Active droplets are fundamental in cell biology and origin of life. With Jonathan Bauermann, @boekhovenlab.bsky.social, Frank Jülicher, and @m-pol.bsky.social, we show that a critical transition influences their size, morphology, ripening and division propensity

journals.aps.org/prx/abstract...

Good news in rough times:
Our work on generalising Lifshitz-Slyosov-Wagner (LSW) theory to active systems, led by the all-mighty Jonathan Bauermann, is out on PRL!! Special thanks to Christoph Weber @m-pol.bsky.social and Frank Jülicher.

doi-org.sire.ub.edu/10.1103/f5x9...

Finally, we move to the opposite limit: fast reactions!
We observe spirals of droplets, but, perhaps surprisingly, phase equilibrium still holds on the mesoscale. Indeed, local averages show that the concentrations in and outside of drops still lie on the binodal manifold!

By imposing timescale separation between slow reactions and fast diffusion, we define a dynamics at phase equilibrium.

We exploit it to study the effects of localisation of B and C in the A-rich and A-poor phases, showing dampening and amplification of the oscillations.

As expected, we see a periodic emergence of droplets:

Proud of this preprint with my friends Jonathan Bauermann and @artemyte.bsky.social, about chemical oscillators & phase separation! Main findings:
1. Phase separation controls frequency and amplitude of oscillations
2. If reactions are fast, spirals of droplets emerge!

arxiv.org/abs/2507.16030

Fun fact 2: we did all experiment in a very reproducible way, using simple kitchen tools. For the imaging part we need a box as a support. Could have been any box, we ended up using a very stereotypical one:

Fun fact 1: after making experiments with a small amount of sauce on the Petri dish, we of course performed the thermodynamic limit:

It was very tempting to model the observed phase behaviour as a lower critical solution temperature, and we did it introducing a minimal theoretical model. However we stress that this is a very oversimplified framework.. Any feedback on this point would be very appreciated!

Then we fixed the starch amount and varied water, finding an interesting paraboloid as the phase boundary between the homogeneous and clumpy phases.

This is why we decided to make a phase diagram varying systematically temperature and the starch amount. We found that above a certain threshold huge mozzarella-like clumps disappear in favour of smaller cheese clusters.

Cacio e pepe is a traditional recipe from Rome. It consists of tonnarelli noodles served with a cream of cheese, starch-enriched water and pepper. Despite its simplicity, it is hard to avoid cheese clumps. Interestingly, omitting starch leads to huge clumps ("mozzarella phase")

1/n Some time ago my colleague, excellent cook, and friend Ivan told me: "Cacio e pepe is the recipe that I screw up more often. Let's make a project studying systematically the physics of that sauce".

Prepare to get cheesy, I'm glad to share the Cacio e paper preprint:

arxiv.org/abs/2501.00536

What sets the size of active droplets? Which factors affect their ripening and facilitate division?
In a project led by the brilliant mind of Jonathan Bauermann, we delve into these profound questions together with Christoph Weber, Frank Jülicher, and Job Boekhoven
arxiv.org/abs/2409.03629