The term has started again at Freie Universität Berlin. This term, I am teaching my favourite subject, quantum information and quantum technologies.

www.physik.fu-berlin.de/en/einrichtu...

Warm thanks to Julio C. Magdalena de la Fuente, Noa Feldman, and Andreas Bauer.

We introduce a method for achieving high-threshold decoding of non-Pauli codes aimed at two-dimensional universality. Our results suggest that genuinely non-Clifford quantum operations in two-dimensional codes can perform comparably to those of a simple quantum memory.

scirate.com/arxiv/2604.0...

In the absence of quantum error correction, circuits of #quantumcomputers can be logarithmically deep.

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

Unfortunately not, no.

But this is a good point: We will add a comment to this effect.

Good question: I would say, quite natural.

QGPU: Parallel logic in quantum LDPC codes Quantum error correction is critical to the design and manufacture of scalable quantum computing systems. Recently, there has been growing interest in quantum low-density parity-check codes as a resou...

📢 New paper. 𝐐𝐆𝐏𝐔: 𝐏𝐚𝐫𝐚𝐥𝐥𝐞𝐥 𝐥𝐨𝐠𝐢𝐜 𝐢𝐧 𝐪𝐮𝐚𝐧𝐭𝐮𝐦 𝐋𝐃𝐏𝐂 𝐜𝐨𝐝𝐞𝐬. A great collaboration w/ Boren Gu, Andi Lui, Armanda Quintavalle, Xian Xu, & @jenseisert.bsky.social

𝐭𝐥𝐝𝐫; Quantum LDPC codes are an exciting architecture for fault-tolerant ... 1/n

scirate.com/arxiv/2603.0...

Thanks for posting.

A PAC-Bayesian approach to generalization for quantum models Generalization is a central concept in machine learning theory, yet for quantum models, it is predominantly analyzed through uniform bounds that depend on a model's overall capacity rather than the sp...

New #QML paper alert! 📝🧠⚛️

🧐 A PAC-Bayesian approach to generalization for quantum models
arxiv.org/abs/2603.22964

This collaboration involved some seriously hard and fun work by @pablones8.bsky.social, Matthias Caro, Carlos Bravo-Prieto, @fjschreiber.bsky.social, and @jenseisert.bsky.social

Measurement-induced non-commutativity in adaptive fermionic linear optics

We show that mid-circuit measurements of fermions with internal degrees of freedom can induce the equivalent of "magic" to free fermionic circuits and render them classically hard to sample.

scirate.com/arxiv/2603.2...

What a week. A highlight for me has been the #quantumtechnologies segment of the Grand Challenges conference of the @berlinualliance.bsky.social. Jerry Chow blew everybody away with his talk.

Wonderful talk, wonderful seeing you.

Thanks for posting.

QGPU: Parallel logic in quantum LDPC codes

scirate.com/arxiv/2603.0...

We introduce #clusteredcycliccodes for #quantumerrorcorrection and show how to pursue highly parallelized surface-code style quantum logic with quantum low density parity check codes featuring simple logicals.

Tight inapproximability of max-LINSAT and implications for decoded quantum interferometry.

scirate.com/arxiv/2603.0...

Warm thanks to @mxkramer.bsky.social and Carsten Schubert for this collaboration.

Thanks a lot for posting.

Warm thanks to the dream team of @sfeoliviero.bsky.social and Lorenzo Leone for this wonderful collaboration.

The unbearable hardness of deciding about magic

We show that determining membership in the stabilizer polytope, which defines the free states of magic-state resource theory, requires super-exponential time exp(n2) in the number of qubits n, even approximately.

scirate.com/arxiv/2602.2...

Once again, notions of #measurement feature strongly, which I find interesting.

There are interesting separations in quantum learning theory depending on whether or not one has access to post-measurement states in quantum measurement.

scirate.com/arxiv/2602.2...

Mid-circuit measurements are a powerful tool for state preparation. In contrast, their usefulness for #quantumcomputation remains comparatively less well understood. We demonstrate that #midcircuitmeasurementscan enable quantum advantages even in shallow circuits.

journals.aps.org/prl/abstract...

Variational #quantumalgorithms and classical variational methods, such as #tensornetworks, provide upper bounds on ground-state energies. This work provides guarantees for lower bounds.

journals.aps.org/pra/abstract...

ParityQC joins PraktiQOM project, developing advanced quantum algorithms for semiconductor chip design - ParityQC ParityQC is a member of the PraktiQOM project, aiming to advance quantum algorithms to solve real-world optimization problems.

We're excited to have kicked off a new project - together with Freie Universität Berlin, Technische Universität Berlin and NXP Semiconductors, and led by @jenseisert.bsky.social.

Our goal is to advance the performance of quantum algorithms to solve real problems in semiconductor chip manufacturing.

This is a paper I very much like, for its foundational and somewhat "rebellious" character: We show that notions channel capacities are strongly altered if one simply assumes that all operations one can implement are efficient.

scirate.com/arxiv/2601.1...

This is a paper I very much like, for its foundational and somewhat "rebellious" character: We show that notions channel capacities are strongly altered if one simply assumes that all operations one can implement are efficient.

scirate.com/arxiv/2601.1...

It has been a great pleasure—and both fun and insightful—to speak with Dr. Thomas Ramge about the future of quantum technologies, broader aspects of science and technology, and what makes science so exciting in the first place.

m.youtube.com/watch?si=mh2...

This is the most technological paper I have been involved in for a while. It presents a below-threshold error reduction in single photons through photon #distillation.

scirate.com/arxiv/2601.0...

Variational optimization of projected entangled-pair states on the triangular lattice.

journals.aps.org/prb/abstract...

The “meta-message” is that the use of tools such as #automaticdifferentiation, and the co-design of the ansatz class and the physical system can improve #tensornetwork methods.

A compellingly simple proof of the speed of sound for interacting bosons On physical grounds, one expects locally interacting quantum many-body systems to feature a finite group velocity. This intuition is rigorously underpinned by Lieb-Robinson bounds that state that loca...

Here the correct link to the paper. scirate.com/arxiv/2601.0...