Product class scaling

For bulk states drawn from the product class (rank-1 density matrices), the entropy disagreement scales as:

$\mathbb{E}|S_A - S_B| \approx 0.798 \cdot d_B^{-1/2} + \mathcal{O}(d_B^{-1})$

The prefactor 0.798 is analytic. It is not fit to data. It comes out of the math. Simulations matched the prediction to under half of one standard deviation at every test point.