Oliver Hahn 🇪🇺
@cosmohahn.bsky.social
Computational Cosmologist, Simulator of Universes, Producer of NaNs, Prof
@univie.ac.at, opinions solely my own, (he/him), 334ppm
@univie.ac.at, opinions solely my own, (he/him), 334ppm
Reposted by Oliver Hahn 🇪🇺
👀 Physicists Take the Imaginary Numbers Out of Quantum Mechanics
Physicists Take the Imaginary Numbers Out of Quantum Mechanics | Quanta Magazine
Quantum mechanics has at last been formulated exclusively with real numbers, bringing a mathematical puzzle at the heart of the theory into a new era of inquiry.
www.quantamagazine.org
November 8, 2025 at 9:31 PM
👀 Physicists Take the Imaginary Numbers Out of Quantum Mechanics
dhaka brakha. such amazing music! it breaks my heart that Ukraine is still not at peace... www.youtube.com/watch?v=H7cp...
DakhaBrakha - Khyma (Live on KEXP)
YouTube video by KEXP
www.youtube.com
November 7, 2025 at 9:04 PM
dhaka brakha. such amazing music! it breaks my heart that Ukraine is still not at peace... www.youtube.com/watch?v=H7cp...
Reposted by Oliver Hahn 🇪🇺
in the #arXiv
The SPHEREx Satellite Mission
by James Bock and co-authors
arxiv.org/abs/2511.02985 #SPHEREx #Cosmology 🧪
The SPHEREx Satellite Mission
by James Bock and co-authors
arxiv.org/abs/2511.02985 #SPHEREx #Cosmology 🧪
November 6, 2025 at 10:57 AM
in the #arXiv
The SPHEREx Satellite Mission
by James Bock and co-authors
arxiv.org/abs/2511.02985 #SPHEREx #Cosmology 🧪
The SPHEREx Satellite Mission
by James Bock and co-authors
arxiv.org/abs/2511.02985 #SPHEREx #Cosmology 🧪
Reposted by Oliver Hahn 🇪🇺
in the #arXiv
Revealing Hidden Cosmic Flows through the Zone of Avoidance with Deep Learning
by Alexandra Dupuy and co-authors
arxiv.org/abs/2511.03919 🧪 #Cosmology
Revealing Hidden Cosmic Flows through the Zone of Avoidance with Deep Learning
by Alexandra Dupuy and co-authors
arxiv.org/abs/2511.03919 🧪 #Cosmology
November 7, 2025 at 10:01 AM
in the #arXiv
Revealing Hidden Cosmic Flows through the Zone of Avoidance with Deep Learning
by Alexandra Dupuy and co-authors
arxiv.org/abs/2511.03919 🧪 #Cosmology
Revealing Hidden Cosmic Flows through the Zone of Avoidance with Deep Learning
by Alexandra Dupuy and co-authors
arxiv.org/abs/2511.03919 🧪 #Cosmology
Reposted by Oliver Hahn 🇪🇺
On 7 November 1878, physicist Lise Meitner was born.
Read Baez’s thread: a real jewel of science storytelling and passion.
Lise Meitner also kicked the door wide open for women in physics with nothing but genius and grit.
Read it, fall in love, share it.
⚛️ 🧪 #physics #HistSci #WomenInSTEM
Read Baez’s thread: a real jewel of science storytelling and passion.
Lise Meitner also kicked the door wide open for women in physics with nothing but genius and grit.
Read it, fall in love, share it.
⚛️ 🧪 #physics #HistSci #WomenInSTEM
Lise Meitner, who discovered nuclear fission and did the experiments that led Pauli to postulate neutrinos, is one of my heroes. She had to work twice as hard for everything, and did so much.
I tell a bit of her story here:
mathstodon.xyz/@johncarlosb...
I tell a bit of her story here:
mathstodon.xyz/@johncarlosb...
