Chargement de la carte…
Specific heat of the Gaussian random bond Ising model on a square lattice
Olga Dimitrova
The free energy and the specific heat of the two-dimensional Gaussian random bond Ising model on a square lattice are found with high accuracy using graph expansion and analysis of continuation of the high-temperature series. At low temperatures the specific heat reveals a zero-temperature criticality described by the power law $C\propto T^1+\alpha$, with $\alpha= 0.65(10)$, the result confirmed independently by counting many-body states in finite size samples. The interpretation of the free energy in terms of droplet excitations gives the density of the two-level states, that follows a novel power law $\rho(\epsilon)\propto \epsilon^\alpha$ at low energies.