Alexander Stottmeister

Even if you think you are not interested, you should take a look 😅.

A plastic sign with a logogram of two people in conversation alongisde text that reads "There are no lone geniuses"

Our new "There are no lone geniuses" sign mounted on the door to the lab.

I made a sign for the lab with our informal lab motto, inspired by this convo between @itaiyanai.bsky.social and Martin Lercher: nightscience.buzzsprout.com/1744020/epis.... A good reminder that talking is among the best forms of thinking!

Ins eigene Fleisch: Warum Kürzungen an Hochschulen allen schaden von Amrei Bahr und Kristin Eichhorn

Sie ist da: Die 1. Ausgabe meines #ArbeitInDerWiss Newsletters bei Steady, wo der Newsletter ab jetzt 1 neues Zuhause hat! 🤩 & dann auch noch 1 gemeinsamer Text mit @drkeichhorn.bsky.social! 🥰 Es geht um Kürzungen an Hochschulen & warum es nun Solidarität mit Geistes- & Sozialwissenschaften braucht.

Indeed :)

Gaussian fermionic embezzlement of entanglement Embezzlement of entanglement allows to extract arbitrary entangled states from a suitable embezzling state using only local operations while perturbing the resource state arbitrarily little. A natural...

Like embezzlement of entanglement but not von Neumann algebras?

Check out
arxiv.org/abs/2509.15749

where we show explicitly that generic Gaussian fermionic states provide universal embezzling families.

Plus: A novel bound relating trace distance of Gaussian states to their covariance matrices.

Uniqueness of purifications is equivalent to Haag duality The uniqueness of purifications of quantum states on a system $A$ up to local unitary transformations on a purifying system $B$ is central to quantum information theory. We show that, if the two syste...

New paper on entanglement in infinite quantum systems with @stotti-alex.bsky.social @arrr.de 🎉: 

arxiv.org/abs/2509.12911

The paper investigates bipartitions of quantum systems with infinitely many degrees of freedom. Small thread below 👇

🥳I am very happy to have been awarded an ERC Starting Grant that I will use to start my own group and explore the large-scale entanglement properties of complex quantum systems.

This would not have been possible without my fantastic collaborators and supervisors. A big "thank you" to all of you! 🙏

I’m an award-winning mathematician. Trump just cut my funding. The “Mozart of Math” tried to stay out of politics. Then it came for his research.

I wrote an op-ed on the world-class STEM research ecosystem in the United States, and how this ecosystem is now under attack on multiple fronts by the current administration: newsletter.ofthebrave.org/p/im-an-awar...

I have some related posts on this at mathstodon.xyz/@tao/1149568... and mathstodon.xyz/deck/@tao/11...

#IPAM (the institute for pure and applied mathematics) is facing a critical shortfall for operating expenses due to an unexpected suspension of NSF funding www.ipam.ucla.edu/news/nsf-fun... . Donations for emergency continuity of operations funding can be made at

giving.ucla.edu/Campaign/Donat

If you find it strange that the inequality involves two arbitrary states, operator-valued weights come to your aid, giving meaning to the inverse of a state. This way, the inequality becomes a statement about the cp-odering of maps from B(H) to the subalgebras associated with systems B and BC.

An inequality between density operators: \rho_A \otimes \sigma_{BC}^{-1} \geq \rho_{AB} \otimes \sigma_C^{-1}

Small paper w/ @lvanluijk.bsky.social and @stotti-alex.bsky.social: We revisit the amazing operator inequality by Lin et al. (arXiv:2211.13372), which implies strong sub-additivity of entropy and find that it's a special case of Connes' theory of spatial derivatives:

arxiv.org/abs/2508.03731

Terence Tao (@teorth.bsky.social) has written a thread on Mastodon about the impact of the federal grant freeze to UCLA, particularly to his own field of Mathematics. UCLA's IPAM (Institute of Pure and Applied Mathematics) could shut down entirely

mathstodon.xyz/@tao/1149568...

For the math folks on here: NSF has suspended Terry Tao's grant. www.nsf.gov/awardsearch/...

