On possible experimental realizations of directed percolation

Directed percolation is one of the most prominent universality classes of n onequilibrium phase transitions and can be found in a large variety of mode ls. Despite its theoretical success, no experiment is known which dearly re produces the critical exponents of directed percolation. The present work c ompares suggested experiments and discusses possible reasons why the observ ation of the critical exponents of directed percolation is obscured or even impossible.