title: Slow relaxation in weakly open rational polygons.
abstract: The interplay between the regular (piecewise-linear) and irregular (vertex-angle) boundary effects in nonintegrable rational polygonal billiards (of m equal sides) is discussed. Decay dynamics in polygons (of perimeter P(m) and small opening Delta) is analyzed through the late-time survival probability S(m) approximately equal t(-delta). Two distinct slow relaxation channels are established. The primary universal channel exhibits relaxation of regular sliding orbits, with delta=1. The secondary channel is given by delta>1 and becomes open when m>P(m)/Delta. It originates from vertex order-disorder dual effects and is due to relaxation of chaoticlike excitations.
authors.affiliation: Departamento de Física, Universidade Federal de Minas Gerais, ICEx, Caixa Postal 702, CEP 30123-970, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Valery B
authors.initials: VB
authors.lastname: Kokshenev
authors.forename: Eduardo
authors.initials: E
authors.lastname: Vicentini