A new approach to the study of the ground-state properties of 2D Ising spin glass

A new approach known as flat histogram method is used to study the ±J Ising spin glass in two dimensions. Temperature dependence of the energy, the entropy, and other physical quantities can be easily calculated and we give the results for the zero-temperature limit. For the ground-state energy and entropy of an infinite system size, we estimate e0=−1.4007±0.0085 and s0=0.0709±0.006, respectively. Both of them agree well with previous calculations. The time to find the ground states as well as the tunneling times of the algorithm are also reported and compared with other methods.