Events

Title: Symmetries in Large-Scale Structure, Dark Matter and Black Holes

Title: Women in Science: The story from India

Abstract: Prof Godbole will present a summary on the status of women in science in India based on two studies that have been conducted at the governmental level. She will discuss various schemes and action plans that have been put in place, both before and after the studies. Programs run by the Indian Academies of Sciences and books that have been brought out, containing autobiographical sketches of Indian women, will be discussed. She will summarize some observations obtained from a survey called ‘Trained Scientific Woman Power: what fraction are we losing and why?’ All these studies have identified goal posts for women in Science in India. Action plans to achieve those will be discussed.
The colloquium will be followed by a short panel discussion on the topic of diversity, focusing on the similarities and differences between the situation in India and the situation in the Netherlands.
After the colloquium drinks will be served at the Academisch Kwartier in the main hall of Science Park 904.

Title: Rotating Matter: The Bearing State

Abstract: Granular materials are characterized by an additional degree of freedom, rotations, which become particularly relevant for spherical particles. They allow for soft modes under shear which do find realizations for instance in tectonic faults. A packing of spheres is called bi-chromatic if every loop formed by contacts is even. In three dimensions, bi-chromatic bearings have many different sliding-free configurations, so called bearing states. 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 space-filling. The construction and mechanical properties of such space-filling bearings will be discussed. Their 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 four-dimensional space-filling 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 power-law mass-radius relation. Under this condition, the average participation per disk is maximized and the energy dissipation rate is homogeneously distributed among elementary rotors. 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).

After the Colloquium, drinks will be served at café ‘De Oerknal’ in the Universum (USC).