BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:The role played by interactions in the assembly of active colloids : Discovering dynamic laws from observations. - Dr Chantal Valeriani\, Uni versidad Complutense de Madrid DTSTART:20221109T143000Z DTEND:20221109T153000Z UID:TALK177374@talks.cam.ac.uk CONTACT:Lisa Masters DESCRIPTION:Active matter systems are composed of non-equilibrium units th at consume energy to perform directed motion [1\,2\,3]. Examples of acive particles at the mesoscopic scale are living\, such as bacteria\, or artif icial\, such as synthetic active colloids [4\,5\,6\,7]. The theoretical fr amework describing these systems has shown tremendous success at finding u niversal phenomenology.\nWhen dealing with active colloids\, on the one si de\, one might think of studying the features of a suspension of particles whose interactions are inspired on Soft Matter (passive) systems\, such a s isotropic (strongly repulsive [8\,9\,10]\, attractive [11\, 12\,13]\, mi celle-inducing [14]) or anisotropic (Janus-like) interactions[15]\, unrave lling the relevance of hydrodynamics [12\, 16].\nOn the other side\, one m ight consider determining the forces that control the dynamics of the indi vidual colloids directly from experiments. Accessing this local informatio n would be the key for understanding the physics governing these systems a nd for creating models that explain the observed collective phenomena.\nFo r this purpose\, we propose a machine-learning tool that uses the collecti ve movement of the particles to learn the active and two-body forces\, con trolling particles’ individual dynamics.\nThe method has been successful ly tested not only on numerical simulations of Active Brownian Particles\, considering different interaction potentials and levels of activity\, but also on experiments of electrophoretic Janus particles\, extracting the a ctive and two-body forces that control the dynamics of the colloids [17].\ nWe foresee that this methodology can open a new avenue for the study and modelling of experimental systems of active particles.\nREFERENCES\n[1] C. Bechinger\, R. Di Leonardo\, H. Lowen\, C. Reichhardt\, G. Volpe\, and G. Volpe\, Reviews of Modern Physics 88\, 045006 (2016)\n[2] M.E. Cates\, J. Tailleur. Annu. Rev. of Condens. Matt. Phys. 6\, pp. 219-244 (2015).\n[3] S.Mallory\,C.ValerianiandA.CacciutoAnnualreviewofPhysicalChemistry\,6959(2 018)\n[4] S. Thutupalli\, R. Seemann\, S. Herminghaus New J. Phys. 13\, 07 3021 (2011).\n[5] W.F. Paxton et al. Chem. Commun. 441\, 3 (2005).\n[6] S. Fournier-Bidoz et al. J. Am. Chem. Soc. 126\, 13424 (2004).\n[7] I. Butti noni\, J. Bialke\, F. Kummel\, H. Lowen\, C. Bechinger\, T. Speck. Phys.Re v. Lett. 110\, 238301 (2013).\n[8] J.Martin Roca\, R Martinez\, A Luis Die z\, L Alexander\, D Aartz\, F Alarcon\, J Ramirez and C Valeriani J chem P hys154\, 164901 (2021)\n[9] DR Rodriguez\, F Alarcon\, R Martinez\, J Ram írez\, C Valeriani\, Soft matter 16 (5)\, 1162 (2020)\n[10] J. Martin Roc a\, R. Martinez\, F.Martinez Pedrero\, J.Ramirez and C Valeriani\, J. Chem . Phys. 156\, 164502 (2022) [11] B. Mognetti\, A. Saric\, S. Angioletti-Ub erti\, A. Cacciuto\, C. Valeriani and D. Frenkel Phys.Rev.Lett.\, 111 2457 02 (2013)\n[12] F.Alarcon\, C.Valeriani and I.Pagonabarraga Soft Matter 10 .1039/ C6SM01752E (2017)\n[13] J.Harder\, S.Mallory\, C.Tung\, C.Valeriani and A.Cacciuto\, J.Chem.Phys. 141 194901 (2014)\n[14] C.Tung\, J.Harder\, C.Valeriani and A.Cacciuto\, Soft Matter 12 555 (2016)\n[15] S.Mallory\, F.Alarcon\, A.Cacciuto and C.Valeriani New Journal of Physics (2017)\n[16] F.Alarcon\, E.Navarro\, C.Valeriani and I.Pagonabarraga\, PRE submitted ( 2018)\n[17] “Discovering dynamic laws from observations with Graph Neura l Networks: the case of self-propelled\, interacting colloids” M. Ruiz-G arcia\, C.M.Barriuso\, L.Alexander\, D.Aarts\, L.Ghiringhelli and C.Valeri ani\, submitted (2022) LOCATION:Wolfson Lecture Theatre\, Dept of Chemistry and Zoom END:VEVENT END:VCALENDAR