We have been working on an active matter game! If you want to challenge your colleagues or family members to a game and have them learn about active matter look no further!
The active matter game has been designed over the course of the ITN as a new outreach activity that everyone can print at home. It has been rigorously tested at almost every Active Matter Meeting. It took a few revisions but we have made a fun game for all ages. You can read all about it in the supplementary info of the new Active Matter book.
The game has been developed and finalised by Alireza Khoshzaban, Carolina van Baalen, David Bronte Ciriza, Davide Breoni, Jesús Manuel Antúnez Domínguez, Laura Natali and Sandrine Heijnen.
You only have to wait until the release date till everything will be online! We can’t wait to share it with you!
Tag: Davide Breoni
Patchy landscapes promote stability of small groups on arXiv
Patchy landscapes promote stability of small groups
Gianni Jacucci, Davide Breoni, Sandrine Heijnen, José Palomo, Philip Jones, Hartmut Löwen, Giorgio Volpe, Sylvain Gigan
arXiv:2310.01620
Abstract: Group formation and coordination are fundamental characteristics of living systems, essential for performing tasks and ensuring survival. Interactions between individuals play a key role in group formation, and the impact of resource distributions is a vibrant area of research. Using active particles in a tuneable optical environment as a model system, we demonstrate that heterogeneous energy source distributions result in smaller, more stable groups with reduced individual exchange between clusters compared to homogeneous conditions. Reduced group sizes can be beneficial to optimise resources in heterogeneous environments and to control information flow within populations. Devoid of biological complications, our system provides insights into the importance of patchy landscapes in ecological dynamics and holds implications for refining swarm intelligence algorithms and enhancing crowd control techniques.
Giant Activity-Induced Stress Plateau in Entangled Polymer Solutions on arXiv
Giant Activity-Induced Stress Plateau in Entangled Polymer Solutions
Presentation by Davide Breoni at the DPG Spring Meeting of the Condensed Matter Section in Dresden, Germany, 26th – 31st of March 2023
Davide presented his work at the 2023 DPG Spring Meeting of the Condensed Matter Section in Dresden, Germany. His presentation “Active Brownian Particles in a disordered motility environment“, focuses on the study of Janus particles in a speckle light field.
Presentation by Davide Breoni at the APS March Meeting in Las Vegas, United States, 5th – 10th of March 2023
Davide presented his work at the 2023 APS March Meeting in Las Vegas, United States. His presentation “Active Brownian Particles in a disordered motility environment“, focuses on the study of Janus particles in a speckle light field.
Interview with Davide Breoni for EPJE highlights
Davide Breoni was interviewed for an highlight article of The European Physical Journal E. The interview “Modelling the collective movement of bacteria” refers to the article “A one-dimensional three-state run-and-tumble model with a ‘cell cycle’“, published on the same EPJE issue.
A one-dimensional three-state run-and-tumble model with a ‘cell cycle’ published in EPJE
Davide Breoni, Fabian Schwarzendahl, Ralf Blossey, Hartmut Löwen
The European Physics Journal E 45, 83 (2022)
arXiv: 2206.00992
DOI:10.1140/epje/s10189-022-00238-7
We study a one-dimensional three-state run-and-tumble model motivated by the bacterium Caulobacter crescentus which displays a cell cycle between two non-proliferating mobile phases and a proliferating sedentary phase. Our model implements kinetic transitions between the two mobile and one sedentary states described in terms of their number densities, where mobility is allowed with different running speeds in forward and backward direction. We start by analyzing the stationary states of the system and compute the mean and squared-displacements for the distribution of all cells, as well as for the number density of settled cells. The latter displays a surprising super-ballistic scaling ∼t^3 at early times. Including repulsive and attractive interactions between the mobile cell populations and the settled cells, we explore the stability of the system and employ numerical methods to study structure formation in the fully nonlinear system. We find traveling waves of bacteria, whose occurrence is quantified in a non-equilibrium state diagram.
Poster by Davide at the Active Matter and Active Media Summer School 2022, Cargèse, France
Brownian particles driven by spatially periodic noise published in EPJE
Brownian particles driven by spatially periodic noise
Davide Breoni, Ralf Blossey, Hartmut Löwen
The European Physical Journal E 45, 18 (2022)
arXiv: 2111.10220
DOI:10.1140/epje/s10189-022-00176-4
We discuss the dynamics of a Brownian particle under the influence of a spatially periodic noise strength in one dimension using analytical theory and computer simulations. In the absence of a deterministic force, the Langevin equation can be integrated formally exactly. We determine the short- and long-time behaviour of the mean displacement (MD) and mean-squared displacement (MSD). In particular we find a very slow dynamics for the mean displacement, scaling as t^(-1/2) with time t. Placed under an additional external periodic force near the critical tilt value we compute the stationary current obtained from the corresponding Fokker-Planck equation and identify an essential singularity if the minimum of the noise strength is zero. Finally, in order to further elucidate the effect of the random periodic driving on the diffusion process, we introduce a phase factor in the spatial noise with respect to the external periodic force and identify the value of the phase shift for which the random force exerts its strongest effect on the long-time drift velocity and diffusion coefficient.
Round Table Discussion on Fluids and Active Matter

In our third round table we had the pleasure of Gareth Alexander, Ignacio Pagonabarraga and Julia Yeomans as our guest panellists. This time the overall theme was “Fluids and Active Matter” and hosted by Chun-Jen Chen, Davide Breoni, Danne van Roon, Audrey Nsamela, Dana Hassan and Sandrine Heijnen.
It started out with an interesting discussion regarding the motivation to get in and what amazes them the most in the field of active matter. Here it became clear that active systems can have their passive counterparts, and works for easy transitions from active to passive systems, but at the same time, such active systems still have the potential to answer many fundamental questions. From this topic, one of the key takeaways was that the project that you are currently working on should be the subject that amazes you the most.
The next topic that stood as the centre of the discussion was turbulence. Turbulence is an interesting phenomenon where a lot of things are still unknown. The intriguing concept here was that real, or fluid-dynamical, turbulence is different from active turbulence. As a clarification, Julia Yeomans introduced the following comparison. Real turbulence is observed in a waterfall where the energy follows the Kolmogorov cascade. In active turbulence, the energy originates from the individual particles moving and does not follow the same energy trend as real turbulence.
As one of the final topics, we were wondering what are the main takeaways regarding active nematics, especially if it’s not your field. We got it set for you in four points. One, it is fundamentally unstable and therefore creates flows. Point number two, motile topological effects. Number three, the potential connection it has to biological systems and the ability to explain similar processes. Finally, number four, the fact that we are looking at non-equilibrium systems.