Oscillations and symmetry breaking in simple models for polymerisation

Astronomy Unit Seminars
Michael Stich
Izaskun Jimenez-Serra
February 23rd, 2018 at 14:30
GO Jones Room 610

Some fundamental building blocks of living matter, such as amino acids and sugars show the preference of one of the two chiral states of an otherwise chemically identical molecule. The origin of this so-called biological homochirality is still a matter of debate, even after decades of intense theoretical and experimental work.  At the heart of many theoretical approaches lies a mechanism responsible for spontaneous mirror symmetry breaking, leading finally to stable stationary states of given chirality. In this talk, we discuss two simple models for general chiral polymerisation processes. In the first one, designed to create symmetry breaking in a similar way as in the Frank model, we observe and discuss oscillations of the chiral states.  We compare this to the phenomenon of chiral excursions, found in similar systems, but which do not show permanent symmetry breaking. In the second one we show how the interaction of mechanical forces with nucleation-fragmentation processes can lead to symmetry breaking.