Lauritz van Luijk
lvanluijk.bsky.social
Lauritz van Luijk
@lvanluijk.bsky.social
Reposted by Lauritz van Luijk
We're a group of fun, loving, and fun-loving people welcoming more :)
November 7, 2025 at 3:45 PM
Reposted by Lauritz van Luijk
If you are interested in doing a postdoc with me, please apply to the IQC postdoctoral fellowship here: iqc-uwaterloo.slideroom.com#/login/progr...
University of Waterloo Attn: Institute for Quantum Computing - SlideRoom
Apply to University of Waterloo Attn: Institute for Quantum Computing. Powered by SlideRoom.
iqc-uwaterloo.slideroom.com
November 6, 2025 at 7:12 PM
Reposted by Lauritz van Luijk
Happy to see that our paper on pure state entanglement and von Neumann algebras with @lvanluijk.bsky.social, @stotti-alex.bsky.social and Reinhard Werner is finally out in CMP 🥳

link.springer.com/article/10.1...
Pure State Entanglement and von Neumann Algebras - Communications in Mathematical Physics
We develop the theory of local operations and classical communication (LOCC) for bipartite quantum systems represented by commuting von Neumann algebras. Our central result is the extension of Nielsen...
link.springer.com
October 30, 2025 at 7:16 PM
Here's a picture of the four of us at my defense some weeks ago.
October 13, 2025 at 7:44 PM
Interested in entanglement theory for systems with infinitely many degrees of freedom? Take a look at my PhD thesis, now available on the arXiv 🥳 arxiv.org/abs/2510.07563
Entanglement in von Neumann Algebraic Quantum Information Theory
In quantum systems with infinitely many degrees of freedom, states can be infinitely entangled across a pair of subsystems, but are there different forms of infinite entanglement? To understand entang...
arxiv.org
October 13, 2025 at 9:01 AM
Reposted by Lauritz van Luijk
Inclined to send around a mail to everyone:

Dear colleagues, friends and family, due to the consequences of QIP's post-submission-arXiv-posting-deadline you won't see or hear from me in the next two weeks while I try to catch up with the literature. Thanks for your understanding.
October 10, 2025 at 8:18 AM
The Trotter product formula has countless applications from quantum simulation to numerical analysis—but sharp error bounds, especially for unbounded Hamiltonians, are often hard.

We prove new state-dependent bounds and apply them to Schrödinger, Dirac and Coulomb dynamics: doi.org/10.1007/s102...
Convergence Rates for the Trotter Splitting for Unbounded Operators - Foundations of Computational Mathematics
We study convergence rates of the Trotter splitting $$\begin{aligned} e^{A+L} = \lim _{n \rightarrow \infty } \Big (e^{L/n} e^{A/n}\Big )^n \end{aligned}$$ e A + L = lim n → ∞ ( e L / n e A / n ) n in the strong operator topology. In the first part, we use complex interpolation theory to treat generators L and A of contraction semigroups on Banach spaces, with L relatively A-bounded. In the second part, we study unitary dynamics on Hilbert spaces and develop a new technique based on the concept of energy constraints. Our results provide a complete picture of the convergence rates for the Trotter splitting for all common types of Schrödinger and Dirac operators, including singular, confining and magnetic vector potentials, as well as molecular many-body Hamiltonians in dimension $$d=3$$ d = 3 . Using the Brezis-Mironescu inequality, we derive convergence rates for the Schrödinger operator with $$V(x)=\pm |x|^{-a}$$ V ( x ) = ± | x | - a potential. In each case, our conditions are fully explicit.
doi.org
October 1, 2025 at 1:29 PM
Reposted by Lauritz van Luijk
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.
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...
arxiv.org
September 22, 2025 at 5:40 AM
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 👇
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...
arxiv.org
September 17, 2025 at 10:22 AM
Reposted by Lauritz van Luijk
🥳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! 🙏
📣 The ERC Starting Grant call results are out!

Find out which early-career researchers will receive funding this year, what they will be investigating, where they will be based... plus lots of other #ERCStG facts & figures for 2025!

