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Jens Eisert @jenseisert.bsky.social · 5d

A data-driven heuristic method using tensor-network ansatze is shown to perform high-fidelity tomography of topological states.

go.aps.org/4nVFFKy

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Jens Eisert @jenseisert.bsky.social · 12d

Computational relative entropy

We take steps towards a computationally efficient quantum information theory.

scirate.com/arxiv/2509.2...

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Jens Eisert @jenseisert.bsky.social · 20d

Efficient distributed inner-product estimation via Pauli sampling

journals.aps.org/prxquantum/a...

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Jens Eisert @jenseisert.bsky.social · Sep 3

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.

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Jens Eisert @jenseisert.bsky.social · Sep 3

The dream team involved @timohillmann.bsky.social, @qec.codes, @lucasberent.bsky.social, Armanda Quintavalle, and Robert Wille.

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Jens Eisert @jenseisert.bsky.social · Sep 3

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.

Localized statistics decoding for quantum low-density parity-check codes - Nature Communications

Quantum low-density parity-check (QLDPC) codes offer lower overhead than topological quantum error-correcting codes, but decoding remains a key challenge for scalable fault-tolerant quantum computing....

www.nature.com

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Jens Eisert @jenseisert.bsky.social · Aug 29

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.

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Jens Eisert @jenseisert.bsky.social · Aug 28

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.

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Jens Eisert @jenseisert.bsky.social · Aug 25

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...

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Jens Eisert @jenseisert.bsky.social · Aug 25

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...

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Jens Eisert @jenseisert.bsky.social · Aug 15

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...

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Jens Eisert @jenseisert.bsky.social · Jul 18

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...

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Jens Eisert @jenseisert.bsky.social · Jul 2

For #CRC183 it is relevant as it once again showcases the power of #measurements.

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Jens Eisert @jenseisert.bsky.social · Jul 2

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.

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Jens Eisert @jenseisert.bsky.social · Jul 2

Short-time simulation of quantum dynamics by Pauli measurements.

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

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Jens Eisert @jenseisert.bsky.social · Jul 1

This is also relevant for @dfg.de #CRC183 and #ML4Q.

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Jens Eisert @jenseisert.bsky.social · Jul 1

www.quantum-randomness.com/clifford-wor...

Workshop: "Clifford commutant and its applications"

www.quantum-randomness.com

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Jens Eisert @jenseisert.bsky.social · Jul 1

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.

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Jens Eisert @jenseisert.bsky.social · Jun 27

Yes, indeed, great fun.

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Jens Eisert @jenseisert.bsky.social · Jun 26

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.

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Jens Eisert @jenseisert.bsky.social · Jun 15

The ride to #Benasque is always magical.

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Jens Eisert @jenseisert.bsky.social · Jun 12

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.

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Jens Eisert @jenseisert.bsky.social · Jun 8

Warm thanks to @fjschreiber.bsky.social and Johannes J. Meyer for the wonderful and productive collaboration.

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Jens Eisert @jenseisert.bsky.social · Jun 8

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

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Jens Eisert @jenseisert.bsky.social · Jun 6

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...

Palo Alto in Dahlem?: Berlin auf dem Weg zur Quantenmetropole

Die Initiative „Berlin Quantum“ nimmt Fahrt auf und will komplexe Quantenwelt besser nutzbar machen – mit jeder Menge Drittmitteln im Rücken.

www.tagesspiegel.de

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