John Carlos Baez (@johncarlosbaez@mathstodon.xyz)
Attached: 1 image
Lise Meitner, who discovered nuclear fission, is one of my heroes. She had to work twice as hard for everything, and did so much.
The Austrian government did not open the universi...
mathstodon.xyz
November 7, 2025 at 10:16 AM
On 7 November 1878, physicist Lise Meitner was born.
Read Baez’s thread: a real jewel of science storytelling and passion.
Lise Meitner also kicked the door wide open for women in physics with nothing but genius and grit.
Read it, fall in love, share it.
⚛️ 🧪 #physics #HistSci #WomenInSTEM
Read Baez’s thread: a real jewel of science storytelling and passion.
Lise Meitner also kicked the door wide open for women in physics with nothing but genius and grit.
Read it, fall in love, share it.
⚛️ 🧪 #physics #HistSci #WomenInSTEM
Amazing! The beginnings of large-scale structure cosmology not even 100 years ago... Today we're reaching per-cent level accuracy.
Cosmography archives
The Distribution of Extra-Galactic Nebulae
by Edwin Hubble (1934)
ui.adsabs.harvard.edu/abs/1934ApJ....
#Cosmology 🧪
The Distribution of Extra-Galactic Nebulae
by Edwin Hubble (1934)
ui.adsabs.harvard.edu/abs/1934ApJ....
#Cosmology 🧪
November 5, 2025 at 8:18 PM
Amazing! The beginnings of large-scale structure cosmology not even 100 years ago... Today we're reaching per-cent level accuracy.
Reposted by Oliver Hahn 🇪🇺
Join us on Friday, 7 Nov, 14-18, for the ESI Medal Symposium in honor of Michele Parrinello, at @esivienna.bsky.social or online. Talks by G. Kresse, @mahrossi.bsky.social, G. Foffi, and M.Parrinello and even some music! 🎶 Should be an interesting afternoon.
www.esi.ac.at/events/e593/
www.esi.ac.at/events/e593/
November 4, 2025 at 5:29 PM
Join us on Friday, 7 Nov, 14-18, for the ESI Medal Symposium in honor of Michele Parrinello, at @esivienna.bsky.social or online. Talks by G. Kresse, @mahrossi.bsky.social, G. Foffi, and M.Parrinello and even some music! 🎶 Should be an interesting afternoon.
www.esi.ac.at/events/e593/
www.esi.ac.at/events/e593/
Reposted by Oliver Hahn 🇪🇺
Academics in Assyria in the 7th c BC complain that admin is preventing them from doing research and teaching
November 3, 2025 at 10:04 AM
Academics in Assyria in the 7th c BC complain that admin is preventing them from doing research and teaching
Reposted by Oliver Hahn 🇪🇺
Another casualty of the LLM revolution.
In "arXiv’s CS category, review articles and position papers must now be accepted at a journal or a conference and complete successful peer review."
In "arXiv’s CS category, review articles and position papers must now be accepted at a journal or a conference and complete successful peer review."
Attention Authors: Updated Practice for Review Articles and Position Papers in arXiv CS Category – arXiv blog
blog.arxiv.org
November 2, 2025 at 4:58 AM
Another casualty of the LLM revolution.
In "arXiv’s CS category, review articles and position papers must now be accepted at a journal or a conference and complete successful peer review."
In "arXiv’s CS category, review articles and position papers must now be accepted at a journal or a conference and complete successful peer review."
Reposted by Oliver Hahn 🇪🇺
Are you a grad student interested in writing for Astrobites, or do you know one? We're recruiting! Apply by November 26 :)
astrobites.org/2025/10/31/a...
astrobites.org/2025/10/31/a...
Apply to Write for Astrobites 2025!
Love astronomy, astrophysics, and science communication? Come join the Astrobites team! Applications due November 26th.
astrobites.org
October 31, 2025 at 6:40 PM
Are you a grad student interested in writing for Astrobites, or do you know one? We're recruiting! Apply by November 26 :)
astrobites.org/2025/10/31/a...
astrobites.org/2025/10/31/a...
