Henry Yuen went into computer science to design video games, but he ended up studying the theoretical foundations of quantum computing. "Looking back, I couldn't have predicted any of the twists and turns that my interests have taken," he said.

A New Complexity Theory for the Quantum Age | Quanta Magazine

Henry Yuen is developing a new mathematical language to describe problems whose inputs and outputs aren’t ordinary numbers.

quantamagazine.org

I'm currently hiring PhD students for my group at QuTech. If you are (or know of) a theory MSc student interested in the theory of how we can utilize quantum systems for new forms of communication, sensing, and simulation, I have a vacancy up. Please check: qutech.nl/vacancy/2-ph...

Very excited to share a new paper with Malvika Joshi (@malvikaraj.bsky.social) on "Constant-Depth Unitary Preparation of Dicke States"! In this work, we offer the first unitary, constant-depth circuits for exact preparation of arbitrary-weight Dicke states. arXiv: arxiv.org/abs/2601.10693

Constant-Depth Unitary Preparation of Dicke States

Dicke states serve as a critical resource in quantum metrology, communication, and computation. However, unitary preparation of Dicke states is limited to logarithmic depth in standard circuit models ...

arxiv.org

Dominik Hangleiter weighs in with an informative post about a much debated question: Has quantum advantage been achieved? This is the first post in a three-part series. quantumfrontiers.com/2026/01/06/h...

Has quantum advantage been achieved?

Recently, I gave a couple of perspective talks on quantum advantage, one at the annual retreat of the CIQC and one at a recent KITP programme. I started off by polling the audience on who believed …

quantumfrontiers.com

Very excited to share a new paper with Malvika Joshi, Avishay Tal, and John Wright on “Improved Lower Bounds for QAC^0”! In this work, we prove the strongest known lower-bounds to date for QAC^0 with the full power of polynomially many ancillae. arXiv: arxiv.org/abs/2512.14643

Improved Lower Bounds for QAC0

In this work, we establish the strongest known lower bounds against QAC$^0$, while allowing its full power of polynomially many ancillae and gates. Our two main results show that: (1) Depth 3 QAC$^0...

arxiv.org

Join us for the first Quantum Cambridge–Oxford–Warwick Colloquium (Quantum COW, if you insist...), 11–12 December 2025 at the University of Oxford. This meeting focuses on Quantum Low-Depth Complexity, with talks, tutorials, and open discussions. Details: qcow.cs.ox.ac.uk

I was very excited to present my first research project on quantum algorithms at QSim 2025! This work, joint with András Gilyén, develops new space-time and space-accuracy tradeoffs for manipulation of block encodings, helping reduce ancilla-overhead in quantum algorithms. youtu.be/7AaZzzoSAic?...

Francisca Vasconcelos: “Methods for Reducing Ancilla-Overhead in Block Encodings”

YouTube video by Institute for Robust Quantum Simulation

youtu.be

In exciting new work with Ben Foxman, @nat-parham.bsky.social , and @henryyuen.bsky.social we show that t-designs and pseudorandom unitaries are implementable in constant (quantum) time! arxiv.org/abs/2508.11487

Random Unitaries in Constant (Quantum) Time

Random unitaries are a central object of study in quantum information, with applications to quantum computation, quantum many-body physics, and quantum cryptography. Recent work has constructed unitar...

arxiv.org

What better way to celebrate the 100th anniversary of quantum mechanics than a foundations conference in Gdańsk? I especially enjoyed learning about modern work on contextuality, quantum speed limits, & generalized probability + sharing ideas on connections between quantum logic and the QSVT ⚛️

I had a lot of fun giving my first philosophy (lightning) talk and catching up with quantum learning theory friends at Foundations of Quantum Computing 2025, in Edinburgh!

I think a lot about what Carl Sagan said in one of his final interviews.

Last week, I spoke at the Surfing the Ocean ERC seminar on faster classical algorithms for finding Nash equilibria of quantum zero-sum games. In particular, we achieve an O(1/\eps) convergence rate -- a quadratic speedup over the Jain-Watrous MMWU algorithm (2009). www.youtube.com/watch?v=lw0J...

Surfing the OCEAN - Francisca Vasconcelos

YouTube video by Erc Ocean

youtube.com

On behalf of Qubit x Qubit: 🚀 Calling all Quantum Computing and Cybersecurity Companies in NY! We're seeking internship hosts in NY state to provide hands-on experience in quantum computing and cybersecurity! 📨 If you’re in NY state and are interested in more details, email us at eqci@the-cs.org.

At QTML 2024, I spoke about recent work with Robert Huang on "Learning shallow quantum circuits with many-qubit gates" (a.k.a. efficient learning of QAC^0 unitaries). In this ~15min talk I discuss the project motivation, key results, and high-level proof ideas. www.youtube.com/watch?v=iRiJ...

Learning shallow quantum circuits with many-qubit gates - Francisca Vasconcelos

YouTube video by QTML Conference

youtube.com

Very excited that our work was featured on @tomgur.bsky.social's 2024 advent calendar, alongside many great math/TCS talks from the year! 😊

Tom Gur@tomgur.bsky.social · 2y ago

Day #11: Francisca Vasconcelos on the Pauli spectrum of QAC^0. This work provides an exciting new approach toward proving quantum circuit lower bounds via a quantum analogue of Fourier analysis, called Pauli analysis. www.youtube.com/watch?v=mpRp...

Day two of #qtml2024 brings another bouquet of exciting talks, e.g, by Maria Schuld and Kristan Temme - and also my plenary talk and a small technical talk have been happening today. I like how the meeting is developing: Lots of solid, rigorous technical work.