Alex Pozas-Kerstjens

Alex Pozas-Kerstjens

@alexpozas.com

Ph.D. in Quantum Info at ICFO. Now at UNIGE, previously at ICMAT and Universidad Complutense de Madrid. La Caixa & SNSF fellow. Quantum ⚛️ & AI . Erdös number: 4.

176 followers157 following74 posts

Alex Pozas-Kerstjens
@alexpozas.com

Looking forward to the ITCE conference, and to talk about our latest results on nonlocality in networks!

Información y Tecnologías Cuánticas en España@qipcspain.bsky.social

*ITCE-11: Quantum Information and Quantum Technologies Conference in Spain* Date and time: 0:00, 5-10-2026 Location: Paraninfo, Edificio Rector Lostau, Campus de la Merced, Universidad de Murcia, Murcia Link: https://itce-11.hbar.es/ ITCE-11 is the eleve… [🌎]

Alex Pozas-Kerstjens reposted

Juan José García-Ripoll
@jjgarciaripoll.bsky.social

Open position in our new institute @quarc-csic.bsky.social Help us create a large nation wide quantum communication infrastructure!

Información y Tecnologías Cuánticas en España@qipcspain.bsky.social

Physicist / Research Engineer in quantum communications (QKD) — QuARC — Quantum Advanced Research Center, CSIC The Quantum Communication Laboratory at QuARC is looking for a Physicist / Research… Plazo: 31/10/2026 https://ritce.hbar.es/jobs/physicist-resea… [🌎]

Alex Pozas-Kerstjens reposted

Instituto de Física Fundamental CSIC (IFF-CSIC)
@iff-csic.bsky.social

👋Este mes damos la bienvenida a Alex Pozas-Kerstjens, nuevo investigador Ramón y Cajal en el IFF. Con su trabajo contribuirá al desarrollo de herramientas para la certificación de fenómenos cuánticos y el diseño de protocolos criptográficos para redes de comunicación cuánticas.

Alex Pozas-Kerstjens reposted

Elies Gil-Fuster
@eliesgf.bsky.social

Yay! Forms are so much fun 🎉🎊 If you're a quantum researcher, we would love it if you could fill the form (<10 minutes) and share it with your network. Thanks!

Greg White@gregswhitenoise.bsky.social

My good friend and famed lover of questionnaires @eliesgf.bsky.social has a simple question for the quantum info community: what do you think when you hear the terms "strong" and "weak simulation? He (and by extension, me) would love it if you filled in this Google Form! forms.gle/wfFcwBPdaafv...

docs.google.comWhat does it mean to simulate a quantum computation?Dear colleagues, We are some quantum researchers at FU Berlin. We were recently surprised among ourselves that we used the same words in very different incompatible ways when it comes to classically...

Alex Pozas-Kerstjens reposted

Antonio Martínez Ron
@aberron.bsky.social

Científicos con las dietas para viajes de trabajo congeladas desde 2002: "Un año perdí 4.500 euros, ahora me limito" www.eldiario.es/1_cbbbda?utm...

eldiario.esCientíficos con las dietas para viajes de trabajo congeladas desde 2002: "Un año perdí 4.500 euros, ahora me limito"La normativa que establece las cuantías para pagar hoteles y comidas contempla 65 euros diarios para dormir, menos de la mitad del precio medio de una habitación en España; los investigadores exigen q...

Alex Pozas-Kerstjens reposted

anil oza
@aniloza.bsky.social

wow — the preprint host, arxiv, is banning authors for a year if they submit papers with hallucinated citations 🤖

Helen Branswell 🇨🇦@helenbranswell.bsky.social

I find this unsettling: A new study in #Lancet shows that the number of faux citations in scientific articles is on the rise, and #AI is likely to blame. @aniloza.bsky.social reports. www.statnews.com/2026/05/07/l...

statnews.comFraudulent citations, blamed on AI hallucinations, are becoming more common in research papers“Fabricated” citations that do not reference real academic papers are spreading in the literature, polluting the public record of science, a new study found
Alex Pozas-Kerstjens
@alexpozas.com

While tiny, this region is crucial. It has been believed for years that quantum nonlocality was impossible in the triangle network with binary-valued outcomes and no inputs. And now we know this is not true! Moreover, the constructions give nice insights on how network nonlocality arises. 7/n

