How to compute the thermodynamics of a glass using a cloned liquid
  The recently proposed strategy for studying the equilibrium thermodynamics of the glass phase using a molecular liquid is reviewed and tested in details on the solvable case of the $p$-spin model. We derive the general phase diagram, and confirm the validity of this procedure. We point out the efficacy of a system of two weakly coupled copies in order to identify the glass transition, and the necessity to study a system with $m<1$ copies ('clones') of the original problem in order to derive the thermodynamic properties of the glass phase. 
Marc Mezard