Predrag Cvitanović

Quantum memories could help make long-baseline optical astronomy a reality – Physics World Single-photon interferometry achieved over 1.5 km

Quantum-entangled sensors placed over a kilometre apart could allow interferometric measurements of optical light with single photon sensitivity, say physicists. 🧪⚛️ ow.ly/9EGZ50YoXKG

Isolating the Effect of Dimensions on Electrons A new layered material enabled researchers to document a dramatic change in metallic electron behavior as the material goes from 3D to 2D.

Theorists expect Anderson localization to set in more readily in two dimensions than in three. Now researchers have demonstrated that tendency directly by progressively removing a crystal's atomic layers until only one remained.

Roger Penrose's 1965 diagram from his seminal paper, "Gravitational Collapse and Space-Time Singularities". It was a key part of the work that earned him the 2020 Nobel Prize in Physics, representing the evolution of a star's gravitational collapse into a black hole and the subsequent formation of a

"We do not believe any group of men adequate enough or wise enough to operate without scrutiny or without criticism. We know that the only way to avoid error is to detect it, that the only way to detect it is to be free to enquire. We know that the wages of secrecy are corruption."
J. R. Oppenheimer

Was a great job - here is my nephew Hallur in our renovated attic apartment - running up and down 6 story staircases. In the old Copenhagen almost no building has an elevator.

YouTube video by PostNord i Danmark Det sidste brev_EN subs

It's two months, and I still miss it
www.youtube.com/watch?v=Z82W...

A key point amidst a thread that resonates with what many in the science community want: *clear* answers and a return to evidence- and independent expert-driven decision making.

Still Fascinated by Physics | UW College of Arts & Sciences "The questions are long-term questions," emeritus professor Marshall Baker says of his theoretical physics, which he is still pursuing at age 91.

Here is Marshall Baker at 91
artsci.washington.edu/news/2023-11...

We have lost Marshall Baker
phys.washington.edu/memoriam

Black and white photo of Lise Meitner. She is standing in what appears to be a greenhouse, as there are several large plants behind her. Meitner is wearing a dark dress and blouse, with a high collar and hat. She is looking to the left of the photographer, with her hands clasped in front of her.

Physicist Lise Meitner was born #OTD in 1878. She discovered fission in uranium with Otto Frisch, and was the first person to understand both its mechanics and implications. A thread! (1/n)
🧪 🔭 👩‍🔬

Image: Atomic Heritage Foundation (photographer unknown)

Confronting Covid's Wake: Quantitative Approaches to Confront (Re)emerging Pathogens Friday Feb 27, 2026, 12pm, Gilmber 390

For those at UVA this Friday, I will be giving a noon Biology seminar on Confronting Covid's Wake: Quantitative Approaches to Confront (Re)emerging Pathogens, spanning models of asymptomatic spread to assessing remerging risks amidst a national measles outbreak.

bio.as.virginia.edu/upcoming-sem...

1941 ad from GA Power promoting streetcars in Atlanta.

1941 ad for Atlanta streetcars:

"All of the people in all of the automobiles out in the stream of traffic could have been accommodated in the one street car."

WTF happened that we don't promote transit like this anymore?

The same BYO algebra mesh topology implementation from yesterday being used with CGA2D/CGA3D to make computing Delaunay and Voronoi triangulation easy and dimension agnostic. The code is the same for 2D and 3D, just parameterized with functions from the two algebras.
#geometer #geometricalgebra

Outstanding post.

Fact and data driven with clear exposition.

Read it!

A vintage sepia-toned portrait photograph of Danish seismologist Inge Lehmann taken in 1932, at around age 44. She is posed formally against a softly draped curtain backdrop, gazing directly at the camera with a calm, intelligent, and composed expression. She has short, neatly waved dark hair and wears a simple, elegant dark blouse or dress with a light-colored V-neck insert or scarf tied loosely. The photographer's signature, "Nachtwey 1932," appears in the lower right corner in a flowing script. The image captures her poised and thoughtful demeanor during the early years of her groundbreaking career in seismology, before her landmark discovery of Earth's solid inner core in 1936. #seismology

Danish seismologist Inge Lehmann fundamentally changed our understanding of the Earth's interior by discovering its solid inner core in 1936. Often referred to as 𝘵𝘩𝘦 𝘮𝘢𝘴𝘵𝘦𝘳 𝘰𝘧 𝘢 𝘣𝘭𝘢𝘤𝘬 𝘢𝘳𝘵 due to her incredible ability to interpret complex seismic records by hand.

She died #OTD in 1993 #WomenInSTEM

Graphs are maximally expressive for higher-order interactions We demonstrate that graph-based models are fully capable of representing higher-order interactions, and have a long history of being used for precisely this purpose. This stands in contrast to a commo...

New on the arxiv:

“Graphs are maximally expressive for higher-order interactions”

arxiv.org/abs/2602.16937

We clarify central misconceptions in the recent literature on "higher-order networks".

w/ @piratepeel.bsky.social , @manlius.bsky.social, and @thilogross.bsky.social

Explainer 🧵: 1/N

Postdoctoral Fellows in Theoretical and Computational Neuroscience

The Grossman Theory Center at UChicago has postdoc openings in computational and theoretical neuroscience.

