In today’s paper, we make important advances in our understanding of tomography of CV Gaussian states!

arxiv.org/pdf/2603.18136

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New paper out ✨

Fault-tolerant Transformation of Spacetime Codes, a collaboration w/ @vasmer.bsky.social, Austin Daniel & Ilan Tzitrin, which started during my internship @xanaduai.bsky.social

scirate.com/arxiv/2509.0...

Let's now see if I can summarize 101 pages (🙈) in a few tweets (and memes!)

New arXiv preprint: we show algorithmic versions of the polynomial Freiman–Ruzsa (PFR) theorem of Gowers, Green, Manners, and Tao. Interestingly, our proof draws on quantum information and stabilizer learning algorithms, which we dequantize into classical algorithms.

arxiv.org/pdf/2509.02338

Correction: the talk will start at 12:30 ET

come listen to @csenrui.bsky.social talk about his recent work at tomorrows seminar on the UF discord. It's open to anyone to attend :)

It took me a while, but I (finally) wrote a "short" (erm) note on the "polynomial+moments method" to prove testing or indistinguishability sample complexity lower bounds. Including the infamous Ω(k/log k) tolerant uniformity testing one.

Comments and feedback welcome!

📝 github.com/ccanonne/pro...

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

Engineering the summer: Advancing quantum computing at IBM

UChicago PME Quantum Engineering PhD student Su-un Lee is spending the summer interning with the #quantum algorithms team at IBM.

Read his Q&A in UChicago PME’s Engineering the Summer series: pme.uchicago.edu/news/enginee...

Title: Unitary designs in nearly optimal depth, Abstract: We construct ε-approximate unitary k-designs on n qubits in circuit depth O(log k log log nk/ε). The depth is exponentially improved over all known results in all three parameters n, k, ε. We further show that each dependence is optimal up to exponentially smaller factors. Our construction uses Õ(nk) ancilla qubits and O(nk) bits of randomness, which are also optimal up to log(nk) factors. An alternative construction achieves a smaller ancilla count Õ(n) with circuit depth O(k log log nk/ε). To achieve these efficient unitary designs, we introduce a highly-structured random unitary ensemble that leverages long-range two-qubit gates and low-depth implementations of random classical hash functions. We also develop a new analytical framework for bounding errors in quantum experiments involving many queries to random unitaries. As an illustration of this framework's versatility, we provide a succinct alternative proof of the existence of pseudorandom unitaries.

What is the min depth you need for a random unitary?

In this work w/ Tommy Schuster, @RobertHuangHY, Fernando Brandão (arxiv.org/abs/2507.06216) we glue random unitary blocks w/ only random phases on log n qubits (fns on log n bits) to get designs in d = log k log log n 🧩

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IQC and Waterloo mourn the loss of Raymond Laflamme | Institute for Quantum Computing | University of Waterloo Raymond Laflamme, a trailblazer in quantum information processing and pioneer of the Institute for Quantum Computing (IQC) at the University of Waterloo, died on June 19 after a lengthy battle with ca...

Raymond Laflamme 1960-2025. A great scientist, renowned for his pioneering contributions to quantum error correction. A great leader, founding director of the Institute for Quantum Computing. A great colleague and teacher whose legacy continues to inspire us.
uwaterloo.ca/institute-fo...

GitHub - csenrui/PauliGST: Codes for Gate-set Pauli noise learning Codes for Gate-set Pauli noise learning. Contribute to csenrui/PauliGST development by creating an account on GitHub.

A theoretical basis for this work is the Gate-set Pauli noise learning framework (arxiv.org/abs/2410.03906) which gives efficient parameterization of gauge parameters in a quasi-local Pauli noise model.

I recently post a notebook illustrating the basic ideas there: github.com/csenrui/Paul...

An exciting collaboration with Edward H. Chen, Laurin E. Fischer, Alireza Seif, Liang Jiang, and other colleagues from IBM Quantum and UChicago.

🪇Disambiguating Pauli noise in quantum computers
scirate.com/arxiv/2505.2...

Quantum noise characterization suffers from "gauge ambiguity" due to noisy initialization and measurements. We show this does not stop us from correctly mitigating errors, both in theory and in up to 92-qubit experiments

Details | Postdoctoral Associate - Computer Science | Careers | Division of Human Resources | Virginia Tech

I'm hiring a postdoc! If you'd like to work with me on quantum learning, error correction, quantum algorithms, and FTQC at Virginia Tech in the Washington, DC metro area, please apply here: careers.pageuppeople.com/968/cw/en-us...

Thank you, Evan! 😁

Thank you Greg 😆!

Thank you Jonathan! Congrats on your recent new position, too!

Hi Felix, thank you! I am starting as a postdoc at Caltech this summer. Will likely continue to work on related directions.

Thank you, Graeme!

I defended my PhD dissertation today!! 🍾🎓⚛️

Thank you to everyone who supported me along this wonderful journey!

Excited to share our first major result from our IARPA Entangled Logical Qubits team!

arxiv.org/abs/2504.07258

@benbrown.bsky.social @universal-soup.bsky.social @evanhockings.bsky.social @georgianixon.bsky.social

1/n I'm excited to share our latest work, Demonstration of robust and efficient quantum property learning with shallow shadows, published in Nature Communications! 🎉

📝 Authors: Hong-Ye Hu, Andi Gu, Swarnadeep Majumder, Hang Ren, Yipei Zhang, Derek S. Wang, Yi-Zhuang You, Zlatko Minev,

Won APS ducks at #APSSummit25 #apsmarch with Su-un Lee and Kento Tsubouchi

Only one week left to submit a contributed talk to QEC 25!
qec25.yalepages.org
August 11 - 15, 2025, hosted at Yale University.

This promises to be the best QEC yet!

Please repost!

Heading to Anaheim for #APSSummit25 #apsmarch.
I will be giving two talks, both on Monday:

1⃣ Efficient self-consistent learning of gate set Pauli noise, 10:24 – 11:00, 258A

2⃣ Generalized cycle benchmarking algorithm for characterizing mid-circuit measurements, 3:36 - 3:48, 256B

Why characterise noise in syndrome extraction circuits? One reason: directly improving quantum error correction!

In simulations of the surface code, we find that noise-aware decoding—calibrating the decoder with noise estimates—improves the code's error suppression factor.

1/n I am stepping away from IBM Quantum after nearly 7 years. This was an unforgettable chapter of my life where I was blessed with the best of colleagues, on a joint mission to bring useful quantum computing to the world, and to help bring up the next generation of young scientists.

Stepping away

A Constant Rate Quantum Computer on a Line We prove by construction that the Bravyi-Poulin-Terhal bound on the spatial density of stabilizer codes does not generalize to stabilizer circuits. To do so, we construct a fault tolerant quantum comp...

If qubits only talk to 1D neighbors, is constant rate fault tolerance possible?

Last year I referee'd a paper claiming it wasn't. My review was "this is wrong but the constructive disproof is too large for this review".

Clearly a reviewer 2 move. Sorry. But I was right! scirate.com/arxiv/2502.1...

Quantum Codes with Addressable and Transversal Non-Clifford Gates The development of quantum codes with good error correction parameters and useful sets of transversal gates is a problem of major interest in quantum error-correction. Abundant prior works have studie...

Check out our recent pre-print: arxiv.org/abs/2502.01864

In this work, we construct the first quantum codes which support transversal and addressable non-Clifford gates!