Alex Pozas-Kerstjens
@alexpozas.com

I also have to say that, while simple, this paper is the result of enormous effort. We pushed characterization software to the limit, and develop new tools based on quantum testers to get to the result. I'm super happy about this result, and proud of having worked in such an amazing team. 8/n, n=8

Alex Pozas-Kerstjens
@alexpozas.com

To look for this realization, we use quantum testers, that are objects that encompass the union of a quantum state and a measurement device. They originate in the field of higher order quantum theory, and we use them to do efficient, stable optimization loops. 5/n

Alex Pozas-Kerstjens
@alexpozas.com

In the end, we find realizations for all visibilities below 0.6245. In parallel, we prove that for all visibilities above 0.6221 the noisy W distribution is nonlocal. So we have this tiny region where it is, both, quantumly realizable and nonlocal! 6/n

Alex Pozas-Kerstjens
@alexpozas.com

Why is it the simplest? Because we just need one source that distributes (two-qubit) entangled states. The other sources distribute classical shared randomness! And, because of this, the parties need to perform (at most) single-qubit measurements. 3/n

Alex Pozas-Kerstjens
@alexpozas.com

In particular, within this construction we look for realizations of mixtures of the W distribution (where the only events with nonzero -and uniform- probability are those in which only one of the parties output 1) with white noise. 4/n

Alex Pozas-Kerstjens
@alexpozas.com

Why is it the smallest? Because it is a just tripartite distribution over binary outcomes, for which we find a realization in the so-called triangle network. If you take a party, a source, or an outcome out, then you end up in a situation where you can always find a local hidden variable model. 2/n

Alex Pozas-Kerstjens
@alexpozas.com

This was a super interesting read for me as a quantum physicist. I learnt that zero-knowledge provers can be hacked, and that cryptographers' and security analysts' way of understanding quantum mechanics is completely different to ours. What an interesting time to live in!

Fredrik Dahlgren@fegge.bsky.social

Two weeks ago, Google published a paper proving in zero-knowledge that they had an efficient implementation of Shor's algorithm. Today, Trail of Bits can prove that we have an even better implementation which beats Google's on all metrics! 🫢 blog.trailofbits.com/2026/04/17/w...

Alex Pozas-Kerstjens reposted

María Gragera Garcés
@grageragarces.github.io

Copilot will use your code for model training starting next month unless you opt out 👇 If you’re a student on the free plan, consider whether you want to disable this before April 24th

Alex Pozas-Kerstjens reposted

Frederik Hahn
@frederikhahn.bsky.social

I am surprised to see this and hope the arXiv stays nonprofit.

Roger Schonfeld@rschon.bsky.social

arXiv is being spun out from Cornell University and is looking for an inaugural CEO. jobs.chronicle.com/job/37961678...

jobs.chronicle.comChief Executive Officer - New York City, New York (US) job with arXiv | 37961678arXiv seeks its first CEO to champion open, free scientific discovery and guide the platform’s next chapter as an independent nonprofit.
Alex Pozas-Kerstjens
@alexpozas.com

This is the last week to apply to the Spring School in near-term quantum computing that we are organizing at @ccbpp.bsky.social. Don't miss it!

Alex Pozas-Kerstjens@alexpozas.com

The @ccbpp.bsky.social Spring School on near-term quantum computing is back! If you are a young (PhD/MSc) researcher in quantum science and want to get exposed to the recent developments on quantum computing, do not hesitate coming to Benasque on March 15 - 21 next year! www.benasque.org/2026ntqc/

benasque.orgSpring School on Near-Term Quantum Computing

Alex Pozas-Kerstjens reposted

Tamás Kriváchy
@krivachytamas.bsky.social

A great read by Retraction Watch. ✅ Nice to see that some Article 1 authors, McCoy et al., actively tried to get help from Springer Nature to fix the incorrect citations to their paper. 😐 Seems like Scopus and Web of Science also have the distorted citations.

Retraction Watch@retractionwatch.com

Bug in Springer Nature metadata may be causing ‘significant, systemic’ citation inflation

retractionwatch.comBug in Springer Nature metadata may be causing ‘significant, systemic’ citation inflationMillions of researchers could be affected by a “dramatic distortion of citation counts” likely caused by flaws in how the academic publishing giant Springer Nature handles article metadata, accordi…