Traveling Phase Boundaries with the Broken Symmetries of Life

15.6 Conclusions

The first surprising conclusion is that a model system with just the three elements that we have characterized as the Broken Symmetries of Life, also “knows time.” Its nonchiral analogue, the traveling nematic-isotropic phase boundary does not “know time.” The argument given is that the existence of an intrinsic length, p ₀, in cholesteric liquid crystals, implies a frequency for its response to perturbations in its structure.

The second surprising feature is our minimal model’s novel route to turbulence. Its non-chiral analogue prepared under identical conditions has no routes to turbulence. In contrast, as it was driven further from equilibrium, our minimal model’s repertoire ranges from a cellular pattern with a single wavelength and frequency, through a wavelength doubling breathing mode, followed by a phase winding flat interface that eventually becomes turbulent.

The macroscopic implication of the Broken Symmetries of Life shown by the minimal model is profound: because living systems necessarily know time, they also have access to turbulence.

Finally, we conclude that with his interest in chirality in liquid crystals for many years now, an interest we have shared, Professor Gerd Heppke has demonstrated his perspicacity and good taste in scientific problems. May you have many more years of happy experiences offered by the ineluctable pleasures of chirality—and the Broken Symmetries of Life—particularly broken time reversal symmetry.