ABSTRACT
A system that moves from equilibrium to nonequilibrium conditions can show amazing phenomena, especially when, out-of-equilibrium, it goes from the linear to the nonlinear regime. A system at the thermodynamic equilibrium is in a stable state. An out-of-equilibrium system with linear dynamics can show stable, unstable or oscillatory states. Nonlinear dynamics can also generate chaotic states. The type of states we can encounter in out-of-equilibrium depends on the contour conditions. By changing the values of parameters, we discover bifurcations. A bifurcation is a modification in the dynamics of a system; the parameter value at which the dynamical change occurs is called bifurcation point. We can have different types of bifurcations. For example, a trans-critical bifurcation is involved in the dramatic transition of a lamp to a laser. An imperfect pitchfork bifurcation has been proposed at the origin of the enantiomeric selection of chiral biomolecules. The theory of bifurcation introduces unequivocally the concept of “history” in natural sciences.
