Mark M. Wilde @markwilde.bsky.social · 20/07/2026
Group photo from "Additivity Problems in Quantum and Classical Information Theory" in Banff, Canada www.birs.ca/workshops/20...
birs.ca
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Markus Heinrich @markusheinrich.bsky.social · 16/07/2026
📢 Fully-funded 3-year PhD in my Quantum Randomness Group @ Uni Cologne as part of our QuantERA consortium: benchmarking, characterization, and learning on bosonic quantum computers. Deadline 12 Aug 2026. More info: www.quantum-randomness.com/joinus #PhD #Quantum #QuantERA
quantum-randomness.com
Quantum Randomness Group / Join us
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