UVienna's Dept. of Mathematics is seeking an assistant professor in 'mathematical foundations of data science'!
Tenure Track-Professur für Mathematische Grundlagen der Data Science
Wir begrüßen insbesondere Bewerber*innen, deren Arbeit die Entwicklung neuartiger mathematischer Methoden mit Anwendungen in den Bereichen Datenwissenschaft und KI umfasst!
Bewerbungsfrist ist der 10.12.2025.
Link siehe unten 👇
Wir begrüßen insbesondere Bewerber*innen, deren Arbeit die Entwicklung neuartiger mathematischer Methoden mit Anwendungen in den Bereichen Datenwissenschaft und KI umfasst!
Bewerbungsfrist ist der 10.12.2025.
Link siehe unten 👇
October 30, 2025 at 8:13 AM
UVienna's Dept. of Mathematics is seeking an assistant professor in 'mathematical foundations of data science'!
Reposted by Oliver Hahn 🇪🇺
Delayed paper day! In work lead by my postdoc Claudia Di Cesare as part of the ALT survey, we provide a detailed census of the so-called star formation main sequence in the early Universe. arxiv.org/pdf/2510.19044
October 28, 2025 at 11:02 AM
Delayed paper day! In work lead by my postdoc Claudia Di Cesare as part of the ALT survey, we provide a detailed census of the so-called star formation main sequence in the early Universe. arxiv.org/pdf/2510.19044
Reposted by Oliver Hahn 🇪🇺
Where does the expanding Universe begin?
The Universe doesn't expand everywhere: the space within our atoms, planet, Solar System, galaxy, and Local Group aren't expanding.
So where does that cosmic expansion begin?
bigthink.com/starts-with-...
#space #astronomy #universe #expansion
The Universe doesn't expand everywhere: the space within our atoms, planet, Solar System, galaxy, and Local Group aren't expanding.
So where does that cosmic expansion begin?
bigthink.com/starts-with-...
#space #astronomy #universe #expansion
Where does the expanding Universe begin?
The planet, the Solar System, and the galaxy aren't expanding. But the whole Universe is. So where does the dividing line begin?
bigthink.com
October 27, 2025 at 3:43 PM
Where does the expanding Universe begin?
The Universe doesn't expand everywhere: the space within our atoms, planet, Solar System, galaxy, and Local Group aren't expanding.
So where does that cosmic expansion begin?
bigthink.com/starts-with-...
#space #astronomy #universe #expansion
The Universe doesn't expand everywhere: the space within our atoms, planet, Solar System, galaxy, and Local Group aren't expanding.
So where does that cosmic expansion begin?
bigthink.com/starts-with-...
#space #astronomy #universe #expansion
Reposted by Oliver Hahn 🇪🇺
"a kind of celebration of ignorance"
October 17, 2025 at 1:06 PM
"a kind of celebration of ignorance"
Reposted by Oliver Hahn 🇪🇺
Commentary by @needhibhalla.bsky.social et al. on the recent attacks on DEI in biomedical research. Data show that diversity in the science increases creativity & success in tackling challenging problems.
🧪 www.nature.com/articles/s41...
🧪 www.nature.com/articles/s41...
October 25, 2025 at 8:42 PM
Commentary by @needhibhalla.bsky.social et al. on the recent attacks on DEI in biomedical research. Data show that diversity in the science increases creativity & success in tackling challenging problems.
🧪 www.nature.com/articles/s41...
🧪 www.nature.com/articles/s41...
