Norwegian version of this page

Guest lectures and seminars - Page 10

Time and place: , NHA 723 and Online
Time and place: , NHA 108

QOMBINE seminar by Satvik Singh (University of Cambridge): The PPT2 conjecture for diagonal unitary covariant map

Time and place: , Niels Henrik Abels hus, 9th floor

Self-assembly is the spontaneous generation of order in systems driven by thermal agitation and interactions. At the molecular level, self-assembly plays an important role in the formation of giant com- plex macromolecules, being quite relevant for living systems. At the mesoscopic level, capillary driven self-assembly has been proposed for building structures in the gap between classical bottom-up and top-down fabrication methods, i.e. at the scales in between 10 micrometers and 1 millimeter. Although the method was proposed 20 years ago, only regular or simple structures were achieved so far. Using both experimental and statistical physics ideas, we demonstrate how to exploit subtle capillary interactions to create elaborate complex structures, as well as functional micromachines. On top of that, we show how such mescoscopic systems can be the analogues of many different physical systems such as folding molecules, molecular locks and keys, and crystal formation.

Time and place: , NHA108

C*-algebra seminar talk by Suvrajit Bhattacharjee (University of Oslo)

Time and place: , Niels Henrik Abels hus, 9th floor

Active solids consume energy to allow for actuation and shape change not possible in equilibrium. In this talk, I will focus on the elasticity of systems as wide-ranging as far-from-equilibrium hydrogels, nanoparticles, and mechanical structures composed of active robotic components. First, I will introduce our recent work on hydrogel spheres being lowered onto a hot plate. As the bottom vaporises, the resulting flow couples tightly to elastic deformations within the sphere, giving either spontaneous bouncing or steady-state floating as manifestations of the so-called elastic Leidenfrost effect. I will present theory and simulations of the floating case, which demonstrate a remarkable phenomenon: the heavier the solid, the higher it floats. I will then discuss the general competition between active boundary stresses and an elastic bulk, giving rise to so-called active elastocapillarity. Finally, I will discuss our current work on using non-reciprocal interactions in active elastic media to program robust mechanical actuation and locomotion. In each case, our results provide theoretical underpinning for recent experimental advances, and point to the design of novel soft machines.