The Sherrington-Kirkpatrick spin glass model: Results of a new theory

Abstract

A new solution of the Sherrington-Kirkpatrick spin glass model is discussed which is valid below the temperature where the replica method becomes unstable. The free energy is lowered, the entropy has no unphysical properties forT→ 0. The specific heat approaches zero exponentially and has a second maximum near a lower critical temperature for given external field. Near the critical point the difference of the free energy to that of Sherrington and Kirkpatrick is extremely small. Thus the Sherrington-Kirkpatrick phase may be undercooled.