Approximation theorems for fermionic Gaussian states
The paper shows how covariance-level structure of Majorana matrices leads to quantitative approximation theorems for fermionic Gaussian states. By applying covariance monogamy under conditions like high degree, exchangeability, or spatial separation, the authors derive product-state approximations and de Finetti theorems. This demonstrates that these common approximations stem directly from constraints on two-point correlations.