Efficient distributed inner-product estimation via Pauli sampling journals.aps.org/prxquantum/a...

Optimal trace distance bounds for free-fermionic states: Testing and improved tomography journals.aps.org/prxquantum/a... How can one optimally learn Gaussian fermionic states? A new trace distance bound is the key. Thanks to Lennart Bittel, @Antonio_ and Lorenzo Leone for this collaboration.

Localized statistics decoding for quantum low-density parity-check codes www.nature.com/articles/s41... A highly efficient and highly parallelizable decoder for qLDPC codes, overcoming a bottleneck in the field. Warm thanks to the team for the collaboration.

A fun discussion at the Oxford Union at #Seeqa2025 circled around the question whether we can reasonably expect quantum computers to have a bigger impact on our lives than classical computers. With Elham Kashefi, Terry Rudolph, Victor Albert, Nathan Wiebe, Graham Smith.

Quantum metrology in the finite-sample regime journals.aps.org/prxquantum/a... We propose an operational framework of #quantummetrology in the practically meaningful regime of a few measurement samples, introducing probably approximately correct (#PAC) metrology.

Random #tensornetworks provide a powerful framework for probing and understanding complex quantum systems, especially in regimes where conventional tools fail. Here, we rigorously investigate dynamical properties of holographic toy models. scirate.com/arxiv/2508.1...

Learning quantum states - aka #quantum state tomography - is strangely sample inefficient for #continuousvariable states. For #Gaussian states, it should be relatively easy. Here, we find an energy independent way, equipped with rigorous performance guarantees. scirate.com/arxiv/2508.1...

Two papers approach the question of how to better classically simulate quantum circuits at large scales and/or in the presence of noise. It turns out that one can go to large system sizes and even equip statements with rigorous guarantees. scirate.com/arxiv/2508.0... scirate.com/arxiv/2508.1...

Where do thermal states in nature come from? We present technical progress: we show that if initial states are slightly perturbed— anyway not known to arbitrary precision—then local thermalization can be rigorously proven, offering a novel perspective on typicality. www.nature.com/articles/s42...

Summer is back, and so are our garden seminars on #quantumerrorcorrection. Thanks so much, Virgile Guemard, for the compelling talk on lifted quantum Tanner codes.

Short-time simulation of quantum dynamics by Pauli measurements. journals.aps.org/pra/abstract...

Teaching is fun. Today, I have covered elements of the Pauli and Clifford groups. Cutely, at the very same moment when in Cologne, a #Berlin-#Cologne workshop is talking place on the Clifford commutant, triggered by two papers only, arxiv.org/abs/2504.12263, arxiv.org/abs/1712.08628.

A minimal tensor network beyond free fermions. www.scipost.org/SciPostPhys.... This work proposes a minimal model extending the duality between classical statistical spin systems and fermionic systems beyond the case of free fermions, for the #CRC183.

The ride to #Benasque is always magical.

Variationally optimizing infinite projected entangled-pair states at large bond dimensions: A split corner transfer matrix renormalization group approach journals.aps.org/prb/abstract... Thanks to Jan Naumann, Erik Lennart Weerda, Matteo Rizzi, and Philipp Schmoll for this #CRC183 collaboration.

Quantum state tomography for states that vary with parameters such as time or control settings attains new capabilities in characterization of evolving quantum states. go.aps.org/3SAelEa

An article in the leading daily newspaper @tagesspiegel.de on #Berlin as a place for doing good research on quantum science and technology. And what BERLIN QUANTUM and several other initiatives have to do with it. www.tagesspiegel.de/themenspezia...

I am delighted to see our joint theoretical-experimental work probing notions of Landauer's principle in the many-body regime published in @nature.com Physics. Landauer's principle is one of the deepest connections between information theory and thermodynamics. www.nature.com/articles/s41...

Quantum computing and artificial intelligence: status and perspectives In recent years, several research lines became important that are located at the intersection of the study of quantum computers and of notions of artificial intelligence. scirate.com/arxiv/2505.2...

"Why do we do quantum? And what does the field have to offer for young researchers?" An outreach and scientific talk to be held today at a supplier workshop of the @munichquantum.bsky.social. indico.munich-quantum-valley.de/event/736/ti... Yesterday, I spoke for the #BMFTR project #MuniQCAtoms.

"Why do we do quantum? And what does the field have to offer for young researchers?" An outreach and scientific talk to be held today at a supplier workshop of the @munichquantum.bsky.social. indico.munich-quantum-valley.de/event/736/ti... Yesterday, I spoke for the #BMFTR project #MuniQCAtoms.

Hardware-tailored logical Clifford circuits for stabilizer codes scirate.com/arxiv/2505.2... This first first author paper of Eric appeared yesterday, but was not picked up by Scirate. It suggests novel strategies for implementing logical Cliffords of stabilizer codes under hardware constraints.

Hardware-tailored logical Clifford circuits for stabilizer codes arxiv.org/abs/2505.20261 It is important to identify strategies for implementing Clifford unitaries at the logical level of stabilizer codes in #quantumerrorcorrection, respecting hardware constraints. Here is one such strategy.

