Conference

Ordinary materials are "passive" in the sense that their constituents are typically made by inert particles which are subjected to thermal fluctuations, internal interactions and external fields but do not move on their own. Living systems, like schools of fish, swarms of birds, pedestrians and swimming microbes are called "active matter" since they are composed of self-propelled particles. Active matter is intrinsically in nonequilibrium and exhibits a plethora of novel phenomena as revealed by a recent combined effort of statistical theory, computer simulation and real-space experiments. After an introduction on biological and artificial self-propelled particles [1], the talk will focus on modelling of active Brownian particles and collective phenomena like motility-induced phase separation. Finally effects of inertia and the formation of active complexes will be discussed including an inertial delay [2], the coexistence of two states with different temperatures [3], an active refrigerator [4] and entropons in active crystals [5].[1] For a review, see:  C. Bechinger, R. di Leonardo, H. Löwen, C. Reichhardt, G. Volpe, G. Volpe,Active particles in complex and crowded environments, Reviews of Modern Physics 88, 045006  (2016).[2] C. Scholz, S. Jahanshahi, A. Ldov, H. Löwen, Inertial delay of self-propelled particles, Nature Communications 9, 5156 (1-9) (2018).[3] S. Mandal, B. Liebchen, H. Löwen, Motility-induced temperature differences in coexisting phases, Phys. Rev. Letters 123, 228001 (2019).[4] L. Hecht, S. Mandal, H. Löwen, B. Liebchen, Active refrigerators powered by inertia, Phys. Rev. Letters 129, 178001 (2022).[5] L. Caprini, U. M. B. Marconi, A. Puglisi, H. Löwen, Entropons as collective excitations in active solids, J. Chem. Phys. 159, 041102 (2023).

Music has long filled a uniquely important role in bridging human culture and biology, stretching back over millennia, and of course today provides respite and remedy in an increasingly stressful world. We do not sing alone. On land, four kinds of animals produce songs or calls: birds, frogs, mammals, and insects. Some of these animals (and fish) also do so underwater. The principal sounds such animal species make are signaling behaviors directly related to mating success and social cohesion and their ranges are molded by their forms and by their particular forest, savannah or seaside habitat.Human music also has origins, motivations and mechanisms in common with other animals. Traces of a long and ongoing history comes from archaeology, anthropology and brain studies. Evidence of a measurable impact on human biology comes from neurobiology, social psychology, and public health.