= Ising auxiliary mean-field free energy
{c}
{title2=$A_{\rm aux}/N=qJm^2/2-k_BT\log[2\cosh(\beta_T(h+qJm))]$}
The approximate <partition function> obtained by decoupling each Ising bond has this <free energy>. The quadratic constant compensates double counting. Its stationary condition is the <self-consistency equation>; away from stationarity $m$ parametrizes the assumed effective field and need not equal that distribution's mean <Ising spin>. It agrees at <stationary points> with the <Bragg-Williams free energy of the Ising model>, although their off-equilibrium expansions differ.
Back to article page