Reposted by Oliver Hahn 🇪🇺
The hierarchy problem (finetuning) of the Standard Model of particle physics is often presented as the question 'why the weak scale is so much smaller than the Planck scale'
But there is also a geometric interpretation that can be understood with little maths (but a lot of physics)
🧵1/11
But there is also a geometric interpretation that can be understood with little maths (but a lot of physics)
🧵1/11
October 25, 2025 at 3:31 PM
The hierarchy problem (finetuning) of the Standard Model of particle physics is often presented as the question 'why the weak scale is so much smaller than the Planck scale'
But there is also a geometric interpretation that can be understood with little maths (but a lot of physics)
🧵1/11
But there is also a geometric interpretation that can be understood with little maths (but a lot of physics)
🧵1/11
Reposted by Oliver Hahn 🇪🇺
The old joke about the why the Bulgarian secret police sent officers out in groups of three. One who could read, one who could write, and one to keep an eye on the two intellectuals.
October 23, 2025 at 9:52 PM
The old joke about the why the Bulgarian secret police sent officers out in groups of three. One who could read, one who could write, and one to keep an eye on the two intellectuals.
Just had a delicious "beyond" burger with jalapeños tonight. enjoyed it very much. and can't say how tired i am of the reactionary EU lobbyist's tired attempt to outlaw plant based products' simulacrum names. Yay tempeh steaks and body milk!
Wall Street previously forecast the plant-based meat firm as a “Reddit stock to watch.”
Beyond Meat’s Rally Hits 1,000%—Here’s What’s Behind The Surge
Wall Street previously forecast the plant-based meat firm as a “Reddit stock to watch.”
www.forbes.com
October 23, 2025 at 7:46 PM
Just had a delicious "beyond" burger with jalapeños tonight. enjoyed it very much. and can't say how tired i am of the reactionary EU lobbyist's tired attempt to outlaw plant based products' simulacrum names. Yay tempeh steaks and body milk!
Exactly! Stupid galaxy rotation curves are neither the strongest nor the only evidence we have for dark matter! Many phenomena are most easily explained by it. Unfortunately we are no longer in the heydays of particle physics where postulated particles got detected within the next years #cosmology
5 undeniable, truthful facts about dark matter
There are always people promoting their own (shoddy) "alternative" ideas to dark matter.
These five undeniable truths box those alternatives into a corner they can't escape from. (Yes, that one too!)
bigthink.com/starts-with-...
#space #astro #physics
There are always people promoting their own (shoddy) "alternative" ideas to dark matter.
These five undeniable truths box those alternatives into a corner they can't escape from. (Yes, that one too!)
bigthink.com/starts-with-...
#space #astro #physics
5 undeniable, truthful facts about dark matter
Dark matter has never been directly detected, but the astronomical evidence for its existence is overwhelming. Here's what to know.
bigthink.com
October 23, 2025 at 6:17 PM
Exactly! Stupid galaxy rotation curves are neither the strongest nor the only evidence we have for dark matter! Many phenomena are most easily explained by it. Unfortunately we are no longer in the heydays of particle physics where postulated particles got detected within the next years #cosmology
Reposted by Oliver Hahn 🇪🇺
It's our best theory of elementary particles and forces. It took centuries of genius to discover that the world is like this, and it's absolutely shocking. But nobody believes it's the last word, so we simply call it The Standard Model.
I will try to explain it...
www.youtube.com/watch?v=0yjx...
I will try to explain it...
www.youtube.com/watch?v=0yjx...
Standard Model - Part 1
YouTube video by John Baez
www.youtube.com
October 22, 2025 at 9:46 AM
It's our best theory of elementary particles and forces. It took centuries of genius to discover that the world is like this, and it's absolutely shocking. But nobody believes it's the last word, so we simply call it The Standard Model.
I will try to explain it...
www.youtube.com/watch?v=0yjx...
I will try to explain it...
www.youtube.com/watch?v=0yjx...
Reposted by Oliver Hahn 🇪🇺
Is the Hubble tension the same thing as dark energy?
#AskEthan
The Hubble tension is a big cosmic puzzle.
Dark energy might be evolving, and still remains mysterious.
But these two problems aren't the same.
Here's what makes them distinct.
bigthink.com/starts-with-...
