Four-dimensional gonihedric gauge spin system
  We perform Monte Carlo simulations of a four-dimensional gauge invariant spin system which describes random surfaces with gonihedric action. We develop the analogy between the flat-crumpled phase transition of the lattice surface model and the liquid-gas phase transition of non-ideal gases, and identify the self-intersection coupling constant $k$ of the surface model with the pressure $P$. As $k$ increases the system moves to a critical point in complete analogy with the situation for non-ideal gases, where the liquid and the gas phases approach each other with increasing $P$. We measure vacuum expectation values of various operators and the corresponding critical indices. 
J.Ambj{\o}rn, G.Koutsoumbas and G.K.Savvidy