Application deadline April 4, 2026.
neuroscience.uchicago.edu/grossmancent...

A classic black-and-white portrait photograph of Nobel Prize-winning physicist Maria Goeppert Mayer, taken in a classroom or lecture setting. She stands in front of a large chalkboard filled with handwritten nuclear physics equations, nuclear mass data, and element symbols (including notations like I¹²⁹, Cr⁵², and various alpha, beta, and gamma values). Goeppert Mayer has a thoughtful, focused expression as she gazes upward slightly, with her lips pursed in concentration. She wears a patterned dress with short-sleeved matching jacket with a geometric black-and-white design, a pearl necklace, and her hair styled in soft curls. In her hands, she holds a wooden slide rule.

Theoretical physicist Maria Goeppert Mayer died #OTD in 1972.

She shared the 1963 #Nobel Prize in Physics (w/Wigner & Jensen) "for their discoveries concerning nuclear shell structure." She was the second woman to win a Nobel in #physics. (Who was the first?)

#WomenInSTEM

Nobel chemistry laureate Frances Arnold: ‘Whole swaths of science are just going to die on the vine’ The Caltech professor on using AI to harness the power of enzymes — and what US funding cuts could mean for research

giftarticle.ft.com/giftarticle/...

When the Cosmic Web Spins

Listen to science journalist Paul Adepoju recount how astronomers discovered that one of the largest structures in the universe—a cosmic filament—is spinning on its axis.

Color photograph of Jennifer Doudna, the Nobel Prize-winning biochemist (2020 Chemistry Nobel, shared with Emmanuelle Charpentier for co-inventing CRISPR-Cas9 gene editing technology). She's a professor at UC Berkeley, a pioneer in molecular biology, and one of the most influential scientists alive today. The portrait captures her in a more recent, casual style: shoulder-length silver-gray hair, bright blue eyes, warm smile, wearing small pearl earrings and a textured maroon/reddish-brown zip-up jacket over a lighter top, set against a plain light gray background.

The first all-female team to share a Nobel Prize in science: biochemists Jennifer Doudna & Emmanuelle Charpentier.

They won the 2020 #Nobel Prize in #Chemistry "for the development of a method for genome editing (CRISPR-Cas9)." Jennifer Doudna was born #OTD in 1964.

#WomenInSTEM

Vilhelm Hammershøi (1864-1916), “En Ung Brystsyg Pige [A Young Consumptive Girl]” (1888), oil on cardboard, 27 x 33.1 cm.

A line curve showing number of awards for fiscal year 2026 compared to fiscal years 2021-2025 for the Directorate for Mathematical and Physical Sciences. The fiscal year 2026 curve lies well below curves for other fiscal years.

Directorate for Mathematical and Physical Sciences

6/11

A line curve showing number of awards for fiscal year 2026 compared to fiscal years 2021-2025 for the Directorate for Computer and Information Science and Engineering. The fiscal year 2026 curve lies well below curves for other fiscal years.

Directorate for Computer and Information Science and Engineering

3/11

A line curve showing number of awards for fiscal year 2026 compared to fiscal years 2021-2025 for the Biological Sciences Directorate. The fiscal year 2026 curve lies well below curves for other fiscal years.

Biological Sciences

2/11

A line curve showing number of awards for fiscal year 2026 compared to fiscal years 2021-2025 across NSF. The fiscal year 2026 curve lies well below curves for other fiscal years.

NSF Update

Funding curve overall. A little bit of progress in the past week, but only a little bit.

Now by Directorate...

1/11

Three postdoctoral fellowships in quantitative biology are available as part of a new Quantitative Biology Initiative in the Department of Biology at the University of Maryland.

Best consideration date: 3/14

Job Ad:
umd.wd1.myworkdayjobs.com/en-US/UMCP/j...

Department:
biology.umd.edu/people

I regularly see people wondering how it's possible that there are so many musicians and writers and film makers and artists from a tiny nation like Iceland.

And the answer is really simple: State funding for art education and artists. I literally get a salary from the government to write books.

Entangled Ions Measure Time Faster An optical clock based on a pair of calcium ions achieves a given precision more quickly when the ions are entangled.

For some applications of atomic clocks—in satellite navigation systems, for example—the answer must be prompt as well as precise. Researchers have now demonstrated a way to use quantum entanglement to halve the measurement time of an ion-based optical clock without compromising its precision.

A color-coded binary tree displaying how to expand (x+y)^3. There are 8=2^3 terms on the bottom, and by putting them in "alphabetical order" and grouping like terms, you see that (x+y)^3 = x^3 + 3x^2y + 3xy^2 + y^3.

My coauthor Dave Perkinson made this diagram to explain the binomial theorem and I think it's the perfect distillation. Here's our draft book, Discrete Structures, if you want more: kyleormsby.github.io/files/113spr... 🧮