#space #astro #cosmology
#AskEthan
The Hubble tension is a big cosmic puzzle.
Dark energy might be evolving, and still remains mysterious.
But these two problems aren't the same.
Here's what makes them distinct.
bigthink.com/starts-with-...
#space #astro #cosmology
Ask Ethan: Is the Hubble tension the same thing as dark energy?
Observations with the Hubble space telescope helped cement dark energy and reveal the Hubble tension. How are these two things so different?
bigthink.com
October 17, 2025 at 4:30 PM
Is the Hubble tension the same thing as dark energy?
#AskEthan
The Hubble tension is a big cosmic puzzle.
Dark energy might be evolving, and still remains mysterious.
But these two problems aren't the same.
Here's what makes them distinct.
bigthink.com/starts-with-...
#space #astro #cosmology
#AskEthan
The Hubble tension is a big cosmic puzzle.
Dark energy might be evolving, and still remains mysterious.
But these two problems aren't the same.
Here's what makes them distinct.
bigthink.com/starts-with-...
#space #astro #cosmology
Reposted by Oliver Hahn 🇪🇺
Remebering Hannah Arendt’s birthday yesterday, 14 Oct 1906.
"The moment we no longer have a free press, anything can happen. What makes it possible for a totalitarian or any other dictatorship to rule is that people are not informed; how can you have an opinion if you are not informed?"
1/
#History
"The moment we no longer have a free press, anything can happen. What makes it possible for a totalitarian or any other dictatorship to rule is that people are not informed; how can you have an opinion if you are not informed?"
1/
#History
October 15, 2025 at 7:36 PM
Remebering Hannah Arendt’s birthday yesterday, 14 Oct 1906.
"The moment we no longer have a free press, anything can happen. What makes it possible for a totalitarian or any other dictatorship to rule is that people are not informed; how can you have an opinion if you are not informed?"
1/
#History
"The moment we no longer have a free press, anything can happen. What makes it possible for a totalitarian or any other dictatorship to rule is that people are not informed; how can you have an opinion if you are not informed?"
1/
#History
Somewhat excited about teaching to our undergrad students today how the velocity field of a fluid can always be decomposed into a scalar (expansion/compression), a vector (rotation), and a tensor (shear) part. Simple and yet profound...
October 15, 2025 at 6:55 PM
Somewhat excited about teaching to our undergrad students today how the velocity field of a fluid can always be decomposed into a scalar (expansion/compression), a vector (rotation), and a tensor (shear) part. Simple and yet profound...
Reposted by Oliver Hahn 🇪🇺
Cosmic inflation’s biggest criticisms can’t undermine its success
There are always lots of arguments to be made against a leading scientific theory.
But good ones?
Take a close look at the ones against inflation, & see how weak-sauce they are.
bigthink.com/starts-with-...
#space #physics #astro
There are always lots of arguments to be made against a leading scientific theory.
But good ones?
Take a close look at the ones against inflation, & see how weak-sauce they are.
bigthink.com/starts-with-...
#space #physics #astro
Cosmic inflation's biggest criticisms can't undermine its success
Inflation's two main criticisms, that it can predict anything and that the "measure problem" remains unsolved, can't erase its successes.
bigthink.com
October 14, 2025 at 3:41 PM
Cosmic inflation’s biggest criticisms can’t undermine its success
There are always lots of arguments to be made against a leading scientific theory.
But good ones?
Take a close look at the ones against inflation, & see how weak-sauce they are.
bigthink.com/starts-with-...
#space #physics #astro
There are always lots of arguments to be made against a leading scientific theory.
But good ones?
Take a close look at the ones against inflation, & see how weak-sauce they are.
bigthink.com/starts-with-...
#space #physics #astro
Reposted by Oliver Hahn 🇪🇺
This is your periodic reminder that you can add coffee stains to your LaTeX documents.
October 12, 2025 at 9:48 PM
This is your periodic reminder that you can add coffee stains to your LaTeX documents.