Morphological and chiral symmetry breaking in reaction-diffusion systems

Morphological and chiral symmetry breaking in reaction-diffusion systems is considered on the basis of the theory of imperfect codimension-two bifurcations. A new type of pattern selection with two triggers is elucidated: (1) morphologically asymmetric structures displaying optical activity can probably be originated from initially racemic and homogeneous conditions when chiral interaction, having the characteristic strength δ (such as electroweak interaction and circularly polarized light) as well as external field, having the characteristic strength η (such as gravitational field and electrostatic field) are considered; (2) the selective sensitivity of molecular chirality and morphological asymmetry is O(δ 1/3) and O(η 1/3), respectively; the sensitivity of mode-mode interaction between chiral polarization and concentration vector is O(δ 2/3) or O(η 2/3), respectively. The relation of these conclusions to the life problem is discussed briefly.