Random Energy Model

The Random Energy Model ( REM for short ) is a toy model in statistical physics of disordered systems, which was proposed in 1980 by Bernard Derrida.

It describes a system with the following three characteristics:

• There are states with energies.
• The energies are Gaussian distributed.
• The energies are independent random variables.

The special feature of SEM is that it can be solved exactly, and, despite its simplicity, important concepts of statistical physics such as the frozen disorder ( quenched disorder), let replica symmetry and replica symmetry breaking (RSB ) studying at him. Considering a REM system in an external magnetic field, it will be found a temperature-dependent phase transition between a frozen and a paramagnetic phase.