Weak-coupling BCS thermodynamic ratios ($2\Delta (0)/(k_B{T}_c)=2\pi e^{-{\gamma }_E},\Delta C/({\gamma }_n{T}_c)=12/[7\zeta (3)]$)

The isotropic weak-coupling BCS theory predicts the gap ratio approximately $3.528$ and the electronic heat-capacity jump approximately $1.426$ in units of the normal-state heat capacity at the transition. These compare distinct measurements of the same paired state. They are conditional predictions of the weak-coupling fully gapped model, rather than universal numbers for all superconductors.