Active cholesterics: odder than odd elasticity

by Dr Ananyo Maitra (Laboratoire Jean Perrin, Sorbonne Universite)

Tuesday 11 May 2021, 15:00 → 17:00 Europe/Stockholm

The zoom link :

https://stockholmuniversity.zoom.us/j/622224375

Meeting ID: 622 224 375

Since most biomolecules are chiral, it is natural for theories of living matter to consider the interplay of chirality and activity. In this talk, I will discuss the active mechanics and dynamics of the best known chiral liquid crystalline phase, the cholesteric. I will show that active cholesterics distinctly differ from active smectics, unlike their equilibrium counterparts, due to the presence of an active, chiral force density that is even more unusual than the ``odd elasticity'' of two-dimensional, chiral active solids. This ``odder elasticity'' leads to a linear elastic force, even at zero strain, in the fluid directions and can be used to engineer a columnar array of vortices, with anti-ferromagnetic vorticity alignment, that can be switched on and off by external strain. A similar odder elastic force also arises in two-dimensional active cholesterics -- a microphase-separated, layered state in a chiral fluid -- generically destabilising it.