MATH+ has secured 7 more years of Excellence funding! 🎉 We advance mathematics to tackle major challenges like climate, health & AI. Berlin stays at the forefront of interdisciplinary research with real-world impact. shorturl.at/xc5gt

I am excited to learn that the cluster of excellence on applied #mathematics @mathplusberlin.bsky.social within the @berlinualliance.bsky.social is going to be funded for the next period as well. Exciting! Looking forward to further productive joint work. Am I the first one to notice?

In the shadow of the Hadamard test: Using the garbage state for good and further modifications scirate.com/arxiv/2505.1... This work adds an unexpected twist to the Hadamard test by exploiting previously overlooked information.

Stochastic noise can be helpful for variational quantum algorithms journals.aps.org/pra/abstract... I am excited to see this work, finally, published. We show that small noise levels can be helpful to avoid saddle points in variational quantum algorithms, from a rigorous perspective.

The abelian state hidden subgroup problem: Learning stabilizer groups and beyond scirate.com/arxiv/2505.1...

The non-Clifford cost of random unitaries scirate.com/arxiv/2505.1... In this work, we explore the ensemble of t-#doped random quantum #Clifford circuits on n qubits, consisting of Clifford circuits interspersed with t single-qubit non-Clifford gates.

Optimal randomized measurements for a family of non-linear quantum properties scirate.com/arxiv/2505.0... We introduce sample optimal schemes for estimating quantities such as tr(O \rho^2) that are important, e.g., in families of error mitigation methods.

Dynamical codes for hardware with noisy readouts We deliver good design choices for measurement schedules for #dynamical codes in #quantumerrorcorrection in the presence of noisy measurements. And define the "teraquop volume" as a new metric. arxiv.org/abs/2505.07658

There are only a few things in life as joyful as explaining quantum teleportation for the first time in a course on #quantuminformationtheory.

Measurement-driven quantum advantages in shallow circuits scirate.com/arxiv/2505.0... This work demonstrates that, using dynamical quantum circuits with mid-circuit measurements, one can achieve quantum advantages even with constant-depth quantum circuits, establishing a separation.

"Coherently mitigating boson samplers with stochastic errors" scirate.com/arxiv/2505.0... This is a step towards #quantumerrormitigation for #sampling problems.

A talk to be held next week in Edinburgh, on entanglement, information, and complexity, and the various unexpected links between the concepts. higgs.ph.ed.ac.uk/workshops/en...

The almost complete team of #QCTiP2025: For the local organization team Jan Felix Witte, the head @peter-jan.bsky.social, Armanda Quintavalle, Tommaso Guaita, and Gregory White (Claudia Thomas missing), for the steering committee me and for the programme committee Matthias Caro.

The group photo of #QCTiP2025, held at @freieuniversitaet.bsky.social and the Harnack House of the Max Planck Society. This is an impressive crowd of active researchers interested in quantum computing theory in practice.

The #QCTiP2025 conference, filled with great vibes, is wrapping up on the department’s rooftop terrace in a relaxed, chilled atmosphere. What a blast!

The second to last afternoon session of #QCTIP2025 features great talks on classical shadows to estimate properties of quantum systems.

The second morning session of #QCTIP2025 today features exciting talks by Richard Puig, Giulio Crognaletti, and Salvatore F. E. Oliviero on learning theory and variational quantum computing.

Kicking off day three of #QCTIP2025, Nathan Wiebe is critical of variational quantum algorithms requiring gradients. And suggests a compelling way out, actually two of them. Standing room only - and this after the conference dinner with free drinks.

The #QCTIP conference dinner is taking place on the rooftops of City West in Berlin.

The industry panel at #QCTiP2025, featuring Fedor Simkovic (IQM), Thomas O’Brien (Google Quantum AI), Ieva Capaite (Phasecraft), Ophelia Crawford (Riverlane), and Coral Westoby (NuQuantum).

The second morning session at #QCTiP2025 featured quantum phase estimation, Hamiltonian simulation, shortest vector problems, verified quantum computing and gates, and entanglement theory by Laura Clinton, Jakob Günther, Joao Doriguello, Christopher Vairogs, Nikolai Mirklin, and Daniel Mills.

The group photo of #QCTiP2025, held at @freieuniversitaet.bsky.social and the Harnack House of the Max Planck Society. This is an impressive crowd of active researchers interested in quantum computing theory in practice.

Day two of #QCTiP2025 kicks off with exciting talks by Alireza Reif, @ghosh_quantum, Marcel Hinsche, Nadish de Silva, Seok-Hyung Lee, and Alexander Schuckert on quantum learning theory and quantum error correction.

The poster sessions provide a fitting conclusion to an exciting first day at #QCTIP2025.

An afternoon session at #QCTiP2025 covers #quantumalgorithms for #quantumchemistry, with exciting talks by Javier Moreno, Oriel Kiss and @dobrautz.bsky.social.

One of the first afternoon sessions at #QCTiP2025 is dedicated to #quantumalgorithms, with exciting talks held by @Noajshu, Xin Wang and Jeffery Yu.

One of the first sessions at #QCTiP2025 is a session on #quantumerrorcorrection, with arresting results in particular on decoding and dynamic codes being presented by Alec Eickbusch, @lucasberent.bsky.social and Laura Caune.