Molecular Parity Violation and Chirality: The Asymmetry of Life and the Symmetry Violations in Physics

Abstract

After a brief introduction into some basic asymmetries observed in nature, such as the biomolecular homochirality in living species on earth, the dominance of matter over antimatter in the observable universe, and irreversibility in physical-chemical processes providing a preferred arrow of time, we provide a discussion of the concepts of fundamental symmetries in physics and of the three different kinds of symmetry breakings, spontaneous, de facto, and de lege, by means of the example of the dynamics of chiral molecules. We then give a brief review of the current status of the theory and experiments on molecular parity violation. We discuss the various hypotheses on the origin of biomolecular homochirality and conclude with some cosmological speculations related to the fundamental symmetry breakings. These include possibilities of observing CPT violation in future experiments providing a possible fundamental basis for irreversibility, as well as possibilities for observing heavy “right-handed” neutrinos as one possible basis for “dark matter” in the universe.