Subcritical bifurcation in spatially extended systems

A theory for noise-driven subcritical instabilities in spatially extended systems is put forward. The theory allows one to calculate the critical bifurcation parameter for a first-order phase transition in such non-equilibrium systems in the thermodynamic limit and analyse the mechanism of phase transition. Two examples with distinctive features are studied in detail to demonstrate the usefulness of the theory and the different scenarios that can occur in the thermodynamic limit of non-equilibrium systems.