Titolo:
Time scale separation and heterogeneous off-equilibrium
dynamics in spin models over random graphs.
We study analytically and numerically the statics and the off-equilibrium
dynamics of spin-models over finitely connected random graphs.
The analysis of the ground state phase diagram allows
us to identify a threshold
value for the connectivity beyond which the loop structure of the graph
becomes thermodynamically relevant.
In hypergraphs, such a percolation of order transition appears
above the percolation transition, with a first order mechanism.
Extensive Glauber dynamics simulations allow us to show that such a loop
structure is responsible for the onset of dynamical features of a local
character, like dynamical heterogeneities and a spontaneous time scale
separation, consistently with previous (experimental and numerical) studies
of structural glasses and spin glasses in their approach to the low
temperature phase.