➡️ buff.ly/IsafuFh

#FrontierResearch 🇪🇺#EUfunded #HorizonEurope
September 4, 2025 at 10:21 AM
Reposted by Lauritz van Luijk
Glad someone took the time to debunk the (obviously nonsensical) claim that Bell inequalities could be violated w/o entanglement. It is astonishing (to say the least) that this claim was made by experienced authors & that it passed peer review in the first place, does not reflect well on the journal
Bell Inequality Violations Without Entanglement? It's Just Postselection
Recently Wang et al. have reported a violation of a Bell inequality without entanglement [arXiv:2507.07756]. We show that their result is an artifact of postselection. It is well known that postselect...
arxiv.org
August 20, 2025 at 9:22 AM
August 7, 2025 at 8:02 AM
Reposted by Lauritz van Luijk
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
August 7, 2025 at 7:38 AM
Reposted by Lauritz van Luijk
For the math folks on here: NSF has suspended Terry Tao's grant. www.nsf.gov/awardsearch/...
NSF Award Search: Award # 2347850
Structure theory for measure-preserving systems, additive combinatorics, and correlations of multiplicative functions
www.nsf.gov
July 31, 2025 at 10:44 PM
Reposted by Lauritz van Luijk
Quantum Toolbox (8): Hadamard's Three-Lines Theorem (1/6)
August 1, 2025 at 10:36 AM
Reposted by Lauritz van Luijk
Henrik will soon talk about entanglement in the thermodynamic limit at LUH :).
July 21, 2025 at 9:50 AM
Reposted by Lauritz van Luijk
I am currently looking for a PhD student who would like to work on position-based cryptography. Details can be found here: andreasbluhm.eu/wp-content/u...

Please spread the word!
andreasbluhm.eu
June 16, 2025 at 11:29 AM
Reposted by Lauritz van Luijk
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.
www.nature.com
May 27, 2025 at 10:01 AM
My paper Energy-limited quantum dynamics was published in CMP! 🎉

doi.org/10.1007/s002...

I'll do a short thread when I find the time for it.
Energy-Limited Quantum Dynamics - Communications in Mathematical Physics
We consider quantum systems with energy constraints relative to a reference Hamiltonian. In general, quantum channels and continuous-time dynamics need not satisfy energy conservation. Physically mean...
doi.org
May 8, 2025 at 4:40 PM
Reposted by Lauritz van Luijk
For this year’s #QIP2025 we sadly had to give our talk as a video.

The upshot: Everyone can already watch @lvanluijk.bsky.social’s nice talk on pure state entanglement and von Neumann algebras!

https://m.youtube.com/watch?v=U70p9sauZ_E

#entanglement #quantum @stotti-alex.bsky.social
Pure state entanglement and von Neumann algebras (QIP 2025)
m.youtube.com
March 5, 2025 at 11:41 AM
Reposted by Lauritz van Luijk
My scientific year 2024 was entirely focussed on the curious „embezzlement of #entanglement“.
Just in time PRL has published our short overview article:

link.aps.org/doi/10.1103/...

Thanks go out to @lvanluijk.bsky.social and @stotti-alex.bsky.social for the intense and fruitful collaboration! 🧪⚛️💚
Relativistic Quantum Fields Are Universal Entanglement Embezzlers
Embezzlement of entanglement refers to the counterintuitive possibility of extracting entangled quantum states from a reference state of an auxiliary system (the ``embezzler'') via local quantum opera...
link.aps.org
December 31, 2024 at 3:41 PM
Reposted by Lauritz van Luijk
A little Christmas present by @kpc.bsky.social at @newscientist.bsky.social covering our work on embezzlement of entanglement to appear in @apsphysics.bsky.social Phys. Rev. Lett.

I‘d like to emphasize the important role of Reinhard F. Werner in this work.

www.newscientist.com/article/2461...
Quantum entanglement can be endlessly 'embezzled' from quantum fields
Some quantum fields that extend throughout all of space-time could be a rich resource of quantum entanglement that can be extracted forever
www.newscientist.com
December 24, 2024 at 9:47 PM