LAUSR

Abstract The Sherrington–Kirkpatrick Ising spin glass model, in the presence of a random magnetic field, is investigated within the framework of the one-step replica symmetry breaking. The two random variables (exchange integral interaction J i j and random magnetic field h i ) are drawn from a joint Gaussian probability density function characterized by a correlation coefficient ρ , assuming positive and negative values. The thermodynamic properties, the three different phase diagrams and system’s parameters are computed with respect to the natural parameters of the joint Gaussian probability density function at non-zero and zero temperatures. The low temperature negative entropy controversy, a result of the replica symmetry approach, has been partly remedied in the current study, leading to a less negative result. In addition, the present system possesses two successive spin glass phase transitions with characteristic temperatures.