It was a pleasure to write this News & Views article for Nature Materials with Vincenzo Vitelli. Congrats to Sheng Chen, Michael Murrell, and all the other authors on their work.

The fourfold way to rupture in active solids Nature Materials - Quadrupolar topological defects act as organization centres for material failure in a biomimetic active nematic solid.

As children, we learn about active nematic liquid crystals, where topological defects organize active stresses into mesmerizing flows. But what about active nematic solids, where defects remain but stresses are resisted? The answer: rupture.

Read our News & Views in Nature Materials: rdcu.be/famDd

New preprint! arxiv.org/abs/2509.17972

Nonequilibrium systems are often nonreciprocal, but when does nonreciprocity *really* matter?

Giulia Garcia Lorenzana & David Martin did the calculations; Yael Avni and I helped; Michel Fruchart, Giulio Biroli, and Vincenzo Vitelli advised

I am hiring 2 PhD students to join my group in at University of Illinois, Chicago, starting Fall 2026.

We will be studying smart materials, from learning active matter to adaptive sociohydrodynamics, using theory and machine learning.

More information found here dsseara.github.io

This work wouldn't have been possible without my amazing coauthors:

Jonathan Colen @olddominionu.bsky.social
Michel Fruchart @gulliver-lab.bsky.social
Yael Avni @uchicago
David Martin @lptmc
Vincenzo Vitelli @uchicago

Everyone here was at some time part of Vincenzo's incredible group @UChicago

Our model can't say why people make the decisions that they do, nor can we say what decisions are "correct", and there is a lot of room for improvement. But this shows that active fluids can be intelligent fluids. In this case, that fluid comprises people.

With its origins in the work of economist Thomas Schelling, active matter physics, and so many other predecessors, we showed that human populations
(A) can be described by a hydrodynamic equation and
(B) propose and validate one such equation against census data

Sociohydrodynamics: Data-driven modeling of social behavior | PNAS Living systems display complex behaviors driven by physical forces as well as decision-making. Hydrodynamic theories hold promise for simplified un...

I am very excited to see this article officially published in @pnas.org

Sociohydrodynamics describes how a bunch of people get together and start making decisions about how they want to move around

doi.org/10.1073/pnas...

Silence is indefensible in the face of efforts to dismantle the institutions, norms, and values that lets science serve everyone. Thank you for the historical reminder, @philipcball.bsky.social

This short course was spearheaded by Emma, and coorganized by myself, Annie Stephenson, and Guillaume Falmagne

Consider signing up for our short course on the Physics of Human Social Systems at the APS Global Summit!

Lectures by Luis Bettencourt and Jean-Philippe Bouchaud and tutorials by @mathemmatician.bsky.social and myself.

@apsphysics.bsky.social @aps-gsnp.bsky.social
summit.aps.org/events/MAR-S...

At an excellent (and lively) meeting @nitmb.bsky.social on learning in biological systems. Enjoy the view of Lake Michigan

I do my best work in conversation with people, so I wouldn't have been able to do any of this without my collaborators and advisors, who are all, objectively, The Best ❤️

If it thinks and moves -- I'm interested!

Happy to be here and feel free to reach out anytime :)

I've also worked on a number of models of non-reciprocal spin systems, exhibiting "vision-cone" like interactions (10.1088/1742-5468/accce7), or multi-species waves (arXiv:2307.08251) and oscillations (aXiv:2311.05471)

I've also worked on energy dissipation in subcellular structures, most recently in the excitable, mechanochemical oscillations of Xenopus oocytes (rdcu.be/d1wWy)

Most of my postdoc has focused on developing a hydrodynamic theory of human residential dynamics. Combining geographical data analysis, machine learning, and both continuum & agent-based models, we find some interesting universality in the movement of people
arxiv.org/abs/2312.17627

I should introduce myself! My name is Danny -- I am a postdoc at UChicago (currently on the faculty job market 🤘). I'm a data-oriented theorist interested in the mechanics and dynamics of living systems, from cells to societies. See below for some research highlights.