A Statistical Mechanical Model of Critical Currents in Superconductors

We present a statistical mechanical model for critical currents which is successful in describing both the in-plane and out-of-plane magnetic field angle dependence of J (c) . This model is constructed using the principle of maximum entropy, that is, by maximizing the information entropy of a distribution, subject to constraints. We show the same approach gives commonly assumed forms for J (c) (B) and J (c) (T). An expression for two or more variables, e.g. J (c) (B,T), therefore, follows the laws of probability for a joint distribution. This gives a useful way to generate predictions for J (c) (B,T) for the DC critical current in wires, cables or coils.