Multipartite Embezzlement of Entanglement Lauritz van Luijk, Alexander Stottmeister, and Henrik Wilming, Quantum 9, 1818 (2025). Embezzlement of entanglement refers to the task of extracting entanglement from an entanglement resource via loca...

Happy to see that our paper on multipartite embezzlement with @lvanluijk.bsky.social and @stotti-alex.bsky.social is finally out in @quantum-journal.bsky.social

quantum-journal.org/papers/q-202...

Math Is Quietly in Crisis over NSF Funding Cuts A 72 percent reduction in federal funding is devastating to math research. The American Mathematical Society is offering $1 million in backstop grants—but it’s likely not enough

The devastating funding cuts to mathematics research in the US will cut-short the careers of a generation of mathematicians. It really is disgraceful, and unbelievably shortsighted. #MathSky
www.scientificamerican.com/article/can-...

Henrik will soon talk about entanglement in the thermodynamic limit at LUH :).

Are you a student or early-career researcher in quantum computing or quantum information? Then the following is for you.

We're organising a focused, community-driven conference at Leibniz Universität Hannover, hosted by Prof. Robert Raussendorf.

🗓️ Save the date: August 27–29, 2025

don't despair! there is still quantum...

🙏

Finding Peter Putnam The forgotten janitor who discovered the logic of the mind

Science writer Amanda Gefter spent more than a decade tracking down the people who knew him, and diving into a vast store of his unpublished work and private papers.

A long read, but fascinating and moving.

Link: nautil.us/finding-pete...

Universal embezzlers naturally emerge in critical fermion systems, study finds Embezzlement of entanglement is an exotic phenomenon in quantum information science, describing the possibility of extracting entanglement from a resource system without changing its quantum state. In...

Thanks to @phys.org.web.brid.gy for covering our recent work with @stotti-alex.bsky.social and @lvanluijk.bsky.social on embezzlement of entanglement in critical systems:

phys.org/news/2025-06...

Paper: www.nature.com/articles/s41...

38th BTM The meeting will begin on Tuesday 9th September at 13:00 and will close around noon on Thursday 11th September. All talks will be held in Abacws.

Cardiff is hosting the 38th British Topology Meeting from 9th - 11th September 2025. The registration is now open! Come along if you are looking for some interesting talks about all things topological. Details can be found here: sites.google.com/view/btm38 #MathSky #topology #AcademicSky

For those wondering what embezzlement of entanglement is, I have heard from Henrik (@arrr.de) that the Cambridge Dictionary is preparing an updated version…

It is interesting to note that our results hold irrespective of the topology of the energy bands w.r.t. quasi-momenta, i.e., also critical points associated with topological phase transitions exhibit universal embezzlement, e.g., in the SSH model.

By Jordan-Wigner duality, our results imply the same property for various ground state sectors of locally interacting spin chains. Technically, we prove that half-chain observable algebras of said models are type III_1 factors.

In general, we prove that embezzling states (ideal infinite-system resources) induces van Dam-Hayden embezzling families, implying that universal embezzlement manifests in finite systems: For any entangled target state, a finite subsystem is sufficient to achieve a given error.

Universal embezzlers are bipartite systems allowing for the local, almost perturbation-free extraction of any entangled state with arbitrary precision. We prove this property for the ground state sector of critical, local, translation-invariant, free fermions on 1d lattices.

Critical Fermions are Universal Embezzlers Universal embezzlers are bipartite quantum systems from which any entangled state may be extracted to arbitrary precision using local operations while perturbing the state of the system arbitrarily li...

We prove that universal embezzlement is ubiquitous in many-body quantum systems following up on our earlier classification of embezzlement of entanglement (youtu.be/XxTFHdrJZBw?...)
This is joint work with L. van Luijk (@lvanluijk.bsky.social) & H. Wilming (@arrr.de).
arxiv.org/abs/2406.11747

Today our paper on universal embezzlement of entanglement in critical fermion systems has been published in Nature Physics:
www.nature.com/articless415...
Another intense collaboration with the great Lauritz (@lvanluijk.bsky.social) & Henrik (@arrr.de).
Below is the former Twitter thread.