Statut  Confirmé 
Série  IPHTGEN 
Domaines  physics 
Date  Mardi 19 Mars 2019 
Heure  11:00 
Institut  IPHT 
Salle  Salle Claude Itzykson, Bât. 774 
Nom de l'orateur  Hans Herrmann 
Prenom de l'orateur  
Addresse email de l'orateur  
Institution de l'orateur  PMMH, ESPCI Paris and UFC, Fortaleza, Brazil 
Titre  Rotating Matter: The Bearing State 
Résumé  A packing of spheres is called bichromatic if every loop formed by contacts is even. Such packings can act as bearings by having all spheres rolling on each other without any slip. In three dimensions, many different of these slidingfree configurations, called bearing states, are possible. If all loops have length four the system exhibits four continuous degrees of freedom and a systematic way of constructing such bearing states can be devised [1]. By considering spheres of different size, packings with bearing states can even be made spacefilling. The construction and mechanical properties of such spacefilling bearings will be discussed. Spacefilling bearing states can be viewed as a realization of solid turbulence exhibiting Kolmogorov scaling and anomalous heat conduction. In three dimensions a continuum of such configurations can be obtained as cuts through fourdimensional spacefilling bearing states. Bearings states can be perceived as physical realizations of networks of oscillators with asymmetrically weighted couplings. These networks can exhibit optimal synchronization properties through tuning of the local interaction strength as a function of node degree or the inertia of their constituting rotor disks through a powerlaw massradius relation. As a consequence, one finds that space filling bearings synchronize fastest, when they are hollow. The synchronization of rotations occurs in avalanches following a broad size distribution [2]. \\ References: \\ {[1]} D.V. Stäger, N.A.M. Araújo, H.J. Herrmann, Phys. Rev. Lett. 116, 254301 (2016) \\ {[2]} N.A.M. Araújo, H. Seybold, R.M. Baram, H.J. Herrmann, J.S. Andrade Jr., Phys. Rev. Lett. 110, 064106 (2013) 
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